Add affine transformations for capsules.

src/debug_tools.rs

@@ -111,6 +111,7 @@ enum DebugFlag {
     StageCollision,
     AnimationBones,
     AttackHitboxes,
+    Hurtboxes,
     Camera,
     DrawThroughGeometry,
 }
@@ -156,6 +157,10 @@ const FIGHTER_MENU: &[DebugMenuEntry] = &[
         label: "Attack hitboxes",
         flag: DebugFlag::AttackHitboxes,
     },
+    DebugMenuEntry::Toggle {
+        label: "Hurtboxes",
+        flag: DebugFlag::Hurtboxes,
+    },
 ];
 
 const WORLD_MENU: &[DebugMenuEntry] = &[
@@ -227,6 +232,7 @@ pub struct DebugSettings {
     pub stage_collision: bool,
     pub animation_bones: bool,
     pub attack_hitboxes: bool,
+    pub hurtboxes: bool,
     pub camera: bool,
     pub draw_through_geometry: bool,
     pub motion_sampling: PresentationMotionMode,
@@ -246,6 +252,7 @@ impl Default for DebugSettings {
             stage_collision: false,
             animation_bones: false,
             attack_hitboxes: false,
+            hurtboxes: false,
             camera: false,
             draw_through_geometry: false,
             motion_sampling: PresentationMotionMode::default(),
@@ -309,6 +316,7 @@ impl DebugSettings {
             DebugFlag::StageCollision => self.stage_collision,
             DebugFlag::AnimationBones => self.animation_bones,
             DebugFlag::AttackHitboxes => self.attack_hitboxes,
+            DebugFlag::Hurtboxes => self.hurtboxes,
             DebugFlag::DrawThroughGeometry => self.draw_through_geometry,
             DebugFlag::Camera => self.camera,
         }
@@ -321,6 +329,7 @@ impl DebugSettings {
             DebugFlag::StageCollision => self.stage_collision = !self.stage_collision,
             DebugFlag::AnimationBones => self.animation_bones = !self.animation_bones,
             DebugFlag::AttackHitboxes => self.attack_hitboxes = !self.attack_hitboxes,
+            DebugFlag::Hurtboxes => self.hurtboxes = !self.hurtboxes,
             DebugFlag::DrawThroughGeometry => {
                 self.draw_through_geometry = !self.draw_through_geometry
             }
@@ -623,6 +632,10 @@ pub fn attack_hitboxes_enabled(settings: Res<DebugSettings>) -> bool {
     settings.attack_hitboxes
 }
 
+pub fn hurtboxes_enabled(settings: Res<DebugSettings>) -> bool {
+    settings.hurtboxes
+}
+
 pub fn camera_debug_enabled(settings: Res<DebugSettings>) -> bool {
     settings.camera
 }

src/fighter/attack.rs

@@ -1,11 +1,22 @@
 use std::collections::{HashMap, VecDeque};
 
-use bevy::{asset::Handle, ecs::component::Component, reflect::Reflect};
+use bevy::prelude::*;
+use bevy_ggrs::prelude::GgrsSchedule;
 use serde::{Deserialize, Serialize};
 
 use crate::{
-    fighter::{FighterAttributes, animation::AnimKind},
-    math::{int::FGi32, vec3::FGVec3},
+    fighter::{
+        Fighter, FighterAttributes, FighterFacingDirection, FighterTranslation,
+        animation::AnimKind,
+        baked_animation::{FighterBoneMatrices, FixedMat4},
+        hurtbox::FixedAffineCapsule,
+        manifest::FighterManifest,
+    },
+    math::{
+        int::{FGi32, FGi32Ext},
+        vec3::FGVec3,
+    },
+    schedule::GameplaySet,
     scripting::FighterAttackScript,
 };
 #[derive(Debug, Default, Clone, Serialize, Deserialize)]
@@ -164,7 +175,69 @@ pub fn update_active_hitbox_list(script: &FighterAttackScript, list: &mut Vec<us
         .collect()
 }
 
+#[derive(Clone, Debug, PartialEq)]
+pub struct FighterSolvedHurtbox {
+    pub hurtbox_idx: usize,
+    pub capsule: FixedAffineCapsule,
+}
+
 #[derive(Component)]
 pub struct FighterAttackScriptAssets {
     pub scripts: HashMap<AttackKind, Handle<FighterAttackScript>>,
 }
+#[derive(Component, Clone, Debug, Default)]
+pub struct FighterSolvedHurtboxes(pub Vec<FighterSolvedHurtbox>);
+
+pub fn solve_hurtboxes(
+    mut query: Query<(
+        &FighterBoneMatrices,
+        &FighterTranslation,
+        &FighterFacingDirection,
+        &mut FighterSolvedHurtboxes,
+        &Fighter,
+    )>,
+    manifests: Res<Assets<FighterManifest>>,
+) {
+    for (matrices, translation, facing_direction, mut solved_hurtboxes, fighter) in &mut query {
+        let manifest = manifests
+            .get(&fighter.manifest)
+            .expect("Manifest should be valid");
+        let fighter_trf = translation.get_3d_transform(facing_direction);
+        solved_hurtboxes.0.clear();
+        for (hurtbox_idx, hurtbox) in manifest.hurtboxes.iter().enumerate() {
+            let bone_matrix = matrices.get_current(&hurtbox.bone);
+
+            if let Some(bone_matrix) = bone_matrix {
+                let to_global = fighter_trf.mul(bone_matrix);
+                let hurtbox_trf = FixedMat4::IDENTITY
+                    .with_rotation(FGVec3::new(
+                        hurtbox.rotation.x.to_radians(),
+                        hurtbox.rotation.y.to_radians(),
+                        hurtbox.rotation.z.to_radians(),
+                    ))
+                    .with_translation(hurtbox.offset);
+                solved_hurtboxes.0.push(FighterSolvedHurtbox {
+                    hurtbox_idx,
+                    capsule: FixedAffineCapsule::new(
+                        to_global.mul(hurtbox_trf),
+                        hurtbox.half_length,
+                        hurtbox.radius,
+                    ),
+                });
+            }
+        }
+    }
+}
+
+pub struct FighterAttackPlugin;
+
+impl Plugin for FighterAttackPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(
+            GgrsSchedule,
+            solve_hurtboxes
+                .after(crate::fighter::baked_animation::update_fighter_bone_matrices)
+                .in_set(GameplaySet::Animation),
+        );
+    }
+}

