Clipping in Cocos2d iPhone

glEnable(GL_SCISSOR_TEST);

// Some region to clip to
CGRect rect = CGRect(100, 100, 200, 200);

CGRect frame = [[[CCDirector sharedDirector] openGLView] frame];

// Adjust for position
CGPoint worldPos = [self convertToWorldSpaceAR:position_];

rect.origin.x = frame.size.height - worldPos.x - rect.origin.x - rect.size.width;
rect.origin.y += worldPos.y;

CGPoint origin = [[CCDirector sharedDirector] convertToGL:rect.origin];

glScissor(origin.x, origin.y, rect.size.height, rect.size.width);
glDisable(GL_SCISSOR_TEST);