[Mesa-dev] [PATCH] blorp: Use normalized coordinates on Gen6

[Eduardo Lima Mitev]

Looks good to me.

Reviewed-by: Eduardo Lima Mitev <elima at igalia.com>

On 06/23/2017 10:51 PM, Ian Romanick wrote:
> From: Ian Romanick <ian.d.romanick at intel.com>
> 
> Apparently, the sampler has some sort of precision issues for
> non-normalized texture coordinates with linear filtering.  This caused
> some small precision issues in scaled blits.  Work around this by using
> normalized coordinates.  There is some extra work necessary because Gen6
> uses TEX (instead of TXF) for some multisample resolve blits.
> 
> Fixes piglit.spec.arb_framebuffer_object.fbo-blit-stretch on SNB.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68365
> Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
> ---
>  src/intel/blorp/blorp_blit.c      | 11 +++++++----
>  src/intel/blorp/blorp_genX_exec.h |  2 +-
>  2 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/src/intel/blorp/blorp_blit.c b/src/intel/blorp/blorp_blit.c
> index f552302..0850473 100644
> --- a/src/intel/blorp/blorp_blit.c
> +++ b/src/intel/blorp/blorp_blit.c
> @@ -1195,9 +1195,10 @@ brw_blorp_build_nir_shader(struct blorp_context *blorp, void *mem_ctx,
>            * representing the four samples that maxe up a pixel.  So we need
>            * to multiply our X and Y coordinates each by 2 and then add 1.
>            */
> -         src_pos = nir_ishl(&b, src_pos, nir_imm_int(&b, 1));
> -         src_pos = nir_iadd(&b, src_pos, nir_imm_int(&b, 1));
> -         src_pos = nir_i2f32(&b, src_pos);
> +         assert(key->src_coords_normalized);
> +         src_pos = nir_fadd(&b,
> +                            nir_i2f32(&b, src_pos),
> +                            nir_imm_float(&b, 0.5f));
>           color = blorp_nir_tex(&b, &v, key, src_pos);
>        } else {
>           /* Gen7+ hardware doesn't automaticaly blend. */
> @@ -1825,7 +1826,9 @@ try_blorp_blit(struct blorp_batch *batch,
>  
>     params->num_samples = params->dst.surf.samples;
>  
> -   if (wm_prog_key->bilinear_filter && batch->blorp->isl_dev->info->gen < 6) {
> +   if ((wm_prog_key->bilinear_filter ||
> +        (wm_prog_key->blend && !wm_prog_key->blit_scaled)) &&
> +       batch->blorp->isl_dev->info->gen <= 6) {
>        /* Gen4-5 don't support non-normalized texture coordinates */
>        wm_prog_key->src_coords_normalized = true;
>        params->wm_inputs.src_inv_size[0] =
> diff --git a/src/intel/blorp/blorp_genX_exec.h b/src/intel/blorp/blorp_genX_exec.h
> index 1d77877..91c0756 100644
> --- a/src/intel/blorp/blorp_genX_exec.h
> +++ b/src/intel/blorp/blorp_genX_exec.h
> @@ -535,7 +535,7 @@ blorp_emit_sampler_state(struct blorp_batch *batch,
>        sampler.VAddressMagFilterRoundingEnable = true;
>        sampler.UAddressMinFilterRoundingEnable = true;
>        sampler.UAddressMagFilterRoundingEnable = true;
> -#if GEN_GEN >= 6
> +#if GEN_GEN > 6
>        sampler.NonnormalizedCoordinateEnable = true;
>  #endif
>     }
>