src/fighter/baked_animation.rs

@@ -28,7 +28,7 @@ use crate::{
         visual::FighterAnimations,
     },
     math::{
-        int::{FGWide, FGi32},
+        int::{FGWide, FGi32, FGi32Ext},
         vec3::FGVec3,
     },
     schedule::GameplaySet,
@@ -108,6 +108,28 @@ impl FixedMat4 {
         self.cols[3][2] = translation.z;
     }
 
+    pub fn with_translation(mut self, translation: FGVec3) -> Self {
+        self.translate(translation);
+        self
+    }
+
+    /// Replaces the rotation with XYZ Euler angles expressed in radians.
+    pub fn with_rotation(mut self, rotation: FGVec3) -> Self {
+        let (sin_x, cos_x) = rotation.x.sin_cos();
+        let (sin_y, cos_y) = rotation.y.sin_cos();
+        let (sin_z, cos_z) = rotation.z.sin_cos();
+        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])
     }
@@ -949,4 +971,26 @@ mod tests {
             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/debug.rs

@@ -1,21 +1,21 @@
 //! Fighter debug views: gizmos and the egui inspector window.
 
-use std::ops::Mul;
+use std::sync::OnceLock;
 
 use bevy::color::palettes::css::ORANGE;
-use bevy::gizmos::primitives::dim3::Capsule3dBuilder;
 use bevy::{color::palettes::css::YELLOW, prelude::*};
 use bevy_egui::{EguiContexts, egui};
 
 use crate::debug_tools::{DebugSettings, FighterDebugRowKind};
 use crate::fighter::animation::FighterAnimationFrame;
+use crate::fighter::attack::FighterSolvedHurtboxes;
 use crate::fighter::baked_animation::{BakedFighterAnimations, FighterBoneMatrices};
 use crate::fighter::ecb::FighterPreviousECB;
-use crate::fighter::manifest::FighterManifest;
+use crate::fighter::hurtbox::FixedAffineCapsule;
 use crate::fighter::state::StateNameDebug;
 use crate::fighter::visual::FighterAnimations;
 use crate::fighter::{
-    Fighter, FighterECB, FighterFacingDirection, FighterHitboxes, FighterPreviousTranslation,
+    FighterECB, FighterFacingDirection, FighterHitboxes, FighterPreviousTranslation,
     FighterTranslation, FighterVelocity,
 };
 use crate::input::FighterInput;
@@ -160,49 +160,154 @@ pub fn animation_debug(query: Query<(&GlobalTransform, &FighterBoneMatrices)>, m
     }
 }
 
