Add waveland snapping (#95)

Reviewed-on: #95
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/state/mod.rs

@@ -120,8 +120,9 @@ pub trait FighterStateImpl: Sized {
 
     fn check_collision_interrupt(
         &mut self,
-        _state_context: &mut CollisionContext,
+        state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
+        state_context.apply_desired_ecb();
         None
     }
 
@@ -260,7 +261,7 @@ pub struct CollisionContext<'a> {
     pub ledge_info: &'a mut FighterLedgeInformation,
     pub fighter_ledge_collision_box: FGRect,
     pub downward_stick_threshold: FGi32,
-    pub(crate) ecb_advanced: bool,
+    pub waveland_snap_distance: FGi32,
 }
 
 impl CollisionContext<'_> {
@@ -268,7 +269,6 @@ impl CollisionContext<'_> {
     /// substep resolver can later replace this with fractional steps.
     pub fn apply_desired_ecb(&mut self) {
         ecb::interpolate_ecb(self.ecb, *self.desired_ecb, FGi32::ONE);
-        self.ecb_advanced = true;
     }
 
     pub fn air_collide_with_stage(
@@ -278,7 +278,7 @@ impl CollisionContext<'_> {
         let ignored_polys = self.surface.ignored_polygon_ids();
         let ignore_soft_platforms = can_ignore_soft_platforms
             && self.input.get_last_frame().movement.y <= -self.downward_stick_threshold;
-        let result = crate::fighter::collision::air_collide_with_stage_substepped(
+        crate::fighter::collision::air_collide_with_stage_substepped(
             self.prev_translation,
             self.translation,
             self.velocity,
@@ -287,15 +287,7 @@ impl CollisionContext<'_> {
             self.stage_collision,
             &ignored_polys,
             ignore_soft_platforms,
-        );
-        self.ecb_advanced = true;
-        result
-    }
-
-    fn finish_ecb_frame(&mut self) {
-        if !self.ecb_advanced {
-            self.apply_desired_ecb();
-        }
+        )
     }
     pub fn air_collide_with_ledges(
         &self,
@@ -502,7 +494,7 @@ impl<'w, 's> FighterFrameQueryItem<'w, 's> {
                 .leave_ground_ecb_frame_lock_duration,
             downward_stick_threshold: game_settings.input_common.run_stick_threshold,
             fighter_ledge_collision_box,
-            ecb_advanced: false,
+            waveland_snap_distance: game_settings.fighter_common.waveland_snap_distance,
         }
     }
 }
@@ -797,13 +789,9 @@ pub fn state_collision_interrupt_system(
             continue;
         }
 
-        let new_state = {
-            let mut collision_context =
-                frame.collision_context(&stage_collision, manifest, &game_settings);
-            let new_state = state.check_collision_interrupt(&mut collision_context);
-            collision_context.finish_ecb_frame();
-            new_state
-        };
+        let new_state = state.check_collision_interrupt(
+            &mut frame.collision_context(&stage_collision, manifest, &game_settings),
+        );
         if let Some(new_state) = new_state {
             transition_state(
                 &mut state,
@@ -872,7 +860,7 @@ mod tests {
         };
         let previous_ecb = FighterPreviousECB::from(ecb);
         let mut presentation_snap = FighterPresentationSnap::default();
-        let mut context = CollisionContext {
+        let context = CollisionContext {
             translation: &mut translation,
             prev_translation: &previous_translation,
             input: &input,
@@ -890,7 +878,7 @@ mod tests {
                 end: FGVec2::lit("1", "-1"),
             },
             downward_stick_threshold: FGi32::ONE,
-            ecb_advanced: false,
+            waveland_snap_distance: FGi32::ZERO,
         };
 
         assert!(context.air_collide_with_ledges().is_none());
@@ -899,7 +887,5 @@ mod tests {
             context.air_collide_with_ledges().map(|result| result.ledge),
             Some(ledge_id)
         );
-        context.finish_ecb_frame();
-        assert_eq!(context.ecb.top, FGVec2::lit("0", "2"));
     }
 }