Implement fast falling

Reviewed-on: #43
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

.gitea/workflows/ci.yml

@@ -23,9 +23,9 @@ jobs:
           "$HOME/.cargo/bin/rustup" toolchain install nightly-2026-09-14 --profile minimal
 
       - name: Cache Rust dependencies and build artifacts
-        uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2.8.2
+        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
         with:
-          prefix-key: v1-rust
+          prefix-key: v2-rust
           shared-key: linux-nightly
           cache-bin: false
 

Cargo.lock

@@ -3468,9 +3468,9 @@ dependencies = [
 
 [[package]]
 name = "gc-adapter-neo"
-version = "1.0.0"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bd350c081bf33e501e9a5a11732294dfe266683d6b58a366b097146f3e633cb5"
+checksum = "120a5b3858ae854c4674ae41a38173e8ea04b814fb3212fd3bdd1b04d414a9d7"
 dependencies = [
  "binread",
  "modular-bitfield",

Cargo.toml

@@ -30,7 +30,7 @@ strum = "0.28.0"
 strum_macros = "0.28.0"
 bevy_asset_loader = "0.27.0"
 ron_asset_manager = "0.9.0"
-gc-adapter-neo = { version = "1.0.0", features = ["libusb"] }
+gc-adapter-neo = { version = "1.1.0", features = ["libusb"] }
 rhai = "1.26.0"
 enum_cycling = "0.2.1"
 enum_cycling_derive = "0.2.1"

README.md

@@ -1,12 +1,15 @@
-# Game Test
+# Shinespark
 
-A Bevy game, editable in the [jackdaw](https://github.com/jbuehler23/jackdaw) editor.
+Fancy heavily advanced platform fighting game
 
-- `cargo run` plays the game standalone; no editor required.
+## Direct P2P Debugging
-- Open the folder in jackdaw to author scenes, then hit Play. The
+
-  editor builds its own artifacts into `.jackdaw/` (gitignored) and
+```text
-  never modifies your manifest or lockfile.
+# Process 1 owns player 0 and listens on 7000.
-- Gameplay lives in `src/lib.rs` (`GamePlugin`); authored scenes live
+cargo run -- --debug-match --players 2 --local-port 7000 \
-  in `assets/*.bsn`.
+  --net-player 0=local --net-player 1=127.0.0.1:7001
-- Components you derive `Reflect` on appear in the editor's inspector
+
-  automatically; no registration code is needed.
+# Process 2 owns player 1 and listens on 7001.
+cargo run -- --debug-match --players 2 --local-port 7001 \
+  --net-player 0=127.0.0.1:7000 --net-player 1=local
+```

assets/fighters/test/test.fighter.ron

@@ -22,7 +22,8 @@
         air_jump_horizontal_velocity: "0.96",
         air_jump_multiplier: "1.0",
         dash_initial_velocity: "1.4",
-        terminal_velocity: "1.6",
+        terminal_velocity: "3.0",
+        fast_fall_speed: "3.5",
         gravity: "0.084",
         weight: "100.0",
         jumpsquat_duration: 5,

assets/game_settings.ron

@@ -17,7 +17,15 @@
         knockback_decay_per_frame: "0.051",
         knockback_launch_velocity_multiplier: "0.03",
         hitstun_frames_per_unit_knockback: "0.4",
-
+        tumble_bounce_hitstop_threshold: 32,
+        attack_ground_to_airborne_transition_vertical_angle_threshold: "90.0",
+        meteor_angle_threshold: "10.0",
+        visual_shake_frames_per_hitstop_frame: "1.2",
+        visual_shake_table: [
+            -3.0, -1.5, 1.5, 3.0
+        ],
+        attacker_visual_shake_multiplier: 0.4,
+        di_max_angle: "18.0"
     ),
     stage_manifest_paths: [
         "stages/battlefield/test.stage.ron"

launch_localtest.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+FIRST="cargo run -- --debug-match --players 2 --local-port 7000 \
+  --net-player 0=local --net-player 1=127.0.0.1:7001"
+SECOND="cargo run -- --debug-match --players 2 --local-port 7001 \
+--net-player 0=127.0.0.1:7000 --net-player 1=local"
+
+(trap 'kill 0' SIGINT; $FIRST & $SECOND)

src/args.rs

@@ -1,5 +1,6 @@
 use bevy::prelude::*;
 use clap::Parser;
+use std::net::SocketAddr;
 use std::path::PathBuf;
 
 #[derive(Parser, Debug, Clone, Resource)]
@@ -15,6 +16,12 @@ pub struct Args {
     pub check_distance: usize,
     #[clap(long, default_value_t = 1)]
     pub players: usize,
+    /// UDP port to bind for a direct peer-to-peer session.
+    #[clap(long, default_value_t = 6969)]
+    pub local_port: u16,
+    /// Player ownership declarations in the form HANDLE=local or HANDLE=ADDRESS.
+    #[clap(long = "net-player", value_name = "HANDLE=local|ADDRESS")]
+    pub net_players: Vec<String>,
     /// Record a replay to this path.
     #[clap(long, conflicts_with = "play_replay")]
     pub record_replay: Option<PathBuf>,
@@ -25,3 +32,41 @@ pub struct Args {
     #[clap(long, value_enum, default_value_t = crate::replay::ReplayFormat::Binary)]
     pub replay_format: crate::replay::ReplayFormat,
 }
+
+pub fn parse_socket_addr(value: &str) -> Result<SocketAddr, String> {
+    let address = value
+        .parse::<SocketAddr>()
+        .map_err(|_| format!("invalid socket address: {value}"))?;
+    if address.port() == 0 {
+        return Err(format!("socket address must use a nonzero port: {value}"));
+    }
+    Ok(address)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_network_options() {
+        let args = Args::try_parse_from([
+            "game",
+            "--local-port",
+            "7000",
+            "--net-player",
+            "0=local",
+            "--net-player",
+            "1=127.0.0.1:7001",
+        ])
+        .unwrap();
+
+        assert_eq!(args.local_port, 7000);
+        assert_eq!(args.net_players, ["0=local", "1=127.0.0.1:7001"]);
+    }
+
+    #[test]
+    fn rejects_invalid_socket_addresses() {
+        assert!(parse_socket_addr("127.0.0.1:0").is_err());
+        assert!(parse_socket_addr("not-an-address").is_err());
+    }
+}

src/debug_tools/save_state.rs

@@ -1,22 +1,12 @@
 use bevy::prelude::*;
 
 use crate::{
-    camera::MatchCamera,
+    camera::MatchCamera, fighter::{
-    fighter::{
+        FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop, FighterHitstopShake, FighterPreviousFacingDirection, FighterPreviousTranslation, FighterTranslation, FighterVelocity, Grounded, animation::FighterAnimationFrame, attack::{
-        FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop,
+            FighterDamage, FighterKnockbackVelocity, FighterPendingHitReaction, FighterPendingHits,
-        FighterPreviousFacingDirection, FighterPreviousTranslation, FighterTranslation,
+            FighterSolvedHurtboxes, FighterStaleMoveQueue,
-        FighterVelocity, Grounded,
+        }, baked_animation::FighterBoneMatrices, state::FighterState,
-        animation::FighterAnimationFrame,
+    }, input::FighterInput, player::Player, stage::line::StageCollision,
-        attack::{
-            FighterDamage, FighterKnockbackVelocity, FighterPendingHitReaction,
-            FighterReceivedAttacks, FighterSolvedHurtboxes, FighterStaleMoveQueue,
-        },
-        baked_animation::FighterBoneMatrices,
-        state::FighterState,
-    },
-    input::FighterInput,
-    player::Player,
-    stage::line::StageCollision,
 };
 
 #[derive(Resource, Default)]
@@ -28,6 +18,7 @@ pub(super) struct DebugSaveState {
 struct Checkpoint {
     fighters: Vec<FighterCheckpoint>,
     stage_collision: StageCollision,
+    pending_hits: FighterPendingHits,
 }
 
 #[derive(Clone)]
@@ -47,10 +38,10 @@ struct FighterCheckpoint {
     damage: FighterDamage,
     pending_hit_reaction: FighterPendingHitReaction,
     hitstop: FighterHitstop,
+    hitstop_shake: FighterHitstopShake,
     knockback_velocity: FighterKnockbackVelocity,
     stale_moves: FighterStaleMoveQueue,
     hitboxes: FighterHitboxes,
-    received_attacks: FighterReceivedAttacks,
     solved_hurtboxes: FighterSolvedHurtboxes,
     bone_matrices: FighterBoneMatrices,
     grounded: bool,
@@ -97,9 +88,11 @@ pub(super) fn save_or_restore(world: &mut World) {
             };
             checkpoint_fighters.push(checkpoint);
         }
+        let pending_hits = world.resource::<FighterPendingHits>().clone();
         world.resource_mut::<DebugSaveState>().checkpoint = Some(Checkpoint {
             fighters: checkpoint_fighters,
             stage_collision,
+            pending_hits,
         });
         info!("Saved debug game state");
         return;
@@ -144,10 +137,10 @@ pub(super) fn save_or_restore(world: &mut World) {
         entity.insert(saved.damage);
         entity.insert(saved.pending_hit_reaction.clone());
         entity.insert(saved.hitstop);
+        entity.insert(saved.hitstop_shake);
         entity.insert(saved.knockback_velocity);
         entity.insert(saved.stale_moves.clone());
         entity.insert(saved.hitboxes.clone());
-        entity.insert(saved.received_attacks.clone());
         entity.insert(saved.solved_hurtboxes.clone());
         entity.insert(saved.bone_matrices.clone());
         if saved.grounded {
@@ -156,6 +149,7 @@ pub(super) fn save_or_restore(world: &mut World) {
             entity.remove::<Grounded>();
         }
     }
+    world.insert_resource(checkpoint.pending_hits.clone());
     world.insert_resource(checkpoint.stage_collision);
     for mut match_camera in world.query::<&mut MatchCamera>().iter_mut(world) {
         match_camera.needs_snap = true;
@@ -181,10 +175,10 @@ fn capture_fighter(world: &World, entity: Entity) -> Option<FighterCheckpoint> {
         damage: *fighter.get::<FighterDamage>()?,
         pending_hit_reaction: fighter.get::<FighterPendingHitReaction>()?.clone(),
         hitstop: *fighter.get::<FighterHitstop>()?,
+        hitstop_shake: *fighter.get::<FighterHitstopShake>()?,
         knockback_velocity: *fighter.get::<FighterKnockbackVelocity>()?,
         stale_moves: fighter.get::<FighterStaleMoveQueue>()?.clone(),
         hitboxes: fighter.get::<FighterHitboxes>()?.clone(),
-        received_attacks: fighter.get::<FighterReceivedAttacks>()?.clone(),
         solved_hurtboxes: fighter.get::<FighterSolvedHurtboxes>()?.clone(),
         bone_matrices: fighter.get::<FighterBoneMatrices>()?.clone(),
         grounded: fighter.contains::<Grounded>(),

src/fighter/attack/directional_influence.rs

@@ -0,0 +1,69 @@
+use fixed::traits::ToFixed;
+use fixed_math::SinCos;
+
+use crate::math::{
+    int::{FGWide, FGi32},
+    vec::FGVec2,
+};
+
+/// Applies DI to a given attack direction
+pub fn apply_directional_influence(
+    receiver_stick: FGVec2,
+    attack_angle: FGi32,
+    di_max_angle: FGi32,
+) -> FGVec2 {
+    let (sin, cos) = attack_angle.sin_cos();
+    let base_launch_direction = FGVec2::new(cos, sin);
+
+    let Some(base_launch_direction) = base_launch_direction.normalize() else {
+        return FGVec2::ZERO;
+    };
+
+    if receiver_stick.length_squared().is_zero() {
+        return base_launch_direction;
+    }
+
+    let normal = FGVec2::new(-base_launch_direction.y, base_launch_direction.x);
+    let di_amount = receiver_stick.dot(normal);
+    let angle_change = di_amount * di_max_angle.to_fixed::<FGWide>();
+    let angle_change = angle_change.clamp(
+        -di_max_angle.to_fixed::<FGWide>(),
+        di_max_angle.to_fixed::<FGWide>(),
+    );
+    let (sin, cos) = (attack_angle + angle_change.to_fixed::<FGi32>()).sin_cos();
+    FGVec2::new(cos, sin).normalize_or_zero()
+}
+
+#[cfg(test)]
+mod test {
+    use crate::{
+        fighter::attack::directional_influence::apply_directional_influence,
+        math::{int::FGi32, vec::FGVec2},
+    };
+
+    #[test]
+    fn di_zero_passes_unmodified() {
+        let di = apply_directional_influence(FGVec2::ZERO, FGi32::lit("0.0"), FGi32::lit("18.0"));
+        const EPSILON: FGi32 = FGi32::from_bits(4);
+        assert!(di.x.abs_diff(FGi32::ONE) < EPSILON);
+        assert!(di.y.abs_diff(FGi32::ZERO) < EPSILON);
+    }
+
+    #[test]
+    fn di_applies_on_the_correct_side() {
+        let di = apply_directional_influence(
+            FGVec2::lit("0.0", "1.0"),
+            FGi32::lit("0.0"),
+            FGi32::lit("18.0"),
+        );
+        assert!(di.x > FGi32::ZERO);
+        assert!(di.y > FGi32::ZERO);
+        let di = apply_directional_influence(
+            FGVec2::lit("0.0", "-1.0"),
+            FGi32::lit("0.0"),
+            FGi32::lit("18.0"),
+        );
+        assert!(di.x > FGi32::ZERO);
+        assert!(di.y < FGi32::ZERO);
+    }
+}

src/fighter/attack/mod.rs

@@ -1,18 +1,20 @@
 use std::collections::{HashMap, VecDeque};
 
+mod reaction;
+pub mod directional_influence;
+
+use bevy::ecs::entity::{EntityMapper, MapEntities};
 use bevy::prelude::*;
-use bevy_ggrs::{Rollback, prelude::GgrsSchedule};
+use bevy_ggrs::{Rollback, RollbackApp, prelude::GgrsSchedule};
-use fixed_math::SinCos;
 use serde::{Deserialize, Serialize};
 
 use crate::{
     fighter::{
-        Fighter, FighterAttributes, FighterFacingDirection, FighterHitboxes, FighterHitstop,
+        Fighter, FighterAttributes, FighterFacingDirection, FighterHitboxes,
         FighterPreviousFacingDirection, FighterPreviousTranslation, FighterRoster,
         FighterTranslation,
         animation::{AnimKind, FighterAnimationFrame},
         baked_animation::{FighterBoneIndexMap, FighterBoneMatrices, FixedMat4},
-        errors::FighterErrors,
         hurtbox::{FixedAffineCapsule, FixedCapsule},
         manifest::FighterManifest,
     },
@@ -41,7 +43,8 @@ pub enum HitReactionKind {
 
 #[derive(Debug, Hash, Clone)]
 pub struct FighterHitReaction {
-    pub launch_velocity: FGVec2,
+    pub launch_velocity: FGi32,
+    pub launch_angle: FGi32,
     pub hitstop_frames: HitStop,
     pub hitstun_frames: u32,
     pub kind: HitReactionKind,
@@ -61,10 +64,13 @@ pub struct FighterLastAttackDebug {
     pub trajectory_points: Vec<Vec3>,
 }
 
-#[derive(Debug, Default, Clone, Deref, DerefMut, Hash)]
+#[derive(Debug, Default, Clone, Deref, DerefMut, Hash, PartialEq, PartialOrd)]
 pub struct HitStop(u32);
 
 impl HitStop {
+    pub fn new(hitstop: u32) -> Self {
+        HitStop(hitstop)
+    }
     pub fn calculate(attack_damage_stalled: FighterDamage, crouch_cancelling: bool) -> Self {
         let a = (attack_damage_stalled.0 / FGi32::lit("3.0") + FGi32::lit("4.0")).round_to_zero();
         let crouch_cancelling_factor = if crouch_cancelling {
@@ -77,6 +83,10 @@ impl HitStop {
 
         Self(frames)
     }
+
+    pub fn calculate_shake_frames(&self, game_settings: &GameSettings) -> u32 {
+        (FGi32::from_num(self.0) * game_settings.fighter_common.visual_shake_frames_per_hitstop_frame).floor().to_num()
+    }
 }
 
 #[derive(Clone, Copy, Debug, Serialize, Deserialize)]
@@ -432,15 +442,26 @@ pub struct FighterAttackScriptAssets {
 #[derive(Component, Clone, Debug, Default, Hash)]
 pub struct FighterSolvedHurtboxes(pub Vec<FighterSolvedHurtbox>);
 