-pub fn hurtbox_debug(
-    query: Query<(
-        &FighterBoneMatrices,
-        &FighterTranslation,
-        &FighterFacingDirection,
-        &Fighter,
-    )>,
-    manifests: Res<Assets<FighterManifest>>,
-    mut gizmos: Gizmos,
+pub fn hurtbox_debug(query: Query<&FighterSolvedHurtboxes>, mut gizmos: Gizmos) {
+    for hurtboxes in &query {
+        for hurtbox in &hurtboxes.0 {
+            draw_affine_capsule(&mut gizmos, hurtbox.capsule, YELLOW);
+        }
+    }
+}
+
+fn draw_affine_capsule(
+    gizmos: &mut Gizmos,
+    capsule: FixedAffineCapsule,
+    color: impl Into<Color> + Copy,
 ) {
-    for (matrices, translation, facing_direction, fighter) in query {
-        let manifest = manifests
-            .get(&fighter.manifest)
-            .expect("Manifest should be valid");
-        let fighter_trf = translation.get_3d_transform(facing_direction);
-        for hurtbox in manifest.hurtboxes.iter() {
-            let bone_matrix = matrices.get_current(&hurtbox.bone);
-
-            if let Some(bone_matrix) = bone_matrix {
-                let to_global = fighter_trf.mul(bone_matrix);
-                let capsule = Capsule3d {
-                    half_length: hurtbox.half_length.to_num(),
-                    radius: hurtbox.radius.to_num(),
-                };
-
-                let hurtbox_trf = Transform::IDENTITY
-                    .with_rotation(Quat::from_euler(
-                        EulerRot::XYZ,
-                        f32::to_radians(hurtbox.rotation.x.to_num()),
-                        f32::to_radians(hurtbox.rotation.y.to_num()),
-                        f32::to_radians(hurtbox.rotation.z.to_num()),
-                    ))
-                    .with_translation(hurtbox.offset.to_vec3());
-
-                let hurtbox_trf = Transform::from_matrix(to_global.to_mat4()).mul(hurtbox_trf);
-
-                gizmos.primitive_3d(
-                    &capsule,
-                    hurtbox_trf.to_isometry(),
-                    bevy::color::palettes::css::YELLOW,
-                );
+    let color = color.into();
+    let wireframe = capsule_wireframe();
+    let transform = capsule.transform.to_mat4();
+    let radius = capsule.radius.to_num::<f32>();
+    let half_length = capsule.half_length.to_num::<f32>();
+    let vertices: Vec<_> = wireframe
+        .vertices
+        .iter()
+        .map(|vertex| {
+            transform.transform_point3(
+                vertex.direction * radius + Vec3::Y * vertex.center_sign * half_length,
+            )
+        })
+        .collect();
+    for &(start, end) in &wireframe.lines {
+        gizmos.line(vertices[start], vertices[end], color);
     }
+}
+
+struct CapsuleWireVertex {
+    direction: Vec3,
+    center_sign: f32,
+}
+
+struct CapsuleWireframe {
+    vertices: Vec<CapsuleWireVertex>,
+    lines: Vec<(usize, usize)>,
+}
+
+fn capsule_wireframe() -> &'static CapsuleWireframe {
+    const RESOLUTION: usize = 16;
+    const HEMISPHERE_STEPS: usize = 4;
+    static WIREFRAME: OnceLock<CapsuleWireframe> = OnceLock::new();
+
+    WIREFRAME.get_or_init(|| {
+        let mut vertices = Vec::new();
+        let mut lines = Vec::new();
+        let mut lower_ring = Vec::with_capacity(RESOLUTION);
+        let mut upper_ring = Vec::with_capacity(RESOLUTION);
+
+        for index in 0..RESOLUTION {
+            let angle = index as f32 * std::f32::consts::TAU / RESOLUTION as f32;
+            let (sin, cos) = angle.sin_cos();
+            lower_ring.push(vertices.len());
+            vertices.push(CapsuleWireVertex {
+                direction: Vec3::new(cos, 0.0, sin),
+                center_sign: -1.0,
+            });
+            upper_ring.push(vertices.len());
+            vertices.push(CapsuleWireVertex {
+                direction: Vec3::new(cos, 0.0, sin),
+                center_sign: 1.0,
+            });
         }
+
+        let lower_pole = vertices.len();
+        vertices.push(CapsuleWireVertex {
+            direction: Vec3::NEG_Y,
+            center_sign: -1.0,
+        });
+        let upper_pole = vertices.len();
+        vertices.push(CapsuleWireVertex {
+            direction: Vec3::Y,
+            center_sign: 1.0,
+        });
+
+        for index in 0..RESOLUTION {
+            let next = (index + 1) % RESOLUTION;
+            lines.push((lower_ring[index], lower_ring[next]));
+            lines.push((upper_ring[index], upper_ring[next]));
+            lines.push((lower_ring[index], upper_ring[index]));
+
+            let angle = index as f32 * std::f32::consts::TAU / RESOLUTION as f32;
+            let (sin_azimuth, cos_azimuth) = angle.sin_cos();
+            let mut lower_previous = lower_ring[index];
+            let mut upper_previous = upper_ring[index];
+            for step in 1..HEMISPHERE_STEPS {
+                let latitude = step as f32 * std::f32::consts::FRAC_PI_2
+                    / HEMISPHERE_STEPS as f32;
+                let (sin_latitude, cos_latitude) = latitude.sin_cos();
+
+                let lower = vertices.len();
+                vertices.push(CapsuleWireVertex {
+                    direction: Vec3::new(
+                        cos_azimuth * cos_latitude,
+                        -sin_latitude,
+                        sin_azimuth * cos_latitude,
+                    ),
+                    center_sign: -1.0,
+                });
+                lines.push((lower_previous, lower));
+                lower_previous = lower;
+
+                let upper = vertices.len();
+                vertices.push(CapsuleWireVertex {
+                    direction: Vec3::new(
+                        cos_azimuth * cos_latitude,
+                        sin_latitude,
+                        sin_azimuth * cos_latitude,
+                    ),
+                    center_sign: 1.0,
+                });
+                lines.push((upper_previous, upper));
+                upper_previous = upper;
+            }
+            lines.push((lower_previous, lower_pole));
+            lines.push((upper_previous, upper_pole));
+        }
+
+        CapsuleWireframe { vertices, lines }
+    })
+}
+
+#[cfg(test)]
+mod capsule_debug_tests {
+    use super::*;
+
+    #[test]
+    fn capsule_wireframe_caps_extend_in_opposite_directions() {
+        let wireframe = capsule_wireframe();
+        let lower: Vec<_> = wireframe
+            .vertices
+            .iter()
+            .filter(|vertex| vertex.center_sign < 0.0)
+            .collect();
+        let upper: Vec<_> = wireframe
+            .vertices
+            .iter()
+            .filter(|vertex| vertex.center_sign > 0.0)
+            .collect();
+
+        assert!(lower.iter().all(|vertex| vertex.direction.y <= 0.0));
+        assert!(upper.iter().all(|vertex| vertex.direction.y >= 0.0));
+        assert!(lower.iter().any(|vertex| vertex.direction == Vec3::NEG_Y));
+        assert!(upper.iter().any(|vertex| vertex.direction == Vec3::Y));
     }
 }
 

