[Mesa-dev] [PATCH] i965/nir: Provide a default LOD for buffer textures

[Jason Ekstrand]

Our hardware requires an LOD for all texelFetch commands even if they are
on buffer textures.  GLSL IR gives us an LOD of 0 in that case, but the LOD
is really rather meaningless.  This commit allows other NIR producers to be
more lazy and not provide one at all.
---
 src/mesa/drivers/dri/i965/brw_fs_nir.cpp   | 4 ++++
 src/mesa/drivers/dri/i965/brw_vec4_nir.cpp | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index c52bc04..6f51ce1 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -2780,6 +2780,10 @@ fs_visitor::nir_emit_texture(const fs_builder &bld, nir_tex_instr *instr)
 
    fs_reg coordinate, shadow_comparitor, lod, lod2, sample_index, mcs, tex_offset;
 
+   /* Our hardware requires a LOD for buffer textures */
+   if (instr->sampler_dim == GLSL_SAMPLER_DIM_BUF)
+      lod = brw_imm_d(0);
+
    for (unsigned i = 0; i < instr->num_srcs; i++) {
       fs_reg src = get_nir_src(instr->src[i].src);
       switch (instr->src[i].src_type) {
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
index cf1f82f..cfb66a5 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
@@ -1558,6 +1558,10 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
                                  nir_tex_instr_dest_size(instr));
    dst_reg dest = get_nir_dest(instr->dest, instr->dest_type);
 
+   /* Our hardware requires a LOD for buffer textures */
+   if (instr->sampler_dim == GLSL_SAMPLER_DIM_BUF)
+      lod = brw_imm_d(0);
+
    /* Load the texture operation sources */
    for (unsigned i = 0; i < instr->num_srcs; i++) {
       switch (instr->src[i].src_type) {
-- 
2.5.0.400.gff86faf