i965: Enable EXT_shader_samples_identical

On the vec4 backend, textureSamplesIdentical() will always return
false.  There are currently no test cases for the vec4 backend, so we
don't have much confidence in any implementation.  We also don't think
anyone is likely to miss it.

v2: Handle immediate value for MCS smarter.  Rebase on changes to
nir_texop_sampels_identical (missing second parameter).  Suggested by
Jason.

v3: Add Neil's code to handle 16x MSAA in the FS.  Also rebase on top of
f9a9ba5e.  Stub out the vec4 implementation.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Neil Roberts <neil@linux.intel.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com> [v2]
Reviewed-by: Chris Forbes <chrisf@ijw.co.nz> [v2]

diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index 8fc7ee42d6b5b20ab2264fe95ef6d86b4dbe4780..b6e5ed6a72b7f9d4161c2edac51b816a923760ce 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -2625,6 +2625,7 @@ fs_visitor::nir_emit_texture(const fs_builder &bld, nir_tex_instr *instr)
          switch (instr->op) {
          case nir_texop_txf:
          case nir_texop_txf_ms:
+         case nir_texop_samples_identical:
             coordinate = retype(src, BRW_REGISTER_TYPE_D);
             break;
          default:
@@ -2687,7 +2688,8 @@ fs_visitor::nir_emit_texture(const fs_builder &bld, nir_tex_instr *instr)
       }
    }
 
-   if (instr->op == nir_texop_txf_ms) {
+   if (instr->op == nir_texop_txf_ms ||
+       instr->op == nir_texop_samples_identical) {
       if (devinfo->gen >= 7 &&
           key_tex->compressed_multisample_layout_mask & (1 << sampler)) {
          mcs = emit_mcs_fetch(coordinate, instr->coord_components, sampler_reg);

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index d97fcf33b62767ad9759d23e48002a4389dfb804..2e04134318ee791d580859daca93df2f7f364fb2 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -259,6 +259,26 @@ fs_visitor::emit_texture(ir_texture_opcode op,
       lod = brw_imm_ud(0u);
    }
 
+   if (op == ir_samples_identical) {
+      fs_reg dst = vgrf(glsl_type::get_instance(dest_type->base_type, 1, 1));
+
+      /* If mcs is an immediate value, it means there is no MCS.  In that case
+       * just return false.
+       */
+      if (mcs.file == BRW_IMMEDIATE_VALUE) {
+         bld.MOV(dst, brw_imm_ud(0u));
+      } else if ((key_tex->msaa_16 & (1 << sampler))) {
+         fs_reg tmp = vgrf(glsl_type::uint_type);
+         bld.OR(tmp, mcs, offset(mcs, bld, 1));
+         bld.CMP(dst, tmp, brw_imm_ud(0u), BRW_CONDITIONAL_EQ);
+      } else {
+         bld.CMP(dst, mcs, brw_imm_ud(0u), BRW_CONDITIONAL_EQ);
+      }
+
+      this->result = dst;
+      return;
+   }
+
    if (coordinate.file != BAD_FILE) {
       /* FINISHME: Texture coordinate rescaling doesn't work with non-constant
        * samplers.  This should only be a problem with GL_CLAMP on Gen7.

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
index 63696a7ad5b95fa9888bd0ec7d3703745c5410d0..28656d45b33a5e844fa07e240d4eb10401171a8b 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
@@ -1615,6 +1615,7 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
          switch (instr->op) {
          case nir_texop_txf:
          case nir_texop_txf_ms:
+         case nir_texop_samples_identical:
             coordinate = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_D,
                                      src_size);
             coord_type = glsl_type::ivec(src_size);
@@ -1695,7 +1696,8 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
       }
    }
 
-   if (instr->op == nir_texop_txf_ms) {
+   if (instr->op == nir_texop_txf_ms ||
+       instr->op == nir_texop_samples_identical) {
       assert(coord_type != NULL);
       if (devinfo->gen >= 7 &&
           key_tex->compressed_multisample_layout_mask & (1 << sampler)) {

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index 08a1f8bb77c1905893ec49d8525bd6e0a9804459..2e4695a28456084b24486e50cf6deb14576e7118 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -909,6 +909,13 @@ vec4_visitor::emit_texture(ir_texture_opcode op,
       unreachable("TXB is not valid for vertex shaders.");
    case ir_lod:
       unreachable("LOD is not valid for vertex shaders.");
+   case ir_samples_identical: {
+      /* There are some challenges implementing this for vec4, and it seems
+       * unlikely to be used anyway.  For now, just return false ways.
+       */
+      emit(MOV(dest, brw_imm_ud(0u)));
+      return;
+   }
    default:
       unreachable("Unrecognized tex op");
    }

diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c
index 386b63c123dc017395e543e26e40c4b0417cf571..2e2459c125bbfbd8c0114be138e6debc427a7681 100644 (file)
--- a/src/mesa/drivers/dri/i965/intel_extensions.c
+++ b/src/mesa/drivers/dri/i965/intel_extensions.c
@@ -333,6 +333,7 @@ intelInitExtensions(struct gl_context *ctx)
       ctx->Extensions.ARB_texture_compression_bptc = true;
       ctx->Extensions.ARB_texture_view = true;
       ctx->Extensions.ARB_shader_storage_buffer_object = true;
+      ctx->Extensions.EXT_shader_samples_identical = true;
 
       if (can_do_pipelined_register_writes(brw)) {
          ctx->Extensions.ARB_draw_indirect = true;