public void texSubImage2D(Image image, int target, int level, int xOffset, int yOffset, int format,
                            int type) {
    throw new UnsupportedOperationException();
  }
public void texSubImage2D ( Image image , int target , int level , int xOffset , int yOffset , int format , int type ) { throw new UnsupportedOperationException ( ) ; }
See http://www.khronos.org/opengles/sdk/docs/man/xhtml/glTexSubImage2D.xml

<p>The default implementation is based on {@link Image#getRgb} and will hand over a RGBA byte
array. Please set the (internal)format and type parameters accordingly; they are mainly
present for future support of different formats. The WebGL implementation will pass through
all parameters.</p>