-#[derive(Component, Clone, Debug, Default, Hash, DerefMut, Deref)]
+#[derive(Clone, Debug, Hash)]
-pub struct FighterReceivedAttacks(
+pub struct FighterHit {
-    pub  Vec<(
+    pub attacker: Entity,
-        /* attacker */ Entity,
+    pub defender: Entity,
-        Handle<FighterAttackScript>,
+    pub attack_script: Handle<FighterAttackScript>,
-        AttackKind,
+    pub attack_kind: AttackKind,
-        /* hitbox_idx */ usize,
+    pub hitbox_index: usize,
-    )>,
+}
-);
+
+#[derive(Resource, Clone, Debug, Default, Hash)]
+pub struct FighterPendingHits(pub Vec<FighterHit>);
+
+impl MapEntities for FighterPendingHits {
+    fn map_entities<M: EntityMapper>(&mut self, entity_mapper: &mut M) {
+        for hit in &mut self.0 {
+            hit.attacker = entity_mapper.get_mapped(hit.attacker);
+            hit.defender = entity_mapper.get_mapped(hit.defender);
+        }
+    }
+}
 
 pub fn solve_hurtboxes(
     mut query: Query<(
@@ -498,19 +519,14 @@ pub fn intersect_attacks_with_hurtboxes(
         &Player,
         &FighterStaleMoveQueue,
     )>,
-    mut query_attacked: Query<(
+    query_attacked: Query<(Entity, &FighterSolvedHurtboxes)>,
-        Entity,
+    mut pending_hits: ResMut<FighterPendingHits>,
-        &FighterSolvedHurtboxes,
-        &Player,
-        &Fighter,
-        &mut FighterReceivedAttacks,
-    )>,
     attack_scripts: Res<Assets<FighterAttackScript>>,
 ) {
+    pending_hits.0.clear();
+
     for &entity_receiving in &roster.0 {
-        let Ok((_, hurtboxes, _, _receiving_fighter, mut received_attacks)) =
+        let Ok((_, hurtboxes)) = query_attacked.get(entity_receiving) else {
-            query_attacked.get_mut(entity_receiving)
-        else {
             continue;
         };
 
@@ -551,12 +567,13 @@ pub fn intersect_attacks_with_hurtboxes(
                 continue;
             };
 
-            received_attacks.push((
+            pending_hits.0.push(FighterHit {
-                entity_hurting,
+                attacker: entity_hurting,
-                active_attack.script.clone(),
+                defender: entity_receiving,
-                active_attack.kind,
+                attack_script: active_attack.script.clone(),
-                hitting_hitbox_idx,
+                attack_kind: active_attack.kind,
-            ));
+                hitbox_index: hitting_hitbox_idx,
+            });
             info!("Hit by hitbox {}!!!!", hitting_hitbox_idx);
 
             active_attack.hit_fighters.push(entity_receiving);
@@ -564,140 +581,21 @@ pub fn intersect_attacks_with_hurtboxes(
     }
 }
 
-pub fn calculate_received_attacks_trajectories(
-    mut attacker: Query<(
-        &mut FighterStaleMoveQueue,
-        &FighterFacingDirection,
-        &FighterHitboxes,
-        &Player,
-        &mut FighterHitstop,
-    )>,
-    receiver: Query<(
-        &mut FighterReceivedAttacks,
-        &mut FighterDamage,
-        &Fighter,
-        &mut FighterPendingHitReaction,
-    )>,
-    attack_scripts: Res<Assets<FighterAttackScript>>,
-    game_settings: Res<GameSettings>,
-    fighter_manifests: Res<Assets<FighterManifest>>,
-) -> Result {
-    for (mut received_attacks, mut receiver_damage, fighter, mut pending_reactions) in receiver {
-        if received_attacks.is_empty() {
-            continue;
-        }
-
-        // we got attacked, time to calculate the total damage
-
-        let damage_data = received_attacks
-            .iter()
-            .filter_map(|(from_entity, attack_script, attack_kind, hitbox_idx)| {
-                let Ok((stale_move_queue, facing_dir, _hitboxes, player, _attacker_hitstop)) =
-                    attacker.get(*from_entity)
-                else {
-                    return None;
-                };
-
-                let Some(attack_script) = attack_scripts.get(attack_script) else {
-                    return None;
-                };
-
-                let hitbox = &attack_script.hitboxes[*hitbox_idx];
-
-                let damage_received =
-                    stale_move_queue.get_attack_damage_multiplier(*attack_kind) * hitbox.damage.0;
-
-                Some((
-                    from_entity,
-                    damage_received,
-                    hitbox,
-                    attack_script,
-                    matches!(facing_dir, FighterFacingDirection::Left),
-                    player.handle,
-                ))
-            })
-            .collect::<Vec<_>>();
-
-        let total_damage_received_this_frame = damage_data
-            .iter()
-            .map(|(_, damage, ..)| damage)
-            .sum::<FGi32>();
-
-        let fighter_manifest = fighter_manifests
-            .get(&fighter.manifest)
-            .ok_or(FighterErrors::FighterManifestNotFound)?;
-
-        let mut reactions = vec![];
-
-        for (attacker_entity, attack_damage, hitbox, _attack_script, facing_left, attacker_slot) in
-            damage_data
-        {
-            let knockback = hitbox.calculate_knockback(
-                &fighter_manifest.attributes,
-                *receiver_damage,
-                FighterDamage(total_damage_received_this_frame),
-                false,
-                false,
-            );
-
-            let angle = match &hitbox.angle {
-                AttackAngle::Normal(angle) => *angle,
-                AttackAngle::Sakurai => FGi32::lit("32.0"),
-            };
-
-            let launch_angle = if facing_left {
-                FGi32::lit("180.0") - angle
-            } else {
-                angle
-            };
-            let (sin, cos) = launch_angle.sin_cos();
-            let launch_direction = FGVec2::new(cos, sin);
-            let hitstop = HitStop::calculate(FighterDamage(attack_damage), false);
-            reactions.push((
-                *attacker_entity,
-                attacker_slot,
-                FighterHitReaction {
-                    launch_velocity: launch_direction * knockback.get_launch_speed(&game_settings),
-                    hitstun_frames: knockback.get_hitstun_frames(&game_settings),
-                    hitstop_frames: hitstop,
-                    kind: HitReactionKind::Flinch,
-                },
-            ));
-        }
-
-        receiver_damage.0 += total_damage_received_this_frame;
-
-        for (attacker_entity, _, reaction) in reactions.iter() {
-            let Ok((.., mut hitstop)) = attacker.get_mut(*attacker_entity) else {
-                continue;
-            };
-
-            hitstop.remaining_frames = reaction.hitstop_frames.max(hitstop.remaining_frames);
-        }
-
-        // Pick attack by port priority
-        pending_reactions.0 = reactions
-            .into_iter()
-            .min_by(|(_, port_a, _), (_, port_b, _)| port_a.cmp(port_b))
-            .map(|(_, _, reaction)| reaction);
-
-        received_attacks.clear();
-    }
-
-    Ok(())
-}
-
 pub struct FighterAttackPlugin;
 
 impl Plugin for FighterAttackPlugin {
     fn build(&self, app: &mut App) {
+        app.init_resource::<FighterPendingHits>()
+            .add_plugins(reaction::FighterReactionPlugin)
+            .rollback_resource_with_clone::<FighterPendingHits>()
+            .update_resource_with_map_entities::<FighterPendingHits>()
+            .checksum_resource_with_hash::<FighterPendingHits>();
         app.add_systems(
             GgrsSchedule,
             (
                 solve_hurtboxes,
                 solve_hitboxes,
                 intersect_attacks_with_hurtboxes,
-                calculate_received_attacks_trajectories,
             )
                 .chain()
                 .after(crate::fighter::baked_animation::update_fighter_bone_matrices)

src/fighter/attack/reaction.rs

@@ -0,0 +1,151 @@
+use bevy::prelude::*;
+use bevy_ggrs::prelude::GgrsSchedule;
+
+use super::*;
+use crate::{
+    fighter::{
+        Fighter, FighterFacingDirection, FighterHitboxes, FighterHitstop, FighterHitstopShake, FighterHitstopShakeKind, FighterHitstopShakeRole, FighterPendingHitReaction, FighterStaleMoveQueue, errors::FighterErrors, manifest::FighterManifest, state::FighterState,
+    }, game_settings::GameSettings, math::{int::FGi32}, player::Player, schedule::GameplaySet, scripting::FighterAttackScript,
+};
+
+pub fn resolve_fighter_hits(
+    mut pending_hits: ResMut<FighterPendingHits>,
+    mut attacker: Query<(
+        &FighterStaleMoveQueue,
+        &FighterFacingDirection,
+        &FighterHitboxes,
+        &Player,
+        &mut FighterHitstop,
+        &mut FighterHitstopShake,
+    )>,
+    mut receiver: Query<(&mut FighterDamage, &Fighter, &mut FighterPendingHitReaction, &FighterState)>,
+    attack_scripts: Res<Assets<FighterAttackScript>>,
+    game_settings: Res<GameSettings>,
+    fighter_manifests: Res<Assets<FighterManifest>>,
+) -> Result {
+    let hits = std::mem::take(&mut pending_hits.0);
+    let mut hit_offset = 0;
+
+    while hit_offset < hits.len() {
+        let defender = hits[hit_offset].defender;
+        let next_defender = hits[hit_offset..]
+            .iter()
+            .position(|hit| hit.defender != defender)
+            .map_or(hits.len(), |offset| hit_offset + offset);
+
+        let Ok((mut receiver_damage, fighter, mut pending_reaction, receiver_state)) = receiver.get_mut(defender)
+        else {
+            hit_offset = next_defender;
+            continue;
+        };
+
+        let damage_data = hits[hit_offset..next_defender]
+            .iter()
+            .filter_map(|hit| {
+                let Ok((stale_move_queue, facing_dir, _hitboxes, player, _, _)) =
+                    attacker.get(hit.attacker)
+                else {
+                    return None;
+                };
+                let attack_script = attack_scripts.get(&hit.attack_script)?;
+                let hitbox = attack_script.hitboxes.get(hit.hitbox_index)?;
+                let damage_received = stale_move_queue
+                    .get_attack_damage_multiplier(hit.attack_kind)
+                    * hitbox.damage.0;
+
+                Some((
+                    hit.attacker,
+                    damage_received,
+                    hitbox,
+                    matches!(facing_dir, FighterFacingDirection::Left),
+                    player.handle,
+                ))
+            })
+            .collect::<Vec<_>>();
+
+        let total_damage_received_this_frame = damage_data
+            .iter()
+            .map(|(_, damage, ..)| damage)
+            .sum::<FGi32>();
+        let fighter_manifest = fighter_manifests
+            .get(&fighter.manifest)
+            .ok_or(FighterErrors::FighterManifestNotFound)?;
+        let mut reactions = Vec::with_capacity(damage_data.len());
+
+        for (attacker_entity, attack_damage, hitbox, facing_left, attacker_slot) in damage_data {
+            let knockback = hitbox.calculate_knockback(
+                &fighter_manifest.attributes,
+                *receiver_damage,
+                FighterDamage(total_damage_received_this_frame),
+                false,
+                false,
+            );
+            let angle = match &hitbox.angle {
+                AttackAngle::Normal(angle) => *angle,
+                AttackAngle::Sakurai => FGi32::lit("32.0"),
+            };
+            let launch_angle = if facing_left {
+                FGi32::lit("180.0") - angle
+            } else {
+                angle
+            };
+
+            let hitstop = HitStop::calculate(FighterDamage(attack_damage), false);
+            reactions.push((
+                attacker_entity,
+                attacker_slot,
+                FighterHitReaction {
+                    launch_velocity: knockback.get_launch_speed(&game_settings),
+                    launch_angle,
+                    hitstun_frames: knockback.get_hitstun_frames(&game_settings),
+                    hitstop_frames: hitstop,
+                    kind: HitReactionKind::Flinch,
+                },
+            ));
+        }
+
+        receiver_damage.0 += total_damage_received_this_frame;
+
+        for (attacker_entity, _, reaction) in &reactions {
+            let Ok((.., mut hitstop, mut hitstop_shake)) = attacker.get_mut(*attacker_entity) else {
+                continue;
+            };
+
+            if hitstop.remaining_frames < reaction.hitstop_frames.0 {
+                let shake_kind = if receiver_state.is_visually_grounded() {
+                    FighterHitstopShakeKind::Horizontal
+                } else {
+                    FighterHitstopShakeKind::Vertical
+                };
+                hitstop.remaining_frames = reaction.hitstop_frames.0;
+                let shake_frames = reaction.hitstop_frames.calculate_shake_frames(&game_settings);
+                hitstop_shake.total_frames = shake_frames;
+                hitstop_shake.remaining_frames = shake_frames;
+                hitstop_shake.kind = shake_kind;
+                hitstop_shake.role = FighterHitstopShakeRole::Attacker;
+            }
+        }
+
+        pending_reaction.0 = reactions
+            .into_iter()
+            .min_by(|(_, port_a, _), (_, port_b, _)| port_a.cmp(port_b))
+            .map(|(_, _, reaction)| reaction);
+
+        hit_offset = next_defender;
+    }
+
+    Ok(())
+}
+
+pub struct FighterReactionPlugin;
+
+impl Plugin for FighterReactionPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(
+            GgrsSchedule,
+            resolve_fighter_hits
+                .in_set(GameplaySet::Attacks)
+                .after(super::intersect_attacks_with_hurtboxes),
+        );
+    }
+}

src/fighter/attributes.rs

@@ -37,6 +37,7 @@ pub struct FighterAttributes {
     pub ground_friction: FGi32,
     pub terminal_velocity: FGi32,
     pub gravity: FGi32,
+    pub fast_fall_speed: FGi32,
     pub weight: FGi32,
     pub air_friction: FGi32,
 

