Add mechanism to ignore platforms (#63)

Reviewed-on: #63
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/surface.rs

@@ -1,6 +1,6 @@
 use bevy::prelude::*;
 
-use crate::{stage::line::StageLineID};
+use crate::stage::line::StageLineID;
 
 #[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
 pub enum EcbLockPolicy {
@@ -15,10 +15,17 @@ pub enum EcbLockPolicy {
 /// This is physics state rather than fighter-state-machine state. Keeping it
 /// separate means grounded, landing, and hitstun states all share one source
 /// of truth for stage contact.
-#[derive(Component, Clone, Copy, Debug, Hash, PartialEq, Eq)]
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+pub struct IgnoredPolygon {
+    pub polygon: usize,
+    pub frames_remaining: u32,
+}
+
+#[derive(Component, Clone, Debug, Hash, PartialEq, Eq)]
 pub enum FighterSurfaceState {
     Airborne {
-        ecb_lock_frames_remaining: u32
+        ecb_lock_frames_remaining: u32,
+        ignored_polys: Vec<IgnoredPolygon>,
     },
     Grounded {
         line_id: StageLineID,
@@ -28,20 +35,21 @@ pub enum FighterSurfaceState {
 impl Default for FighterSurfaceState {
     fn default() -> Self {
         Self::Airborne {
-            ecb_lock_frames_remaining: 0
+            ecb_lock_frames_remaining: 0,
+            ignored_polys: vec![],
         }
     }
 }
 
 impl FighterSurfaceState {
-    pub fn is_grounded(self) -> bool {
+    pub fn is_grounded(&self) -> bool {
         matches!(self, Self::Grounded { .. })
     }
 
-    pub fn line_id(self) -> Option<StageLineID> {
+    pub fn line_id(&self) -> Option<StageLineID> {
         match self {
             Self::Airborne { .. } => None,
-            Self::Grounded { line_id } => Some(line_id),
+            Self::Grounded { line_id } => Some(*line_id),
         }
     }
 
@@ -49,13 +57,46 @@ impl FighterSurfaceState {
         *self = Self::Grounded { line_id };
     }
 
+    pub fn ignore_polygon(&mut self, polygon: usize, duration_frames: u32) {
+        let Self::Airborne { ignored_polys, .. } = self else {
+            return;
+        };
+
+        if duration_frames == 0 {
+            return;
+        }
+
+        if let Some(ignored) = ignored_polys.iter_mut().find(|ignored| ignored.polygon == polygon) {
+            ignored.frames_remaining = duration_frames;
+        } else {
+            ignored_polys.push(IgnoredPolygon {
+                polygon,
+                frames_remaining: duration_frames,
+            });
+        }
+    }
+
+    pub fn is_polygon_ignored(&self, polygon: usize) -> bool {
+        matches!(self, Self::Airborne { ignored_polys, .. }
+            if ignored_polys.iter().any(|ignored| ignored.polygon == polygon))
+    }
+
+    pub(crate) fn ignored_polygon_ids(&self) -> Vec<usize> {
+        match self {
+            Self::Airborne { ignored_polys, .. } => {
+                ignored_polys.iter().map(|ignored| ignored.polygon).collect()
+            }
+            Self::Grounded { .. } => vec![],
+        }
+    }
+
     pub(crate) fn apply_airborne_policy(
         &mut self,
         policy: EcbLockPolicy,
         ecb_lock_duration: u32,
     ) {
-        let current_lock = match *self {
-            Self::Airborne { ecb_lock_frames_remaining } => ecb_lock_frames_remaining,
+        let current_lock = match self {
+            Self::Airborne { ecb_lock_frames_remaining, .. } => *ecb_lock_frames_remaining,
             Self::Grounded { .. } => 0,
         };
         let ecb_lock_frames_remaining = match policy {
@@ -65,14 +106,27 @@ impl FighterSurfaceState {
             EcbLockPolicy::Preserve => current_lock,
             EcbLockPolicy::Clear => 0,
         };
-        *self = Self::Airborne { ecb_lock_frames_remaining };
+        let ignored_polys = match self {
+            Self::Airborne { ignored_polys, .. } => ignored_polys.clone(),
+            Self::Grounded { .. } => vec![],
+        };
+        *self = Self::Airborne { ecb_lock_frames_remaining, ignored_polys };
     }
 
     pub(crate) fn tick_ecb_lock(&mut self) {
-        if let Self::Airborne { ecb_lock_frames_remaining } = self {
+        if let Self::Airborne { ecb_lock_frames_remaining, .. } = self {
             *ecb_lock_frames_remaining = ecb_lock_frames_remaining.saturating_sub(1);
         }
     }
+
+    pub(crate) fn tick_ignored_polygons(&mut self) {
+        if let Self::Airborne { ignored_polys, .. } = self {
+            for ignored in ignored_polys.iter_mut() {
+                ignored.frames_remaining = ignored.frames_remaining.saturating_sub(1);
+            }
+            ignored_polys.retain(|ignored| ignored.frames_remaining > 0);
+        }
+    }
 }
 
 #[cfg(test)]
@@ -109,6 +163,7 @@ mod tests {
             surface,
             FighterSurfaceState::Airborne {
                 ecb_lock_frames_remaining: 4,
+                ignored_polys: vec![],
             }
         );
     }
@@ -124,7 +179,41 @@ mod tests {
             surface,
             FighterSurfaceState::Airborne {
                 ecb_lock_frames_remaining: 5,
+                ignored_polys: vec![],
             }
         );
     }
+
+    #[test]
+    fn ignored_polygon_expires_after_requested_frames() {
+        let mut surface = FighterSurfaceState::default();
+        surface.ignore_polygon(3, 2);
+
+        assert!(surface.is_polygon_ignored(3));
+        surface.tick_ignored_polygons();
+        assert!(surface.is_polygon_ignored(3));
+        surface.tick_ignored_polygons();
+        assert!(!surface.is_polygon_ignored(3));
+    }
+
+    #[test]
+    fn ignoring_polygon_refreshes_existing_entry() {
+        let mut surface = FighterSurfaceState::default();
+        surface.ignore_polygon(3, 2);
+        surface.ignore_polygon(3, 5);
+        surface.tick_ignored_polygons();
+        surface.tick_ignored_polygons();
+        assert!(surface.is_polygon_ignored(3));
+    }
+
+    #[test]
+    fn airborne_policy_preserves_ignored_polygons_and_landing_clears_them() {
+        let mut surface = FighterSurfaceState::default();
+        surface.ignore_polygon(3, 5);
+        surface.apply_airborne_policy(EcbLockPolicy::Restart, 2);
+        assert!(surface.is_polygon_ignored(3));
+
+        surface.land(StageLineID { polygon: 0, segment: 0 });
+        assert!(!surface.is_polygon_ignored(3));
+    }
 }