Add waveland snapping (#95)

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

src/fighter/state/air.rs

@@ -129,6 +129,7 @@ pub fn collision_interrupt(
 ) -> Option<FighterState> {
     if ctx.velocity.y <= FGi32::ZERO {
         if let Some(ledge_result) = ctx.air_collide_with_ledges() {
+            ctx.apply_desired_ecb();
             return Some(FighterState::LedgeGrab(LedgeGrabState::new(ledge_result.ledge)));
         }
     }

src/fighter/state/air_dodge.rs

@@ -1,17 +1,9 @@
 use crate::{
     fighter::{
-        FighterInvulnerabilityState,
-        animation::AnimKind,
-        state::{
-            CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
-            UpdateContext,
-            air::{self, AirborneStateCommon},
-            fall::FallState,
-            land::LandingType,
+        FighterInvulnerabilityState, animation::AnimKind, state::{
+            CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext, UpdateContext, air::{self, AirborneStateCommon}, fall::FallState, land::{LandingState, LandingType},
         },
-    },
-    input,
-    math::vec::FGVec2,
+    }, input, math::vec::FGVec2, stage::line::{StageLineID, StagePolyLineSegmentType},
 };
 
 #[derive(Debug, Clone, Hash)]
@@ -52,6 +44,27 @@ impl FighterStateImpl for AirDodgeState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
+        let can_wavesnap = self.direction.y.is_zero() || self.direction.y.is_negative();
+        
+        if can_wavesnap {
+            for (poly_idx, poly) in state_context.stage_collision.stage_polys.iter().enumerate() {
+                for (segment_idx, segment) in poly.segments.iter().enumerate() {
+                    if !matches!(segment.segment_type, StagePolyLineSegmentType::Floor) {
+                        continue;
+                    }
+                    let bottom_point = state_context.translation.0 + state_context.ecb.get_bottom_point();
+                    let point_in_segment = segment.segment.closest_point(bottom_point);
+                    let dist_to_segment = point_in_segment.distance(bottom_point);
+                    if dist_to_segment <= state_context.waveland_snap_distance {
+                        state_context.ecb.bottom = point_in_segment - state_context.translation.0;
+                        state_context.ecb.rebase_onto_bottom();
+                        state_context.surface.land(StageLineID { polygon: poly_idx, segment: segment_idx }, state_context.ledge_info);
+                        return Some(FighterState::Land(LandingState::create(LandingType::Special)));
+                    }
+                }
+            }
+        }
+
         air::collision_interrupt(state_context, LandingType::Special, false)
     }
 

src/fighter/state/angel.rs

@@ -43,12 +43,13 @@ impl FighterStateImpl for AngelState {
     
     fn check_collision_interrupt(
         &mut self,
-        _state_context: &mut super::CollisionContext,
+        state_context: &mut super::CollisionContext,
     ) -> Option<super::FighterState> {
+        state_context.apply_desired_ecb();
         None
     }
     
     fn surface_policy(&self) -> super::SurfacePolicy {
         super::SurfacePolicy::Airborne(crate::fighter::surface::EcbLockPolicy::Clear)
     }
-}
+}

src/fighter/state/ground.rs

@@ -211,7 +211,6 @@ pub fn collide_with_stage_grounded(
                 crate::fighter::surface::EcbLockPolicy::StartOnDetach,
                 state_context.leave_ground_ecb_lock_duration,
             );
-            state_context.ecb_advanced = true;
             return GroundedMotionResult::InAir;
         };
         match resolve_grounded_position(
@@ -238,7 +237,6 @@ pub fn collide_with_stage_grounded(
                     crate::fighter::surface::EcbLockPolicy::StartOnDetach,
                     state_context.leave_ground_ecb_lock_duration,
                 );
-                state_context.ecb_advanced = true;
                 return GroundedMotionResult::InAir;
             }
         }
@@ -247,7 +245,6 @@ pub fn collide_with_stage_grounded(
     *state_context.ecb = current_ecb;
     state_context.translation.0 = current_position;
     state_context.surface.land(line_id, state_context.ledge_info);
-    state_context.ecb_advanced = true;
     GroundedMotionResult::InGround
 }
 