src/fighter/baked_animation/asset_baking.rs

@@ -0,0 +1,456 @@
+use super::{
+    BAKED_ANIMATION_FPS,
+    runtime::{BakedAnimationClip, BakedFighterAnimations},
+};
+use crate::math::fixed_transform::FixedMat4;
+use crate::fighter::{animation::AnimKind, manifest::FighterManifest};
+use bevy::{
+    asset::{
+        AssetLoader, AssetPath, AsyncWriteExt, LoadContext,
+        io::{Reader, Writer},
+        processor::LoadTransformAndSave,
+        saver::{AssetSaver, SavedAsset},
+        transformer::{AssetTransformer, TransformedAsset},
+    },
+    prelude::*,
+    reflect::TypePath,
+};
+use serde::Deserialize;
+use std::{collections::HashMap, io, path::Path};
+
+#[derive(Deserialize)]
+struct FighterBakeDeclaration {
+    manifest_path: String,
+}
+#[derive(Asset, TypePath)]
+struct FighterBakeSource {
+    model_bytes: Vec<u8>,
+    buffers: Vec<Vec<u8>>,
+    animations: HashMap<AnimKind, String>,
+}
+#[derive(Default, TypePath)]
+struct FighterBakeSourceLoader;
+
+impl AssetLoader for FighterBakeSourceLoader {
+    type Asset = FighterBakeSource;
+    type Settings = ();
+    type Error = io::Error;
+    async fn load(
+        &self,
+        reader: &mut dyn Reader,
+        _: &Self::Settings,
+        load_context: &mut LoadContext<'_>,
+    ) -> Result<Self::Asset, Self::Error> {
+        let mut declaration = Vec::new();
+        reader.read_to_end(&mut declaration).await?;
+        let declaration: FighterBakeDeclaration = ron::de::from_bytes(&declaration)
+            .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+        let manifest_bytes = load_context
+            .read_asset_bytes(&declaration.manifest_path)
+            .await
+            .map_err(|error| io::Error::other(error.to_string()))?;
+        let manifest: FighterManifest = ron::de::from_bytes(&manifest_bytes)
+            .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+        let model_bytes = load_context
+            .read_asset_bytes(&manifest.model_path)
+            .await
+            .map_err(|error| io::Error::other(error.to_string()))?;
+        let gltf = gltf::Gltf::from_slice(&model_bytes)
+            .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+        let mut buffers = Vec::with_capacity(gltf.buffers().len());
+        for buffer in gltf.buffers() {
+            let bytes = match buffer.source() {
+                gltf::buffer::Source::Uri(uri) => load_context
+                    .read_asset_bytes(AssetPath::from_path_buf(
+                        Path::new(&manifest.model_path)
+                            .parent()
+                            .unwrap_or_else(|| Path::new(""))
+                            .join(uri),
+                    ))
+                    .await
+                    .map_err(|error| io::Error::other(error.to_string()))?,
+                gltf::buffer::Source::Bin => gltf.blob.clone().ok_or_else(|| {
+                    io::Error::new(io::ErrorKind::InvalidData, "missing glTF binary blob")
+                })?,
+            };
+            buffers.push(bytes);
+        }
+        Ok(FighterBakeSource {
+            model_bytes,
+            buffers,
+            animations: manifest.animations,
+        })
+    }
+    fn extensions(&self) -> &[&str] {
+        &["fighterbake"]
+    }
+}
+
+#[derive(Default, TypePath)]
+struct BakedFighterAnimationsLoader;
+impl AssetLoader for BakedFighterAnimationsLoader {
+    type Asset = BakedFighterAnimations;
+    type Settings = ();
+    type Error = io::Error;
+    async fn load(
+        &self,
+        reader: &mut dyn Reader,
+        _: &Self::Settings,
+        _: &mut LoadContext<'_>,
+    ) -> Result<Self::Asset, Self::Error> {
+        let mut bytes = Vec::new();
+        reader.read_to_end(&mut bytes).await?;
+        bincode::deserialize(&bytes)
+            .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))
+    }
+    fn extensions(&self) -> &[&str] {
+        &["fighterbake"]
+    }
+}
+
+#[derive(Default, TypePath)]
+struct FighterBakeTransformer;
+impl AssetTransformer for FighterBakeTransformer {
+    type AssetInput = FighterBakeSource;
+    type AssetOutput = BakedFighterAnimations;
+    type Settings = ();
+    type Error = io::Error;
+    async fn transform<'a>(
+        &'a self,
+        source: TransformedAsset<Self::AssetInput>,
+        _: &'a Self::Settings,
+    ) -> Result<TransformedAsset<Self::AssetOutput>, Self::Error> {
+        let baked = bake_gltf(&source.model_bytes, &source.buffers, &source.animations)?;
+        Ok(source.replace_asset(baked))
+    }
+}
+
+#[derive(Default, TypePath)]
+struct BakedFighterAnimationsSaver;
+impl AssetSaver for BakedFighterAnimationsSaver {
+    type Asset = BakedFighterAnimations;
+    type Settings = ();
+    type OutputLoader = BakedFighterAnimationsLoader;
+    type Error = io::Error;
+    async fn save(
+        &self,
+        writer: &mut Writer,
+        asset: SavedAsset<'_, '_, Self::Asset>,
+        _: &Self::Settings,
+        _: AssetPath<'_>,
+    ) -> Result<(), Self::Error> {
+        let bytes = bincode::serialize(&*asset)
+            .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+        writer.write_all(&bytes).await
+    }
+}
+type FighterBakeProcessor = LoadTransformAndSave<
+    FighterBakeSourceLoader,
+    FighterBakeTransformer,
+    BakedFighterAnimationsSaver,
+>;
+
+pub struct BakedAnimationPlugin;
+impl Plugin for BakedAnimationPlugin {
+    fn build(&self, app: &mut App) {
+        app.init_asset::<BakedFighterAnimations>()
+            .register_asset_loader(FighterBakeSourceLoader)
+            .register_asset_loader(BakedFighterAnimationsLoader)
+            .register_asset_processor(FighterBakeProcessor::new(
+                FighterBakeTransformer,
+                BakedFighterAnimationsSaver,
+            ))
+            .set_default_asset_processor::<FighterBakeProcessor>("fighterbake")
+            .add_systems(
+                bevy_ggrs::prelude::GgrsSchedule,
+                super::runtime::update_fighter_bone_matrices
+                    .in_set(crate::schedule::GameplaySet::Animation),
+            )
+            .add_systems(
+                Update,
+                super::visual_binding::apply_baked_fighter_visual_pose,
+            )
+            .add_observer(super::visual_binding::bind_fighter_visual_bones);
+    }
+}
+
+fn bake_gltf(
+    bytes: &[u8],
+    buffer_bytes: &[Vec<u8>],
+    animations: &HashMap<AnimKind, String>,
+) -> io::Result<BakedFighterAnimations> {
+    let gltf = gltf::Gltf::from_slice(bytes)
+        .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+    let buffers = gltf
+        .buffers()
+        .zip(buffer_bytes)
+        .map(|(buffer, bytes)| {
+            if bytes.len() < buffer.length() {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    format!(
+                        "glTF buffer {} is too short: expected {}, got {}",
+                        buffer.index(),
+                        buffer.length(),
+                        bytes.len()
+                    ),
+                ));
+            }
+            Ok(gltf::buffer::Data(bytes.clone()))
+        })
+        .collect::<io::Result<Vec<_>>>()?;
+    if buffers.len() != gltf.buffers().len() {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidData,
+            "glTF buffer data is incomplete",
+        ));
+    }
+    bake_gltf_document(gltf.document, buffers, animations)
+}
+
+pub(super) fn bake_gltf_document(
+    document: gltf::Document,
+    buffers: Vec<gltf::buffer::Data>,
+    animations: &HashMap<AnimKind, String>,
+) -> io::Result<BakedFighterAnimations> {
+    let nodes: Vec<_> = document.nodes().collect();
+    if nodes.is_empty() {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidData,
+            "fighter model has no nodes",
+        ));
+    }
+    let mut parents = vec![None; nodes.len()];
+    for node in &nodes {
+        for child in node.children() {
+            parents[child.index()] = Some(node.index());
+        }
+    }
+    let names = nodes
+        .iter()
+        .map(|node| {
+            node.name().map(str::to_owned).ok_or_else(|| {
+                io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    format!("node {} has no name", node.index()),
+                )
+            })
+        })
+        .collect::<io::Result<Vec<_>>>()?;
+    let mut pending = HashMap::<&str, Vec<AnimKind>>::new();
+    for (kind, name) in animations {
+        pending.entry(name).or_default().push(*kind);
+    }
+    let mut clips = Vec::with_capacity(pending.len());
+    let mut clip_indices = HashMap::with_capacity(animations.len());
+    for animation in document.animations() {
+        let name = animation.name().ok_or_else(|| {
+            io::Error::new(
+                io::ErrorKind::InvalidData,
+                format!("animation {} has no name", animation.index()),
+            )
+        })?;
+        let Some(kinds) = pending.remove(name) else {
+            continue;
+        };
+        let channels = animation
+            .channels()
+            .map(|channel| read_channel(channel, &buffers))
+            .collect::<io::Result<Vec<_>>>()?;
+        let duration = channels
+            .iter()
+            .filter_map(Channel::duration)
+            .fold(0.0_f32, f32::max);
+        let frame_count = baked_frame_count(duration, BAKED_ANIMATION_FPS);
+        let mut frames = Vec::with_capacity(frame_count);
+        for frame in 0..frame_count {
+            let time = (frame as f32 / BAKED_ANIMATION_FPS as f32).min(duration);
+            frames.push(
+                nodes
+                    .iter()
+                    .map(|node| local_transform(node.clone(), &channels, time))
+                    .collect::<io::Result<Vec<_>>>()?,
+            );
+        }
+        let index = clips.len();
+        clips.push(BakedAnimationClip { frames });
+        for kind in kinds {
+            clip_indices.insert(kind, index);
+        }
+    }
+    if clips.is_empty() {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidData,
+            "fighter model has no animations",
+        ));
+    }
+    if !pending.is_empty() {
+        let mut missing = pending.keys().copied().collect::<Vec<_>>();
+        missing.sort_unstable();
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidData,
+            format!(
+                "fighter model has no animations named {}",
+                missing.join(", ")
+            ),
+        ));
+    }
+    Ok(BakedFighterAnimations {
+        frame_rate: BAKED_ANIMATION_FPS,
+        bone_names: names,
+        parents,
+        clips,
+        clip_indices,
+    })
+}
+
+pub(super) fn baked_frame_count(duration: f32, frame_rate: u32) -> usize {
+    let frame = duration as f64 * frame_rate as f64;
+    let nearest_frame = frame.round();
+    let last_frame = if (frame - nearest_frame).abs() < 0.0001 {
+        nearest_frame
+    } else {
+        frame.ceil()
+    };
+    last_frame as usize + 1
+}
+
+#[derive(Clone)]
+pub(super) struct Channel {
+    pub(super) node: usize,
+    pub(super) property: gltf::animation::Property,
+    pub(super) interpolation: gltf::animation::Interpolation,
+    pub(super) times: Vec<f32>,
+    pub(super) values: ChannelValues,
+}
+impl Channel {
+    fn duration(&self) -> Option<f32> {
+        self.times.last().copied()
+    }
+}
+#[derive(Clone)]
+pub(super) enum ChannelValues {
+    Vec3(Vec<[f32; 3]>),
+    Rotation(Vec<[f32; 4]>),
+}
+
+fn read_channel(
+    channel: gltf::animation::Channel<'_>,
+    buffers: &[gltf::buffer::Data],
+) -> io::Result<Channel> {
+    let reader = channel.reader(|buffer| Some(&buffers[buffer.index()].0));
+    let times = reader
+        .read_inputs()
+        .ok_or_else(|| {
+            io::Error::new(io::ErrorKind::InvalidData, "animation channel has no input")
+        })?
+        .collect();
+    let values = match reader.read_outputs().ok_or_else(|| {
+        io::Error::new(
+            io::ErrorKind::InvalidData,
+            "animation channel has no output",
+        )
+    })? {
+        gltf::animation::util::ReadOutputs::Translations(values)
+        | gltf::animation::util::ReadOutputs::Scales(values) => {
+            ChannelValues::Vec3(values.collect())
+        }
+        gltf::animation::util::ReadOutputs::Rotations(values) => {
+            ChannelValues::Rotation(values.into_f32().collect())
+        }
+        gltf::animation::util::ReadOutputs::MorphTargetWeights(_) => {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "morph target animation is not supported for bone baking",
+            ));
+        }
+    };
+    if channel.sampler().interpolation() == gltf::animation::Interpolation::CubicSpline {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidData,
+            "cubic spline animation is not supported for bone baking",
+        ));
+    }
+    Ok(Channel {
+        node: channel.target().node().index(),
+        property: channel.target().property(),
+        interpolation: channel.sampler().interpolation(),
+        times,
+        values,
+    })
+}
+
+fn local_transform(node: gltf::Node<'_>, channels: &[Channel], time: f32) -> io::Result<FixedMat4> {
+    let (mut translation, mut rotation, mut scale) = match node.transform() {
+        gltf::scene::Transform::Decomposed {
+            translation,
+            rotation,
+            scale,
+        } => (
+            Vec3::from(translation),
+            Quat::from_array(rotation),
+            Vec3::from(scale),
+        ),
+        gltf::scene::Transform::Matrix { matrix } => {
+            return FixedMat4::from_mat4(Mat4::from_cols_array_2d(&matrix));
+        }
+    };
+    for channel in channels
+        .iter()
+        .filter(|channel| channel.node == node.index())
+    {
+        match (&channel.values, channel.property) {
+            (ChannelValues::Vec3(values), gltf::animation::Property::Translation) => {
+                translation = Vec3::from(sample_vec3(channel, values, time))
+            }
+            (ChannelValues::Vec3(values), gltf::animation::Property::Scale) => {
+                scale = Vec3::from(sample_vec3(channel, values, time))
+            }
+            (ChannelValues::Rotation(values), gltf::animation::Property::Rotation) => {
+                rotation = Quat::from_array(sample_rotation(channel, values, time))
+            }
+            _ => {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "animation property does not match its values",
+                ));
+            }
+        }
+    }
+    FixedMat4::from_mat4(Mat4::from_scale_rotation_translation(
+        scale,
+        rotation,
+        translation,
+    ))
+}
+fn sample_index(channel: &Channel, time: f32) -> (usize, usize, f32) {
+    let next = channel.times.partition_point(|key| *key <= time);
+    if next == 0 {
+        return (0, 0, 0.0);
+    }
+    if next == channel.times.len() {
+        let last = next - 1;
+        return (last, last, 0.0);
+    }
+    let previous = next - 1;
+    let factor = (time - channel.times[previous]) / (channel.times[next] - channel.times[previous]);
+    (previous, next, factor)
+}
+pub(super) fn sample_vec3(channel: &Channel, values: &[[f32; 3]], time: f32) -> [f32; 3] {
+    let (from, to, factor) = sample_index(channel, time);
+    if channel.interpolation == gltf::animation::Interpolation::Step {
+        return values[from];
+    }
+    Vec3::from(values[from])
+        .lerp(Vec3::from(values[to]), factor)
+        .to_array()
+}
+fn sample_rotation(channel: &Channel, values: &[[f32; 4]], time: f32) -> [f32; 4] {
+    let (from, to, factor) = sample_index(channel, time);
+    if channel.interpolation == gltf::animation::Interpolation::Step {
+        return values[from];
+    }
+    Quat::from_array(values[from])
+        .slerp(Quat::from_array(values[to]), factor)
+        .to_array()
+}

