st/mesa: allow TXB2/TXL2 to work with cube array shadow textures

It's a bit asymmetric, but it's such a contrived use-case, and not a lot
of drivers will support it.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4014>

diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
index e053e821ecd54abfea2c7f1d4a14e5dbe01870a2..1e80edb8f070a0668856e99bc943af762011c364 100644 (file)
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -735,7 +735,8 @@ This instruction replicates its result.
   Presumably shadow 2d arrays and shadow 3d targets could use
   this encoding too, but this is not legal.
 
-  shadow cube map arrays are neither possible nor required.
+  if the target is a shadow cube map array, the reference value is in
+  src1.y.
 
 .. math::
 
@@ -826,7 +827,8 @@ This instruction replicates its result.
   Presumably shadow 3d / 2d array / cube targets could use
   this encoding too, but this is not legal.
 
-  shadow cube map arrays are neither possible nor required.
+  if the target is a shadow cube map array, the reference value is in
+  src1.y.
 
 .. math::
 

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index 952327a3b20e025a8d4d73853675fe1a3ca770cd..6c531ca53652e85c24dc57773621c250669ad2d8 100644 (file)
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -4300,14 +4300,13 @@ glsl_to_tgsi_visitor::visit(ir_texture *ir)
    enum tgsi_opcode opcode = TGSI_OPCODE_NOP;
    const glsl_type *sampler_type = ir->sampler->type;
    unsigned sampler_array_size = 1, sampler_base = 0;
-   bool is_cube_array = false, is_cube_shadow = false;
+   bool is_cube_array = false;
    ir_variable *var = ir->sampler->variable_referenced();
    unsigned i;
 
    /* if we are a cube array sampler or a cube shadow */
    if (sampler_type->sampler_dimensionality == GLSL_SAMPLER_DIM_CUBE) {
       is_cube_array = sampler_type->sampler_array;
-      is_cube_shadow = sampler_type->sampler_shadow;
    }
 
    if (ir->coordinate) {
@@ -4345,7 +4344,8 @@ glsl_to_tgsi_visitor::visit(ir_texture *ir)
       }
       break;
    case ir_txb:
-      if (is_cube_array || is_cube_shadow) {
+      if (is_cube_array ||
+         (sampler_type->sampler_shadow && sampler_type->coordinate_components() >= 3)) {
          opcode = TGSI_OPCODE_TXB2;
       }
       else {
@@ -4362,7 +4362,7 @@ glsl_to_tgsi_visitor::visit(ir_texture *ir)
       if (this->has_tex_txf_lz && ir->lod_info.lod->is_zero()) {
          opcode = TGSI_OPCODE_TEX_LZ;
       } else {
-         opcode = is_cube_array ? TGSI_OPCODE_TXL2 : TGSI_OPCODE_TXL;
+         opcode = (is_cube_array || (sampler_type->sampler_shadow && sampler_type->coordinate_components() >= 3)) ? TGSI_OPCODE_TXL2 : TGSI_OPCODE_TXL;
          ir->lod_info.lod->accept(this);
          lod_info = this->result;
       }
@@ -4500,11 +4500,21 @@ glsl_to_tgsi_visitor::visit(ir_texture *ir)
       ir->shadow_comparator->accept(this);
 
       if (is_cube_array) {
-         cube_sc = get_temp(glsl_type::float_type);
-         cube_sc_dst = st_dst_reg(cube_sc);
-         cube_sc_dst.writemask = WRITEMASK_X;
+         if (lod_info.file != PROGRAM_UNDEFINED) {
+            // If we have both a cube array *and* a bias/lod, stick the
+            // comparator into the .Y of the second argument.
+            st_src_reg tmp = get_temp(glsl_type::vec2_type);
+            cube_sc_dst = st_dst_reg(tmp);
+            cube_sc_dst.writemask = WRITEMASK_X;
+            emit_asm(ir, TGSI_OPCODE_MOV, cube_sc_dst, lod_info);
+            lod_info = tmp;
+            cube_sc_dst.writemask = WRITEMASK_Y;
+         } else {
+            cube_sc = get_temp(glsl_type::float_type);
+            cube_sc_dst = st_dst_reg(cube_sc);
+            cube_sc_dst.writemask = WRITEMASK_X;
+         }
          emit_asm(ir, TGSI_OPCODE_MOV, cube_sc_dst, this->result);
-         cube_sc_dst.writemask = WRITEMASK_X;
       }
       else {
          if ((sampler_type->sampler_dimensionality == GLSL_SAMPLER_DIM_2D &&