[Glamor] [PATCH] Allow to create textured pixmaps from gbm_bo without using gem names

[davyaxel at free.fr]

>
>
> There seems to be a last issue to settle: texture format.
>
> Dri3 protocol doesn't share any information about the format of the buffers.
>
> That means for example that we can't know of which format is an imported buffer,
>  until the pixmap is associated to a window (then we can check the window visual).
>
> This is a problem I'm not sure the best way to solve.
> Perhaps a way is to always use GL_BGRA over GL_RGBA for example, even if the content doesn't match to that.
> I think this is already what happens when the pixmap has a textured created from a buffer comming from the DDX.
>
I think the best approach is to consider we live in an argb8888 world (which seems a pretty good asumption right now).

We can't know which component order will result when allocating a texture with GL_BGRA of GL_RGBA.
For example with gallium drivers, GL_RGBA (the one we use now for all textures) is ABGR8888.
To ensure we use ARGB8888, the best to me seems to allocate an argb8888 gbm_bo, and create the texture from it (after converting to an image).

Glamor Dri3 support could do that, and keep the old way when dri3 isn't enabled.

Axel Davy