src/fighter/hurtbox.rs

@@ -0,0 +1,267 @@
+//! Fixed-point convex geometry used by fighter hurtboxes.
+
+use crate::{
+    fighter::baked_animation::FixedMat4,
+    math::{
+        int::{FGWide, FGi32},
+        vec3::FGVec3,
+    },
+};
+
+/// A capsule after an arbitrary affine transform. Non-uniform scale turns the
+/// spherical caps and circular cylinder into ellipsoidal geometry.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct FixedAffineCapsule {
+    pub transform: FixedMat4,
+    pub half_length: FGi32,
+    pub radius: FGi32,
+}
+
+/// An ordinary world-space capsule, used for swept attack volumes.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct FixedCapsule {
+    pub start: FGVec3,
+    pub end: FGVec3,
+    pub radius: FGi32,
+}
+
+impl FixedCapsule {
+    pub fn new(start: FGVec3, end: FGVec3, radius: FGi32) -> Self {
+        Self { start, end, radius }
+    }
+}
+
+impl FixedAffineCapsule {
+    pub fn new(transform: FixedMat4, half_length: FGi32, radius: FGi32) -> Self {
+        Self {
+            transform,
+            half_length,
+            radius,
+        }
+    }
+
+    pub fn transform_point(self, point: FGVec3) -> FGVec3 {
+        self.transform.transform_point(point)
+    }
+
+    /// Tests the exact affine hurtbox against an ordinary world-space capsule.
+    pub fn intersects(self, rhs: FixedCapsule) -> bool {
+        let mut direction = rhs.start - self.transform.get_translation();
+        if direction == FGVec3::ZERO {
+            direction = FGVec3::new(FGi32::ONE, FGi32::ZERO, FGi32::ZERO);
+        }
+        let mut simplex = [FGVec3::ZERO; 4];
+        let mut simplex_len = 0;
+        for _ in 0..20 {
+            let point = self.support(direction) - rhs.support(-direction);
+            if point.dot(direction) < FGWide::ZERO {
+                return false;
+            }
+            for index in (1..=simplex_len.min(3)).rev() {
+                simplex[index] = simplex[index - 1];
+            }
+            simplex[0] = point;
+            simplex_len += 1;
+            if update_simplex(&mut simplex, &mut simplex_len, &mut direction) {
+                return true;
+            }
+            if direction == FGVec3::ZERO {
+                return true;
+            }
+        }
+        // A capped GJK iteration means the origin remains enclosed by the
+        // current simplex to fixed-point precision, so conservatively collide.
+        true
+    }
+
+}
+
+trait SupportMap {
+    fn support(self, direction: FGVec3) -> FGVec3;
+}
+
+impl SupportMap for FixedAffineCapsule {
+    fn support(self, direction: FGVec3) -> FGVec3 {
+        let local_direction = FGVec3::new(
+            dot_column(self.transform, 0, direction),
+            dot_column(self.transform, 1, direction),
+            dot_column(self.transform, 2, direction),
+        );
+        let round = local_direction.normalized().unwrap_or(FGVec3::new(
+            FGi32::ONE,
+            FGi32::ZERO,
+            FGi32::ZERO,
+        )) * self.radius;
+        let endpoint = if local_direction.y >= FGi32::ZERO {
+            self.half_length
+        } else {
+            -self.half_length
+        };
+        self.transform_point(round + FGVec3::new(FGi32::ZERO, endpoint, FGi32::ZERO))
+    }
+}
+
+impl SupportMap for FixedCapsule {
+    fn support(self, direction: FGVec3) -> FGVec3 {
+        let endpoint = if self.start.dot(direction) >= self.end.dot(direction) {
+            self.start
+        } else {
+            self.end
+        };
+        endpoint
+            + direction
+                .normalized()
+                .unwrap_or(FGVec3::new(FGi32::ONE, FGi32::ZERO, FGi32::ZERO))
+                * self.radius
+    }
+}
+
+fn dot_column(matrix: FixedMat4, column: usize, vector: FGVec3) -> FGi32 {
+    FGi32::from_num(
+        FGWide::from_num(matrix.cols[column][0]) * FGWide::from_num(vector.x)
+            + FGWide::from_num(matrix.cols[column][1]) * FGWide::from_num(vector.y)
+            + FGWide::from_num(matrix.cols[column][2]) * FGWide::from_num(vector.z),
+    )
+}
+
+fn cross(lhs: FGVec3, rhs: FGVec3) -> FGVec3 {
+    FGVec3::new(
+        FGi32::from_num(
+            FGWide::from_num(lhs.y) * FGWide::from_num(rhs.z)
+                - FGWide::from_num(lhs.z) * FGWide::from_num(rhs.y),
+        ),
+        FGi32::from_num(
+            FGWide::from_num(lhs.z) * FGWide::from_num(rhs.x)
+                - FGWide::from_num(lhs.x) * FGWide::from_num(rhs.z),
+        ),
+        FGi32::from_num(
+            FGWide::from_num(lhs.x) * FGWide::from_num(rhs.y)
+                - FGWide::from_num(lhs.y) * FGWide::from_num(rhs.x),
+        ),
+    )
+}
+
+fn triple_cross(lhs: FGVec3, middle: FGVec3, rhs: FGVec3) -> FGVec3 {
+    cross(cross(lhs, middle), rhs)
+}
+
+fn update_simplex(
+    simplex: &mut [FGVec3; 4],
+    simplex_len: &mut usize,
+    direction: &mut FGVec3,
+) -> bool {
+    let a = simplex[0];
+    let ao = -a;
+    match *simplex_len {
+        2 => {
+            let ab = simplex[1] - a;
+            if ab.dot(ao) > FGWide::ZERO {
+                *direction = triple_cross(ab, ao, ab);
+            } else {
+                *simplex_len = 1;
+                *direction = ao;
+            }
+            false
+        }
+        3 => {
+            let b = simplex[1];
+            let c = simplex[2];
+            let ab = b - a;
+            let ac = c - a;
+            let abc = cross(ab, ac);
+            if cross(abc, ac).dot(ao) > FGWide::ZERO {
+                if ac.dot(ao) > FGWide::ZERO {
+                    simplex[1] = c;
+                    *simplex_len = 2;
+                    *direction = triple_cross(ac, ao, ac);
+                } else {
+                    *simplex_len = 2;
+                    *direction = triple_cross(ab, ao, ab);
+                }
+            } else if cross(ab, abc).dot(ao) > FGWide::ZERO {
+                *simplex_len = 2;
+                *direction = triple_cross(ab, ao, ab);
+            } else if abc.dot(ao) > FGWide::ZERO {
+                *direction = abc;
+            } else {
+                simplex.swap(1, 2);
+                *direction = -abc;
+            }
+            false
+        }
+        4 => {
+            let b = simplex[1];
+            let c = simplex[2];
+            let d = simplex[3];
+            for (first, second, opposite) in [(b, c, d), (c, d, b), (d, b, c)] {
+                let mut normal = cross(first - a, second - a);
+                if normal.dot(opposite - a) > FGWide::ZERO {
+                    normal = -normal;
+                }
+                if normal.dot(ao) > FGWide::ZERO {
+                    simplex[0] = a;
+                    simplex[1] = first;
+                    simplex[2] = second;
+                    *simplex_len = 3;
+                    *direction = normal;
+                    return false;
+                }
+            }
+            true
+        }
+        _ => {
+            *direction = ao;
+            false
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn affine_capsule(x: &str, scale_y: &str) -> FixedAffineCapsule {
+        let mut transform = FixedMat4::IDENTITY;
+        transform.cols[1][1] = FGi32::lit(scale_y);
+        transform.translate(FGVec3::lit(x, "0", "0"));
+        FixedAffineCapsule::new(transform, FGi32::lit("1"), FGi32::lit("1"))
+    }
+
+    fn capsule(x: &str) -> FixedCapsule {
+        FixedCapsule::new(
+            FGVec3::lit(x, "-1", "0"),
+            FGVec3::lit(x, "1", "0"),
+            FGi32::lit("1"),
+        )
+    }
+
+    #[test]
+    fn detects_touching_and_separated_capsules() {
+        assert!(affine_capsule("0", "1").intersects(capsule("2")));
+        assert!(!affine_capsule("0", "1").intersects(capsule("2.01")));
+    }
+
+    #[test]
+    fn affine_scale_changes_capsule_intersection() {
+        let sphere = FixedAffineCapsule::new(
+            FixedMat4::IDENTITY,
+            FGi32::ZERO,
+            FGi32::lit("1"),
+        );
+        let mut squashed_transform = FixedMat4::IDENTITY;
+        squashed_transform.cols[1][1] = FGi32::lit("0.5");
+        let squashed = FixedAffineCapsule::new(
+            squashed_transform,
+            FGi32::ZERO,
+            FGi32::lit("1"),
+        );
+        let target = FixedCapsule::new(
+            FGVec3::lit("0", "1.4", "0"),
+            FGVec3::lit("0", "1.4", "0"),
+            FGi32::lit("0.5"),
+        );
+
+        assert!(sphere.intersects(target));
+        assert!(!squashed.intersects(target));
+    }
+}