src/fighter/baked_animation/mod.rs

@@ -0,0 +1,250 @@
+//! Deterministic, fighter-local skeletal animation samples for gameplay and rendering.
+
+mod asset_baking;
+mod runtime;
+mod visual_binding;
+
+pub use asset_baking::BakedAnimationPlugin;
+pub use crate::math::fixed_transform::FixedMat4;
+pub use runtime::{
+    BakedAnimationClip, BakedFighterAnimations, FighterBoneIndexMap, FighterBoneMatrices,
+    update_fighter_bone_matrices,
+};
+
+pub const BAKED_ANIMATION_FPS: u32 = 60;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::fighter::{animation::AnimKind, manifest::FighterManifest};
+    use crate::math::{int::FGi32, vec3::FGVec3};
+    use asset_baking::{
+        Channel, ChannelValues, bake_gltf_document, baked_frame_count, sample_vec3,
+    };
+    use std::collections::HashMap;
+
+    #[test]
+    fn configured_fighter_clips_bake_to_fixed_point_frames() {
+        let manifest: FighterManifest = ron::from_str(include_str!(
+            "../../../assets/fighters/test/test.fighter.ron"
+        ))
+        .unwrap();
+        let (document, buffers, _) = gltf::import(concat!(
+            env!("CARGO_MANIFEST_DIR"),
+            "/assets/fighters/test/test_fighter.gltf"
+        ))
+        .unwrap();
+        let baked = bake_gltf_document(document, buffers, &manifest.animations).unwrap();
+
+        assert_eq!(baked.frame_rate, BAKED_ANIMATION_FPS);
+        assert_eq!(baked.frame_count(AnimKind::Wait), Some(121));
+        assert_eq!(baked.frame_count(AnimKind::Walk), Some(33));
+        assert_eq!(baked.frame_count(AnimKind::Run), Some(33));
+        assert_eq!(baked.frame_count(AnimKind::Dash), Some(21));
+        assert_eq!(baked.frame_count(AnimKind::Landing), Some(9));
+        assert_eq!(baked.frame_count(AnimKind::JumpBack), Some(57));
+        assert_eq!(baked.clip_indices.len(), manifest.animations.len());
+        assert_eq!(
+            baked.clip(AnimKind::Wait).unwrap().frames[0].len(),
+            baked.bone_names.len()
+        );
+        assert_eq!(baked.parents.len(), baked.bone_names.len());
+    }
+
+    #[test]
+    fn pose_sampling_wraps_repeating_frames_and_clamps_finished_frames() {
+        let first = FixedMat4::IDENTITY;
+        let mut second = FixedMat4::IDENTITY;
+        second.translate(FGVec3::lit("2", "0", "0"));
+        let mut terminal = FixedMat4::IDENTITY;
+        terminal.translate(FGVec3::lit("4", "0", "0"));
+        let baked = BakedFighterAnimations {
+            frame_rate: BAKED_ANIMATION_FPS,
+            bone_names: vec!["root".into()],
+            parents: vec![None],
+            clips: vec![BakedAnimationClip {
+                frames: vec![vec![first], vec![second], vec![terminal]],
+            }],
+            clip_indices: HashMap::from([(AnimKind::Wait, 0)]),
+        };
+        let repeating = crate::fighter::animation::FighterAnimationFrame {
+            kind: AnimKind::Wait,
+            frame: 3,
+            repeat: true,
+        };
+        let finished = crate::fighter::animation::FighterAnimationFrame {
+            kind: AnimKind::Wait,
+            frame: 4,
+            repeat: false,
+        };
+        assert_eq!(baked.sample_pose(&repeating), Some(&[second][..]));
+        assert_eq!(baked.sample_pose(&finished), Some(&[terminal][..]));
+    }
+
+    #[test]
+    fn frame_count_snaps_source_frame_rounding_error_to_the_bake_grid() {
+        assert_eq!(baked_frame_count(0.533333361, 60), 33);
+        assert_eq!(baked_frame_count(0.333333343, 60), 21);
+        assert_eq!(baked_frame_count(0.133333340, 60), 9);
+        assert_eq!(baked_frame_count(2.0, 60), 121);
+    }
+
+    #[test]
+    fn linear_source_channel_is_resampled_between_thirty_hz_keys() {
+        let channel = Channel {
+            node: 0,
+            property: gltf::animation::Property::Translation,
+            interpolation: gltf::animation::Interpolation::Linear,
+            times: vec![0.0, 1.0 / 30.0],
+            values: ChannelValues::Vec3(vec![[0.0, 0.0, 0.0], [2.0, 0.0, 0.0]]),
+        };
+        let ChannelValues::Vec3(values) = &channel.values else {
+            unreachable!()
+        };
+        assert_eq!(sample_vec3(&channel, values, 1.0 / 60.0), [1.0, 0.0, 0.0]);
+    }
+
+    #[test]
+    fn presentation_pose_interpolates_previous_and_current_local_transforms() {
+        let mut previous = FixedMat4::IDENTITY;
+        previous.translate(FGVec3::lit("2", "0", "0"));
+        let mut current = FixedMat4::IDENTITY;
+        current.translate(FGVec3::lit("6", "0", "0"));
+        let transform = runtime::interpolate_transform(previous, current, 0.25);
+        assert_eq!(
+            transform.translation,
+            bevy::prelude::Vec3::new(3.0, 0.0, 0.0)
+        );
+    }
+
+    #[test]
+    fn bone_matrix_component_keeps_names_aligned_with_the_current_pose() {
+        let first = FixedMat4::IDENTITY;
+        let mut second = FixedMat4::IDENTITY;
+        second.translate(FGVec3::lit("0", "3", "0"));
+        let mut matrices = FighterBoneMatrices::default();
+        matrices.set_pose(
+            &["root".into(), "hand".into()],
+            &[None, Some(0)],
+            &[first, second],
+            FGi32::ONE,
+        );
+        assert_eq!(matrices.get_current("hand"), Some(second));
+        assert_eq!(
+            matrices.iter().collect::<Vec<_>>(),
+            vec![("root", first), ("hand", second)]
+        );
+    }
+
+    #[test]
+    fn local_pose_reconstructs_model_space_for_gameplay() {
+        let mut root = FixedMat4::IDENTITY;
+        root.translate(FGVec3::lit("10", "0", "0"));
+        let mut hand = FixedMat4::IDENTITY;
+        hand.translate(FGVec3::lit("0", "3", "0"));
+        let mut matrices = FighterBoneMatrices::default();
+        matrices.set_pose(
+            &["root".into(), "hand".into()],
+            &[None, Some(0)],
+            &[root, hand],
+            FGi32::ONE,
+        );
+        assert_eq!(matrices.local(1), Some(hand));
+        assert_eq!(
+            matrices.get_current("hand").unwrap().get_translation(),
+            FGVec3::lit("10", "3", "0")
+        );
+        assert_eq!(
+            matrices
+                .local(1)
+                .unwrap()
+                .to_mat4()
+                .transform_point3(bevy::prelude::Vec3::ZERO),
+            bevy::prelude::Vec3::new(0.0, 3.0, 0.0)
+        );
+    }
+
+    #[test]
+    fn model_scale_affects_gameplay_bones_without_changing_visual_locals() {
+        let mut root = FixedMat4::IDENTITY;
+        root.translate(FGVec3::lit("1", "0", "0"));
+        let mut hand = FixedMat4::IDENTITY;
+        hand.translate(FGVec3::lit("0", "2", "0"));
+        let mut matrices = FighterBoneMatrices::default();
+        matrices.set_pose(
+            &["root".into(), "hand".into()],
+            &[None, Some(0)],
+            &[root, hand],
+            FGi32::lit("10"),
+        );
+        assert_eq!(matrices.local(1), Some(hand));
+        assert_eq!(
+            matrices.get_current("hand").unwrap().get_translation(),
+            FGVec3::lit("10", "20", "0")
+        );
+    }
+
+    #[test]
+    fn fixed_matrix_transforms_points() {
+        let transform = FixedMat4 {
+            cols: [
+                [FGi32::lit("2"), FGi32::ZERO, FGi32::ZERO, FGi32::ZERO],
+                [FGi32::ZERO, FGi32::lit("3"), FGi32::ZERO, FGi32::ZERO],
+                [FGi32::ZERO, FGi32::ZERO, FGi32::lit("4"), FGi32::ZERO],
+                [
+                    FGi32::lit("10"),
+                    FGi32::lit("-5"),
+                    FGi32::lit("1.5"),
+                    FGi32::ONE,
+                ],
+            ],
+        };
+        assert_eq!(
+            transform.transform_point(FGVec3::lit("1.25", "-2", "0.5")),
+            FGVec3::lit("12.5", "-11", "3.5")
+        );
+    }
+
+    #[test]
+    fn fixed_matrix_rotates_points_around_y() {
+        let transform = FixedMat4 {
+            cols: [
+                [FGi32::ONE, FGi32::ZERO, FGi32::ZERO, FGi32::ZERO],
+                [FGi32::ZERO, FGi32::ONE, FGi32::ZERO, FGi32::ZERO],
+                [FGi32::ZERO, FGi32::ZERO, FGi32::ONE, FGi32::ZERO],
+                [
+                    FGi32::lit("10"),
+                    FGi32::lit("2"),
+                    FGi32::lit("-3"),
+                    FGi32::ONE,
+                ],
+            ],
+        };
+        assert_eq!(
+            transform
+                .rotate_y(5)
+                .transform_point(FGVec3::lit("1", "0", "0")),
+            FGVec3::lit("10", "2", "-4")
+        );
+    }
+
+    #[test]
+    fn fixed_matrix_builders_set_euler_rotation_and_translation() {
+        let transform = FixedMat4::IDENTITY
+            .with_rotation(FGVec3::lit("0", "0", "1.5707963267948966"))
+            .with_translation(FGVec3::lit("10", "2", "-3"));
+        assert_eq!(
+            transform.transform_point(FGVec3::lit("1", "0", "0")),
+            FGVec3::lit("10", "3", "-3")
+        );
+        assert_eq!(transform.get_translation(), FGVec3::lit("10", "2", "-3"));
+    }
+
+    #[test]
+    fn fixed_matrix_rotation_builder_preserves_translation() {
+        let transform = FixedMat4::IDENTITY
+            .with_translation(FGVec3::lit("4", "5", "6"))
+            .with_rotation(FGVec3::lit("0", "0", "1.5707963267948966"));
+        assert_eq!(transform.get_translation(), FGVec3::lit("4", "5", "6"));
+    }
+}

src/fighter/baked_animation/runtime.rs

@@ -0,0 +1,244 @@
+use std::collections::HashMap;
+
+use bevy::prelude::*;
+use serde::{Deserialize, Serialize};
+
+use super::{BAKED_ANIMATION_FPS};
+
+use crate::{
+    fighter::{
+        Fighter,
+        animation::{AnimKind, FighterAnimationFrame},
+        manifest::FighterManifest,
+        visual::FighterAnimations,
+    },
+    math::int::FGi32,
+    math::fixed_transform::FixedMat4
+};
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct BakedAnimationClip {
+    pub frames: Vec<Vec<FixedMat4>>,
+}
+
+#[derive(Asset, bevy::reflect::TypePath, Clone, Debug, Serialize, Deserialize)]
+#[type_path = "shinespark::fighter::baked_animation"]
+pub struct BakedFighterAnimations {
+    pub frame_rate: u32,
+    pub bone_names: Vec<String>,
+    pub parents: Vec<Option<usize>>,
+    pub(super) clips: Vec<BakedAnimationClip>,
+    pub(super) clip_indices: HashMap<AnimKind, usize>,
+}
+
+impl BakedFighterAnimations {
+    pub fn contains_bone(&self, bone: &str) -> bool {
+        self.bone_names.iter().any(|name| name == bone)
+    }
+    pub fn has_unique_bone_names(&self) -> bool {
+        let mut names = std::collections::HashSet::with_capacity(self.bone_names.len());
+        self.bone_names.iter().all(|name| names.insert(name))
+    }
+    pub fn sample_pose(&self, frame: &FighterAnimationFrame) -> Option<&[FixedMat4]> {
+        let frames = &self.clip(frame.kind)?.frames;
+        let frame_index = if frame.repeat {
+            let loop_frame_count = frames.len().saturating_sub(1).max(1) as u32;
+            frame.frame % loop_frame_count
+        } else {
+            frame.frame
+        };
+        frames
+            .get(frame_index as usize)
+            .or_else(|| frames.last())
+            .map(Vec::as_slice)
+    }
+    pub fn frame_count(&self, kind: AnimKind) -> Option<u32> {
+        self.clip(kind).map(|clip| clip.frames.len() as u32)
+    }
+    pub(super) fn clip(&self, kind: AnimKind) -> Option<&BakedAnimationClip> {
+        self.clip_indices
+            .get(&kind)
+            .and_then(|index| self.clips.get(*index))
+    }
+}
+
+#[derive(Component, Clone, Debug, Default)]
+pub struct FighterBoneMatrices {
+    bone_names: Vec<String>,
+    parents: Vec<Option<usize>>,
+    matrices: Vec<FixedMat4>,
+    previous_frame_matrices: Vec<FixedMat4>,
+    local_matrices: Vec<FixedMat4>,
+    previous_local_matrices: Vec<FixedMat4>,
+}
+
+#[derive(Component, Clone, Debug, Default)]
+pub struct FighterBoneIndexMap(pub HashMap<String, usize>);
+
+impl FighterBoneMatrices {
+    pub fn get(&self, bone: &str) -> Option<(FixedMat4, FixedMat4)> {
+        let index = self.bone_names.iter().position(|name| name == bone)?;
+        Some((
+            *self.previous_frame_matrices.get(index)?,
+            *self.matrices.get(index)?,
+        ))
+    }
+    pub fn get_current(&self, bone: &str) -> Option<FixedMat4> {
+        let index = self.bone_names.iter().position(|name| name == bone)?;
+        self.matrices.get(index).copied()
+    }
+    pub fn get_index(&self, index: usize) -> Option<(FixedMat4, FixedMat4)> {
+        Some((
+            *self.previous_frame_matrices.get(index)?,
+            *self.matrices.get(index)?,
+        ))
+    }
+    pub fn get_current_index(&self, index: usize) -> Option<FixedMat4> {
+        self.matrices.get(index).copied()
+    }
+    pub fn iter(&self) -> impl Iterator<Item = (&str, FixedMat4)> {
+        self.bone_names
+            .iter()
+            .map(String::as_str)
+            .zip(self.matrices.iter().copied())
+    }
+    pub fn local(&self, index: usize) -> Option<FixedMat4> {
+        self.local_matrices.get(index).copied()
+    }
+    pub(super) fn presentation_local(
+        &self,
+        index: usize,
+        overstep_fraction: f32,
+    ) -> Option<Transform> {
+        let current = self.local_matrices.get(index).copied()?;
+        let previous = self
+            .previous_local_matrices
+            .get(index)
+            .copied()
+            .unwrap_or(current);
+        Some(interpolate_transform(previous, current, overstep_fraction))
+    }
+    pub(super) fn set_pose(
+        &mut self,
+        bone_names: &[String],
+        parents: &[Option<usize>],
+        local: &[FixedMat4],
+        model_scale: FGi32,
+    ) {
+        assert_eq!(
+            bone_names.len(),
+            local.len(),
+            "baked animation pose does not match its bone names"
+        );
+        assert_eq!(
+            bone_names.len(),
+            parents.len(),
+            "baked bone parents do not match names"
+        );
+        if self.bone_names.is_empty() {
+            self.bone_names.extend_from_slice(bone_names);
+            self.parents.extend_from_slice(parents);
+        } else {
+            assert_eq!(self.bone_names, bone_names, "baked bone names changed");
+            assert_eq!(self.parents, parents, "baked bone parents changed");
+        }
+        std::mem::swap(&mut self.matrices, &mut self.previous_frame_matrices);
+        std::mem::swap(&mut self.local_matrices, &mut self.previous_local_matrices);
+        self.local_matrices.clear();
+        self.local_matrices.extend_from_slice(local);
+        let mut model = vec![None; local.len()];
+        for index in 0..local.len() {
+            resolve_model_transform(index, parents, local, &mut model)
+                .expect("baked bone hierarchy should be valid");
+        }
+        let model_scale = FixedMat4 {
+            cols: [
+                [model_scale, FGi32::ZERO, FGi32::ZERO, FGi32::ZERO],
+                [FGi32::ZERO, model_scale, FGi32::ZERO, FGi32::ZERO],
+                [FGi32::ZERO, FGi32::ZERO, model_scale, FGi32::ZERO],
+                [FGi32::ZERO, FGi32::ZERO, FGi32::ZERO, FGi32::ONE],
+            ],
+        };
+        self.matrices = model
+            .into_iter()
+            .map(|matrix| model_scale.mul(matrix.expect("baked bone hierarchy should be valid")))
+            .collect();
+    }
+}
+
+pub fn update_fighter_bone_matrices(
+    mut fighters: Query<(
+        &FighterAnimationFrame,
+        &FighterAnimations,
+        &Fighter,
+        &mut FighterBoneMatrices,
+        &mut FighterBoneIndexMap,
+    )>,
+    baked_assets: Res<Assets<BakedFighterAnimations>>,
+    manifests: Res<Assets<FighterManifest>>,
+) {
+    for (frame, animations, fighter, mut matrices, mut bone_indices) in &mut fighters {
+        let baked = baked_assets
+            .get(&animations.baked)
+            .expect("fighter baked animation asset should be loaded before the match starts");
+        assert_eq!(
+            baked.frame_rate, BAKED_ANIMATION_FPS,
+            "fighter baked animation rate does not match the simulation rate"
+        );
+        let pose = baked
+            .sample_pose(frame)
+            .expect("fighter animation frame should select a baked pose");
+        let manifest = manifests
+            .get(&fighter.manifest)
+            .expect("fighter manifest should be loaded before the match starts");
+        matrices.set_pose(
+            &baked.bone_names,
+            &baked.parents,
+            pose,
+            manifest.model_scale,
+        );
+        if bone_indices.0.is_empty() {
+            bone_indices.0.extend(
+                baked
+                    .bone_names
+                    .iter()
+                    .enumerate()
+                    .map(|(index, name)| (name.clone(), index)),
+            );
+        }
+    }
+}
+
+fn resolve_model_transform(
+    index: usize,
+    parents: &[Option<usize>],
+    local: &[FixedMat4],
+    model: &mut [Option<FixedMat4>],
+) -> std::io::Result<FixedMat4> {
+    if let Some(value) = model[index] {
+        return Ok(value);
+    }
+    let value = match parents[index] {
+        Some(parent) => resolve_model_transform(parent, parents, local, model)?.mul(local[index]),
+        None => local[index],
+    };
+    model[index] = Some(value);
+    Ok(value)
+}
+
+pub(super) fn interpolate_transform(
+    previous: FixedMat4,
+    current: FixedMat4,
+    factor: f32,
+) -> Transform {
+    let (previous_scale, previous_rotation, previous_translation) =
+        previous.to_mat4().to_scale_rotation_translation();
+    let (current_scale, current_rotation, current_translation) =
+        current.to_mat4().to_scale_rotation_translation();
+    let factor = factor.clamp(0.0, 1.0);
+    Transform {
+        translation: previous_translation.lerp(current_translation, factor),
+        rotation: previous_rotation.slerp(current_rotation, factor),
+        scale: previous_scale.lerp(current_scale, factor),
+    }
+}

src/fighter/baked_animation/visual_binding.rs

@@ -0,0 +1,107 @@
+use bevy::prelude::*;
+use bevy::world_serialization::{WorldInstanceReady, WorldInstanceSpawner};
+use bevy_ggrs::GgrsFrameTiming;
+use std::collections::{HashMap, HashSet};
+
+use super::{BakedFighterAnimations, FighterBoneMatrices};
+use crate::fighter::visual::FighterAnimations;
+
+#[derive(Component)]
+pub(super) struct BakedFighterBone {
+    fighter: Entity,
+    index: usize,
+}
+
+pub(super) fn bind_fighter_visual_bones(
+    ready: On<WorldInstanceReady>,
+    mut commands: Commands,
+    spawner: Res<WorldInstanceSpawner>,
+    fighters: Query<&FighterAnimations>,
+    baked_assets: Res<Assets<BakedFighterAnimations>>,
+    nodes: Query<(&Name, Option<&ChildOf>)>,
+    animation_players: Query<(), With<AnimationPlayer>>,
+) {
+    let fighter = ready.entity;
+    let Ok(animations) = fighters.get(fighter) else {
+        return;
+    };
+    let baked = baked_assets
+        .get(&animations.baked)
+        .expect("fighter baked animation asset should be loaded before its visual scene");
+    let entities = spawner
+        .iter_instance_entities(ready.instance_id)
+        .collect::<HashSet<_>>();
+    for &entity in &entities {
+        if animation_players.contains(entity) {
+            commands.entity(entity).remove::<AnimationPlayer>();
+        }
+    }
+    let mut indices = HashMap::with_capacity(baked.bone_names.len());
+    for (index, name) in baked.bone_names.iter().enumerate() {
+        let key = (baked.parents[index], name.as_str());
+        assert!(
+            indices.insert(key, index).is_none(),
+            "fighter GLTF has duplicate node names under the same parent"
+        );
+    }
+    let mut assigned = HashMap::new();
+    let mut remaining = entities.iter().copied().collect::<Vec<_>>();
+    while !remaining.is_empty() {
+        let mut next = Vec::new();
+        let mut progress = false;
+        for entity in remaining {
+            let Ok((name, parent)) = nodes.get(entity) else {
+                continue;
+            };
+            let parent = parent.map(ChildOf::parent);
+            let parent_index = match parent {
+                Some(parent) if entities.contains(&parent) => {
+                    if let Some(index) = assigned.get(&parent) {
+                        Some(*index)
+                    } else if nodes.get(parent).ok().is_some_and(|(name, _)| {
+                        baked.bone_names.iter().any(|bone| bone == name.as_str())
+                    }) {
+                        next.push(entity);
+                        continue;
+                    } else {
+                        None
+                    }
+                }
+                _ => None,
+            };
+            if let Some(&index) = indices.get(&(parent_index, name.as_str())) {
+                assigned.insert(entity, index);
+                progress = true;
+            }
+        }
+        if !progress {
+            break;
+        }
+        remaining = next;
+    }
+    if assigned.len() != baked.bone_names.len() {
+        warn!(fighter = ?fighter, bound = assigned.len(), expected = baked.bone_names.len(), "could not bind every baked fighter node to its visual scene");
+    }
+    for (entity, index) in assigned {
+        commands
+            .entity(entity)
+            .insert(BakedFighterBone { fighter, index });
+    }
+}
+
+pub(super) fn apply_baked_fighter_visual_pose(
+    mut nodes: Query<(&mut Transform, &BakedFighterBone)>,
+    fighters: Query<&FighterBoneMatrices>,
+    timing: Res<GgrsFrameTiming>,
+) {
+    let overstep_fraction = timing.overstep_fraction();
+    for (mut transform, bone) in &mut nodes {
+        let Ok(matrices) = fighters.get(bone.fighter) else {
+            continue;
+        };
+        let Some(local) = matrices.presentation_local(bone.index, overstep_fraction) else {
+            continue;
+        };
+        *transform = local;
+    }
+}

