Fix xserver build

[Michel Dänzer]

On Tue, 2006-10-10 at 00:38 +0200, Edgar Toernig wrote:
> 
> All GL apps issue "libGL warning: 3D driver claims to not support visual 0x4b"

See https://bugs.freedesktop.org/show_bug.cgi?id=6689 .

> and compiz can't find the texture_from_pixmap
> extension.

[...]

> Forcing compiz to indirect rendering (LIBGL_ALWAYS_INDIRECT=1)
> (or removing the extension check) 

GLX_EXT_tfp only works with indirect rendering with AIGLX, compiz
actually has a command line switch --indirect-rendering for that.

> gets a little bit further (some graphics garbage) but it only produces
> a lot of error messages that it can't bind windows and
> pixmaps to textures.  It can be ctrl-C'ed though and
> everything turns back to normal. [1]
> 
> So, why is the GLX_EXT_texture_from_pixmap not working?

It's related to the recent reorganization of the server GLX code. The
current code is missing a dispatch entry for GetDrawableAttributesSGIX,
so compiz doesn't know which texture target to use.

What I'm not sure about yet is whether it's expected that the server
gets a request for GetDrawableAttributesSGIX when compiz calls the
result of glXGetProcAddressARB("glXQueryDrawable"). There might be an
issue in libGL as well.

It's all a little messy right now, but I understand Ian Romanick is
planning to push some more changes soon which will hopefully clear
things up. In the meantime, you could use the 1.1 branch or master from
before commit d7a7f12361d31001bbd9394a57de029ef0b934b8.


> [1] Another fruitless try was to change the "caveat" of
> visual 0x4b from Ncon to None but that just produces an
> error in libGL about depth 0 something (maybe the 0-bit
> wide depth-buffer).

The visual is marked as non-conformant to prevent it from getting picked
up by default for this and other reasons.


-- 
Earthling Michel Dänzer           |          http://tungstengraphics.com
Libre software enthusiast         |          Debian, X and DRI developer