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@alum.mit.edu>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Rob Clark <robdclark@gmail.com>

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index f46f614..cf200fd 100644 (file)
--- 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;
 }