Mesa (master): nir: allow texture offsets with cube maps

[Ilia Mirkin]

Module: Mesa
Branch: master
Commit: ab336e8b46b6d7016519681c59b9aedf3fea04ad
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=ab336e8b46b6d7016519681c59b9aedf3fea04ad

Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Sun Nov 19 12:27:12 2017 -0500

nir: allow texture offsets with cube maps

GL doesn't have this, but some hardware supports it. This is convenient
for lowering tg4 to plain texture calls, which is necessary on Adreno
A4xx hardware.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
Reviewed-by: Rob Clark <robdclark at gmail.com>

---

 src/compiler/nir/nir.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index f46f614711..cf200fdc66 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -1364,8 +1364,7 @@ nir_tex_instr_src_size(const nir_tex_instr *instr, unsigned src)
    if (instr->src[src].src_type == nir_tex_src_ms_mcs)
       return 4;
 
-   if (instr->src[src].src_type == nir_tex_src_offset ||
-       instr->src[src].src_type == nir_tex_src_ddx ||
+   if (instr->src[src].src_type == nir_tex_src_ddx ||
        instr->src[src].src_type == nir_tex_src_ddy) {
       if (instr->is_array)
          return instr->coord_components - 1;
@@ -1373,6 +1372,18 @@ nir_tex_instr_src_size(const nir_tex_instr *instr, unsigned src)
          return instr->coord_components;
    }
 
+   /* Usual APIs don't allow cube + offset, but we allow it, with 2 coords for
+    * the offset, since a cube maps to a single face.
+    */
+   if (instr->src[src].src_type == nir_tex_src_offset) {
+      if (instr->sampler_dim == GLSL_SAMPLER_DIM_CUBE)
+         return 2;
+      else if (instr->is_array)
+         return instr->coord_components - 1;
+      else
+         return instr->coord_components;
+   }
+
    return 1;
 }