check for colorGradingTexture

src/Materials/Textures/babylon.colorGradingTexture.ts

@@ -87,6 +87,11 @@ module BABYLON {
             this._texture = texture;
 
             var callback = (text: string | ArrayBuffer) => {
+
+                if (typeof text !== "string") {
+                    return;
+                }
+
                 var data: Nullable<Uint8Array> = null;
                 var tempData: Nullable<Float32Array> = null;