Refresh documentation and add test script

Fixes #19

Splits the baked animation implementation into focused fixed-transform, runtime, visual-binding, and asset-baking modules behind the existing public facade. Preserves public APIs, serialized field order, TypePath, plugin registration, schedules, and runtime behavior.

Reviewed-on: #38
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

.cargo/config.toml

@@ -1,7 +1,7 @@
 # for Linux
 [target.x86_64-unknown-linux-gnu]
 linker = "clang"
-rustflags = ["-C", "link-arg=-fuse-ld=/usr/bin/mold", "-Zshare-generics=y", ]
+rustflags = ["-C", "link-arg=-fuse-ld=/usr/bin/mold", "-Zshare-generics=y", "-D", "warnings", ]
 
 [unstable]
 codegen-backend = true

.gitea/workflows/ci.yml

@@ -23,8 +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: v2-rust
           shared-key: linux-nightly
           cache-bin: false
 
@@ -45,7 +46,7 @@ jobs:
             pkg-config
 
       - name: Build
-        run: RUSTFLAGS="-D warnings" cargo build --locked -j 4
+        run: cargo build --locked -j 4
 
       - name: Run unit tests
         run: cargo test --locked --lib -j 4

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
+```

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/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/state/air.rs

@@ -1,3 +1,6 @@
+use crate::fighter::state::ground::GroundedStateCommon;
+use crate::fighter::state::land::{LandingState, LandingType};
+use crate::fighter::state::{CollisionContext, FighterState};
 use crate::fighter::*;
 
 pub fn integrate_gravity(velocity: &mut FighterVelocity, attributes: &FighterAttributes) {
@@ -53,6 +56,27 @@ pub fn apply_air_motion(
     translation.0 += velocity.0;
 }
 
+pub fn update_standard_motion(ctx: &mut crate::fighter::state::UpdateContext) {
+    integrate_gravity(ctx.velocity, ctx.fighter_attributes);
+    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::*;

src/fighter/state/air_dodge.rs

@@ -3,10 +3,7 @@ use crate::{
         animation::AnimKind,
         state::{
             CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
-            UpdateContext, air,
+            UpdateContext, air, fall::FallState, land::LandingType,
-            fall::FallState,
-            ground::GroundedStateCommon,
-            land::{LandingState, LandingType},
         },
     },
     input,
@@ -43,19 +40,7 @@ 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) {

src/fighter/state/dash.rs

@@ -1,5 +1,3 @@
-use std::hash::Hasher;
-
 use super::{
     CollisionContext, EnterContext, FighterStateImpl, InterruptContext, UpdateContext, ground, run,
     wait, walk,
@@ -7,22 +5,15 @@ 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)]
+#[derive(Debug, Clone, Hash)]
 pub struct DashState {
     direction: FighterFacingDirection,
     pub ground_common: GroundedStateCommon,
 }
 
-impl std::hash::Hash for DashState {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        self.direction.hash(state);
-    }
-}
-
 impl DashState {
     pub fn new(direction: FighterFacingDirection, ground_common: GroundedStateCommon) -> Self {
         Self {
@@ -115,13 +106,7 @@ 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
-        }
     }
 }
 

src/fighter/state/fall.rs

@@ -1,7 +1,5 @@
 use super::{CollisionContext, EnterContext, FighterStateImpl, InterruptContext, UpdateContext};
 use crate::fighter::animation::AnimKind;
-use crate::fighter::state::ground::GroundedStateCommon;
-use crate::fighter::state::land::{LandingState, LandingType};
 use crate::fighter::state::{FighterState, air, jump};
 
 #[derive(Debug, Clone, Copy, Hash)]
@@ -18,36 +16,17 @@ 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);
-        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
-        }
     }
 }
 

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, 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)),
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/fighter/state/hitstun.rs

@@ -6,8 +6,8 @@ use crate::{
             CollisionContext, EnterContext, ExitContext, FighterState, FighterStateImpl,
             InterruptContext, UpdateContext, air,
             fall::FallState,
-            ground::{GroundedMotionResult, GroundedStateCommon, collide_with_stage_grounded},
+            ground::{GroundedStateCommon, collision_interrupt},
-            land::{LandingState, LandingType},
+            land::LandingType,
             wait::WaitState,
         },
     },
@@ -88,29 +88,10 @@ 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
-                }
             }
         }
     }

src/fighter/state/jump.rs

@@ -7,9 +7,7 @@ use crate::{
             CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
             UpdateContext, air,
             air_dodge::{self, AirDodgeState},
-            fall::FallState,
+            ground::{self, GroundedStateCommon},
-            ground::{self, GroundedMotionResult, GroundedStateCommon},
-            land::{LandingState, LandingType},
         },
     },
     input::FighterCommands,
@@ -84,40 +82,14 @@ 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) {
@@ -139,17 +111,7 @@ 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);
-        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 +169,10 @@ 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
-        }
     }
 }
 

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) {

src/fighter/state/mod.rs

@@ -150,6 +150,7 @@ 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<'_> {
@@ -290,6 +291,7 @@ impl<'w, 's> FighterFrameQueryItem<'w, 's> {
             fighter_attributes: attributes,
             attack_scripts,
             attack_script_assets,
+            facing_direction: &self.facing_direction
         }
     }
 

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 +62,7 @@ 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
-        }
     }
 }
 

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 +47,14 @@ 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
-        }
     }
 }
 

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 +37,14 @@ 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
-        }
     }
 }
 

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 +54,7 @@ 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
-        }
     }
 }
 

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)
+        ));
     }
 }