[Mesa-dev] nv3x xfce4 compositing issue, making good progress, need help / input

[Ilia Mirkin]

On Mon, Sep 28, 2015 at 10:14 AM, Hans de Goede <hdegoede at redhat.com> wrote:
> On 25-09-15 17:21, Ilia Mirkin wrote:
>> Looking at the spec, it actually looks like you can drop
>> GLX_TEXTURE_2D_BIT to make 2D textures go away, and mark them all RECT
>> in bo_from_handle() [for nv3x only of course].
>
>
> Erm, unless I'm mistaken nv3x does not do RECT at all since it does
> not support NPOT textures ...
>
> We actually end up using TEXTURE_2D on nv3c because of this, on nv4x
> which does support RECT there is no issue.

RECT textures are different from NPOT textures. RECT textures come in
from the GL_TEXTURE_RECTANGLE binding point and have the following
differences:
 - no mipmaps
 - unscaled (non-normalized) coordinate space

All NVIDIA hardware since nv10 supports these, the gallium state
tracker unconditionally exports NV_texture_rectangle support (which
also enables ARB_texture_rectangle).

nv3x does indeed not support ARB_texture_npot which allows you to have
npot-sized textures with GL_TEXTURE_2D (which means that you get
normalized coordinates, mipmaps, etc).

Cheers,

  -ilia