Mesa (master): blorp: Use normalized coordinates on Gen6

[Ian Romanick]

Module: Mesa
Branch: master
Commit: 1b101ca809debb9b730d99b92e8f0153f08aeb57
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=1b101ca809debb9b730d99b92e8f0153f08aeb57

Author: Ian Romanick <ian.d.romanick at intel.com>
Date:   Mon Jun  5 17:34:38 2017 -0700

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 at intel.com>
Reviewed-by: Eduardo Lima Mitev <elima at igalia.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 f552302aa8..0850473eba 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 1d77877db5..91c0756bf3 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
    }