fix: fixing prevPosition updating (#55)

kurtome · Aug 26, 2024 · 64170f2 · 64170f2
1 parent 8a8d82c
commit 64170f2
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Showing 5 changed files with 111 additions and 84 deletions.
diff --git a/examples/standard_platformer/pubspec.lock b/examples/standard_platformer/pubspec.lock
@@ -93,18 +93,18 @@ packages:
     dependency: transitive
     description:
       name: crypto
-      sha256: ff625774173754681d66daaf4a448684fb04b78f902da9cb3d308c19cc5e8bab
+      sha256: ec30d999af904f33454ba22ed9a86162b35e52b44ac4807d1d93c288041d7d27
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.3"
+    version: "3.0.5"
   ffi:
     dependency: transitive
     description:
       name: ffi
-      sha256: "493f37e7df1804778ff3a53bd691d8692ddf69702cf4c1c1096a2e41b4779e21"
+      sha256: "16ed7b077ef01ad6170a3d0c57caa4a112a38d7a2ed5602e0aca9ca6f3d98da6"
       url: "https://pub.dev"
     source: hosted
-    version: "2.1.2"
+    version: "2.1.3"
   file:
     dependency: transitive
     description:
@@ -192,7 +192,7 @@ packages:
       path: "../../packages/leap"
       relative: true
     source: path
-    version: "0.7.0"
+    version: "0.8.0"
   lints:
     dependency: transitive
     description:
@@ -245,10 +245,10 @@ packages:
     dependency: transitive
     description:
       name: path_provider_android
-      sha256: "490539678396d4c3c0b06efdaab75ae60675c3e0c66f72bc04c2e2c1e0e2abeb"
+      sha256: "6f01f8e37ec30b07bc424b4deabac37cacb1bc7e2e515ad74486039918a37eb7"
       url: "https://pub.dev"
     source: hosted
-    version: "2.2.9"
+    version: "2.2.10"
   path_provider_foundation:
     dependency: transitive
     description:
@@ -338,10 +338,10 @@ packages:
     dependency: transitive
     description:
       name: synchronized
-      sha256: "539ef412b170d65ecdafd780f924e5be3f60032a1128df156adad6c5b373d558"
+      sha256: a824e842b8a054f91a728b783c177c1e4731f6b124f9192468457a8913371255
       url: "https://pub.dev"
     source: hosted
-    version: "3.1.0+1"
+    version: "3.2.0"
   term_glyph:
     dependency: transitive
     description:
@@ -407,5 +407,5 @@ packages:
     source: hosted
     version: "6.5.0"
 sdks:
-  dart: ">=3.4.0 <4.0.0"
+  dart: ">=3.5.0 <4.0.0"
   flutter: ">=3.22.0"
diff --git a/packages/leap/lib/src/entities/behaviors/apply_velocity_behavior.dart b/packages/leap/lib/src/entities/behaviors/apply_velocity_behavior.dart
@@ -7,7 +7,7 @@ class ApplyVelocityBehavior extends PhysicalBehavior {
 
   @override
   void update(double dt) {
-    super.update(dt);
+    parent.prevPosition.setFrom(position);
 
     if (parent.statuses
         .where((s) => s is IgnoredByWorld || s is IgnoresVelocity)

diff --git a/packages/leap/lib/src/entities/moving_platform.dart b/packages/leap/lib/src/entities/moving_platform.dart
@@ -20,6 +20,12 @@ abstract class MovingPlatform extends PhysicalEntity {
     // with the platform.
     super.priority = 2,
   }) : super(static: true) {
+    // Behaviors
+    add(_ApplySpeedBehavior());
+    add(ApplyVelocityBehavior());
+    add(_PreventOvershotPositionBehavior());
+    add(_MoveEntitiesAtopBehavior());
+
     tags.add(CommonTags.ground);
 
     position = initialPosition;
@@ -56,6 +62,8 @@ abstract class MovingPlatform extends PhysicalEntity {
   /// at the front (index 0).
   late final List<Vector2> positionPath;
 
+  Vector2 get nextPosition => positionPath[_nextPathNode];
+
   /// What to do when reaching the end of the tilePath.
   final MovingPlatformLoopMode loopMode;
 
@@ -70,75 +78,6 @@ abstract class MovingPlatform extends PhysicalEntity {
     positionPath = _calculatePositionPath(position, tilePath, tileSize);
   }
 
