[Mesa-dev] [PATCH v2 1/2] etnaviv: fix varying interpolation

[Philipp Zabel]

On Fri, 2017-09-15 at 18:04 +0200, Lucas Stach wrote:
> It seems that newer cores don't use the PA_ATTRIBUTES to decide if the
> varying should bypass the flat shading, but derive this from the
> component
> use. This fixes flat shading on GC880+.
> 
> VARYING_COMPONENT_USE_POINTCOORD is a bit of a misnomer now, as it
> isn't
> only used for pointcoords, but missing a better name I left it as-is.
> 
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
> v2: fix invalid vreg assignment
---
>  src/gallium/drivers/etnaviv/etnaviv_compiler.c | 23 ++++++++++-------------
>  1 file changed, 10 insertions(+), 13 deletions(-)
> 
> diff --git a/src/gallium/drivers/etnaviv/etnaviv_compiler.c b/src/gallium/drivers/etnaviv/etnaviv_compiler.c
> index 165ab74298a4..d86d0561503a 100644
> --- a/src/gallium/drivers/etnaviv/etnaviv_compiler.c
> +++ b/src/gallium/drivers/etnaviv/etnaviv_compiler.c
> @@ -2607,6 +2607,7 @@ etna_link_shader(struct etna_shader_link_info *info,
>        const struct etna_shader_inout *fsio = &fs->infile.reg[idx];
>        const struct etna_shader_inout *vsio = etna_shader_vs_lookup(vs, fsio);
>        struct etna_varying *varying;
> +      bool interpolate = fsio->semantic.Name != TGSI_SEMANTIC_COLOR;
>  
>        assert(fsio->reg > 0 && fsio->reg <= ARRAY_SIZE(info->varyings));
>  
> @@ -2616,28 +2617,24 @@ etna_link_shader(struct etna_shader_link_info *info,
>        varying = &info->varyings[fsio->reg - 1];
>        varying->num_components = fsio->num_components;
>  
> -      if (fsio->semantic.Name == TGSI_SEMANTIC_COLOR) /* colors affected by flat shading */
> +      if (interpolate) /* colors affected by flat shading */

This was (!interpolate) before, and looks like it should still be?
With that addressed,

Reviewed-by: Philipp Zabel <p.zabel at pengutronix.de>

>           varying->pa_attributes = 0x200;
>        else /* texture coord or other bypasses flat shading */
>           varying->pa_attributes = 0x2f1;
>  
> -      if (fsio->semantic.Name == TGSI_SEMANTIC_PCOORD) {
> -         varying->use[0] = VARYING_COMPONENT_USE_POINTCOORD_X;
> -         varying->use[1] = VARYING_COMPONENT_USE_POINTCOORD_Y;
> -         varying->use[2] = VARYING_COMPONENT_USE_USED;
> -         varying->use[3] = VARYING_COMPONENT_USE_USED;
> -         varying->reg = 0; /* replaced by point coord -- doesn't matter */
> +      varying->use[0] = interpolate ? VARYING_COMPONENT_USE_POINTCOORD_X : VARYING_COMPONENT_USE_USED;
> +      varying->use[1] = interpolate ? VARYING_COMPONENT_USE_POINTCOORD_Y : VARYING_COMPONENT_USE_USED;
> +      varying->use[2] = VARYING_COMPONENT_USE_USED;
> +      varying->use[3] = VARYING_COMPONENT_USE_USED;
> +
> +
> +      if (fsio->semantic.Name == TGSI_SEMANTIC_PCOORD)
>           continue;

Since for point coord we just continue here without setting varying->reg 
at all ...

> -      }
>  
>        if (vsio == NULL)
>           return true; /* not found -- link error */
>  
> -      varying->use[0] = VARYING_COMPONENT_USE_USED;
> -      varying->use[1] = VARYING_COMPONENT_USE_USED;
> -      varying->use[2] = VARYING_COMPONENT_USE_USED;
> -      varying->use[3] = VARYING_COMPONENT_USE_USED;
> -      varying->reg = vsio->reg;
> +      varying->reg = vsio->reg; /* replaced by point coord -- doesn't matter */

... is the comment still relevant here? Maybe this should be moved up
there.

>     }
>  
>     assert(info->num_varyings == fs->infile.num_reg);

regards
Philipp