blorp: Use normalized coordinates on Gen6

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

diff --git a/src/intel/blorp/blorp_blit.c b/src/intel/blorp/blorp_blit.c
index f552302aa858fb81836904a95e34aa3af7f1db00..0850473eba30bf2bf3c30d3c095d4ea8e42d84fe 100644 (file)
--- 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 1d77877db5397121ef09e1cba13c0630cf940c6f..91c0756bf3573c79026e418841e29cadf52552cb 100644 (file)
--- 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
    }