Initial work on attack and hitbox interpolation

src/fighter/attack.rs

@@ -1,9 +1,13 @@
-use std::collections::HashMap;
+use std::collections::{HashMap, VecDeque};
 
 use bevy::{asset::Handle, ecs::component::Component, reflect::Reflect};
 use serde::{Deserialize, Serialize};
 
-use crate::{fighter::animation::AnimKind, math::{int::FGi32, vec3::FGVec3}, scripting::FighterAttackScript};
+use crate::{
+    fighter::{FighterAttributes, animation::AnimKind},
+    math::{int::FGi32, vec3::FGVec3},
+    scripting::FighterAttackScript,
+};
 #[derive(Debug, Default, Clone, Serialize, Deserialize)]
 pub struct FighterDamage(FGi32);
 
@@ -16,7 +20,7 @@ impl FighterDamage {
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub enum KnockbackType {
     Normal,
-    Fixed
+    Fixed,
 }
 
 impl KnockbackType {
@@ -41,7 +45,7 @@ impl Knockback {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum AttackAngle {
     Normal(FGi32),
-    Sakurai
+    Sakurai,
 }
 
 impl Default for AttackAngle {
@@ -51,7 +55,6 @@ impl Default for AttackAngle {
 }
 
 impl AttackAngle {
-
     pub fn make_normal(angle: FGi32) -> Self {
         Self::Normal(angle)
     }
@@ -91,16 +94,77 @@ pub struct AttackHitbox {
     pub knockback: Knockback,
     pub knockback_growth: FGi32,
     pub start_frame: u32,
-    pub end_frame: u32
+    pub end_frame: u32,
+}
+
+pub struct StaleMoveQueue(pub VecDeque<AttackKind>);
+
+impl AttackHitbox {
+    /// Knockback calculation
+    pub fn calculate_knockback(
+        &self,
+        attack: AttackKind,
+        
+        receiver_attribs: &FighterAttributes,
+        receiver_damage: FighterDamage,
+        total_damage_received_this_frame: FighterDamage,
+        interrupted_smash_charge: bool,
+        receiver_crouching: bool,
+    ) -> Knockback {
+        /// Weight that produces a weight modifier of exactly 1.0. Weight-independent
+        /// attacks pass this value in place of the target's real weight.
+        const BASELINE_WEIGHT: FGi32 = FGi32::lit("100.0");
+
+        /// Applied to the weight-scaled damage term.
+        const KB_GAIN: FGi32 = FGi32::lit("1.4");
+
+        /// Constant floor added to the damage term before knockback growth scales it.
+        /// At 0% and 0 damage, knockback reduces to KB_OFFSET * s + b.
+        const KB_OFFSET: FGi32 = FGi32::lit("18.0");
+
+        /// Knockback growth is authored in percent (110 means 1.1x).
+        const KB_GROWTH_SCALE: FGi32 = FGi32::lit("0.01");
+        const DAMAGE_TERM_DIVISOR: FGi32 = FGi32::lit("20.0");
+        const DAMAGE_BONUS: FGi32 = FGi32::lit("2.0");  // effective damage floor in the damage term
+        const CHARGE_SMASH_INTERRUPTION_MODIFIER: FGi32 = FGi32::lit("1.2");
+        const CROUCH_CANCEL_MODIFIER: FGi32 = FGi32::lit("0.666667");
+        
+        let attack_damage_unstalled = self.damage.0;
+
+        let modifier = {
+            let mut out = FGi32::ONE;
+            if interrupted_smash_charge {
+                out *= CHARGE_SMASH_INTERRUPTION_MODIFIER
+            } else if receiver_crouching {
+                out *= CROUCH_CANCEL_MODIFIER
+            }
+            out
+        };
+
+        let s = KB_GROWTH_SCALE * self.knockback_growth;
+        let p = receiver_damage.0.floor() + total_damage_received_this_frame.0;
+        let d = attack_damage_unstalled;
+        let damage_term = p / DAMAGE_TERM_DIVISOR * (d + DAMAGE_BONUS);
+
+        let scaled = damage_term * (FGi32::lit("2.0") * BASELINE_WEIGHT)
+            / (receiver_attribs.weight + BASELINE_WEIGHT);
+        let kb = (scaled * KB_GAIN + KB_OFFSET) * s + self.knockback.0;
+        
+        Knockback(modifier * kb)
+    }
 }
 