src/fighter/manifest.rs

@@ -7,7 +7,10 @@ use strum::IntoEnumIterator;
 use strum_macros::EnumIter;
 
 use crate::{
-    AppState, fighter::{FighterAttributes, FighterCameraProfile, animation::AnimKind, attack::AttackKind}, game_settings::GameSettings, math::{int::FGi32, vec3::FGVec3},
+    AppState,
+    fighter::{FighterAttributes, FighterCameraProfile, animation::AnimKind, attack::AttackKind},
+    game_settings::GameSettings,
+    math::{int::FGi32, vec3::FGVec3},
 };
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize, Reflect, EnumIter)]
@@ -23,7 +26,7 @@ pub struct FighterHurtbox {
     #[reflect(ignore)]
     pub half_length: FGi32,
     #[reflect(ignore)]
-    pub radius: FGi32
+    pub radius: FGi32,
 }
 
 #[derive(Serialize, Deserialize, Clone, Asset, Reflect)]

src/fighter/mod.rs

@@ -13,6 +13,7 @@ pub mod baked_animation;
 pub mod collision;
 pub mod debug;
 pub mod ecb;
+pub mod hurtbox;
 pub mod manifest;
 pub mod motion;
 pub mod state;
@@ -29,7 +30,7 @@ pub use motion::{FighterPreviousTranslation, FighterTranslation, FighterVelocity
 
 use crate::{
     fighter::{
-        attack::FighterAttackScriptAssets,
+        attack::{FighterAttackPlugin, FighterAttackScriptAssets, FighterSolvedHurtboxes},
         manifest::FighterManifest,
         state::{FighterState, fall::FallState},
         visual::FighterAnimations,
@@ -105,7 +106,7 @@ pub struct Fighter {
 
 impl Plugin for FighterPlugin {
     fn build(&self, app: &mut App) {
-        app
+        app.add_plugins(FighterAttackPlugin)
             // Every state gets a chance to interrupt itself, in priority order.
             .add_systems(
                 GgrsSchedule,
@@ -171,10 +172,11 @@ impl Plugin for FighterPlugin {
             )
             .add_systems(
                 FixedPostUpdate,
-                debug::hurtbox_debug
+                debug::hurtbox_debug.run_if(crate::debug_tools::hurtboxes_enabled),
             )
             .rollback_component_with_clone::<FighterState>()
             .rollback_component_with_clone::<FighterHitboxes>()
+            .rollback_component_with_clone::<FighterSolvedHurtboxes>()
             .checksum_component_with_hash::<FighterState>()
             .checksum_component_with_hash::<FighterFacingDirection>()
             .register_type::<FighterFacingDirection>();
@@ -230,9 +232,12 @@ pub fn spawn_fighter(
         attack_scripts,
         FighterState::Fall(FallState),
         animation::FighterAnimationFrame::new(animation::AnimKind::Wait, true),
+        (
             baked_animation::FighterBoneMatrices::default(),
+            FighterSolvedHurtboxes::default(),
             FighterVisual,
             FighterInput::default(),
             crate::camera::FighterCameraExtents::default(),
+        ),
     ));
 }

