====== Extending Sparrow ======

Sometimes, you want to squeeze out the last bit of performance. You want to make the calls to OpenGL yourself. In Sparrow, that's easy to do. Just override the "render:" method that is implemented by any display object.

<code objc>
- (void)render:(SPRenderSupport *)support
{
    [support bindTexture:mTexture];

    glEnable(GL_POINT_SPRITE_OES);
    // ...
    glDisable(GL_POINT_SPRITE_OES);
}
</code>

In that sample, the developer wants to use OpenGL point sprites. By overriding the "render:" method, Sparrow will use this custom code to draw the object.

  * When the render method is executed, OpenGL's transformation matrices are already pointing to the local coordinate system.
  * The "support" object contains some methods that help during rendering, e.g. a "bindTexture:" method that only forwards the call to OpenGL if another texture is bound.

If you want to take this path, I recommend you have a look at Sparrow's default rendering code, and find some orientation there.