Fix #14992 (#14994)

BabylonJS · Apr 16, 2024 · c9644ea · c9644ea
1 parent 3fdd140
commit c9644ea
Showing 1 changed file with 15 additions and 3 deletions.
diff --git a/packages/dev/core/src/Animations/runtimeAnimation.ts b/packages/dev/core/src/Animations/runtimeAnimation.ts
@@ -111,6 +111,8 @@ export class RuntimeAnimation {
      */
     private _previousElapsedTime: number = 0;
 
+    private _yoyoDirection: number = 1;
+
     /**
      * The previous absolute frame of the runtime animation (meaning, without taking into account the from/to values, only the elapsed time and the fps)
      */
@@ -512,14 +514,24 @@ export class RuntimeAnimation {
         let highLimitValue = 0;
 
         // Apply the yoyo function if required
-        if (loop && this._animationState.loopMode === Animation.ANIMATIONLOOPMODE_YOYO) {
+        let yoyoLoop = false;
+        const yoyoMode = loop && this._animationState.loopMode === Animation.ANIMATIONLOOPMODE_YOYO;
+        if (yoyoMode) {
             const position = (absoluteFrame - from) / frameRange;
 
             // Apply the yoyo curve
-            const yoyoPosition = Math.abs(Math.sin(position * Math.PI));
+            const sin = Math.sin(position * Math.PI);
+            const yoyoPosition = Math.abs(sin);
 
             // Map the yoyo position back to the range
             absoluteFrame = yoyoPosition * frameRange + from;
+
+            const direction = sin >= 0 ? 1 : -1;
+            if (this._yoyoDirection !== direction) {
+                yoyoLoop = true;
+            }
+
+            this._yoyoDirection = direction;
         }
 
         this._previousElapsedTime = elapsedTimeSinceAnimationStart;
@@ -628,7 +640,7 @@ export class RuntimeAnimation {
         const events = this._events;
 
         // Reset event/state if looping
-        if ((speedRatio > 0 && this.currentFrame > currentFrame) || (speedRatio < 0 && this.currentFrame < currentFrame)) {
+        if ((!yoyoMode && ((speedRatio > 0 && this.currentFrame > currentFrame) || (speedRatio < 0 && this.currentFrame < currentFrame))) || (yoyoMode && yoyoLoop)) {
             this._onLoop();
 
             // Need to reset animation events