From d31db60a758649bba24c08b993e032543193f968 Mon Sep 17 00:00:00 2001
From: DrChat <arkolbed@gmail.com>
Date: Thu, 1 Mar 2018 13:46:44 -0600
Subject: [PATCH] [SPIR-V] tfetch UseRegisterLOD support

---
 src/xenia/gpu/spirv_shader_translator.cc | 7 +++++++
 src/xenia/gpu/spirv_shader_translator.h  | 1 +
 2 files changed, 8 insertions(+)

diff --git a/src/xenia/gpu/spirv_shader_translator.cc b/src/xenia/gpu/spirv_shader_translator.cc
index fda637ee3..376d04f17 100644
--- a/src/xenia/gpu/spirv_shader_translator.cc
+++ b/src/xenia/gpu/spirv_shader_translator.cc
@@ -111,6 +111,8 @@ void SpirvShaderTranslator::StartTranslation() {
                          "pc");
   a0_ = b.createVariable(spv::StorageClass::StorageClassFunction, int_type_,
                          "a0");
+  lod_ = b.createVariable(spv::StorageClass::StorageClassFunction, float_type_,
+                          "lod");
 
   // Uniform constants.
   Id float_consts_type =
@@ -1843,6 +1845,10 @@ void SpirvShaderTranslator::ProcessTextureFetchInstruction(
       spv::Builder::TextureParameters params = {0};
       params.coords = src;
       params.sampler = texture;
+      if (instr.attributes.use_register_lod) {
+        params.lod = b.createLoad(lod_);
+      }
+
       dest =
           b.createTextureCall(spv::NoPrecision, vec4_float_type_, false, false,
                               false, false, is_vertex_shader(), params);
@@ -1906,6 +1912,7 @@ void SpirvShaderTranslator::ProcessTextureFetchInstruction(
       // <lod register> = src1.x (MIP level)
       // ... immediately after
       // tfetch UseRegisterLOD=true
+      b.createStore(b.createCompositeExtract(src, float_type_, 0), lod_);
     } break;
 
     default:
diff --git a/src/xenia/gpu/spirv_shader_translator.h b/src/xenia/gpu/spirv_shader_translator.h
index c1e97d127..ec822e8e2 100644
--- a/src/xenia/gpu/spirv_shader_translator.h
+++ b/src/xenia/gpu/spirv_shader_translator.h
@@ -149,6 +149,7 @@ class SpirvShaderTranslator : public ShaderTranslator {
   spv::Id loop_count_ = 0;   // Loop counter stack
   spv::Id ps_ = 0, pv_ = 0;  // IDs of previous results
   spv::Id pc_ = 0;           // Program counter
+  spv::Id lod_ = 0;          // LOD register
   spv::Id pos_ = 0;
   spv::Id push_consts_ = 0;
   spv::Id interpolators_ = 0;