src/fighter/state/air_dodge.rs

@@ -1,14 +1,10 @@
-
-
 use crate::{
     fighter::{
         animation::AnimKind,
         collision,
         state::{
-            FighterState, FighterStateContext, FighterStateImpl, air,
-            fall::FallState,
-            ground::GroundedStateCommon,
-            land::LandingState,
+            FighterState, FighterStateContext, FighterStateImpl, air, fall::FallState,
+            ground::GroundedStateCommon, land::LandingState,
         },
     },
     input,
@@ -51,9 +47,7 @@ impl FighterStateImpl for AirDodgeState {
             let grounded_common = GroundedStateCommon {
                 current_line_id: res.line_id,
             };
-            Some(FighterState::Land(LandingState {
-                grounded_common
-            }))
+            Some(FighterState::Land(LandingState { grounded_common }))
         } else {
             None
         }

src/fighter/state/dash.rs

@@ -1,4 +1,4 @@
-use std::hash::{Hasher};
+use std::hash::Hasher;
 
 use super::{FighterStateContext, FighterStateImpl, ground, run, wait, walk};
 use crate::fighter::FighterFacingDirection;

src/fighter/state/fall.rs

@@ -45,9 +45,7 @@ impl FighterStateImpl for FallState {
             let grounded_common = GroundedStateCommon {
                 current_line_id: res.line_id,
             };
-            Some(FighterState::Land(LandingState {
-                grounded_common
-            }))
+            Some(FighterState::Land(LandingState { grounded_common }))
         } else {
             None
         }

src/fighter/state/ground.rs

@@ -2,7 +2,9 @@
 //! ECS types so it stays cheap to reason about and to unit-test — it has to be
 //! bit-for-bit deterministic for rollback.
 
-use crate::fighter::state::{FighterState, FighterStateContext, dash, ground_attack, turn, wait, walk};
+use crate::fighter::state::{
+    FighterState, FighterStateContext, dash, ground_attack, turn, wait, walk,
+};
 use crate::fighter::{
     FighterAttributes, FighterPreviousTranslation, FighterTranslation, FighterVelocity,
 };

src/fighter/state/ground_attack.rs

@@ -1,6 +1,12 @@
 use fixed::types::I16F16;
 
-use crate::{fighter::{attack::{AttackKind, update_active_hitbox_list}, state::{FighterState, FighterStateImpl, ground::GroundedStateCommon, wait::WaitState}}, math::int::FGi32};
+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 {
@@ -11,10 +17,13 @@ pub struct GroundAttackState {
 impl FighterStateImpl for GroundAttackState {
     const NAME: &'static str = "GroundAttack";
 
-    fn check_interrupt(&self, state_context: &mut super::FighterStateContext) -> Option<FighterState> {
+    fn check_interrupt(
+        &self,
+        state_context: &mut super::FighterStateContext,
+    ) -> Option<FighterState> {
         if state_context.is_current_animation_finished() {
             Some(FighterState::Wait(WaitState {
-                grounded_common: self.grounded_common.clone()
+                grounded_common: self.grounded_common.clone(),
             }))
         } else {
             None
@@ -22,16 +31,23 @@ impl FighterStateImpl for GroundAttackState {
     }
 
     fn update(&mut self, state_context: &mut super::FighterStateContext) {
-        let script = state_context.attack_scripts.get(&state_context.attack_script_assets.scripts[&self.attack_kind]);
+        let script = state_context
+            .attack_scripts
+            .get(&state_context.attack_script_assets.scripts[&self.attack_kind]);
         if let Some(script) = script {
             let animation_frame = state_context.get_current_animation_frame();
-            update_active_hitbox_list(script, &mut state_context.hitboxes.active_hitboxes, animation_frame);
+            update_active_hitbox_list(
+                script,
+                &mut state_context.hitboxes.active_hitboxes,
+                animation_frame,
+            );
         }
     }
 
     fn on_enter(&mut self, state_context: &mut super::FighterStateContext) {
         state_context.play_animation(self.attack_kind.get_animation(), false);
-        state_context.hitboxes.attack_script = Some(state_context.attack_script_assets.scripts[&self.attack_kind].clone());
+        state_context.hitboxes.attack_script =
+            Some(state_context.attack_script_assets.scripts[&self.attack_kind].clone());
         state_context.hitboxes.active_hitboxes.clear();
     }
 
@@ -47,9 +63,14 @@ 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) {
-
+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 {
@@ -58,7 +79,7 @@ pub fn check_interrupt(state_context: &super::FighterStateContext, grounded_comm
 
