[Mesa-dev] [PATCH 2/2] i965: Implement ARB_texture_filter_minmax

[Ian Romanick]

On 11/14/2017 02:54 PM, Scott D Phillips wrote:
> On gen >= 9, minmax reduction modes are available as a flag in
> SAMPLER_STATE.
> ---
>  docs/features.txt                             |  2 +-
>  src/mesa/drivers/dri/i965/brw_formatquery.c   |  4 ++++
>  src/mesa/drivers/dri/i965/genX_state_upload.c | 10 ++++++++++
>  src/mesa/drivers/dri/i965/intel_extensions.c  |  1 +
>  4 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/features.txt b/docs/features.txt
> index 86d07ba80b..9ec3f2b975 100644
> --- a/docs/features.txt
> +++ b/docs/features.txt
> @@ -312,7 +312,7 @@ Khronos, ARB, and OES extensions that are not part of any OpenGL or OpenGL ES ve
>    GL_ARB_sparse_texture                                 not started
>    GL_ARB_sparse_texture2                                not started
>    GL_ARB_sparse_texture_clamp                           not started
> -  GL_ARB_texture_filter_minmax                          not started
> +  GL_ARB_texture_filter_minmax                          DONE (i965)
>    GL_EXT_memory_object                                  DONE (radeonsi)
>    GL_EXT_memory_object_fd                               DONE (radeonsi)
>    GL_EXT_memory_object_win32                            not started
> diff --git a/src/mesa/drivers/dri/i965/brw_formatquery.c b/src/mesa/drivers/dri/i965/brw_formatquery.c
> index 4f3b9e467b..bb2281f571 100644
> --- a/src/mesa/drivers/dri/i965/brw_formatquery.c
> +++ b/src/mesa/drivers/dri/i965/brw_formatquery.c
> @@ -107,6 +107,10 @@ brw_query_internal_format(struct gl_context *ctx, GLenum target,
>        break;
>     }
>  
> +   case GL_TEXTURE_REDUCTION_MODE_ARB:
> +      params[0] = GL_TRUE;
> +      break;
> +

Can Gen9 actually support all formats?  When this was getting discussed
in Khronos, I thought we had some format restrictions.  This is the
difference between the EXT and the ARB extension.  If we don't actually
have any restrictions on Gen9, a good follow-on would be to add support
for the EXT... since that doesn't have the OpenGL 3.3 requirement and
has interactions with OpenGL ES.

I also thought that Gen8 could do some min/max modes.  Perhaps that's
where the restrictions were that I was thinking of...

>     default:
>        /* By default, we call the driver hook's fallback function from the frontend,
>         * which has generic implementation for all pnames.
> diff --git a/src/mesa/drivers/dri/i965/genX_state_upload.c b/src/mesa/drivers/dri/i965/genX_state_upload.c
> index 453b8e4add..8af907648b 100644
> --- a/src/mesa/drivers/dri/i965/genX_state_upload.c
> +++ b/src/mesa/drivers/dri/i965/genX_state_upload.c
> @@ -5094,6 +5094,16 @@ genX(update_sampler_state)(struct brw_context *brw,
>     samp_st.LODPreClampEnable = true;
>  #endif
>  
> +#if GEN_GEN >= 9
> +   if (sampler->ReductionMode != GL_WEIGHTED_AVERAGE_ARB) {
> +      samp_st.ReductionTypeEnable = true;
> +      if (sampler->ReductionMode == GL_MIN)
> +         samp_st.ReductionType = MINIMUM;
> +      else
> +         samp_st.ReductionType = MAXIMUM;
> +   }
> +#endif
> +
>     GENX(SAMPLER_STATE_pack)(brw, sampler_state, &samp_st);
>  }
>  
> diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c
> index 4d17393948..e280474875 100644
> --- a/src/mesa/drivers/dri/i965/intel_extensions.c
> +++ b/src/mesa/drivers/dri/i965/intel_extensions.c
> @@ -285,6 +285,7 @@ intelInitExtensions(struct gl_context *ctx)
>     if (devinfo->gen >= 9) {
>        ctx->Extensions.ANDROID_extension_pack_es31a = true;
>        ctx->Extensions.ARB_shader_stencil_export = true;
> +      ctx->Extensions.ARB_texture_filter_minmax = true;
>        ctx->Extensions.KHR_blend_equation_advanced_coherent = true;
>        ctx->Extensions.KHR_texture_compression_astc_ldr = true;
>        ctx->Extensions.KHR_texture_compression_astc_sliced_3d = true;
>