D3D / VideoCommon: generate HLSL from SPIRV

Source/Core/VideoBackends/D3DCommon/Shader.cpp

@@ -4,7 +4,13 @@
 #include "VideoBackends/D3DCommon/Shader.h"
 
 #include <fstream>
+#include <optional>
+#include <string_view>
+
+#include <fmt/format.h>
 #include <wrl/client.h>
+#include "disassemble.h"
+#include "spirv_hlsl.hpp"
 
 #include "Common/Assert.h"
 #include "Common/FileUtil.h"
@@ -14,9 +20,141 @@
 #include "Common/StringUtil.h"
 #include "Common/Version.h"
 
+#include "VideoCommon/Spirv.h"
 #include "VideoCommon/VideoBackendBase.h"
 #include "VideoCommon/VideoConfig.h"
 
+namespace
+{
+// Regarding the UBO bind points, we subtract one from the binding index because
+// the OpenGL backend requires UBO #0 for non-block uniforms (at least on NV).
+// This allows us to share the same shaders but use bind point #0 in the D3D
+// backends. None of the specific shaders use UBOs, instead they use push
+// constants, so when/if the GL backend moves to uniform blocks completely this
+// subtraction can be removed.
+constexpr std::string_view SHADER_HEADER = R"(
+  // Target GLSL 4.5.
+  #version 450 core
+  #define ATTRIBUTE_LOCATION(x) layout(location = x)
+  #define FRAGMENT_OUTPUT_LOCATION(x) layout(location = x)
+  #define FRAGMENT_OUTPUT_LOCATION_INDEXED(x, y) layout(location = x, index = y)
+  #define UBO_BINDING(packing, x) layout(packing, binding = (x - 1))
+  #define SAMPLER_BINDING(x) layout(binding = x)
+  #define TEXEL_BUFFER_BINDING(x) layout(binding = x)
+  #define SSBO_BINDING(x) layout(binding = (x + 2))
+  #define VARYING_LOCATION(x) layout(location = x)
+  #define FORCE_EARLY_Z layout(early_fragment_tests) in
+
+  // hlsl to glsl function translation
+  #define float2 vec2
+  #define float3 vec3
+  #define float4 vec4
+  #define uint2 uvec2
+  #define uint3 uvec3
+  #define uint4 uvec4
+  #define int2 ivec2
+  #define int3 ivec3
+  #define int4 ivec4
+  #define frac fract
+  #define lerp mix
+
+  #define API_D3D 1
+)";
+constexpr std::string_view COMPUTE_SHADER_HEADER = R"(
+  // Target GLSL 4.5.
+  #version 450 core
+  // All resources are packed into one descriptor set for compute.
+  #define UBO_BINDING(packing, x) layout(packing, binding = (x - 1))
+  #define SAMPLER_BINDING(x) layout(binding = x)
+  #define TEXEL_BUFFER_BINDING(x) layout(binding = x)
+  #define IMAGE_BINDING(format, x) layout(format, binding = x)
+
+  // hlsl to glsl function translation
+  #define float2 vec2
+  #define float3 vec3
+  #define float4 vec4
+  #define uint2 uvec2
+  #define uint3 uvec3
+  #define uint4 uvec4
+  #define int2 ivec2
+  #define int3 ivec3
+  #define int4 ivec4
+  #define frac fract
+  #define lerp mix
+
+  #define API_D3D 1
+)";
+
+std::optional<std::string> GetHLSLFromSPIRV(SPIRV::CodeVector spv, D3D_FEATURE_LEVEL feature_level)
+{
+  spirv_cross::CompilerHLSL::Options options;
+  switch (feature_level)
+  {
+  case D3D_FEATURE_LEVEL_10_0:
+    options.shader_model = 40;
+    break;
+  case D3D_FEATURE_LEVEL_10_1:
+    options.shader_model = 41;
+    break;
+  default:
+    options.shader_model = 50;
+    break;
+  };
+
+  spirv_cross::CompilerHLSL compiler(std::move(spv));
+  compiler.set_hlsl_options(options);
+
+  return compiler.compile();
+}
+
+std::optional<SPIRV::CodeVector> GetSpirv(ShaderStage stage, std::string_view source)
+{
+  switch (stage)
+  {
+  case ShaderStage::Vertex:
+  {
+    const auto full_source = fmt::format("{}{}", SHADER_HEADER, source);
+    return SPIRV::CompileVertexShader(full_source);
+  }
+
+  case ShaderStage::Geometry:
+  {
+    // Spirv cross does not currently support hlsl geometry shaders
+    return std::nullopt;
+  }
+
+  case ShaderStage::Pixel:
+  {
+    const auto full_source = fmt::format("{}{}", SHADER_HEADER, source);
+    return SPIRV::CompileFragmentShader(full_source);
+  }
+
+  case ShaderStage::Compute:
+  {
+    const auto full_source = fmt::format("{}{}", COMPUTE_SHADER_HEADER, source);
+    return SPIRV::CompileComputeShader(full_source);
+  }
+  };
+
+  return std::nullopt;
+}
+
+std::optional<std::string> GetHLSL(D3D_FEATURE_LEVEL feature_level, ShaderStage stage,
+                                   std::string_view source)
+{
+  if (stage == ShaderStage::Geometry)
+  {
+    return std::string{source};
+  }
+  else if (const auto spirv = GetSpirv(stage, source))
+  {
+    return GetHLSLFromSPIRV(std::move(*spirv), feature_level);
+  }
+
+  return std::nullopt;
+}
+}  // namespace
+
 namespace D3DCommon
 {
 Shader::Shader(ShaderStage stage, BinaryData bytecode)
@@ -95,6 +233,10 @@ static const char* GetCompileTarget(D3D_FEATURE_LEVEL feature_level, ShaderStage
 std::optional<Shader::BinaryData> Shader::CompileShader(D3D_FEATURE_LEVEL feature_level,
                                                         ShaderStage stage, std::string_view source)
 {
+  const auto hlsl = GetHLSL(feature_level, stage, source);
+  if (!hlsl)
+    return std::nullopt;
+
   static constexpr D3D_SHADER_MACRO macros[] = {{"API_D3D", "1"}, {nullptr, nullptr}};
   const UINT flags = g_ActiveConfig.bEnableValidationLayer ?
                          (D3DCOMPILE_DEBUG | D3DCOMPILE_SKIP_OPTIMIZATION) :
@@ -103,7 +245,7 @@ std::optional<Shader::BinaryData> Shader::CompileShader(D3D_FEATURE_LEVEL featur
 
