Re: [Mesa3d-dev] Texture formats

[Gareth H. <ga...@va...>]

Brian Paul wrote:
> 
> In the s/w rasterizer I've been replacing the texture Format and Type
> checks with comparisons against the new MESA_FORMAT_* tokens.
> 
> And in the texture-object-completeness function, I'm going to check
> if all mipmaps are of the same format by comparing the TexFormat field
> instead of the Format/Type fields.
> 
> So, the Type field really might not be needed anymore.  However, it
> wouldn't be bad to keep it around a bit longer, I think.

Sounds good.

I have a quick question regarding color lookup tables.  If a driver
doesn't support paletted textures, the only failure case is when the
data format is a GL_COLOR_INDEX(_*) type and the internalFormat is
GL_COLOR_INDEX, right?  If the internalFormat is anything else, it goes
through the color lookup table, which defaults to 0 for all channels,
right?

So, if I've got this right, the driver would have to inspect
internalFormat if the data format was GL_COLOR_INDEX(_*) and choose an
appropriate final destination format, skip the first conversion pass,
call the texstore functions to perform the LUT conversion, and then call
_mesa_convert_texsubimage*() to convert the GLchan-based post-LUT image
to the final image format.  Does this sound correct?

-- Gareth