-  @override
-  @mustCallSuper
-  void updateAfter(double dt) {
-    if (!_stopped) {
-      _updatePositionAndLoop(dt);
-
-      final deltaX = x - prevPosition.x;
-      final deltaY = y - prevPosition.y;
-      // Update the position of anything on top of this platform. Ideally
-      // this happens before the other entity's collision logic
-      leapWorld.physicals
-          .where((other) => other.collisionInfo.downCollision == this)
-          .forEach((element) {
-        element.x += deltaX;
-        element.y += deltaY;
-      });
-    }
-
-    super.updateAfter(dt);
-  }
-
-  void _updatePositionAndLoop(double dt) {
-    if (position == positionPath[_nextPathNode]) {
-      if (_reversing) {
-        _nextPathNode -= 1;
-      } else {
-        _nextPathNode += 1;
-      }
-
-      if (_nextPathNode < 0) {
-        _reversing = false;
-        _nextPathNode = 1;
-      }
-      if (_nextPathNode >= positionPath.length) {
-        switch (loopMode) {
-          case MovingPlatformLoopMode.none:
-            _stopped = true;
-          case MovingPlatformLoopMode.resetAndLoop:
-            position.x = positionPath[0].x;
-            position.y = positionPath[0].y;
-            _nextPathNode = 1;
-          case MovingPlatformLoopMode.reverseAndLoop:
-            _reversing = true;
-            _nextPathNode = positionPath.length - 2;
-        }
-      }
-    }
-
-    final nextPosition = positionPath[_nextPathNode];
-
-    final lastX = position.x;
-    if (nextPosition.x > x) {
-      position.x += dt * moveSpeed.x * tileSize;
-      position.x = position.x.clamp(lastX, nextPosition.x);
-    } else {
-      position.x -= dt * moveSpeed.x * tileSize;
-      position.x = position.x.clamp(nextPosition.x, lastX);
-    }
-
-    final lastY = position.y;
-    if (nextPosition.y > y) {
-      position.y += dt * moveSpeed.y * tileSize;
-      position.y = position.y.clamp(lastY, nextPosition.y);
-    } else {
-      position.y -= dt * moveSpeed.y * tileSize;
-      position.y = position.y.clamp(nextPosition.y, lastY);
-    }
-  }
-
   static Vector2 _parseMoveSpeed(TiledObject tiledObject) {
     final x = tiledObject.properties.getValue<double>('MoveSpeedX') ?? 1;
     final y = tiledObject.properties.getValue<double>('MoveSpeedY') ?? 1;
@@ -217,3 +156,90 @@ enum MovingPlatformLoopMode {
   /// start the path again.
   reverseAndLoop,
 }
+
+class _ApplySpeedBehavior extends PhysicalBehavior<MovingPlatform> {
+  @override
+  void update(double dt) {
+    if (parent._stopped) {
+      return;
+    }
+
+    if (position == parent.positionPath[parent._nextPathNode]) {
+      if (parent._reversing) {
+        parent._nextPathNode -= 1;
+      } else {
+        parent._nextPathNode += 1;
+      }
+
+      if (parent._nextPathNode < 0) {
+        parent._reversing = false;
+        parent._nextPathNode = 1;
+      }
+      if (parent._nextPathNode >= parent.positionPath.length) {
+        switch (parent.loopMode) {
+          case MovingPlatformLoopMode.none:
+            parent._stopped = true;
+          case MovingPlatformLoopMode.resetAndLoop:
+            position.x = parent.positionPath[0].x;
+            position.y = parent.positionPath[0].y;
+            parent._nextPathNode = 1;
+          case MovingPlatformLoopMode.reverseAndLoop:
+            parent._reversing = true;
+            parent._nextPathNode = parent.positionPath.length - 2;
+        }
+      }
+    }
+
+    if (parent.nextPosition.x > parent.x) {
+      velocity.x = parent.moveSpeed.x * parent.tileSize;
+    } else {
+      velocity.x = -parent.moveSpeed.x * parent.tileSize;
+    }
+
+    if (parent.nextPosition.y > parent.y) {
+      velocity.y = parent.moveSpeed.y * parent.tileSize;
+    } else {
+      velocity.y = -parent.moveSpeed.y * parent.tileSize;
+    }
+  }
+}
+
+class _MoveEntitiesAtopBehavior extends PhysicalBehavior<MovingPlatform> {
+  @override
+  void update(double dt) {
+    if (!parent._stopped) {
+      final deltaX = x - prevPosition.x;
+      final deltaY = y - prevPosition.y;
+      // Update the position of anything on top of this platform. Ideally
+      // this happens before the other entity's collision logic
+      leapWorld.physicals
+          .where((other) => other.collisionInfo.downCollision == parent)
+          .forEach((element) {
+        element.x += deltaX;
+        element.y += deltaY;
+      });
+    }
+  }
+}
+
+class _PreventOvershotPositionBehavior
+    extends PhysicalBehavior<MovingPlatform> {
+  @override
+  void update(double dt) {
+    if (parent.nextPosition.x > parent.prevPosition.x) {
+      position.x =
+          position.x.clamp(parent.prevPosition.x, parent.nextPosition.x);
+    } else {
+      position.x =
+          position.x.clamp(parent.nextPosition.x, parent.prevPosition.x);
+    }
+
+    if (parent.nextPosition.y > parent.prevPosition.y) {
+      position.y =
+          position.y.clamp(parent.prevPosition.y, parent.nextPosition.y);
+    } else {
+      position.y =
+          position.y.clamp(parent.nextPosition.y, parent.prevPosition.y);
+    }
+  }
+}
diff --git a/packages/leap/lib/src/entities/physical_entity.dart b/packages/leap/lib/src/entities/physical_entity.dart
@@ -63,7 +63,9 @@ abstract class PhysicalEntity extends PositionedEntity {
   /// [collisionInfo] from last game tick
   final CollisionInfo prevCollisionInfo = CollisionInfo();
 
-  /// [position] from last game tick
+  /// [position] from last game tick.
+  /// Typically set by [ApplyVelocityBehavior], but if an entity
+  /// manages its own position state it should set this itself
   final Vector2 prevPosition = Vector2.zero();
 
   /// Multiplier on standard gravity, see [LeapWorld].
@@ -127,7 +129,6 @@ abstract class PhysicalEntity extends PositionedEntity {
   @mustCallSuper
   void updateAfter(double dt) {
     _updateDebugHitbox();
-    prevPosition.setFrom(position);
   }
 
   void _updateDebugHitbox() {

diff --git a/packages/leap/pubspec.lock b/packages/leap/pubspec.lock
@@ -53,10 +53,10 @@ packages:
     dependency: transitive
     description:
       name: crypto
-      sha256: ff625774173754681d66daaf4a448684fb04b78f902da9cb3d308c19cc5e8bab
+      sha256: ec30d999af904f33454ba22ed9a86162b35e52b44ac4807d1d93c288041d7d27
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.3"
+    version: "3.0.5"
   fake_async:
     dependency: transitive
     description: