[Mesa-dev] [PATCH] softpipe: don't clamp or do logical operations on floating-point buffers.

Morgan Armand morgan.devel at gmail.com
Sun Nov 6 06:21:29 PST 2011


Unless I'm missing something, no there is no ROPs defined for floating points operands.
The ARB_color_buffer_float specification says:

36. Should logical operations be disabled for floating-point color buffers?
    RESOLVED:  Yes.  This matches the behavior in the ATI specification.

Besides that, the result of the blending equation is no longer clamped when dealing
with FP buffers.

On 11/6/2011 3:08 PM, Corbin Simpson wrote:
> It's entirely possible that I'm still asleep, but what problem does this solve? Are ROPs not defined for FP operands?
> 
> Sending from a mobile, pardon my terseness. ~ C.
> 
> On Nov 6, 2011 4:31 AM, "Morgan Armand" <morgan.devel at gmail.com <mailto:morgan.devel at gmail.com>> wrote:
> 
>     ---
>      src/gallium/drivers/softpipe/sp_quad_blend.c |   78 ++++++++++++++++++-------
>      1 files changed, 56 insertions(+), 22 deletions(-)
> 
>     diff --git a/src/gallium/drivers/softpipe/sp_quad_blend.c b/src/gallium/drivers/softpipe/sp_quad_blend.c
>     index 598df26..4813ada 100644
>     --- a/src/gallium/drivers/softpipe/sp_quad_blend.c
>     +++ b/src/gallium/drivers/softpipe/sp_quad_blend.c
>     @@ -702,19 +702,19 @@ blend_quad(struct quad_stage *qs,
>         */
>        switch (softpipe->blend->rt[blend_index].rgb_func) {
>        case PIPE_BLEND_ADD:
>     -      VEC4_ADD_SAT(quadColor[0], source[0], blend_dest[0]); /* R */
>     -      VEC4_ADD_SAT(quadColor[1], source[1], blend_dest[1]); /* G */
>     -      VEC4_ADD_SAT(quadColor[2], source[2], blend_dest[2]); /* B */
>     +      VEC4_ADD(quadColor[0], source[0], blend_dest[0]); /* R */
>     +      VEC4_ADD(quadColor[1], source[1], blend_dest[1]); /* G */
>     +      VEC4_ADD(quadColor[2], source[2], blend_dest[2]); /* B */
>           break;
>        case PIPE_BLEND_SUBTRACT:
>     -      VEC4_SUB_SAT(quadColor[0], source[0], blend_dest[0]); /* R */
>     -      VEC4_SUB_SAT(quadColor[1], source[1], blend_dest[1]); /* G */
>     -      VEC4_SUB_SAT(quadColor[2], source[2], blend_dest[2]); /* B */
>     +      VEC4_SUB(quadColor[0], source[0], blend_dest[0]); /* R */
>     +      VEC4_SUB(quadColor[1], source[1], blend_dest[1]); /* G */
>     +      VEC4_SUB(quadColor[2], source[2], blend_dest[2]); /* B */
>           break;
>        case PIPE_BLEND_REVERSE_SUBTRACT:
>     -      VEC4_SUB_SAT(quadColor[0], blend_dest[0], source[0]); /* R */
>     -      VEC4_SUB_SAT(quadColor[1], blend_dest[1], source[1]); /* G */
>     -      VEC4_SUB_SAT(quadColor[2], blend_dest[2], source[2]); /* B */
>     +      VEC4_SUB(quadColor[0], blend_dest[0], source[0]); /* R */
>     +      VEC4_SUB(quadColor[1], blend_dest[1], source[1]); /* G */
>     +      VEC4_SUB(quadColor[2], blend_dest[2], source[2]); /* B */
>           break;
>        case PIPE_BLEND_MIN:
>           VEC4_MIN(quadColor[0], source[0], blend_dest[0]); /* R */
>     @@ -735,13 +735,13 @@ blend_quad(struct quad_stage *qs,
>         */
>        switch (softpipe->blend->rt[blend_index].alpha_func) {
>        case PIPE_BLEND_ADD:
>     -      VEC4_ADD_SAT(quadColor[3], source[3], blend_dest[3]); /* A */
>     +      VEC4_ADD(quadColor[3], source[3], blend_dest[3]); /* A */
>           break;
>        case PIPE_BLEND_SUBTRACT:
>     -      VEC4_SUB_SAT(quadColor[3], source[3], blend_dest[3]); /* A */
>     +      VEC4_SUB(quadColor[3], source[3], blend_dest[3]); /* A */
>           break;
>        case PIPE_BLEND_REVERSE_SUBTRACT:
>     -      VEC4_SUB_SAT(quadColor[3], blend_dest[3], source[3]); /* A */
>     +      VEC4_SUB(quadColor[3], blend_dest[3], source[3]); /* A */
>           break;
>        case PIPE_BLEND_MIN:
>           VEC4_MIN(quadColor[3], source[3], blend_dest[3]); /* A */
>     @@ -856,6 +856,10 @@ blend_fallback(struct quad_stage *qs,
> 
>        for (cbuf = 0; cbuf < softpipe->framebuffer.nr_cbufs; cbuf++)
>        {
>     +      const enum pipe_format format =
>     +         softpipe->framebuffer.cbufs[cbuf]->format;
>     +      const struct util_format_description *desc =
>     +         util_format_description(format);
>           /* which blend/mask state index to use: */
>           const uint blend_buf = blend->independent_blend_enable ? cbuf : 0;
>           float dest[4][QUAD_SIZE];
>     @@ -909,10 +913,19 @@ blend_fallback(struct quad_stage *qs,
> 
> 
>              if (blend->logicop_enable) {
>     -            logicop_quad( qs, quadColor, dest );
>     +            if (desc->channel[0].type != UTIL_FORMAT_TYPE_FLOAT) {
>     +               logicop_quad( qs, quadColor, dest );
>     +            }
>              }
>              else if (blend->rt[blend_buf].blend_enable) {
>                 blend_quad(qs, quadColor, dest, blend_color, blend_buf);
>     +
>     +            /* If fixed-point dest color buffer, need to clamp the outgoing
>     +             * fragment colors now.
>     +             */
>     +            if (clamp) {
>     +               clamp_colors(quadColor);
>     +            }
>              }
> 
>              rebase_colors(bqs->base_format[cbuf], quadColor);
>     @@ -969,6 +982,13 @@ blend_single_add_src_alpha_inv_src_alpha(struct quad_stage *qs,
>              }
>           }
> 
>     +      /* If fixed-point dest color buffer, need to clamp the incoming
>     +       * fragment colors now.
>     +       */
>     +      if (bqs->clamp[0]) {
>     +         clamp_colors(quadColor);
>     +      }
>     +
>           VEC4_MUL(source[0], quadColor[0], alpha); /* R */
>           VEC4_MUL(source[1], quadColor[1], alpha); /* G */
>           VEC4_MUL(source[2], quadColor[2], alpha); /* B */
>     @@ -978,12 +998,19 @@ blend_single_add_src_alpha_inv_src_alpha(struct quad_stage *qs,
>           VEC4_MUL(dest[0], dest[0], one_minus_alpha); /* R */
>           VEC4_MUL(dest[1], dest[1], one_minus_alpha); /* G */
>           VEC4_MUL(dest[2], dest[2], one_minus_alpha); /* B */
>     -      VEC4_MUL(dest[3], dest[3], one_minus_alpha); /* B */
>     +      VEC4_MUL(dest[3], dest[3], one_minus_alpha); /* A */
> 
>     -      VEC4_ADD_SAT(quadColor[0], source[0], dest[0]); /* R */
>     -      VEC4_ADD_SAT(quadColor[1], source[1], dest[1]); /* G */
>     -      VEC4_ADD_SAT(quadColor[2], source[2], dest[2]); /* B */
>     -      VEC4_ADD_SAT(quadColor[3], source[3], dest[3]); /* A */
>     +      VEC4_ADD(quadColor[0], source[0], dest[0]); /* R */
>     +      VEC4_ADD(quadColor[1], source[1], dest[1]); /* G */
>     +      VEC4_ADD(quadColor[2], source[2], dest[2]); /* B */
>     +      VEC4_ADD(quadColor[3], source[3], dest[3]); /* A */
>     +
>     +      /* If fixed-point dest color buffer, need to clamp the outgoing
>     +       * fragment colors now.
>     +       */
>     +      if (bqs->clamp[0]) {
>     +         clamp_colors(quadColor);
>     +      }
> 
>           rebase_colors(bqs->base_format[0], quadColor);
> 
>     @@ -1035,10 +1062,17 @@ blend_single_add_one_one(struct quad_stage *qs,
>              clamp_colors(quadColor);
>           }
> 
>     -      VEC4_ADD_SAT(quadColor[0], quadColor[0], dest[0]); /* R */
>     -      VEC4_ADD_SAT(quadColor[1], quadColor[1], dest[1]); /* G */
>     -      VEC4_ADD_SAT(quadColor[2], quadColor[2], dest[2]); /* B */
>     -      VEC4_ADD_SAT(quadColor[3], quadColor[3], dest[3]); /* A */
>     +      VEC4_ADD(quadColor[0], quadColor[0], dest[0]); /* R */
>     +      VEC4_ADD(quadColor[1], quadColor[1], dest[1]); /* G */
>     +      VEC4_ADD(quadColor[2], quadColor[2], dest[2]); /* B */
>     +      VEC4_ADD(quadColor[3], quadColor[3], dest[3]); /* A */
>     +
>     +      /* If fixed-point dest color buffer, need to clamp the outgoing
>     +       * fragment colors now.
>     +       */
>     +      if (bqs->clamp[0]) {
>     +         clamp_colors(quadColor);
>     +      }
> 
>           rebase_colors(bqs->base_format[0], quadColor);
> 
>     --
>     1.7.7.1.msysgit.0
> 
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