docs: public void update(int width, int height, int sampleCount) {
          if (capturing) {
              throw new IllegalStateException("Cannot update backing texture while capturing");
          }
  
          this.width = width;
          this.height = height;
  
          if (sampleCount == 0)
              captureTexture = new GVRRenderTexture(getGVRContext(), width, height);
          else
              captureTexture = new GVRRenderTexture(getGVRContext(), width, height, sampleCount);
  
          setRenderTexture(captureTexture);
          readBackBuffer = new int[width * height];
      }