Implement hitstop shake (#42)

Reviewed-on: #42
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/state/air_dodge.rs

@@ -49,6 +49,12 @@ impl FighterStateImpl for AirDodgeState {
         state_context.velocity.0 =
             self.direction * state_context.fighter_attributes.air_dodge_velocity;
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        false
+    }
 }
 
 pub fn check_input(state_context: &InterruptContext) -> Option<FighterState> {

src/fighter/state/dash.rs

@@ -108,6 +108,12 @@ impl FighterStateImpl for DashState {
     ) -> Option<FighterState> {
         ground::collision_interrupt(state_context, &mut self.ground_common, true)
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }
 
 fn check_smash_input_with_dir(state_context: &InterruptContext) -> Option<FighterFacingDirection> {

src/fighter/state/fall.rs

@@ -28,6 +28,12 @@ impl FighterStateImpl for FallState {
             crate::fighter::state::land::LandingType::Normal,
         )
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        false
+    }
 }
 
 pub fn check_input(state_context: &InterruptContext) -> Option<FighterState> {

src/fighter/state/ground_attack.rs

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

src/fighter/state/hitstun.rs

@@ -95,4 +95,13 @@ impl FighterStateImpl for HitstunState {
             }
         }
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        match self.hitstop_kind {
+            HitstopStateKind::Grounded(_) => true,
+            HitstopStateKind::Airborne => false,
+        }
+    }
 }

src/fighter/state/jump.rs

@@ -96,6 +96,12 @@ impl FighterStateImpl for JumpSquatState {
         state_context.play_animation(AnimKind::JumpSquat, false);
         state_context.input.clear_command(FighterCommands::Jump);
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }
 
 impl FighterStateImpl for JumpState {
@@ -174,6 +180,12 @@ impl FighterStateImpl for JumpState {
             crate::fighter::state::land::LandingType::Normal,
         )
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        false
+    }
 }
 
 pub fn check_input(

src/fighter/state/land.rs

@@ -69,4 +69,10 @@ impl FighterStateImpl for LandingState {
             }
         };
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }

src/fighter/state/mod.rs

@@ -16,8 +16,7 @@ use crate::fighter::manifest::FighterManifest;
 use crate::fighter::state::hitstun::HitstunState;
 use crate::fighter::visual::FighterAnimations;
 use crate::fighter::{
-    Fighter, FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop,
-    FighterPreviousTranslation, FighterTranslation, FighterVelocity,
+    Fighter, FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop, FighterHitstopShake, FighterHitstopShakeKind, FighterHitstopShakeRole, FighterPreviousTranslation, FighterTranslation, FighterVelocity,
 };
 use crate::game_settings::GameSettings;
 use crate::input::FighterInput;
@@ -66,6 +65,10 @@ macro_rules! fighter_states {
             pub fn check_collision_interrupt(&mut self, ctx: &mut CollisionContext) -> Option<FighterState> {
                 match self { $(Self::$variant(s) => s.check_collision_interrupt(ctx)),* }
             }
+
+            pub fn is_visually_grounded(&self) -> bool {
+                match self { $(Self::$variant(s) => s.is_visually_grounded()),* }
+            }
         }
 
         $(impl From<$ty> for FighterState {
@@ -91,6 +94,10 @@ pub trait FighterStateImpl: Sized {
     ) -> Option<FighterState> {
         None
     }
+
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool;
 }
 
 pub struct AnimationStatus {
@@ -320,6 +327,7 @@ pub struct StatefulFighterQuery {
     pub attack_script_assets: &'static FighterAttackScriptAssets,
     pub pending_hit_reaction: &'static mut FighterPendingHitReaction,
     pub hitstop: &'static mut FighterHitstop,
+    pub hitstop_shake: &'static mut FighterHitstopShake,
 }
 
 pub fn state_update_system(
@@ -384,6 +392,7 @@ pub fn state_interrupt_system(
             attack_script_assets,
             mut pending_hit_reaction,
             mut hitstop,
+            mut hitstop_shake,
         } = fighter;
         let manifest = fighter_manifests
             .get(&fighter.manifest)
@@ -391,6 +400,16 @@ pub fn state_interrupt_system(
 
         let new_state = if let Some(reaction) = pending_hit_reaction.take() {
             hitstop.remaining_frames = *reaction.hitstop_frames;
+            let shake_frames = reaction.hitstop_frames.calculate_shake_frames(&game_settings);
+            hitstop_shake.role = FighterHitstopShakeRole::Receiver;
+            hitstop_shake.total_frames = shake_frames;
+            hitstop_shake.remaining_frames = shake_frames;
+            hitstop_shake.kind = if state.is_visually_grounded() {
+                FighterHitstopShakeKind::Horizontal
+            } else {
+                FighterHitstopShakeKind::Vertical
+            };
+            
             let mut hitstop_kind = match &*state {
                 FighterState::Wait(value) => {
                     hitstun::HitstopStateKind::Grounded(value.grounded_common.clone())

src/fighter/state/run.rs

@@ -64,6 +64,12 @@ impl FighterStateImpl for RunState {
     ) -> Option<FighterState> {
         ground::collision_interrupt(state_context, &mut self.grounded_common, true)
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }
 
 pub fn check_input(

src/fighter/state/turn.rs

@@ -56,6 +56,12 @@ impl FighterStateImpl for TurnState {
     ) -> Option<FighterState> {
         ground::collision_interrupt(state_context, &mut self.grounded_common, false)
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }
 
 pub fn check_input(

src/fighter/state/wait.rs

@@ -46,6 +46,12 @@ impl FighterStateImpl for WaitState {
     ) -> Option<FighterState> {
         ground::collision_interrupt(state_context, &mut self.grounded_common, false)
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }
 
 pub fn check_input(

src/fighter/state/walk.rs

@@ -56,6 +56,12 @@ impl FighterStateImpl for WalkState {
     ) -> Option<FighterState> {
         ground::collision_interrupt(state_context, &mut self.grounded_common, false)
     }
+    
+    fn is_visually_grounded<'a>(
+        &'a self,
+    ) -> bool {
+        true
+    }
 }
 
 pub fn check_input(