From 2c90680bc281bade225c48148d37b497e4836f88 Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Sun, 8 Sep 2024 19:43:18 +1000
Subject: [PATCH] PostProcessing/FX: Use SPIR-V instead of GLSL for Vulkan

---
 dep/reshadefx/src/effect_codegen_spirv.cpp | 26 +++++++++++++++++++---
 src/util/postprocessing_shader_fx.cpp      | 25 ++++++++-------------
 2 files changed, 32 insertions(+), 19 deletions(-)

diff --git a/dep/reshadefx/src/effect_codegen_spirv.cpp b/dep/reshadefx/src/effect_codegen_spirv.cpp
index e95c78202..994b1377e 100644
--- a/dep/reshadefx/src/effect_codegen_spirv.cpp
+++ b/dep/reshadefx/src/effect_codegen_spirv.cpp
@@ -390,6 +390,25 @@ private:
 			return {};
 		const function &entry_point = *entry_point_it->get();
 
+		const auto write_entry_point = [this](const spirv_instruction& oins, std::basic_string<char>& spirv) {
+			assert(oins.operands.size() > 2);
+			spirv_instruction nins(oins.op, oins.type, oins.result);
+			nins.add(oins.operands[0]);
+			nins.add(oins.operands[1]);
+			nins.add_string("main");
+
+			size_t param_start_index = 2;
+			while (param_start_index < oins.operands.size() && (oins.operands[param_start_index] & 0xFF000000) != 0)
+				param_start_index++;
+
+			// skip zero
+			param_start_index++;
+
+			for (size_t i = param_start_index; i < oins.operands.size(); i++)
+				nins.add(oins.operands[i]);
+			nins.write(spirv);
+		};
+
 		// Build list of IDs to remove
 		std::vector<spv::Id> variables_to_remove;
 #if 1
@@ -414,7 +433,7 @@ private:
 			// Only add the matching entry point
 			if (inst.operands[1] == entry_point.id)
 			{
-				inst.write(spirv);
+				write_entry_point(inst, spirv);
 			}
 			else
 			{
@@ -482,8 +501,9 @@ private:
 			if (func.definition.instructions.empty())
 				continue;
 
-			assert(func.declaration.instructions[_debug_info ? 1 : 0].op == spv::OpFunction);
-			const spv::Id definition = func.declaration.instructions[_debug_info ? 1 : 0].result;
+			const bool has_line = (_debug_info && func.declaration.instructions[0].op == spv::OpLine);
+			assert(func.declaration.instructions[has_line ? 1 : 0].op == spv::OpFunction);
+			const spv::Id definition = func.declaration.instructions[has_line ? 1 : 0].result;
 
 #if 1
 			if (std::find(functions_to_remove.begin(), functions_to_remove.end(), definition) != functions_to_remove.end())
diff --git a/src/util/postprocessing_shader_fx.cpp b/src/util/postprocessing_shader_fx.cpp
index 3e022d721..219b398e6 100644
--- a/src/util/postprocessing_shader_fx.cpp
+++ b/src/util/postprocessing_shader_fx.cpp
@@ -82,8 +82,8 @@ static std::unique_ptr<reshadefx::codegen> CreateRFXCodegen()
     case RenderAPI::Vulkan:
     case RenderAPI::Metal:
     {
-      return std::unique_ptr<reshadefx::codegen>(reshadefx::create_codegen_glsl(
-        460, false, true, debug_info, uniforms_to_spec_constants, false, (rapi == RenderAPI::Vulkan)));
+      return std::unique_ptr<reshadefx::codegen>(reshadefx::create_codegen_spirv(
+        true, debug_info, uniforms_to_spec_constants, false, (rapi == RenderAPI::Vulkan)));
     }
 
     case RenderAPI::OpenGL:
@@ -1303,9 +1303,6 @@ GPUTexture* PostProcessing::ReShadeFXShader::GetTextureByID(TextureID id, GPUTex
 bool PostProcessing::ReShadeFXShader::CompilePipeline(GPUTexture::Format format, u32 width, u32 height,
                                                       ProgressCallback* progress)
 {
-  const RenderAPI api = g_gpu_device->GetRenderAPI();
-  const bool needs_main_defn = (api != RenderAPI::D3D11 && api != RenderAPI::D3D12);
-
   m_valid = false;
   m_textures.clear();
   m_passes.clear();
@@ -1342,20 +1339,16 @@ bool PostProcessing::ReShadeFXShader::CompilePipeline(GPUTexture::Format format,
     return false;
   }
 
-  // TODO: If using spv, this will be populated.
-  // const std::string effect_code = cg->finalize_code();
-
-  auto get_shader = [api, needs_main_defn, &cg](const std::string& name, const std::span<Sampler> samplers,
-                                                GPUShaderStage stage) {
+  const RenderAPI api = g_gpu_device->GetRenderAPI();
+  auto get_shader = [api, &cg](const std::string& name, const std::span<Sampler> samplers, GPUShaderStage stage) {
     const std::string real_code = cg->finalize_code_for_entry_point(name);
-
-#if 0
-    FileSystem::WriteStringToFile(fmt::format("D:\\reshade_{}.txt", Path::SanitizeFileName(name)).c_str(), real_code);
-#endif
+    const GPUShaderLanguage lang = (api == RenderAPI::Vulkan || api == RenderAPI::Metal) ?
+                                     GPUShaderLanguage::SPV :
+                                     ShaderGen::GetShaderLanguageForAPI(api);
+    const char* entry_point = (lang == GPUShaderLanguage::HLSL) ? name.c_str() : "main";
 
     Error error;
-    std::unique_ptr<GPUShader> sshader = g_gpu_device->CreateShader(
-      stage, ShaderGen::GetShaderLanguageForAPI(api), real_code, &error, needs_main_defn ? "main" : name.c_str());
+    std::unique_ptr<GPUShader> sshader = g_gpu_device->CreateShader(stage, lang, real_code, &error, entry_point);
     if (!sshader)
       ERROR_LOG("Failed to compile function '{}': {}", name, error.GetDescription());