   Microsoft::WRL::ComPtr<ID3DBlob> code;
   Microsoft::WRL::ComPtr<ID3DBlob> errors;
-  HRESULT hr = d3d_compile(source.data(), source.size(), nullptr, macros, nullptr, "main", target,
+  HRESULT hr = d3d_compile(hlsl->data(), hlsl->size(), nullptr, macros, nullptr, "main", target,
                            flags, 0, &code, &errors);
   if (FAILED(hr))
   {
@@ -111,12 +253,20 @@ std::optional<Shader::BinaryData> Shader::CompileShader(D3D_FEATURE_LEVEL featur
     std::string filename = VideoBackendBase::BadShaderFilename(target, num_failures++);
     std::ofstream file;
     File::OpenFStream(file, filename, std::ios_base::out);
-    file.write(source.data(), source.size());
+    file.write(hlsl->data(), hlsl->size());
     file << "\n";
     file.write(static_cast<const char*>(errors->GetBufferPointer()), errors->GetBufferSize());
     file << "\n";
     file << "Dolphin Version: " + Common::GetScmRevStr() + "\n";
     file << "Video Backend: " + g_video_backend->GetDisplayName();
+
+    if (const auto spirv = GetSpirv(stage, source))
+    {
+      file << "\nOriginal Source: \n";
+      file << source << std::endl;
+      file << "SPIRV: \n";
+      spv::Disassemble(file, *spirv);
+    }
     file.close();
 
     PanicAlertFmt("Failed to compile {}: {}\nDebug info ({}):\n{}", filename, Common::HRWrap(hr),