add entry point to ref texture for RefractionPostProcess

src/PostProcess/babylon.refractionPostProcess.ts

@@ -1,11 +1,22 @@
 module BABYLON {
     export class RefractionPostProcess extends PostProcess {
-        private _refRexture: Texture;
+        private _refTexture: Texture;
+        private _ownRefractionTexture = true;
+
+        public set refractionTexture(value: Texture) {
+            if (this._refTexture && this._ownRefractionTexture) {
+                this._refTexture.dispose();
+            }
+
+            this._refTexture = value;
+            this._ownRefractionTexture = false;
+        }
+
         constructor(name: string, refractionTextureUrl: string, public color: Color3, public depth: number, public colorLevel: number, options: number | PostProcessOptions, camera: Camera, samplingMode?: number, engine?: Engine, reusable?: boolean) {
             super(name, "refraction", ["baseColor", "depth", "colorLevel"], ["refractionSampler"], options, camera, samplingMode, engine, reusable);
 
             this.onActivateObservable.add((cam: Camera) => {
-                this._refRexture = this._refRexture || new Texture(refractionTextureUrl, cam.getScene());
+                this._refTexture = this._refTexture || new Texture(refractionTextureUrl, cam.getScene());
             });
 
             this.onApplyObservable.add((effect: Effect) => {
@@ -13,14 +24,15 @@
                 effect.setFloat("depth", this.depth);
                 effect.setFloat("colorLevel", this.colorLevel);
 
-                effect.setTexture("refractionSampler", this._refRexture);
+                effect.setTexture("refractionSampler", this._refTexture);
             });
         }
 
         // Methods
         public dispose(camera: Camera): void {
-            if (this._refRexture) {
-                this._refRexture.dispose();
+            if (this._refTexture && this._ownRefractionTexture) {
+                this._refTexture.dispose();
+                (<any>this._refTexture) = null;
             }
 
             super.dispose(camera);