[Mesa-dev] [PATCH 08/15] i965/blorp: Implement proper texel fetch messages for Gen7.

[Ian Romanick]

On 05/11/2012 11:03 AM, Paul Berry wrote:
> On Gen6, texel fetch is always accomplished using the SAMPLE_LD
> message, which accepts arguments (u, v, r, lod, si).  On Gen7, there
> are two* texel fetch messages: SAMPLE_LD for non-MSAA surfaces, taking
> arguments (u, lod, v), and SAMPLE_LD2DSS for MSAA surfaces, taking
> arguments (si, u, v).
>
> *Technically, there are other texel fetch messages, but they are used
> for "compressed" MSAA surfaces, which we don't yet support.
>
> This patch adds the proper message types and argument orderings for
> Gen7.

Other than the comment below, this patch is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

> ---
>   src/mesa/drivers/dri/i965/brw_blorp_blit.cpp |   32 ++++++++++++++++++++++++-
>   src/mesa/drivers/dri/i965/brw_defines.h      |    1 +
>   2 files changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> index 07e9dd7..afed517 100644
> --- a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
> @@ -944,15 +944,43 @@ brw_blorp_blit_program::sample()
>   void
>   brw_blorp_blit_program::texel_fetch()
>   {
> -   static const sampler_message_arg args[5] = {
> +   static const sampler_message_arg gen6_args[5] = {
>         SAMPLER_MESSAGE_ARG_U_INT,
>         SAMPLER_MESSAGE_ARG_V_INT,
>         SAMPLER_MESSAGE_ARG_ZERO_INT, /* R */
>         SAMPLER_MESSAGE_ARG_ZERO_INT, /* LOD */
>         SAMPLER_MESSAGE_ARG_SI_INT
>      };
> +   static const sampler_message_arg gen7_ld_args[3] = {
> +      SAMPLER_MESSAGE_ARG_U_INT,
> +      SAMPLER_MESSAGE_ARG_ZERO_INT, /* LOD */
> +      SAMPLER_MESSAGE_ARG_V_INT
> +   };
> +   static const sampler_message_arg gen7_ld2dss_args[3] = {
> +      SAMPLER_MESSAGE_ARG_SI_INT,
> +      SAMPLER_MESSAGE_ARG_U_INT,
> +      SAMPLER_MESSAGE_ARG_V_INT
> +   };
>
> -   texture_lookup(GEN5_SAMPLER_MESSAGE_SAMPLE_LD, args, s_is_zero ? 2 : 5);
> +   switch (brw->intel.gen) {
> +   case 6:
> +      texture_lookup(GEN5_SAMPLER_MESSAGE_SAMPLE_LD, gen6_args,
> +                     s_is_zero ? 2 : 5);
> +      break;
> +   case 7:
> +      if (key->tex_samples>  0) {
> +         texture_lookup(GEN7_SAMPLER_MESSAGE_SAMPLE_LD2DSS,
> +                        gen7_ld2dss_args, ARRAY_SIZE(gen7_ld2dss_args));
> +      } else {
> +         assert(s_is_zero);
> +         texture_lookup(GEN5_SAMPLER_MESSAGE_SAMPLE_LD, gen7_ld_args,
> +                        ARRAY_SIZE(gen7_ld_args));
> +      }
> +      break;
> +   default:
> +      assert(false);

We usually do this is as

	assert(!"Should not get here.");

There are also a lot of places where more descriptive messages are used.

> +      break;
> +   };
>   }
>
>   void
> diff --git a/src/mesa/drivers/dri/i965/brw_defines.h b/src/mesa/drivers/dri/i965/brw_defines.h
> index aaab5a2..a087f70 100644
> --- a/src/mesa/drivers/dri/i965/brw_defines.h
> +++ b/src/mesa/drivers/dri/i965/brw_defines.h
> @@ -830,6 +830,7 @@ enum brw_message_target {
>   #define GEN5_SAMPLER_MESSAGE_SAMPLE_LOD_COMPARE  6
>   #define GEN5_SAMPLER_MESSAGE_SAMPLE_LD           7
>   #define GEN5_SAMPLER_MESSAGE_SAMPLE_RESINFO      10
> +#define GEN7_SAMPLER_MESSAGE_SAMPLE_LD2DSS       31
>
>   /* for GEN5 only */
>   #define BRW_SAMPLER_SIMD_MODE_SIMD4X2                   0