I'm trying to render to a texture (really thought it would be easier than this!)

I found this resource: which seems to be exactly what I want

I'm getting a ClassCastException however, on GL11ExtensionPack gl11ep = (GL11ExtensionPack) gl;

Can anyone tell me why?

  public void renderToTexture(GLRenderer glRenderer, GL10 gl)
  {
    boolean checkIfContextSupportsExtension = checkIfContextSupportsExtension(gl, "GL_OES_framebuffer_object");
    if(checkIfContextSupportsExtension)
    {
      GL11ExtensionPack gl11ep = (GL11ExtensionPack) gl;

      int mFrameBuffer = createFrameBuffer(gl,texture.getWidth(), texture.getHeight(), texture.getGLID());

      gl11ep.glBindFramebufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, mFrameBuffer);

      gl.glViewport(0, 0,texture.getWidth(), texture.getHeight());
      gl.glLoadIdentity();

      int halfWidth = texture.getWidth()/2;//width/2;
      int halfHeight = texture.getHeight()/2;//height/2;

      GLU.gluOrtho2D(gl, -halfWidth, halfWidth , -halfHeight, halfHeight);

      gl.glMatrixMode(GL10.GL_MODELVIEW);
      gl.glLoadIdentity();

      gl.glEnable(GL10.GL_TEXTURE_2D);

      Quad quad = new Quad(texture.getWidth(), texture.getHeight());
      quad.setTexture(texture);

      SpriteRenderable sr = new SpriteRenderable(quad);
      //sr.setPosition(new Interpolation<Vector2>(new Vector2(-(float)texture.getWidth()/2f,-(float)texture.getHeight()/2f)));
      //sr.setPosition(new Interpolation<Vector2>(new Vector2((float)(texture.getWidth()/2f),0)));
      //sr.setPosition(new Interpolation<Vector2>(new Vector2(200,-200)));

      sr.setAngle(0.05f);

      sr.renderTo(glRenderer, gl, 1);

      for (Renderable renderable : renderThese)
      {
        if (renderable.isVisible()) {
          renderable.renderTo(glRenderer, gl, 1);
        }
      }

      gl11ep.glBindFramebufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, 0);
    }
  }