src/fighter/debug.rs

@@ -9,7 +9,7 @@ use bevy_egui::{EguiContexts, egui};
 use crate::debug_tools::{DebugSettings, FighterDebugRowKind};
 use crate::fighter::animation::FighterAnimationFrame;
 use crate::fighter::attack::{
-    FighterKnockbackVelocity, FighterLastAttackDebug, FighterPendingHitReaction,
+    self, FighterKnockbackVelocity, FighterLastAttackDebug, FighterPendingHitReaction,
     FighterSolvedHurtboxes,
 };
 use crate::fighter::baked_animation::{BakedFighterAnimations, FighterBoneMatrices};
@@ -382,14 +382,14 @@ pub fn attack_debug_gather(
         &FighterPendingHitReaction,
         &FighterTranslation,
         &Fighter,
+        &FighterInput,
     )>,
     mut commands: Commands,
     manifests: Res<Assets<FighterManifest>>,
     game_settings: Res<GameSettings>,
 ) -> Result {
-    for (entity, reaction, translation, fighter) in query {
+    for (entity, reaction, translation, fighter, input) in query {
         let Some(ref hit) = reaction.0 else {
-            commands.entity(entity).remove::<FighterLastAttackDebug>();
             continue;
         };
 
@@ -397,7 +397,13 @@ pub fn attack_debug_gather(
             .get(&fighter.manifest)
             .ok_or(FighterErrors::FighterManifestNotFound)?;
 
-        let mut knockback_vel = FighterKnockbackVelocity(hit.launch_velocity);
+        let launch_dir = attack::directional_influence::apply_directional_influence(
+            input.get_last_frame().movement,
+            hit.launch_angle,
+            game_settings.fighter_common.di_max_angle,
+        );
+
+        let mut knockback_vel = FighterKnockbackVelocity(launch_dir * hit.launch_velocity);
         let mut fighter_vel = FighterVelocity(FGVec2::ZERO);
         let mut translation = Vec3::new(translation.x.to_num(), translation.y.to_num(), 0.0);
 
@@ -406,7 +412,7 @@ pub fn attack_debug_gather(
         points.reserve(hit.hitstun_frames as usize);
 
         for _ in 1..hit.hitstun_frames {
-            air::integrate_gravity(&mut fighter_vel, &manifest.attributes);
+            air::integrate_gravity(&mut fighter_vel, &manifest.attributes, false);
 
             let vel = knockback_vel.length();
             let new_vel = vel

src/fighter/mod.rs

@@ -33,24 +33,13 @@ pub use motion::{
 };
 
 use crate::{
-    AppState,
+    AppState, fighter::{
-    fighter::{
         attack::{
             AttackKind, FighterAttackPlugin, FighterAttackScriptAssets, FighterDamage,
-            FighterKnockbackVelocity, FighterPendingHitReaction, FighterReceivedAttacks,
+            FighterKnockbackVelocity, FighterPendingHitReaction, FighterSolvedHurtboxes,
-            FighterSolvedHurtboxes, FighterStaleMoveQueue,
+            FighterStaleMoveQueue,
-        },
+        }, baked_animation::{FighterBoneIndexMap, FighterBoneMatrices}, manifest::FighterManifest, state::{FighterState, air::AirborneStateCommon, fall::FallState}, visual::FighterAnimations,
-        baked_animation::{FighterBoneIndexMap, FighterBoneMatrices},
+    }, input::FighterInput, math::{int::FGi32, vec::FGVec2}, player::Player, schedule::GameplaySet, scripting::FighterAttackScript, stage::line::StageCollision,
-        manifest::FighterManifest,
-        state::{FighterState, fall::FallState},
-        visual::FighterAnimations,
-    },
-    input::FighterInput,
-    math::{int::FGi32, vec::FGVec2},
-    player::Player,
-    schedule::GameplaySet,
-    scripting::FighterAttackScript,
-    stage::line::StageCollision,
 };
 use state::state_interrupt_system;
 
@@ -65,7 +54,30 @@ pub enum FighterFacingDirection {
     Right,
 }
 
+#[derive(Component, Copy, Clone, Hash, Debug, PartialEq, Reflect, Default)]
+pub enum FighterHitstopShakeKind {
+    #[default]
+    Horizontal,
+    Vertical
+}
+
+#[derive(Component, Copy, Clone, Hash, Debug, PartialEq, Reflect, Default)]
+pub enum FighterHitstopShakeRole {
+    #[default]
+    Attacker,
+    Receiver
+}
+
 #[derive(Component, Default, Copy, Clone, Hash)]
+pub struct FighterHitstopShake {
+    pub remaining_frames: u32,
+    pub total_frames: u32,
+    pub kind: FighterHitstopShakeKind,
+    pub role: FighterHitstopShakeRole
+}
+
+#[derive(Component, Default, Copy, Clone, Hash)]
+#[require(FighterHitstopShake)]
 pub struct FighterHitstop {
     pub remaining_frames: u32,
 }
@@ -116,12 +128,12 @@ pub struct FighterVisual;
 
 #[derive(Component)]
 #[require(
-    FighterReceivedAttacks,
     FighterStaleMoveQueue,
     FighterDamage,
     FighterPendingHitReaction,
     FighterHitstop,
-    FighterKnockbackVelocity
+    FighterKnockbackVelocity,
+    FighterTranslation,
 )]
 pub struct Fighter {
     pub manifest: Handle<FighterManifest>,
@@ -199,8 +211,6 @@ impl Plugin for FighterPlugin {
             .checksum_component_with_hash::<FighterHitstop>()
             .rollback_component_with_copy::<FighterKnockbackVelocity>()
             .checksum_component_with_hash::<FighterKnockbackVelocity>()
-            .rollback_component_with_clone::<FighterReceivedAttacks>()
-            .checksum_component_with_hash::<FighterReceivedAttacks>()
             .rollback_resource_with_reflect::<StageCollision>()
             // Debug views.
             .add_systems(
@@ -233,6 +243,7 @@ impl Plugin for FighterPlugin {
             .rollback_component_with_clone::<FighterState>()
             .rollback_component_with_clone::<FighterHitboxes>()
             .rollback_component_with_clone::<FighterBoneMatrices>()
+            .rollback_component_with_clone::<FighterHitstopShake>()
             .checksum_component_with_hash::<FighterHitboxes>()
             .rollback_component_with_clone::<FighterSolvedHurtboxes>()
             .checksum_component_with_hash::<FighterSolvedHurtboxes>()
@@ -288,7 +299,7 @@ pub fn spawn_fighter(
             visual_root,
             animations,
             attack_scripts,
-            FighterState::Fall(FallState),
+            FighterState::Fall(FallState::new(AirborneStateCommon::default())),
             animation::FighterAnimationFrame::new(animation::AnimKind::Wait, true),
             (
                 baked_animation::FighterBoneMatrices::default(),
@@ -302,8 +313,9 @@ pub fn spawn_fighter(
         .id()
 }
 
-pub fn decay_hitstop(query: Query<&mut FighterHitstop>) {
+pub fn decay_hitstop(query: Query<(&mut FighterHitstop, &mut FighterHitstopShake)>) {
-    for mut hitstop in query {
+    for (mut hitstop, mut hitstop_shake) in query {
         hitstop.remaining_frames = hitstop.remaining_frames.saturating_sub(1);
+        hitstop_shake.remaining_frames = hitstop_shake.remaining_frames.saturating_sub(1);
     }
 }

src/fighter/motion.rs

@@ -5,6 +5,8 @@ use bevy::prelude::*;
 use bevy_ggrs::GgrsFrameTiming;
 
 use crate::debug_tools::PresentationMotionMode;
+use crate::fighter::{FighterHitstopShake};
+use crate::game_settings::GameSettings;
 use crate::{
     fighter::{FighterECB, FighterFacingDirection, baked_animation::FixedMat4},
     math::{int::FGi32, vec::FGVec2, vec3::FGVec3},
@@ -58,13 +60,15 @@ pub fn apply_fighter_translation_to_visuals(
         &FighterTranslation,
         &FighterPreviousTranslation,
         &FighterECB,
+        &FighterHitstopShake,
         &mut Transform,
     )>,
     timing: Res<GgrsFrameTiming>,
     debug_settings: Res<crate::debug_tools::DebugSettings>,
+    game_settings: Res<GameSettings>,
 ) {
     let overstep_fraction = timing.overstep_fraction();
-    for (translation, previous_translation, ecb, mut transform) in query {
+    for (translation, previous_translation, ecb, hitstop_shake, mut transform) in query {
         let translation = sample_presentation_translation(
             *previous_translation,
             *translation,
@@ -77,6 +81,28 @@ pub fn apply_fighter_translation_to_visuals(
             translation.y + bottom.y.to_num::<f32>(),
             0.0,
         );
+
+        if hitstop_shake.remaining_frames > 0 && hitstop_shake.total_frames > 0 && !game_settings.fighter_common.visual_shake_table.is_empty() {
+            let total = hitstop_shake.total_frames as f32;
+            let curr = hitstop_shake.remaining_frames as f32;
+            let elapsed = 1.0 - curr / total;
+
+            
+            let access_index = (hitstop_shake.remaining_frames as usize) % game_settings.fighter_common.visual_shake_table.len();
+            let shake_multiplier = match hitstop_shake.role {
+                super::FighterHitstopShakeRole::Attacker => game_settings.fighter_common.attacker_visual_shake_multiplier,
+                super::FighterHitstopShakeRole::Receiver => 1.0,
+            };
+            let shake_amount: f32 = 1.0 - EaseFunction::QuinticIn.sample(elapsed).unwrap_or_default();
+            let shake_amount = game_settings.fighter_common.visual_shake_table[access_index] * shake_amount * shake_multiplier;
+
+            let shake_offset = match hitstop_shake.kind {
+                super::FighterHitstopShakeKind::Horizontal => Vec3::new(shake_amount, 0.0, 0.0),
+                super::FighterHitstopShakeKind::Vertical => Vec3::new(0.0, shake_amount, 0.0),
+            };
+
+            transform.translation += shake_offset;
+        }
     }
 }
 
@@ -85,22 +111,15 @@ pub fn apply_air_motion(
         &FighterVelocity,
         &mut FighterTranslation,
         &mut FighterPreviousTranslation,
-        &mut Transform,
     )>,
     _time: Res<Time<Fixed>>,
 ) {
-    for (velocity, mut translation, mut prev_translation, _transform) in fighters {
+    for (velocity, mut translation, mut prev_translation) in fighters {
         prev_translation.0 = translation.0;
         translation.0 += velocity.0;
     }
 }
 
-pub fn copy_fighter_transform_to_visuals(fighters: Query<(&FighterTranslation, &mut Transform)>) {
-    for (translation, mut transform) in fighters {
-        transform.translation = Vec3::new(translation.x.to_num(), translation.y.to_num(), 0.0);
-    }
-}
-
 pub fn fighter_movement() {}
 
 pub fn snapshot_fighter_motion(

src/fighter/state/air.rs

@@ -1,8 +1,45 @@
+use crate::fighter::state::ground::GroundedStateCommon;
+use crate::fighter::state::land::{LandingState, LandingType};
+use crate::fighter::state::{CollisionContext, FighterState};
 use crate::fighter::*;
+use crate::input::FighterCommands;
 
-pub fn integrate_gravity(velocity: &mut FighterVelocity, attributes: &FighterAttributes) {
+#[derive(Default, Debug, Clone, Copy, Hash)]
+pub struct AirborneStateCommon {
+    pub is_fast_falling: bool,
+}
+
+pub fn process_fast_fall(
+    airborne_state_common: &mut AirborneStateCommon,
+    input: &mut FighterInput,
+    velocity: &mut FighterVelocity,
+    attributes: &FighterAttributes,
+) {
+    if velocity.y.is_negative() {
+        if input.has_command(FighterCommands::SmashMoveDown) {
+            airborne_state_common.is_fast_falling = true;
+        }
+        input.clear_command(FighterCommands::SmashMoveDown);
+    }
+
+    if airborne_state_common.is_fast_falling {
+        velocity.y = -attributes.fast_fall_speed;
+    }
+}
+
+pub fn integrate_gravity(
+    velocity: &mut FighterVelocity,
+    attributes: &FighterAttributes,
+    fast_fall: bool
+) {
     velocity.y -= attributes.gravity;
-    velocity.y = velocity.y.max(-attributes.terminal_velocity);
+
+    let terminal_vel = if fast_fall {
+        -attributes.fast_fall_speed
+    } else {
+        -attributes.terminal_velocity
+    };
+    velocity.y = velocity.y.max(terminal_vel);
 }
 
 pub fn apply_air_drift(
@@ -53,6 +90,31 @@ pub fn apply_air_motion(
     translation.0 += velocity.0;
 }
 
+pub fn update_standard_motion(
+    ctx: &mut crate::fighter::state::UpdateContext,
+    airborne_common: &mut AirborneStateCommon,
+) {
+    process_fast_fall(airborne_common, ctx.input, &mut ctx.velocity, ctx.fighter_attributes);
+    integrate_gravity(ctx.velocity, ctx.fighter_attributes, airborne_common.is_fast_falling);
+    apply_air_drift(ctx.velocity, ctx.fighter_attributes, ctx.input);
+    apply_air_motion(ctx.velocity, ctx.translation, ctx.prev_translation);
+}
+
+pub fn collision_interrupt(
+    ctx: &mut CollisionContext,
+    landing_type: LandingType,
+) -> Option<FighterState> {
+    let res = ctx.air_collide_with_stage()?;
+    ctx.translation.0 = res.hit_position - ctx.ecb.get_bottom_point();
+    let grounded_common = GroundedStateCommon {
+        current_line_id: res.line_id,
+    };
+    Some(FighterState::Land(LandingState::create(
+        grounded_common,
+        landing_type,
+    )))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -86,6 +148,7 @@ mod tests {
             air_drift_max: FGi32::lit("1.2"),
             ground_friction: FGi32::ZERO,
             terminal_velocity: FGi32::ZERO,
+            fast_fall_speed: FGi32::ZERO,
             gravity: FGi32::ZERO,
             weight: FGi32::lit("1"),
             air_friction: FGi32::lit("0.001"),

src/fighter/state/air_dodge.rs

@@ -1,16 +1,9 @@
 use crate::{
     fighter::{
-        animation::AnimKind,
+        animation::AnimKind, state::{
-        state::{
+            CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext, UpdateContext, air::{self, AirborneStateCommon}, fall::FallState, land::LandingType,
-            CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
-            UpdateContext, air,
-            fall::FallState,
-            ground::GroundedStateCommon,
-            land::{LandingState, LandingType},
         },
-    },
+    }, input, math::vec::FGVec2,
-    input,
-    math::vec::FGVec2,
 };
 