         Some(FighterState::GroundAttack(GroundAttackState {
             attack_kind,
-            grounded_common: grounded_common.clone()
+            grounded_common: grounded_common.clone(),
         }))
     } else {
         None

src/fighter/state/jump.rs

@@ -1,4 +1,3 @@
-
 use bevy::prelude::*;
 
 use crate::{
@@ -239,9 +238,7 @@ impl FighterStateImpl for JumpState {
             let grounded_common = GroundedStateCommon {
                 current_line_id: res.line_id,
             };
-            Some(FighterState::Land(LandingState {
-                grounded_common
-            }))
+            Some(FighterState::Land(LandingState { grounded_common }))
         } else {
             None
         }

src/fighter/state/land.rs

@@ -13,14 +13,12 @@ use crate::fighter::{
 
 #[derive(Debug, Clone, Hash)]
 pub struct LandingState {
-    pub grounded_common: GroundedStateCommon
+    pub grounded_common: GroundedStateCommon,
 }
 
 impl LandingState {
     pub fn create(grounded_common: GroundedStateCommon) -> Self {
-        Self {
-            grounded_common
-        }
+        Self { grounded_common }
     }
 }
 
@@ -30,7 +28,9 @@ impl FighterStateImpl for LandingState {
     fn check_interrupt(&self, state_context: &mut FighterStateContext) -> Option<FighterState> {
         if state_context.is_current_animation_finished() {
             grounded_movement_standstill_common_interrupts(state_context, &self.grounded_common)
-        } else if state_context.get_current_animation_frame() >= state_context.fighter_manifest.attributes.landing_iasa {
+        } else if state_context.get_current_animation_frame()
+            >= state_context.fighter_manifest.attributes.landing_iasa
+        {
             dash::check_input(state_context, &self.grounded_common).or_else(|| {
                 ground::grounded_movement_common_interrupts(state_context, &self.grounded_common)
                     .or_else(|| walk::check_input(state_context, &self.grounded_common))

src/fighter/state/run.rs

@@ -1,4 +1,3 @@
-
 use bevy::prelude::*;
 
 use super::{FighterStateContext, FighterStateImpl, ground, wait, walk};

src/fighter/state/turn.rs

@@ -2,7 +2,7 @@ use super::{FighterStateContext, FighterStateImpl};
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::fall::FallState;
 use crate::fighter::state::ground::{self, GroundedMotionResult, GroundedStateCommon};
-use crate::fighter::state::{dash, jump, wait, walk, FighterState};
+use crate::fighter::state::{FighterState, dash, jump, wait, walk};
 
 #[derive(Debug, Clone, Hash)]
 pub struct TurnState {

src/fighter/state/wait.rs

@@ -1,12 +1,8 @@
-
-
 use super::{FighterStateContext, FighterStateImpl, ground};
 use crate::fighter::animation::AnimKind;
-use crate::fighter::state::fall::FallState;
-use crate::fighter::state::ground::{
-    GroundedMotionResult, GroundedStateCommon,
-};
 use crate::fighter::state::FighterState;
+use crate::fighter::state::fall::FallState;
+use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
 
 #[derive(Debug, Clone, Hash)]
 pub struct WaitState {
@@ -16,12 +12,14 @@ pub struct WaitState {
 impl FighterStateImpl for WaitState {
     const NAME: &'static str = "Wait";
     fn check_interrupt(&self, state_context: &mut FighterStateContext) -> Option<FighterState> {
-        if let Some(state) = ground::grounded_movement_common_interrupts(state_context, &self.grounded_common) {
+        if let Some(state) =
+            ground::grounded_movement_common_interrupts(state_context, &self.grounded_common)
+        {
             Some(state)
         } else if let Some(state) = ground::grounded_movement_standstill_common_interrupts(
             state_context,
-            &self.grounded_common)
-        {
+            &self.grounded_common,
+        ) {
             // Don't transition into yourself
             if let FighterState::Wait(_) = state {
                 None

src/fighter/state/walk.rs

@@ -1,10 +1,9 @@
-
 use super::{FighterStateContext, FighterStateImpl, dash, ground, wait};
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
 use crate::fighter::state::fall::FallState;
-use crate::fighter::state::turn;
 use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
+use crate::fighter::state::turn;
 
 #[derive(Debug, Clone, Hash)]
 pub struct WalkState {
@@ -15,9 +14,8 @@ impl FighterStateImpl for WalkState {
     const NAME: &'static str = "Walk";
     fn check_interrupt(&self, state_context: &mut FighterStateContext) -> Option<FighterState> {
         if let Some(state) = turn::check_input(state_context, &self.grounded_common) {
-            return Some(state)
-        }
-        else if let Some(state) =
+            return Some(state);
+        } else if let Some(state) =
             ground::grounded_movement_common_interrupts(state_context, &self.grounded_common)
         {
             return Some(state);

