Updates to GLX_EXT_texture_from_pixmap

[Deron Johnson]

James Jones wrote On 03/09/06 14:09,:
>
>     Rendering to the drawable, either using the GL or other means, while it is
>     bound to a texture is not allowed.  It is the responsibility of the user
>     to enforce this constraint.  If the drawable is rendered to while it is
>     bound as a texture, the contents become undefined.

This is very different from what we discussed at the X developer's
conference. I thought we agreed that rendering to a drawable while it is
being bound as a texture would be blocked, and that the rendering would
proceed as soon as the drawable was unbound. The overall desired behave
was to give the effect of conceptually having bind make a copy of the
texture.

To disallow user rendering while the drawable is bound as a texture
makes the entire extension unusable. What happens to rendering that
is sent to the drawable while it is bound? Is it discarded? Does
it generate an error? Either way, there is no way that the client
rendering to the drawable can synchronize with the composite manager
to make sure that this doesn't happen. Not only that, the restriction
of disallowing drawing during texturing is not even needed for
devices on which the bind does a real copy.

I think we should go back to the semantics we agreed upon at the
X developer conference and have implementions hold off rendering
to the drawable while it is bound, if necessary.