 #[derive(Debug, Clone, Hash)]
@@ -23,7 +16,7 @@ impl FighterStateImpl for AirDodgeState {
 
     fn check_interrupt(&self, state_context: &mut InterruptContext) -> Option<FighterState> {
         if state_context.is_current_animation_finished() {
-            Some(FighterState::Fall(FallState))
+            Some(FighterState::Fall(FallState::new(AirborneStateCommon::default())))
         } else {
             None
         }
@@ -43,19 +36,7 @@ impl FighterStateImpl for AirDodgeState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let Some(res) = state_context.air_collide_with_stage() {
+        air::collision_interrupt(state_context, LandingType::Special)
-            // Adjust translation
-            state_context.translation.0 = res.hit_position - state_context.ecb.get_bottom_point();
-            let grounded_common = GroundedStateCommon {
-                current_line_id: res.line_id,
-            };
-            Some(FighterState::Land(LandingState {
-                grounded_common,
-                landing_type: LandingType::Special,
-            }))
-        } else {
-            None
-        }
     }
 
     fn on_enter(&mut self, state_context: &mut EnterContext) {
@@ -64,6 +45,12 @@ impl FighterStateImpl for AirDodgeState {
         state_context.velocity.0 =
             self.direction * state_context.fighter_attributes.air_dodge_velocity;
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        false
+    }
 }
 
 pub fn check_input(state_context: &InterruptContext) -> Option<FighterState> {

src/fighter/state/dash.rs

@@ -5,8 +5,7 @@ use super::{
 use crate::fighter::FighterFacingDirection;
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
-use crate::fighter::state::fall::FallState;
+use crate::fighter::state::ground::GroundedStateCommon;
-use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
 use crate::input::FighterCommands::{SmashMoveLeft, SmashMoveRight};
 
 #[derive(Debug, Clone, Hash)]
@@ -107,13 +106,13 @@ impl FighterStateImpl for DashState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
+        ground::collision_interrupt(state_context, &mut self.ground_common, true)
-            ground::collide_with_stage_grounded(state_context, &mut self.ground_common, true)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
     }
 }
 

src/fighter/state/fall.rs

@@ -1,14 +1,24 @@
 use super::{CollisionContext, EnterContext, FighterStateImpl, InterruptContext, UpdateContext};
 use crate::fighter::animation::AnimKind;
-use crate::fighter::state::ground::GroundedStateCommon;
+use crate::fighter::state::air::AirborneStateCommon;
-use crate::fighter::state::land::{LandingState, LandingType};
 use crate::fighter::state::{FighterState, air, jump};
 
-#[derive(Debug, Clone, Copy, Hash)]
+#[derive(Debug, Clone, Copy, Hash, Default)]
-pub struct FallState;
+pub struct FallState {
+    airborne_state_common: AirborneStateCommon
+}
+
+impl FallState {
+    pub fn new(airborne_state_common: AirborneStateCommon) -> Self {
+        Self {
+            airborne_state_common
+        }
+    }
+}
 
 impl FighterStateImpl for FallState {
     const NAME: &'static str = "Fall";
+    
     fn check_interrupt(&self, state_context: &mut InterruptContext) -> Option<FighterState> {
         jump::check_input_double_jump(state_context)
     }
@@ -18,44 +28,23 @@ impl FighterStateImpl for FallState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        air::integrate_gravity(state_context.velocity, state_context.fighter_attributes);
+        air::update_standard_motion(state_context, &mut self.airborne_state_common);
-        air::apply_air_drift(
-            state_context.velocity,
-            state_context.fighter_attributes,
-            state_context.input,
-        );
-        air::apply_air_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let Some(res) = state_context.air_collide_with_stage() {
+        air::collision_interrupt(
-            // Adjust translation
+            state_context,
-            state_context.translation.0 = res.hit_position - state_context.ecb.get_bottom_point();
+            crate::fighter::state::land::LandingType::Normal,
-            let grounded_common = GroundedStateCommon {
+        )
-                current_line_id: res.line_id,
-            };
-            Some(FighterState::Land(LandingState::create(
-                grounded_common,
-                LandingType::Normal,
-            )))
-        } else {
-            None
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        false
     }
 }
 
-pub fn check_input(state_context: &InterruptContext) -> Option<FighterState> {
-    let input_frame = state_context.input.get_last_frame();
-
-    if input_frame.movement.x.abs() < state_context.game_settings.input_common.stick_deadzone {
-        return Some(FighterState::Fall(FallState));
-    }
-    None
-}

src/fighter/state/ground.rs

@@ -3,7 +3,7 @@
 //! bit-for-bit deterministic for rollback.
 
 use crate::fighter::state::{
-    CollisionContext, FighterState, InterruptContext, dash, ground_attack, turn, wait, walk,
+    CollisionContext, FighterState, InterruptContext, air, dash, fall, ground_attack, turn, wait, walk,
 };
 use crate::fighter::{
     FighterAttributes, FighterPreviousTranslation, FighterTranslation, FighterVelocity,
@@ -163,6 +163,22 @@ pub fn apply_grounded_motion(
     translation.0 += FGVec2::new(velocity.0.x, FGi32::ZERO);
 }
 
+pub fn update_friction_motion(ctx: &mut crate::fighter::state::UpdateContext) {
+    let friction = if ctx.velocity.x.abs() > ctx.fighter_attributes.max_walk_vel {
+        ctx.fighter_attributes.ground_friction
+            * ctx
+                .game_settings
+                .fighter_common
+                .ground_friction_over_walk_speed_multiplier
+    } else {
+        ctx.fighter_attributes.ground_friction
+    };
+
+    let ground_velocity = ctx.velocity.x;
+    ctx.velocity.x += apply_grounded_friction(friction, ground_velocity);
+    apply_grounded_motion(ctx.velocity, ctx.translation, ctx.prev_translation);
+}
+
 pub fn collide_with_stage_grounded(
     state_context: &mut CollisionContext,
     ground_common: &mut GroundedStateCommon,
@@ -210,6 +226,17 @@ pub fn collide_with_stage_grounded(
     }
 }
 
+pub fn collision_interrupt(
+    ctx: &mut CollisionContext,
+    common: &mut GroundedStateCommon,
+    can_walk_off: bool,
+) -> Option<FighterState> {
+    match collide_with_stage_grounded(ctx, common, can_walk_off) {
+        GroundedMotionResult::InGround => None,
+        GroundedMotionResult::InAir => Some(FighterState::Fall(fall::FallState::new(air::AirborneStateCommon::default()))),
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/fighter/state/ground_attack.rs

@@ -67,6 +67,12 @@ impl FighterStateImpl for GroundAttackState {
     ) -> Option<FighterState> {
         None
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }
 
 pub fn check_interrupt(

src/fighter/state/hitstun.rs

@@ -1,13 +1,14 @@
 use crate::{
     fighter::{
         animation::AnimKind,
-        attack::FighterHitReaction,
+        attack::{self, FighterHitReaction},
         state::{
             CollisionContext, EnterContext, ExitContext, FighterState, FighterStateImpl,
-            InterruptContext, UpdateContext, air,
+            InterruptContext, UpdateContext,
+            air::{self, AirborneStateCommon},
             fall::FallState,
-            ground::{GroundedMotionResult, GroundedStateCommon, collide_with_stage_grounded},
+            ground::{GroundedStateCommon, collision_interrupt},
-            land::{LandingState, LandingType},
+            land::LandingType,
             wait::WaitState,
         },
     },
@@ -24,6 +25,17 @@ pub enum HitstopStateKind {
 pub struct HitstunState {
     pub hit_reaction: FighterHitReaction,
     pub hitstop_kind: HitstopStateKind,
+    knockback_applied: bool,
+}
+
+impl HitstunState {
+    pub fn new(hit_reaction: FighterHitReaction, hitstop_kind: HitstopStateKind) -> Self {
+        Self {
+            hit_reaction,
+            hitstop_kind,
+            knockback_applied: false,
+        }
+    }
 }
 
 impl FighterStateImpl for HitstunState {
@@ -51,7 +63,9 @@ impl FighterStateImpl for HitstunState {
                         grounded_common: grounded_state_common.clone(),
                     }))
                 }
-                HitstopStateKind::Airborne => Some(FighterState::Fall(FallState)),
+                HitstopStateKind::Airborne => {
+                    Some(FighterState::Fall(FallState::new(AirborneStateCommon::default())))
+                }
             }
         } else {
             None
@@ -59,7 +73,23 @@ impl FighterStateImpl for HitstunState {
     }
 
     fn update(&mut self, ctx: &mut UpdateContext) {
-        air::integrate_gravity(ctx.velocity, ctx.fighter_attributes);
+        if !self.knockback_applied {
+            let launch_direction = attack::directional_influence::apply_directional_influence(
+                ctx.input.get_last_frame().movement,
+                self.hit_reaction.launch_angle,
+                ctx.game_settings.fighter_common.di_max_angle,
+            );
+
+            ctx.knockback_velocity.0 = launch_direction * self.hit_reaction.launch_velocity;
+            self.knockback_applied = true;
+        }
+
+        match self.hitstop_kind {
+            HitstopStateKind::Grounded(_) => {}
+            HitstopStateKind::Airborne => {
+                air::integrate_gravity(ctx.velocity, ctx.fighter_attributes, false);
+            }
+        }
 
         let speed = ctx.knockback_velocity.length();
         let next_speed = speed
@@ -77,7 +107,6 @@ impl FighterStateImpl for HitstunState {
             HitstopStateKind::Airborne => AnimKind::FlinchAir,
         };
         state_context.play_animation(animation, false);
-        state_context.knockback_velocity.0 = self.hit_reaction.launch_velocity;
     }
 
     fn on_exit(&mut self, _state_context: &mut ExitContext) {}
@@ -88,30 +117,18 @@ impl FighterStateImpl for HitstunState {
     ) -> Option<FighterState> {
         match &mut self.hitstop_kind {
             HitstopStateKind::Grounded(grounded_state_common) => {
-                if let GroundedMotionResult::InAir =
+                collision_interrupt(state_context, grounded_state_common, true)
-                    collide_with_stage_grounded(state_context, grounded_state_common, true)
-                {
-                    Some(FighterState::Fall(FallState {}))
-                } else {
-                    None
-                }
             }
             HitstopStateKind::Airborne => {
-                if let Some(res) = state_context.air_collide_with_stage() {
+                air::collision_interrupt(state_context, LandingType::Normal)
-                    // Adjust translation
-                    state_context.translation.0 =
-                        res.hit_position - state_context.ecb.get_bottom_point();
-                    let grounded_common = GroundedStateCommon {
-                        current_line_id: res.line_id,
-                    };
-                    Some(FighterState::Land(LandingState::create(
-                        grounded_common,
-                        LandingType::Normal,
-                    )))
-                } else {
-                    None
             }
         }
     }
+
+    fn is_visually_grounded<'a>(&'a self) -> bool {
+        match self.hitstop_kind {
+            HitstopStateKind::Grounded(_) => true,
+            HitstopStateKind::Airborne => false,
+        }
     }
 }

src/fighter/state/jump.rs

@@ -2,18 +2,10 @@ use bevy::prelude::*;
 
 use crate::{
     fighter::{
-        animation::AnimKind,
+        animation::AnimKind, state::{
-        state::{
+            CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext, UpdateContext, air::{self, AirborneStateCommon}, air_dodge::{self, AirDodgeState}, ground::{self, GroundedStateCommon},
-            CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
-            UpdateContext, air,
-            air_dodge::{self, AirDodgeState},
-            fall::FallState,
-            ground::{self, GroundedMotionResult, GroundedStateCommon},
-            land::{LandingState, LandingType},
         },
-    },
+    }, input::FighterCommands, math::{int::FGi32, vec::FGVec2},
-    input::FighterCommands,
-    math::{int::FGi32, vec::FGVec2},
 };
 #[derive(Debug, Hash, Clone, Copy)]
 pub enum JumpType {
@@ -25,6 +17,7 @@ pub enum JumpType {
 #[derive(Debug, Clone, Hash)]
 pub struct JumpState {
     jump_type: JumpType,
+    airborne_state_common: AirborneStateCommon,
 }
 
 #[derive(Debug, Clone, Hash)]
@@ -76,7 +69,7 @@ impl FighterStateImpl for JumpSquatState {
             } else {
                 JumpType::ShortHop
             };
-            Some(FighterState::Jump(JumpState { jump_type }))
+            Some(FighterState::Jump(JumpState { jump_type, airborne_state_common: AirborneStateCommon::default() }))
         } else {
             None
         }
@@ -84,46 +77,26 @@ impl FighterStateImpl for JumpSquatState {
 
     fn update(&mut self, state_context: &mut UpdateContext) {
         self.duration_counter += 1;
-
+        ground::update_friction_motion(state_context);
-        let friction =
-            if state_context.velocity.x.abs() > state_context.fighter_attributes.max_walk_vel {
-                state_context.fighter_attributes.ground_friction
-                    * state_context
-                        .game_settings
-                        .fighter_common
-                        .ground_friction_over_walk_speed_multiplier
-            } else {
-                state_context.fighter_attributes.ground_friction
-            };
-
-        let ground_velocity = state_context.velocity.x;
-
-        state_context.velocity.x += ground::apply_grounded_friction(friction, ground_velocity);
-
-        ground::apply_grounded_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
+        ground::collision_interrupt(state_context, &mut self.grounded_common, false)
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
     }
 
     fn on_enter(&mut self, state_context: &mut EnterContext) {
         state_context.play_animation(AnimKind::JumpSquat, false);
         state_context.input.clear_command(FighterCommands::Jump);
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }
 
 impl FighterStateImpl for JumpState {
@@ -132,6 +105,7 @@ impl FighterStateImpl for JumpState {
         if state_context.input.has_command(FighterCommands::Jump) {
             Some(FighterState::Jump(JumpState {
                 jump_type: JumpType::DoubleJump,
+                airborne_state_common: AirborneStateCommon::default()
             }))
         } else {
             air_dodge::check_input(state_context)
@@ -139,17 +113,7 @@ impl FighterStateImpl for JumpState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        air::integrate_gravity(state_context.velocity, state_context.fighter_attributes);
+        air::update_standard_motion(state_context, &mut self.airborne_state_common);
-        air::apply_air_drift(
-            state_context.velocity,
-            state_context.fighter_attributes,
-            state_context.input,
-        );
-        air::apply_air_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
     }
 
     fn on_enter(&mut self, state_context: &mut EnterContext) {
@@ -207,19 +171,16 @@ impl FighterStateImpl for JumpState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let Some(res) = state_context.air_collide_with_stage() {
+        air::collision_interrupt(
-            // Adjust translation
+            state_context,
-            state_context.translation.0 = res.hit_position - state_context.ecb.get_bottom_point();
+            crate::fighter::state::land::LandingType::Normal,
-            let grounded_common = GroundedStateCommon {
+        )
-                current_line_id: res.line_id,
-            };
-            Some(FighterState::Land(LandingState::create(
-                grounded_common,
-                LandingType::Normal,
-            )))
-        } else {
-            None
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        false
     }
 }
 
@@ -240,6 +201,7 @@ pub fn check_input_double_jump(state_context: &InterruptContext) -> Option<Fight
         .then(|| {
             FighterState::Jump(JumpState {
                 jump_type: JumpType::DoubleJump,
+                airborne_state_common: AirborneStateCommon::default()
             })
         })
 }

src/fighter/state/land.rs

@@ -3,11 +3,7 @@ use crate::fighter::{
     state::{
         CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
         UpdateContext, dash,
-        fall::FallState,
+        ground::{self, GroundedStateCommon, grounded_movement_standstill_common_interrupts},
-        ground::{
-            self, GroundedMotionResult, GroundedStateCommon,
-            grounded_movement_standstill_common_interrupts,
-        },
         walk,
     },
 };
@@ -53,39 +49,14 @@ impl FighterStateImpl for LandingState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        let friction =
+        ground::update_friction_motion(state_context);
-            if state_context.velocity.x.abs() > state_context.fighter_attributes.max_walk_vel {
-                state_context.fighter_attributes.ground_friction
-                    * state_context
-                        .game_settings
-                        .fighter_common
-                        .ground_friction_over_walk_speed_multiplier
-            } else {
-                state_context.fighter_attributes.ground_friction
-            };
-
-        let ground_velocity = state_context.velocity.x;
-
-        state_context.velocity.x += ground::apply_grounded_friction(friction, ground_velocity);
-
-        ground::apply_grounded_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
+        ground::collision_interrupt(state_context, &mut self.grounded_common, true)
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, true)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
     }
 
     fn on_enter(&mut self, state_context: &mut EnterContext) {
@@ -98,4 +69,10 @@ impl FighterStateImpl for LandingState {
             }
         };
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }

src/fighter/state/mod.rs

@@ -7,8 +7,7 @@ use bevy::prelude::*;
 
 use crate::fighter::animation::{AnimKind, FighterAnimationFrame};
 use crate::fighter::attack::{
-    FighterAttackScriptAssets, FighterKnockbackVelocity, FighterPendingHitReaction,
+    FighterAttackScriptAssets, FighterKnockbackVelocity, FighterPendingHitReaction, FighterStaleMoveQueue, HitStop,
-    FighterStaleMoveQueue,
 };
 use crate::fighter::attributes::FighterAttributes;
 use crate::fighter::baked_animation::BakedFighterAnimations;
@@ -17,11 +16,11 @@ use crate::fighter::manifest::FighterManifest;
 use crate::fighter::state::hitstun::HitstunState;
 use crate::fighter::visual::FighterAnimations;
 use crate::fighter::{
-    Fighter, FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop,
+    Fighter, FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop, FighterHitstopShake, FighterHitstopShakeKind, FighterHitstopShakeRole, FighterPreviousTranslation, FighterTranslation, FighterVelocity,
-    FighterPreviousTranslation, FighterTranslation, FighterVelocity,
 };
 use crate::game_settings::GameSettings;
 use crate::input::FighterInput;
+use crate::math::int::FGi32;
 use crate::scripting::FighterAttackScript;
 use crate::stage::line::StageCollision;
 
