code: public static void checkDepthStencilRenderableTexture2D(
      final JCGLTextureFormat t)
      throws JCGLExceptionFormatError
    {
      if (isDepthRenderable(t)
        && isStencilRenderable(t)) {
        return;
      }
  
      final String m =
        String.format("Format %s is not depth+stencil-renderable", t);
      assert m != null;
      throw new JCGLExceptionFormatError(m);
    }
docs: Check that the texture is of a depth+stencil-renderable format.
  
  @param t The texture
  
  @throws JCGLExceptionFormatError If the texture is not of the correct
  format