@@ -419,7 +416,7 @@ mod tests {
                 origin: FGVec2::ZERO,
                 end: FGVec2::ZERO,
             },
-            ecb_advanced: false,
+            waveland_snap_distance: FGi32::ZERO,
         };
 
         assert!(matches!(
@@ -484,7 +481,7 @@ mod tests {
                 origin: FGVec2::ZERO,
                 end: FGVec2::ZERO,
             },
-            ecb_advanced: false,
+            waveland_snap_distance: FGi32::ZERO,
         };
 
         assert!(matches!(

src/fighter/state/ledge_action.rs

@@ -144,8 +144,9 @@ impl FighterStateImpl for LedgeActionState {
 
     fn check_collision_interrupt(
         &mut self,
-        _state_context: &mut CollisionContext,
+        state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
+        state_context.apply_desired_ecb();
         None
     }
 

src/fighter/state/ledge_wait.rs

@@ -102,8 +102,9 @@ impl FighterStateImpl for LedgeWaitState {
 
     fn check_collision_interrupt(
         &mut self,
-        _state_context: &mut CollisionContext,
+        state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
+        state_context.apply_desired_ecb();
         None
     }
 

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"));
     }
 }

src/game_settings.rs

@@ -66,6 +66,8 @@ pub struct FighterSettingsCommon {
     pub sakurai_angle_high_knockback_angle: FGi32,
     /// past this threshold, the knockback is considered high, so it will use [sakurai_angle_high_knockback_angle]
     pub sakurai_angle_knockback_threshold: FGi32,
+
+    pub waveland_snap_distance: FGi32,
 }
 #[derive(Reflect, Serialize, Deserialize, Clone)]
 #[reflect(opaque)]

src/input/buffer.rs

@@ -717,7 +717,6 @@ pub fn postprocess_input(
                 FighterAttackCommandType::Neutral
             };
 
-            dbg!(input.movement_flick.y, attack_type);
             input.set_lifetime(FighterCommands::Attack, tap);
             input.set_attack_command_type(attack_type);
         }

src/stage/debug.rs

@@ -1,15 +1,15 @@
 use bevy::{color::palettes::css::RED, prelude::*};
 
 use crate::{
-    match_loading::MatchConfig, math::{int::FGi32, vec3::FGVec3}, stage::{
-        line::{StageCollision, StageLedgeSide},
-        manifest::{StageManifest, StageManifestRegistry},
+    game_settings::GameSettings, match_loading::MatchConfig, math::{int::FGi32, vec3::FGVec3}, stage::{
+        line::{StageCollision, StageLedgeSide, StagePolyLineSegmentType}, manifest::{StageManifest, StageManifestRegistry},
     },
 };
 
-pub fn debug_draw_scene(mut gizmos: Gizmos, stage_collision: Res<StageCollision>) {
+pub fn debug_draw_scene(mut gizmos: Gizmos, stage_collision: Res<StageCollision>, game_settings: Res<GameSettings>) {
     for poly in stage_collision.stage_polys.iter() {
-        for segment in &poly.segments {
+        for (segment, next_segment) in poly.segments.iter().zip(poly.segments.iter().cycle().skip(1)) {
+            let wavedash_normal = ((next_segment.normal.to_vec2() + segment.normal.to_vec2()) * 0.5).normalize();
             let from = segment.segment.point1().to_vec2();
             let to = segment.segment.point2().to_vec2();
             let from_3d = Vec3::new(from.x, from.y, 0.0);
@@ -18,6 +18,16 @@ pub fn debug_draw_scene(mut gizmos: Gizmos, stage_collision: Res<StageCollision>
             gizmos.line(from_3d, end_3d, RED);
             let midpoint = (from_3d + end_3d) * 0.5;
             gizmos.arrow(midpoint, midpoint + normal_3d, RED);
+            if matches!(segment.segment_type, StagePolyLineSegmentType::Floor) {
+                let radius = game_settings.fighter_common.waveland_snap_distance.to_num::<f32>();
+                let a = segment.segment.point1().to_vec2();
+                let a = Vec3::new(a.x, a.y, 0.0);
+                let b = segment.segment.point2().to_vec2();
+                let b = Vec3::new(b.x, b.y, 0.0);
+                let offset = Vec3::new(wavedash_normal.x, wavedash_normal.y, 0.0) * radius;
+                gizmos.line(a + offset, b + offset, bevy::color::palettes::css::HOT_PINK);
+                gizmos.line(a - offset, b - offset, bevy::color::palettes::css::HOT_PINK);
+            }
         }
     }