src/math/int.rs

@@ -1,2 +1,99 @@
 pub type FGi32 = fixed::FixedI32<fixed::types::extra::U16>;
 pub type FGWide = fixed::FixedI128<fixed::types::extra::U32>;
+
+/// Angle conversions for the game's Q16.16 fixed-point values.
+pub trait FGi32Ext {
+    fn to_radians(self) -> FGi32;
+    fn sin_cos(self) -> (FGi32, FGi32);
+}
+
+impl FGi32Ext for FGi32 {
+    fn to_radians(self) -> FGi32 {
+        FGi32::from_num(FGWide::from_num(self) * FGWide::lit("0.01745329251994329576923690768489"))
+    }
+
+    fn sin_cos(self) -> (FGi32, FGi32) {
+        const PI: FGi32 = FGi32::lit("3.14159265358979323846");
+        const HALF_PI: FGi32 = FGi32::lit("1.57079632679489661923");
+        const TWO_PI: FGi32 = FGi32::lit("6.28318530717958647692");
+        const CORDIC_GAIN_INVERSE: FGi32 = FGi32::lit("0.60725293500888125617");
+        const ANGLES: [FGi32; 16] = [
+            FGi32::lit("0.78539816339744830962"),
+            FGi32::lit("0.46364760900080611621"),
+            FGi32::lit("0.24497866312686415417"),
+            FGi32::lit("0.12435499454676143503"),
+            FGi32::lit("0.06241880999595734847"),
+            FGi32::lit("0.03123983343026827625"),
+            FGi32::lit("0.01562372862047683080"),
+            FGi32::lit("0.00781234106010111130"),
+            FGi32::lit("0.00390623013196697183"),
+            FGi32::lit("0.00195312251647881869"),
+            FGi32::lit("0.00097656218955931943"),
+            FGi32::lit("0.00048828121119489829"),
+            FGi32::lit("0.00024414062014936177"),
+            FGi32::lit("0.00012207031189367021"),
+            FGi32::lit("0.00006103515617420878"),
+            FGi32::lit("0.00003051757811552610"),
+        ];
+
+        let mut angle = self % TWO_PI;
+        if angle > PI {
+            angle -= TWO_PI;
+        } else if angle < -PI {
+            angle += TWO_PI;
+        }
+        let mut sign = FGi32::ONE;
+        if angle > HALF_PI {
+            angle -= PI;
+            sign = FGi32::NEG_ONE;
+        } else if angle < -HALF_PI {
+            angle += PI;
+            sign = FGi32::NEG_ONE;
+        }
+
+        let mut x = CORDIC_GAIN_INVERSE;
+        let mut y = FGi32::ZERO;
+        for (index, step) in ANGLES.into_iter().enumerate() {
+            let scale = FGi32::from_bits(1 << (16 - index));
+            if angle >= FGi32::ZERO {
+                let next_x = x - y * scale;
+                y += x * scale;
+                x = next_x;
+                angle -= step;
+            } else {
+                let next_x = x + y * scale;
+                y -= x * scale;
+                x = next_x;
+                angle += step;
+            }
+        }
+        let snap_axis = |value: FGi32| {
+            const EPSILON: FGi32 = FGi32::from_bits(4);
+            if value.abs() <= EPSILON {
+                FGi32::ZERO
+            } else if (value.abs() - FGi32::ONE).abs() <= EPSILON {
+                if value < FGi32::ZERO {
+                    FGi32::NEG_ONE
+                } else {
+                    FGi32::ONE
+                }
+            } else {
+                value
+            }
+        };
+        (snap_axis(y * sign), snap_axis(x * sign))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn fixed_degrees_convert_to_radians() {
+        assert_eq!(
+            FGi32::lit("180").to_radians(),
+            FGi32::lit("3.1415863037109375")
+        );
+    }
+}

src/math/vec3.rs

@@ -1,7 +1,8 @@
 use bevy::prelude::*;
 use serde::{Deserialize, Serialize};
+use std::ops::{Add, Mul, Neg, Sub};
 
-use crate::math::int::FGi32;
+use crate::math::int::{FGWide, FGi32};
 
 #[derive(Clone, Copy, PartialEq, Default, Debug, Reflect, Serialize, Deserialize, Hash)]
 #[reflect(opaque)]
@@ -12,13 +13,14 @@ pub struct FGVec3 {
 }
 
 impl FGVec3 {
+    pub const ZERO: Self = Self {
+        x: FGi32::ZERO,
+        y: FGi32::ZERO,
+        z: FGi32::ZERO,
+    };
 
-    pub fn new(x: FGi32, y: FGi32, z: FGi32) -> Self {
-        Self {
-            x,
-            y,
-            z
-        }
+    pub const fn new(x: FGi32, y: FGi32, z: FGi32) -> Self {
+        Self { x, y, z }
     }
 
     pub fn lit(x: &str, y: &str, z: &str) -> Self {
@@ -32,6 +34,61 @@ impl FGVec3 {
     pub fn to_vec3(&self) -> Vec3 {
         Vec3::new(self.x.to_num(), self.y.to_num(), self.z.to_num())
     }
+
+    pub fn dot(self, rhs: Self) -> FGWide {
+        FGWide::from_num(self.x) * FGWide::from_num(rhs.x)
+            + FGWide::from_num(self.y) * FGWide::from_num(rhs.y)
+            + FGWide::from_num(self.z) * FGWide::from_num(rhs.z)
+    }
+
+    pub fn length_squared(self) -> FGWide {
+        self.dot(self)
+    }
+
+    pub fn normalized(self) -> Option<Self> {
+        let length_squared = self.length_squared();
+        if length_squared == FGWide::ZERO {
+            return None;
+        }
+        let length = length_squared.sqrt();
+        Some(Self::new(
+            FGi32::from_num(FGWide::from_num(self.x) / length),
+            FGi32::from_num(FGWide::from_num(self.y) / length),
+            FGi32::from_num(FGWide::from_num(self.z) / length),
+        ))
+    }
+}
+
+impl Add for FGVec3 {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Self::new(self.x + rhs.x, self.y + rhs.y, self.z + rhs.z)
+    }
+}
+
+impl Sub for FGVec3 {
+    type Output = Self;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        Self::new(self.x - rhs.x, self.y - rhs.y, self.z - rhs.z)
+    }
+}
+
+impl Neg for FGVec3 {
+    type Output = Self;
+
+    fn neg(self) -> Self::Output {
+        Self::new(-self.x, -self.y, -self.z)
+    }
+}
+
+impl Mul<FGi32> for FGVec3 {
+    type Output = Self;
+
+    fn mul(self, rhs: FGi32) -> Self::Output {
+        Self::new(self.x * rhs, self.y * rhs, self.z * rhs)
+    }
 }
 
 impl From<(&str, &str, &str)> for FGVec3 {