node masking for scene beginAnimation functions

src/babylon.scene.ts

@@ -2520,10 +2520,11 @@
          * @param speedRatio defines the speed in which to run the animation (1.0 by default)
          * @param onAnimationEnd defines the function to be executed when the animation ends
          * @param animatable defines an animatable object. If not provided a new one will be created from the given params
+         * @param targetMask defines if the target should be animated if animations are present (called recursively on descendant animatables)
          * @returns the animatable object created for this animation
          */
-        public beginWeightedAnimation(target: any, from: number, to: number, weight = 1.0, loop?: boolean, speedRatio: number = 1.0, onAnimationEnd?: () => void, animatable?: Animatable): Animatable {
-            let returnedAnimatable = this.beginAnimation(target, from, to, loop, speedRatio, onAnimationEnd, animatable, false);
+        public beginWeightedAnimation(target: any, from: number, to: number, weight = 1.0, loop?: boolean, speedRatio: number = 1.0, onAnimationEnd?: () => void, animatable?: Animatable, targetMask?: (target: any) => boolean): Animatable { 
+            let returnedAnimatable = this.beginAnimation(target, from, to, loop, speedRatio, onAnimationEnd, animatable, false, targetMask);
             returnedAnimatable.weight = weight;
 
             return returnedAnimatable;
@@ -2539,9 +2540,10 @@
          * @param onAnimationEnd defines the function to be executed when the animation ends
          * @param animatable defines an animatable object. If not provided a new one will be created from the given params
          * @param stopCurrent defines if the current animations must be stopped first (true by default)
+         * @param targetMask determines if a target should be excluded if animations are present (this is called recursively on descendant animatables regardless of return value)
          * @returns the animatable object created for this animation
          */
-        public beginAnimation(target: any, from: number, to: number, loop?: boolean, speedRatio: number = 1.0, onAnimationEnd?: () => void, animatable?: Animatable, stopCurrent = true): Animatable {
+        public beginAnimation(target: any, from: number, to: number, loop?: boolean, speedRatio: number = 1.0, onAnimationEnd?: () => void, animatable?: Animatable, stopCurrent = true, targetMask?: (target: any) => boolean): Animatable {
 
             if (from > to && speedRatio > 0) {
                 speedRatio *= -1;
@@ -2555,8 +2557,9 @@
                 animatable = new Animatable(this, target, from, to, loop, speedRatio, onAnimationEnd);
             }
 
+            const shouldMaskOutTarget = targetMask ? targetMask(target) : false;
             // Local animations
-            if (target.animations) {
+            if (target.animations && !shouldMaskOutTarget) {
                 animatable.appendAnimations(target, target.animations);
             }
 
@@ -2564,7 +2567,7 @@
             if (target.getAnimatables) {
                 var animatables = target.getAnimatables();
                 for (var index = 0; index < animatables.length; index++) {
-                    this.beginAnimation(animatables[index], from, to, loop, speedRatio, onAnimationEnd, animatable, stopCurrent);
+                    this.beginAnimation(animatables[index], from, to, loop, speedRatio, onAnimationEnd, animatable, stopCurrent, targetMask);
                 }
             }