Mesa (master): swr: add support for upper-left fragcoord position

[Ilia Mirkin]

Module: Mesa
Branch: master
Commit: 6364491a0ba4d97270ddfee223b4c2f79cc691f1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=6364491a0ba4d97270ddfee223b4c2f79cc691f1

Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Sat Nov 12 18:58:46 2016 -0500

swr: add support for upper-left fragcoord position

Fixes glsl-arb-fragment-coord-conventions.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
Reviewed-by: Tim Rowley <timothy.o.rowley at intel.com>

---

 src/gallium/drivers/swr/swr_shader.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/swr/swr_shader.cpp b/src/gallium/drivers/swr/swr_shader.cpp
index 38a916e..04637e5 100644
--- a/src/gallium/drivers/swr/swr_shader.cpp
+++ b/src/gallium/drivers/swr/swr_shader.cpp
@@ -480,8 +480,14 @@ BuilderSWR::CompileFS(struct swr_context *ctx, swr_jit_fs_key &key)
          inputs[attrib][3] = wrap(VIMMED1(1.0f));
          continue;
       } else if (semantic_name == TGSI_SEMANTIC_POSITION) { // gl_FragCoord
-         inputs[attrib][0] = wrap(LOAD(pPS, {0, SWR_PS_CONTEXT_vX, PixelPositions_center}, "vX"));
-         inputs[attrib][1] = wrap(LOAD(pPS, {0, SWR_PS_CONTEXT_vY, PixelPositions_center}, "vY"));
+         if (swr_fs->info.base.properties[TGSI_PROPERTY_FS_COORD_PIXEL_CENTER] ==
+             TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER) {
+            inputs[attrib][0] = wrap(LOAD(pPS, {0, SWR_PS_CONTEXT_vX, PixelPositions_center}, "vX"));
+            inputs[attrib][1] = wrap(LOAD(pPS, {0, SWR_PS_CONTEXT_vY, PixelPositions_center}, "vY"));
+         } else {
+            inputs[attrib][0] = wrap(LOAD(pPS, {0, SWR_PS_CONTEXT_vX, PixelPositions_UL}, "vX"));
+            inputs[attrib][1] = wrap(LOAD(pPS, {0, SWR_PS_CONTEXT_vY, PixelPositions_UL}, "vY"));
+         }
          inputs[attrib][2] = wrap(LOAD(pPS, {0, SWR_PS_CONTEXT_vZ}, "vZ"));
          inputs[attrib][3] =
             wrap(LOAD(pPS, {0, SWR_PS_CONTEXT_vOneOverW, PixelPositions_center}, "vOneOverW"));