 pub fn update_active_hitbox_list(script: &FighterAttackScript, list: &mut Vec<usize>, frame: u32) {
-    *list = script.hitboxes.iter().enumerate().filter(|(_, hb)| {
-        hb.start_frame <= frame && hb.end_frame > frame
-    }).map(|(i, _)| i).collect()
+    *list = script
+        .hitboxes
+        .iter()
+        .enumerate()
+        .filter(|(_, hb)| hb.start_frame <= frame && hb.end_frame > frame)
+        .map(|(i, _)| i)
+        .collect()
 }
 
 #[derive(Component)]
 pub struct FighterAttackScriptAssets {
-    pub scripts: HashMap<AttackKind, Handle<FighterAttackScript>>
-}
+    pub scripts: HashMap<AttackKind, Handle<FighterAttackScript>>,
+}

src/fighter/attributes.rs

@@ -36,6 +36,7 @@ pub struct FighterAttributes {
     pub ground_friction: FGi32,
     pub terminal_velocity: FGi32,
     pub gravity: FGi32,
+    pub weight: FGi32,
     pub air_friction: FGi32,
 
     pub air_dodge_duration: u32,

src/fighter/baked_animation.rs

@@ -102,6 +102,10 @@ impl FixedMat4 {
         self.cols[3][2] = translation.z;
     }
 
+    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 {
@@ -187,10 +191,25 @@ impl BakedFighterAnimations {
 pub struct FighterBoneMatrices {
     bone_names: Vec<String>,
     matrices: Vec<FixedMat4>,
+    previous_frame_matrices: Vec<FixedMat4>,
 }
 
 impl FighterBoneMatrices {
-    pub fn get(&self, bone: &str) -> Option<FixedMat4> {
+    pub fn get(&self, bone: &str) -> Option<(FixedMat4, FixedMat4)> {
+        let index = self.bone_names.iter().position(|name| name == bone)?;
+        let curr = self.matrices.get(index).copied();
+        let prev = self.previous_frame_matrices.get(index).copied();
+
+        if let Some(prev) = prev {
+            if let Some(curr) = curr {
+                return Some((prev, curr));
+            }
+        }
+
+        None
+    }
+
+    pub fn get_current(&self, bone: &str) -> Option<FixedMat4> {
         let index = self.bone_names.iter().position(|name| name == bone)?;
         self.matrices.get(index).copied()
     }
@@ -213,6 +232,7 @@ impl FighterBoneMatrices {
         } else {
             assert_eq!(self.bone_names, bone_names, "baked bone names changed");
         }
+        std::mem::swap(&mut self.matrices, &mut self.previous_frame_matrices);
         self.matrices.clear();
         self.matrices.extend_from_slice(matrices);
     }
@@ -707,7 +727,7 @@ mod tests {
         let mut matrices = FighterBoneMatrices::default();
         matrices.set_pose(&["root".into(), "hand".into()], &[first, second]);
 
-        assert_eq!(matrices.get("hand"), Some(second));
+        assert_eq!(matrices.get_current("hand"), Some(second));
         assert_eq!(
             matrices.iter().collect::<Vec<_>>(),
             vec![("root", first), ("hand", second)]

src/fighter/debug.rs

@@ -1,6 +1,7 @@
 //! Fighter debug views: gizmos and the egui inspector window.
 
 use bevy::color::palettes::css::ORANGE;
+use bevy::gizmos::primitives::dim3::Capsule3dBuilder;
 use bevy::{color::palettes::css::YELLOW, prelude::*};
 use bevy_egui::{EguiContexts, egui};
 
@@ -178,22 +179,35 @@ pub fn attack_debug(
                 let radius = script.hitboxes[*i].radius;
                 let bone = &script.hitboxes[*i].bone;
 
