[Mesa-dev] [PATCH 5/6] i965/draw: Do resolves properly for textures used by TXF

[Iago Toral]

On Wed, 2018-01-10 at 11:22 -0800, Jason Ekstrand wrote:
> ---
>  src/mesa/drivers/dri/i965/brw_draw.c | 41
> ++++++++++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_draw.c
> b/src/mesa/drivers/dri/i965/brw_draw.c
> index 4945dec..9fd44e4 100644
> --- a/src/mesa/drivers/dri/i965/brw_draw.c
> +++ b/src/mesa/drivers/dri/i965/brw_draw.c
> @@ -40,6 +40,7 @@
>  #include "swrast_setup/swrast_setup.h"
>  #include "drivers/common/meta.h"
>  #include "util/bitscan.h"
> +#include "util/bitset.h"
>  
>  #include "brw_blorp.h"
>  #include "brw_draw.h"
> @@ -371,6 +372,20 @@ intel_disable_rb_aux_buffer(struct brw_context
> *brw,
>     return found;
>  }
>  
> +static void
> +mark_textures_used_for_txf(BITSET_WORD *used_for_txf,
> +                           const struct gl_program *prog)
> +{
> +   if (!prog)
> +      return;
> +
> +   unsigned mask = prog->SamplersUsed & prog-
> >info.textures_used_by_txf;
> +   while (mask) {
> +      int s = u_bit_scan(&mask);
> +      BITSET_SET(used_for_txf, prog->SamplerUnits[s]);
> +   }
> +}
> +
>  /**
>   * \brief Resolve buffers before drawing.
>   *
> @@ -386,6 +401,18 @@ brw_predraw_resolve_inputs(struct brw_context
> *brw, bool rendering)
>     memset(brw->draw_aux_buffer_disabled, 0,
>            sizeof(brw->draw_aux_buffer_disabled));
>  
> +   BITSET_DECLARE(used_for_txf, MAX_COMBINED_TEXTURE_IMAGE_UNITS);
> +   memset(used_for_txf, 0, sizeof(used_for_txf));
> +   if (rendering) {
> +      mark_textures_used_for_txf(used_for_txf, ctx-
> >VertexProgram._Current);
> +      mark_textures_used_for_txf(used_for_txf, ctx-
> >TessCtrlProgram._Current);
> +      mark_textures_used_for_txf(used_for_txf, ctx-
> >TessEvalProgram._Current);
> +      mark_textures_used_for_txf(used_for_txf, ctx-
> >GeometryProgram._Current);
> +      mark_textures_used_for_txf(used_for_txf, ctx-
> >FragmentProgram._Current);
> +   } else {
> +      mark_textures_used_for_txf(used_for_txf, ctx-
> >ComputeProgram._Current);
> +   }
> +
>     /* Resolve depth buffer and render cache of each enabled texture.
> */
>     int maxEnabledUnit = ctx->Texture._MaxEnabledTexImageUnit;
>     for (int i = 0; i <= maxEnabledUnit; i++) {
> @@ -422,6 +449,20 @@ brw_predraw_resolve_inputs(struct brw_context
> *brw, bool rendering)
>                                      min_layer, num_layers,
>                                      disable_aux);
>  
> +      /* If any programs are using it with texelFetch, we may need
> to also do
> +       * a prepare with an sRGB format to ensure texelFetch works
> "properly".
> +       */

I am not sure I understand this. The only way that txf_format and
view_format can be different is if the texture format is sRGB and the
user has selected GL_SKIP_DECODE_EXT, right? If the user selected that,
it would mean that they do not want sRGB decoded data when sampling,
but I understand that is what they would get, since we are preparing
the MT with the sRGB format in this case. What am I missing?

> +      if (BITSET_TEST(used_for_txf, i)) {
> +         enum isl_format txf_format =
> +            translate_tex_format(brw, tex_obj->_Format,
> GL_DECODE_EXT);
> +         if (txf_format != view_format) {
> +            intel_miptree_prepare_texture(brw, tex_obj->mt,
> txf_format,
> +                                          min_level, num_levels,
> +                                          min_layer, num_layers,
> +                                          disable_aux);
> +         }
> +      }
> +
>        brw_cache_flush_for_read(brw, tex_obj->mt->bo);
>  
>        if (tex_obj->base.StencilSampling ||