Re: [Mesa3d-dev] Shader texture access

[Shachar K. <sha...@gm...>]

Yes: I'm working on 7.3 sources, and looking at prog_execute.c
mesa_execute_program() under OPCODE_TEX/TXB/TXD.

My claim was too broad though, I am wondering very specifically about the
use of the inst->TexSrcUnit field. In OPCODE_TXB it is used directly as an
index into the ctx->Texture.Unit array (for the purpose of fetchig the LOD
bias), but in fetch_texel() we have "unit =
machine->Samplers[inst->TexSrcUnit]" that is, there is an indirect mapping
between the instruciton field and the actual texture unit index.

On Mon, Mar 30, 2009 at 5:32 PM, Brian Paul <br...@vm...> wrote:

> Shachar Kaufman wrote:
> > Hi all,
> >
> > I noticed shader texture access, when done from TEX instructions, takes
> > the TexSrcUnit instruction field into the program's Samplers map to find
> > the intended texture unit. When done through TXB or TXD instructions
> > this mapping with Samplers does not take place.
> >
> > Is this on purpose?
>
> Can you be more specific about where you're seeing this in the code?
>
> Thanks.
>
> -Brian
>
>