-                let trf = matrices.get(bone);
-                if let Some(trf) = trf {
-                    let trf = player_trf.mul(trf);
-                    let start = player_trf.transform_point(FGVec3::lit("0.0", "1.0", "0.0"));
-                    let end = player_trf.transform_point(FGVec3::lit("0.0", "1.0", "1.0"));
-                    let pos = trf.transform_point(offset);
-                    let pos_draw = Vec3::new(pos.x.to_num(), pos.y.to_num(), pos.z.to_num());
-                    //Primitive
-                    //gizmos.primitive_3d(, isometry, color)
-                    gizmos.sphere(pos_draw, radius.to_num(), bevy::color::palettes::css::RED);
+                let trfs = matrices.get(bone);
+                if let Some((prev_trf, curr_trf)) = trfs {
+                    let prev_trf = player_trf.mul(prev_trf);
+                    let curr_trf = player_trf.mul(curr_trf);
+                    
+                    let prev_pos = prev_trf.transform_point(offset);
+                    let curr_pos = curr_trf.transform_point(offset);
+
+                    let prev_pos_draw = Vec3::new(prev_pos.x.to_num(), prev_pos.y.to_num(), prev_pos.z.to_num());
+                    let curr_pos_draw = Vec3::new(curr_pos.x.to_num(), curr_pos.y.to_num(), curr_pos.z.to_num());
+
+                    let dist = Dir3::new_and_length(curr_pos_draw - prev_pos_draw);
+
+                    if let Ok((aim_dir, dist)) = dist {
+                        let attack_capsule = Capsule3d {
+                            half_length: dist * 0.5,
+                            radius: radius.to_num()
+                        };
+                        let mut capsule_draw_trf = Transform::IDENTITY;
+                        capsule_draw_trf.align(Dir3::Y, aim_dir, Dir3::X, aim_dir.any_orthonormal_vector());
+                        capsule_draw_trf.translation = (prev_pos_draw + curr_pos_draw) * 0.5;
+                        gizmos.primitive_3d(&attack_capsule, capsule_draw_trf.to_isometry(), bevy::color::palettes::css::RED);
+                    }
+
+
+
+                    gizmos.sphere(prev_pos_draw, radius.to_num(), bevy::color::palettes::css::RED.darker(0.5));
+                    gizmos.sphere(curr_pos_draw, radius.to_num(), bevy::color::palettes::css::RED);
 
-                    gizmos.arrow(
-                        start.to_vec3(),
-                        end.to_vec3(),
-                        bevy::color::palettes::css::RED,
-                    );
                 } else {
                     warn!("Bone not found required by attack script: {}", bone);
                 }

src/fighter/state/ground_attack.rs

@@ -1,4 +1,6 @@
-use crate::fighter::{attack::{AttackKind, update_active_hitbox_list}, state::{FighterState, FighterStateImpl, ground::GroundedStateCommon, wait::WaitState}};
+use fixed::types::I16F16;
+
+use crate::{fighter::{attack::{AttackKind, update_active_hitbox_list}, state::{FighterState, FighterStateImpl, ground::GroundedStateCommon, wait::WaitState}}, math::int::FGi32};
 
 #[derive(Clone, Debug, Hash)]
 pub struct GroundAttackState {
@@ -47,8 +49,15 @@ impl FighterStateImpl for GroundAttackState {
 
 pub fn check_interrupt(state_context: &super::FighterStateContext, grounded_common: &GroundedStateCommon) -> Option<FighterState> {
     if state_context.input.has_command(crate::input::FighterCommands::Attack) {
+
+        let attack_kind = if state_context.input.get_last_frame().movement.y > FGi32::ZERO {
+            AttackKind::UpTilt
+        } else {
+            AttackKind::Jab
+        };
+
         Some(FighterState::GroundAttack(GroundAttackState {
-            attack_kind: AttackKind::Jab,
+            attack_kind,
             grounded_common: grounded_common.clone()
         }))
     } else {