@@ -66,6 +65,10 @@ macro_rules! fighter_states {
             pub fn check_collision_interrupt(&mut self, ctx: &mut CollisionContext) -> Option<FighterState> {
                 match self { $(Self::$variant(s) => s.check_collision_interrupt(ctx)),* }
             }
+
+            pub fn is_visually_grounded(&self) -> bool {
+                match self { $(Self::$variant(s) => s.is_visually_grounded()),* }
+            }
         }
 
         $(impl From<$ty> for FighterState {
@@ -91,6 +94,10 @@ pub trait FighterStateImpl: Sized {
     ) -> Option<FighterState> {
         None
     }
+
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool;
 }
 
 pub struct AnimationStatus {
@@ -141,7 +148,7 @@ pub struct ExitContext<'a> {
 pub struct UpdateContext<'a> {
     pub translation: &'a mut FighterTranslation,
     pub prev_translation: &'a mut FighterPreviousTranslation,
-    pub input: &'a FighterInput,
+    pub input: &'a mut FighterInput,
     pub hitboxes: &'a mut FighterHitboxes,
     pub velocity: &'a mut FighterVelocity,
     pub knockback_velocity: &'a mut FighterKnockbackVelocity,
@@ -150,6 +157,7 @@ pub struct UpdateContext<'a> {
     pub fighter_attributes: &'a FighterAttributes,
     pub attack_scripts: &'a Assets<FighterAttackScript>,
     pub attack_script_assets: &'a FighterAttackScriptAssets,
+    pub facing_direction: &'a FighterFacingDirection,
 }
 
 impl UpdateContext<'_> {
@@ -281,7 +289,7 @@ impl<'w, 's> FighterFrameQueryItem<'w, 's> {
         UpdateContext {
             translation: &mut self.translation,
             prev_translation: &mut self.prev_translation,
-            input: &self.input,
+            input: &mut self.input,
             hitboxes: &mut self.hitboxes,
             velocity: &mut self.velocity,
             knockback_velocity: &mut self.knockback_velocity,
@@ -290,6 +298,7 @@ impl<'w, 's> FighterFrameQueryItem<'w, 's> {
             fighter_attributes: attributes,
             attack_scripts,
             attack_script_assets,
+            facing_direction: &self.facing_direction
         }
     }
 
@@ -318,6 +327,7 @@ pub struct StatefulFighterQuery {
     pub attack_script_assets: &'static FighterAttackScriptAssets,
     pub pending_hit_reaction: &'static mut FighterPendingHitReaction,
     pub hitstop: &'static mut FighterHitstop,
+    pub hitstop_shake: &'static mut FighterHitstopShake,
 }
 
 pub fn state_update_system(
@@ -382,6 +392,7 @@ pub fn state_interrupt_system(
             attack_script_assets,
             mut pending_hit_reaction,
             mut hitstop,
+            mut hitstop_shake,
         } = fighter;
         let manifest = fighter_manifests
             .get(&fighter.manifest)
@@ -389,7 +400,17 @@ pub fn state_interrupt_system(
 
         let new_state = if let Some(reaction) = pending_hit_reaction.take() {
             hitstop.remaining_frames = *reaction.hitstop_frames;
-            let hitstop_kind = match &*state {
+            let shake_frames = reaction.hitstop_frames.calculate_shake_frames(&game_settings);
+            hitstop_shake.role = FighterHitstopShakeRole::Receiver;
+            hitstop_shake.total_frames = shake_frames;
+            hitstop_shake.remaining_frames = shake_frames;
+            hitstop_shake.kind = if state.is_visually_grounded() {
+                FighterHitstopShakeKind::Horizontal
+            } else {
+                FighterHitstopShakeKind::Vertical
+            };
+            
+            let mut hitstop_kind = match &*state {
                 FighterState::Wait(value) => {
                     hitstun::HitstopStateKind::Grounded(value.grounded_common.clone())
                 }
@@ -410,10 +431,30 @@ pub fn state_interrupt_system(
                 }
                 _ => hitstun::HitstopStateKind::Airborne,
             };
-            Some(FighterState::Hitstun(HitstunState {
+
-                hit_reaction: reaction,
+            if let hitstun::HitstopStateKind::Grounded(_) = hitstop_kind {
+                let straight_up_angle = FGi32::lit("90.0");
+                if reaction.hitstop_frames >= HitStop::new(game_settings.fighter_common.tumble_bounce_hitstop_threshold) {
+                    hitstop_kind = hitstun::HitstopStateKind::Airborne;
+                // TODO: Use floor normal here
+                } else if reaction.launch_angle.abs_diff(straight_up_angle) < game_settings.fighter_common.attack_ground_to_airborne_transition_vertical_angle_threshold {
+                        hitstop_kind = hitstun::HitstopStateKind::Airborne;
+                } else {
+                    // straight down is 270
+                    let straight_down_angle = FGi32::lit("270.0");
+                    let meteor_threshold = game_settings.fighter_common.meteor_angle_threshold;
+                    if (reaction.launch_angle - straight_down_angle).abs() <= meteor_threshold {
+                        // TODO: Floor bounce
+                        hitstop_kind = hitstun::HitstopStateKind::Airborne;
+                    }
+                }
+            }
+
+            info!("Entering hitstop kind: {:?}", hitstop_kind);
+            Some(FighterState::Hitstun(HitstunState::new(
+                reaction,
                 hitstop_kind,
-            }))
+            )))
         } else if hitstop.remaining_frames > 0 {
             None
         } else {

src/fighter/state/run.rs

@@ -6,9 +6,7 @@ use super::{
 };
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
-use crate::fighter::state::fall::FallState;
+use crate::fighter::state::ground::GroundedStateCommon;
-use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
-use crate::math::int::FGi32;
 
 #[derive(Component, Debug, Clone, Hash)]
 pub struct RunState {
@@ -43,7 +41,7 @@ impl FighterStateImpl for RunState {
         let last_frame = state_context.input.get_last_frame();
         let (accel, target_vel) = state_context
             .fighter_attributes
-            .get_accel_and_target_dashrun(&last_frame, FGi32::ONE);
+            .get_accel_and_target_dashrun(&last_frame, state_context.facing_direction.to_sign());
         let accel = ground::compute_ground_accel(
             accel,
             target_vel,
@@ -64,13 +62,13 @@ impl FighterStateImpl for RunState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
+        ground::collision_interrupt(state_context, &mut self.grounded_common, true)
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
     }
 }
 

src/fighter/state/turn.rs

@@ -1,7 +1,6 @@
 use super::{CollisionContext, EnterContext, FighterStateImpl, InterruptContext, UpdateContext};
 use crate::fighter::animation::AnimKind;
-use crate::fighter::state::fall::FallState;
+use crate::fighter::state::ground::{self, GroundedStateCommon};
-use crate::fighter::state::ground::{self, GroundedMotionResult, GroundedStateCommon};
 use crate::fighter::state::{FighterState, dash, jump, wait, walk};
 use crate::input::FighterCommands;
 
@@ -48,39 +47,20 @@ impl FighterStateImpl for TurnState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        let friction =
+        ground::update_friction_motion(state_context);
-            if state_context.velocity.x.abs() > state_context.fighter_attributes.max_walk_vel {
-                state_context.fighter_attributes.ground_friction
-                    * state_context
-                        .game_settings
-                        .fighter_common
-                        .ground_friction_over_walk_speed_multiplier
-            } else {
-                state_context.fighter_attributes.ground_friction
-            };
-
-        let ground_velocity = state_context.velocity.x;
-
-        state_context.velocity.x += ground::apply_grounded_friction(friction, ground_velocity);
-
-        ground::apply_grounded_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
+        ground::collision_interrupt(state_context, &mut self.grounded_common, false)
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
     }
 }
 

src/fighter/state/wait.rs

@@ -3,8 +3,7 @@ use super::{
 };
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
-use crate::fighter::state::fall::FallState;
+use crate::fighter::state::ground::GroundedStateCommon;
-use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
 
 #[derive(Debug, Clone, Hash)]
 pub struct WaitState {
@@ -38,39 +37,20 @@ impl FighterStateImpl for WaitState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        let friction =
+        ground::update_friction_motion(state_context);
-            if state_context.velocity.x.abs() > state_context.fighter_attributes.max_walk_vel {
-                state_context.fighter_attributes.ground_friction
-                    * state_context
-                        .game_settings
-                        .fighter_common
-                        .ground_friction_over_walk_speed_multiplier
-            } else {
-                state_context.fighter_attributes.ground_friction
-            };
-
-        let ground_velocity = state_context.velocity.x;
-
-        state_context.velocity.x += ground::apply_grounded_friction(friction, ground_velocity);
-
-        ground::apply_grounded_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
+        ground::collision_interrupt(state_context, &mut self.grounded_common, false)
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
     }
 }
 

src/fighter/state/walk.rs

@@ -4,8 +4,7 @@ use super::{
 };
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
-use crate::fighter::state::fall::FallState;
+use crate::fighter::state::ground::GroundedStateCommon;
-use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
 
 #[derive(Debug, Clone, Hash)]
 pub struct WalkState {
@@ -55,13 +54,13 @@ impl FighterStateImpl for WalkState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
+        ground::collision_interrupt(state_context, &mut self.grounded_common, false)
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
     }
 }
 

src/game_settings.rs

@@ -9,12 +9,36 @@ use crate::{math::int::FGi32, menus::style::FGUiStyle};
 #[reflect(opaque)]
 pub struct FighterSettingsCommon {
     pub walk_speed_ease: FGi32,
+
+    /// Maximum allowed horizontal velocity
     pub ground_max_horizontal_velocity: FGi32,
+
+    /// Ground friction applied when the fighter is above the walk speed
     pub ground_friction_over_walk_speed_multiplier: FGi32,
     pub knockback_stacking_window: u32,
     pub knockback_decay_per_frame: FGi32,
+
+    /// Multiplier that translates knockback -> game unit velocity
     pub knockback_launch_velocity_multiplier: FGi32,
     pub hitstun_frames_per_unit_knockback: FGi32,
+
+    /// If an attack's hitstop > this value it will cause a grounded fighter to either bounce (if a meteor/spike)
+    /// or to become airborne
+    pub tumble_bounce_hitstop_threshold: u32,
+
+    /// Angle diff from straight down under which the attack will count as a meteor
+    pub meteor_angle_threshold: FGi32,
+
+    /// Angle diff from straight up under which the attack will force an airborne state 
+    pub attack_ground_to_airborne_transition_vertical_angle_threshold: FGi32,
+    pub visual_shake_frames_per_hitstop_frame: FGi32,
+    // offsets applied when the fighter is in hitstop
+    pub visual_shake_table: Vec<f32>,
+    /// The attacker will always get less hitstop
+    pub attacker_visual_shake_multiplier: f32,
+    
+    /// Maximum angle changed caused by directional influence
+    pub di_max_angle: FGi32,
 }
 #[derive(Reflect, Serialize, Deserialize, Clone)]
 #[reflect(opaque)]

src/input/buffer.rs

@@ -20,6 +20,8 @@ pub enum FighterCommands {
     Jump,
     Shield,
     Attack,
+    SmashMoveUp,
+    SmashMoveDown,
     SmashMoveLeft,
     SmashMoveRight,
 }
@@ -60,6 +62,8 @@ impl FighterAttackCommandType {
 pub struct FighterCommandLifetimes {
     smash_move_left: u8,
     smash_move_right: u8,
+    smash_move_down: u8,
+    smash_move_up: u8,
     jump: u8,
     shield: u8,
     attack: u8,
@@ -72,6 +76,8 @@ impl Index<FighterCommands> for FighterCommandLifetimes {
         match command {
             FighterCommands::SmashMoveLeft => &self.smash_move_left,
             FighterCommands::SmashMoveRight => &self.smash_move_right,
+            FighterCommands::SmashMoveDown => &self.smash_move_down,
+            FighterCommands::SmashMoveUp => &self.smash_move_up,
             FighterCommands::Jump => &self.jump,
             FighterCommands::Shield => &self.shield,
             FighterCommands::Attack => &self.attack,
@@ -84,6 +90,8 @@ impl IndexMut<FighterCommands> for FighterCommandLifetimes {
         match command {
             FighterCommands::SmashMoveLeft => &mut self.smash_move_left,
             FighterCommands::SmashMoveRight => &mut self.smash_move_right,
+            FighterCommands::SmashMoveDown => &mut self.smash_move_down,
+            FighterCommands::SmashMoveUp => &mut self.smash_move_up,
             FighterCommands::Jump => &mut self.jump,
             FighterCommands::Shield => &mut self.shield,
             FighterCommands::Attack => &mut self.attack,
@@ -221,6 +229,19 @@ pub fn postprocess_input(
         let mut x_flick_detected =
             x_abs >= axis_threshold && input.frames_in_x_flick_deadzone <= frame_threshold;
 
+        if y_flick_detected {
+            input.clear_command(FighterCommands::SmashMoveUp);
+            input.clear_command(FighterCommands::SmashMoveDown);
+
+            let command_to_set = if input.current_frame.movement.y > 0.0 {
+                FighterCommands::SmashMoveUp
+            } else {
+                FighterCommands::SmashMoveDown
+            };
+
+            input.set_lifetime(command_to_set, game_settings.input_common.input_buffer_size);
+        }
+
         // if both flicks are detected, only one wins
 
         if x_flick_detected && y_flick_detected {

src/input/gamecube/poll.rs

@@ -45,8 +45,8 @@ impl GcPortState {
             dpad_right: b.dpad_right(),
             left_trigger_digital: b.left_trigger(),
             right_trigger_digital: b.right_trigger(),
-            left_stick: cal.left_stick(&c),
+            left_stick: cal.left_stick_coords(&c),
-            right_stick: cal.right_stick(&c),
+            right_stick: cal.right_stick_coords(&c),
             triggers: (c.triggers.left.raw(), c.triggers.right.raw()),
         }
     }

src/lib.rs

@@ -71,6 +71,7 @@ pub enum AppState {
     LoadingMatch,
     PreparingMatch,
     InMatch,
+    MatchDisconnected,
     MatchLoadFailed,
 }
 

src/match_loading.rs

@@ -8,25 +8,28 @@ use bevy_ggrs::prelude::Session;
 use serde::{Deserialize, Serialize};
 
 use crate::{
-    AppState,
     args::Args,
     fighter::{
-        FighterId, FighterRoster,
         animation::AnimKind,
         attack::{AttackKind, FighterAttackScriptAssets},
-        baked_animation::{BAKED_ANIMATION_FPS, BakedFighterAnimations},
+        baked_animation::{BakedFighterAnimations, BAKED_ANIMATION_FPS},
         manifest::{FighterManifest, FighterManifestRegistry},
         spawn_fighter,
         visual::FighterAnimations,
+        FighterId, FighterRoster,
     },
     input::{LocalInputAssignments, LocalInputSource},
     math::{int::FGi32, vec::FGVec2},
-    netcode::{GGRSCfg, session::create_session},
+    netcode::{
+        session::{create_session, ConnectionStatus, SessionConfig},
+        GGRSCfg,
+    },
     scripting::FighterAttackScript,
     stage::{
         self,
         manifest::{StageId, StageManifest, StageManifestRegistry},
     },
+    AppState,
 };
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
@@ -140,6 +143,7 @@ pub fn initiate_match(
     next_state: &mut NextState<AppState>,
     request: PendingMatch,
 ) {
+    commands.remove_resource::<crate::netcode::session::MatchDisconnected>();
     commands.insert_resource(request);
     next_state.set(AppState::LoadingMatch);
 }
@@ -176,6 +180,14 @@ pub fn initiate_default_match(
         }
         return;
     }
+    let session_config = match SessionConfig::from_args(&args, args.players) {
+        Ok(config) => config,
+        Err(error) => {
+            error!("Invalid network configuration: {error}");
+            next_state.set(AppState::MatchLoadFailed);
+            return;
+        }
+    };
     let players = (0..args.players)
         .map(|handle| MatchPlayer {
             handle,
@@ -183,10 +195,21 @@ pub fn initiate_default_match(
         })
         .collect();
 
-    assigments.push((0, LocalInputSource::Keyboard));
+    assigments.clear();
+    let local_handles = session_config
+        .players
+        .iter()
+        .enumerate()
+        .filter_map(|(handle, player)| {
+            matches!(player, crate::netcode::session::PlayerConnection::Local).then_some(handle)
+        });
+    let mut local_handles = local_handles;
+    if let Some(handle) = local_handles.next() {
+        assigments.push((handle, LocalInputSource::Keyboard));
+    }
 
