WebGLRenderer.isNewNormalMap is a new method that returns a boolean if the given parameters are not currently used.

Author: photonstorm

src/renderer/webgl/WebGLRenderer.js

@@ -778,7 +778,7 @@ var WebGLRenderer = new Class({
 
             gl.bindTexture(gl.TEXTURE_2D, tempTexture);
 
-            gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array([ 0, 0, 255, 255 ]));
+            gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array([ 255, 255, 255, 255 ]));
 
             tempTextures[index] = tempTexture;
 
@@ -1416,6 +1416,22 @@ var WebGLRenderer = new Class({
         return textureSource.glIndex;
     },
 
+    /**
+     * Checks to see if the given diffuse and normal map textures are already bound, or not.
+     *
+     * @method Phaser.Renderer.WebGL.WebGLRenderer#isNewNormalMap
+     * @since 3.25.0
+     *
+     * @param {WebGLTexture} texture - The WebGL diffuse texture.
+     * @param {WebGLTexture} normalMap - The WebGL normal map texture.
+     *
+     * @return {boolean} Returns `false` if this combination is already set, or `true` if it's a new combination.
+     */
+    isNewNormalMap: function (texture, normalMap)
+    {
+        return (this.textureZero !== texture || this.normalTexture !== normalMap);
+    },
+
     /**
      * Binds a texture directly to texture unit zero then activates it.
      * If the texture is already at unit zero, it skips the bind.