-    for (idx, entity) in gamepads.iter().take(args.players - 1).enumerate() {
+    for (entity, handle) in gamepads.iter().zip(local_handles) {
-        assigments.push((idx + 1, LocalInputSource::Gamepad(entity)));
+        assigments.push((handle, LocalInputSource::Gamepad(entity)));
     }
 
     initiate_match(
@@ -373,6 +396,16 @@ pub fn prepare_match(
         ));
     }
 
+    let session_config = match SessionConfig::from_args(&args, request.players.len()) {
+        Ok(config) => config,
+        Err(error) => {
+            fail_match(
+                &mut next_state,
+                &format!("invalid network configuration: {error}"),
+            );
+            return;
+        }
+    };
     let session = match create_session(&args, request.players.len()) {
         Ok(session) => session,
         Err(error) => {
@@ -418,6 +451,8 @@ pub fn prepare_match(
     }
 
     commands.insert_resource(FighterRoster(fighter_roster));
+    commands.insert_resource(session_config);
+    commands.insert_resource(ConnectionStatus::default());
     commands.insert_resource::<Session<GGRSCfg>>(session);
     next_state.set(AppState::InMatch);
 }
@@ -448,6 +483,8 @@ pub fn cleanup_match(
         commands.entity(fighter).despawn();
     }
     commands.remove_resource::<Session<GGRSCfg>>();
+    commands.remove_resource::<SessionConfig>();
+    commands.remove_resource::<ConnectionStatus>();
     commands.remove_resource::<stage::line::StageCollision>();
     commands.remove_resource::<MatchAssets>();
     commands.remove_resource::<PendingMatch>();

src/math/fixed_transform.rs

@@ -0,0 +1,136 @@
+use std::io;
+
+use bevy::prelude::*;
+
+use crate::math::{
+    int::{FGWide, FGi32, FGi32Ext},
+    vec3::FGVec3,
+};
+
+/// Parent transforms are composed after quantization, which makes every runtime sample platform-independent.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, serde::Serialize, serde::Deserialize, Hash)]
+pub struct FixedMat4 {
+    pub cols: [[FGi32; 4]; 4],
+}
+
+impl FixedMat4 {
+    pub const IDENTITY: Self = Self {
+        cols: [
+            [FGi32::ONE, FGi32::ZERO, FGi32::ZERO, FGi32::ZERO],
+            [FGi32::ZERO, FGi32::ONE, FGi32::ZERO, FGi32::ZERO],
+            [FGi32::ZERO, FGi32::ZERO, FGi32::ONE, FGi32::ZERO],
+            [FGi32::ZERO, FGi32::ZERO, FGi32::ZERO, FGi32::ONE],
+        ],
+    };
+
+    pub fn from_mat4(matrix: Mat4) -> io::Result<Self> {
+        let values = matrix.to_cols_array();
+        let mut cols = [[FGi32::ZERO; 4]; 4];
+        for (index, value) in values.into_iter().enumerate() {
+            cols[index / 4][index % 4] = FGi32::checked_from_num(value).ok_or_else(|| {
+                io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "animation transform overflows Q16.16",
+                )
+            })?;
+        }
+        Ok(Self { cols })
+    }
+
+    pub fn to_mat4(self) -> Mat4 {
+        Mat4::from_cols_array_2d(&self.cols.map(|column| column.map(|value| value.to_num())))
+    }
+
+    pub fn mul(self, rhs: Self) -> Self {
+        let mut cols = [[FGi32::ZERO; 4]; 4];
+        for column in 0..4 {
+            for row in 0..4 {
+                let mut value = FGWide::ZERO;
+                for k in 0..4 {
+                    value +=
+                        FGWide::from_num(self.cols[k][row]) * FGWide::from_num(rhs.cols[column][k]);
+                }
+                cols[column][row] = FGi32::from_num(value);
+            }
+        }
+        Self { cols }
+    }
+
+    pub fn transform_point(self, point: FGVec3) -> FGVec3 {
+        let input = [point.x, point.y, point.z, FGi32::ONE];
+        let mut output = [FGi32::ZERO; 3];
+        for row in 0..3 {
+            let mut value = FGWide::ZERO;
+            for (column, input) in input.into_iter().enumerate() {
+                value += FGWide::from_num(self.cols[column][row]) * FGWide::from_num(input);
+            }
+            output[row] = FGi32::from_num(value);
+        }
+        FGVec3 {
+            x: output[0],
+            y: output[1],
+            z: output[2],
+        }
+    }
+
+    pub fn translate(&mut self, translation: FGVec3) {
+        self.cols[3][0] = translation.x;
+        self.cols[3][1] = translation.y;
+        self.cols[3][2] = translation.z;
+    }
+    pub fn with_translation(mut self, translation: FGVec3) -> Self {
+        self.translate(translation);
+        self
+    }
+
+    pub fn with_rotation(mut self, rotation: FGVec3) -> Self {
+        let (sin_x, cos_x) = rotation.x.sin_cos_rads();
+        let (sin_y, cos_y) = rotation.y.sin_cos_rads();
+        let (sin_z, cos_z) = rotation.z.sin_cos_rads();
+        self.cols[0][0] = cos_y * cos_z;
+        self.cols[0][1] = cos_x * sin_z + sin_x * sin_y * cos_z;
+        self.cols[0][2] = sin_x * sin_z - cos_x * sin_y * cos_z;
+        self.cols[1][0] = -cos_y * sin_z;
+        self.cols[1][1] = cos_x * cos_z - sin_x * sin_y * sin_z;
+        self.cols[1][2] = sin_x * cos_z + cos_x * sin_y * sin_z;
+        self.cols[2][0] = sin_y;
+        self.cols[2][1] = -sin_x * cos_y;
+        self.cols[2][2] = cos_x * cos_y;
+        self
+    }
+
+    pub fn get_translation(&self) -> FGVec3 {
+        FGVec3::new(self.cols[3][0], self.cols[3][1], self.cols[3][2])
+    }
+
+    pub fn rotate_y(self, quarter_turns: u8) -> Self {
+        let rotation = match quarter_turns % 4 {
+            0 => Self::IDENTITY,
+            1 => Self {
+                cols: [
+                    [FGi32::ZERO, FGi32::ZERO, FGi32::NEG_ONE, FGi32::ZERO],
+                    [FGi32::ZERO, FGi32::ONE, FGi32::ZERO, FGi32::ZERO],
+                    [FGi32::ONE, FGi32::ZERO, FGi32::ZERO, FGi32::ZERO],
+                    [FGi32::ZERO, FGi32::ZERO, FGi32::ZERO, FGi32::ONE],
+                ],
+            },
+            2 => Self {
+                cols: [
+                    [FGi32::NEG_ONE, FGi32::ZERO, FGi32::ZERO, FGi32::ZERO],
+                    [FGi32::ZERO, FGi32::ONE, FGi32::ZERO, FGi32::ZERO],
+                    [FGi32::ZERO, FGi32::ZERO, FGi32::NEG_ONE, FGi32::ZERO],
+                    [FGi32::ZERO, FGi32::ZERO, FGi32::ZERO, FGi32::ONE],
+                ],
+            },
+            _ => Self {
+                cols: [
+                    [FGi32::ZERO, FGi32::ZERO, FGi32::ONE, FGi32::ZERO],
+                    [FGi32::ZERO, FGi32::ONE, FGi32::ZERO, FGi32::ZERO],
+                    [FGi32::NEG_ONE, FGi32::ZERO, FGi32::ZERO, FGi32::ZERO],
+                    [FGi32::ZERO, FGi32::ZERO, FGi32::ZERO, FGi32::ONE],
+                ],
+            },
+        };
+        self.mul(rotation)
+    }
+}

src/math/mod.rs

@@ -1,4 +1,5 @@
 pub mod int;
 pub mod segment;
 pub mod vec;
+pub mod fixed_transform;
 pub mod vec3;

src/netcode/session.rs

@@ -1,49 +1,234 @@
-//! Bringing up the GGRS session and reporting what it does.
+//! Bringing up GGRS sessions and reporting their connection lifecycle.
+
+use std::net::SocketAddr;
 
 use bevy::prelude::*;
 use bevy_ggrs::{ggrs::UdpNonBlockingSocket, prelude::*};
+use thiserror::Error;
 
-use crate::args::Args;
+use crate::args::{parse_socket_addr, Args};
 use crate::netcode::GGRSCfg;
 
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum PlayerConnection {
+    Local,
+    Remote(SocketAddr),
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Resource)]
+pub struct SessionConfig {
+    pub local_port: u16,
+    pub players: Vec<PlayerConnection>,
+}
+
+#[derive(Debug, Error, PartialEq, Eq)]
+pub enum SessionConfigError {
+    #[error("a session must have at least one player")]
+    NoPlayers,
+    #[error("local UDP port must be nonzero")]
+    LocalPortZero,
+    #[error("invalid network player declaration `{0}`; expected HANDLE=local or HANDLE=ADDRESS")]
+    InvalidPlayerDeclaration(String),
+    #[error("network player handle {0} is outside the session player range")]
+    PlayerHandleOutOfRange(usize),
+    #[error("network player handle {0} was declared more than once")]
+    DuplicatePlayerHandle(usize),
+    #[error("network player {0} has an invalid address: {1}")]
+    InvalidRemoteAddress(usize, String),
+    #[error("at least one player must be local")]
+    NoLocalPlayers,
+    #[error("network player declarations are not supported in sync-test or replay mode")]
+    UnsupportedOfflineNetworkConfig,
+}
+
+impl SessionConfig {
+    pub fn from_args(args: &Args, player_count: usize) -> Result<Self, SessionConfigError> {
+        if player_count == 0 {
+            return Err(SessionConfigError::NoPlayers);
+        }
+        if args.local_port == 0 {
+            return Err(SessionConfigError::LocalPortZero);
+        }
+        if (args.synctest || args.play_replay.is_some()) && !args.net_players.is_empty() {
+            return Err(SessionConfigError::UnsupportedOfflineNetworkConfig);
+        }
+
+        let mut players = vec![PlayerConnection::Local; player_count];
+        for declaration in &args.net_players {
+            let Some((handle, address)) = declaration.split_once('=') else {
+                return Err(SessionConfigError::InvalidPlayerDeclaration(
+                    declaration.clone(),
+                ));
+            };
+            let handle = handle
+                .parse::<usize>()
+                .map_err(|_| SessionConfigError::InvalidPlayerDeclaration(declaration.clone()))?;
+            if handle >= player_count {
+                return Err(SessionConfigError::PlayerHandleOutOfRange(handle));
+            }
+            if !matches!(players[handle], PlayerConnection::Local)
+                || args.net_players[..]
+                    .iter()
+                    .take_while(|item| *item != declaration)
+                    .any(|item| {
+                        item.split_once('=')
+                            .and_then(|(handle, _)| handle.parse::<usize>().ok())
+                            == Some(handle)
+                    })
+            {
+                return Err(SessionConfigError::DuplicatePlayerHandle(handle));
+            }
+            players[handle] = if address == "local" {
+                PlayerConnection::Local
+            } else {
+                PlayerConnection::Remote(
+                    parse_socket_addr(address)
+                        .map_err(|error| SessionConfigError::InvalidRemoteAddress(handle, error))?,
+                )
+            };
+        }
+
+        if !players
+            .iter()
+            .any(|player| matches!(player, PlayerConnection::Local))
+        {
+            return Err(SessionConfigError::NoLocalPlayers);
+        }
+        Ok(Self {
+            local_port: args.local_port,
+            players,
+        })
+    }
+}
+
 pub fn create_session(args: &Args, player_count: usize) -> Result<Session<GGRSCfg>> {
+    let config = SessionConfig::from_args(args, player_count)
+        .map_err(|error| bevy::ecs::error::BevyError::from(error.to_string()))?;
     let mut sess_build = SessionBuilder::<GGRSCfg>::new()
         .with_num_players(player_count)?
         .with_check_distance(args.check_distance)
-        .with_input_delay(args.input_delay); // (optional) set input delay for the local player
+        .with_input_delay(args.input_delay);
 
-    for i in 0..player_count {
+    for (handle, player) in config.players.iter().enumerate() {
-        sess_build = sess_build.add_player(PlayerType::Local, i)?;
+        let player_type = match player {
+            PlayerConnection::Local => PlayerType::Local,
+            PlayerConnection::Remote(address) => PlayerType::Remote(*address),
+        };
+        sess_build = sess_build.add_player(player_type, handle)?;
     }
 
     if args.synctest {
-        println!("Start synctest!");
+        info!("starting GGRS sync test");
-        let sess = sess_build.start_synctest_session()?;
+        Ok(Session::SyncTest(sess_build.start_synctest_session()?))
-        Ok(Session::SyncTest(sess))
     } else {
-        println!("Start p2p!");
+        info!(
-        let socket = UdpNonBlockingSocket::bind_to_port(6969)?;
+            "starting direct UDP P2P session on port {}",
-        let sess = sess_build.start_p2p_session(socket)?;
+            config.local_port
-        Ok(Session::P2P(sess))
+        );
+        let socket = UdpNonBlockingSocket::bind_to_port(config.local_port)?;
+        Ok(Session::P2P(sess_build.start_p2p_session(socket)?))
     }
 }
 
-pub fn print_events_system(session: Option<ResMut<Session<GGRSCfg>>>) {
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Resource)]
-    let Some(mut session) = session else {
+pub enum ConnectionStatus {
+    #[default]
+    Connecting,
+    Running,
+    Interrupted,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Resource)]
+pub struct MatchDisconnected {
+    pub address: SocketAddr,
+}
+
+pub fn print_events_system(
+    mut commands: Commands,
+    mut next_state: ResMut<NextState<crate::AppState>>,
+    mut status: Option<ResMut<ConnectionStatus>>,
+    session: Option<ResMut<Session<GGRSCfg>>>,
+) {
+    let (Some(mut session), Some(status)) = (session, status.as_deref_mut()) else {
         return;
     };
-    match session.as_mut() {
+    let Session::P2P(session) = session.as_mut() else {
-        Session::P2P(s) => {
+        return;
-            for event in s.events() {
+    };
+    for event in session.events() {
         match event {
-                    GgrsEvent::Disconnected { .. } | GgrsEvent::NetworkInterrupted { .. } => {
+            GgrsEvent::NetworkInterrupted { addr, .. } => {
-                        warn!("GGRS event: {event:?}")
+                warn!("GGRS network interrupted: {addr}");
+                *status = ConnectionStatus::Interrupted;
             }
-                    GgrsEvent::DesyncDetected { .. } => error!("GGRS event: {event:?}"),
+            GgrsEvent::NetworkResumed { addr } => {
+                info!("GGRS network resumed: {addr}");
+                *status = ConnectionStatus::Running;
+            }
+            GgrsEvent::Disconnected { addr } => {
+                error!("GGRS peer disconnected: {addr}");
+                commands.insert_resource(MatchDisconnected { address: addr });
+                next_state.set(crate::AppState::MatchDisconnected);
+            }
+            GgrsEvent::Synchronized { .. } => {
+                info!("GGRS session synchronized");
+                *status = ConnectionStatus::Running;
+            }
+            GgrsEvent::DesyncDetected { .. } => error!("GGRS desync detected: {event:?}"),
             _ => info!("GGRS event: {event:?}"),
         }
     }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use clap::Parser;
+
+    fn args(values: &[&str]) -> Args {
+        Args::try_parse_from(values).unwrap()
     }
-        _ => {}
+
+    #[test]
+    fn defaults_to_local_players() {
+        let config = SessionConfig::from_args(&args(&["game", "--players", "2"]), 2).unwrap();
+        assert_eq!(
+            config.players,
+            [PlayerConnection::Local, PlayerConnection::Local]
+        );
+    }
+
+    #[test]
+    fn configures_remote_players_by_handle() {
+        let config = SessionConfig::from_args(
+            &args(&["game", "--players", "2", "--net-player", "1=127.0.0.1:7001"]),
+            2,
+        )
+        .unwrap();
+        assert!(matches!(config.players[0], PlayerConnection::Local));
+        assert!(matches!(config.players[1], PlayerConnection::Remote(_)));
+    }
+
+    #[test]
+    fn validates_handles_and_local_ownership() {
+        let duplicate = args(&[
+            "game",
+            "--players",
+            "2",
+            "--net-player",
+            "1=127.0.0.1:7001",
+            "--net-player",
+            "1=127.0.0.1:7002",
+        ]);
+        assert!(matches!(
+            SessionConfig::from_args(&duplicate, 2),
+            Err(SessionConfigError::DuplicatePlayerHandle(1))
+        ));
+
+        let no_local = args(&["game", "--players", "1", "--net-player", "0=127.0.0.1:7001"]);
+        assert!(matches!(
+            SessionConfig::from_args(&no_local, 1),
+            Err(SessionConfigError::NoLocalPlayers)
+        ));
     }
 }