MetalDevice: Explicitly bind fragment resources

Fixes adaptive downsampling with Metal renderer.

src/util/metal_device.mm

@@ -638,7 +638,7 @@ std::unique_ptr<GPUShader> MetalDevice::CreateShaderFromSource(GPUShaderStage st
     return {};
   }
 
-  std::optional<std::string> msl = SPIRVCompiler::CompileSPIRVToMSL(spirv.value());
+  std::optional<std::string> msl = SPIRVCompiler::CompileSPIRVToMSL(stage, spirv.value());
   if (!msl.has_value())
   {
     Log_ErrorPrintf("Failed to compile SPIR-V to MSL.");

src/util/shadergen.cpp

@@ -336,8 +336,8 @@ void ShaderGen::DeclareTexture(std::stringstream& ss, const char* name, u32 inde
 {
   if (m_glsl)
   {
-    if (IsVulkan())
-      ss << "layout(set = " << (m_has_uniform_buffer ? 1 : 0) << ", binding = " << index << ") ";
+    if (m_spirv)
+      ss << "layout(set = " << ((m_has_uniform_buffer || IsMetal()) ? 1 : 0) << ", binding = " << index << ") ";
     else if (m_use_glsl_binding_layout)
       ss << "layout(binding = " << index << ") ";
 
@@ -354,8 +354,8 @@ void ShaderGen::DeclareTextureBuffer(std::stringstream& ss, const char* name, u3
 {
   if (m_glsl)
   {
-    if (IsVulkan())
-      ss << "layout(set = 0, binding = " << index << ") ";
+    if (m_spirv)
+      ss << "layout(set = " << ((m_has_uniform_buffer || IsMetal()) ? 1 : 0) << ", binding = " << index << ") ";
     else if (m_use_glsl_binding_layout)
       ss << "layout(binding = " << index << ") ";
 

src/util/spirv_compiler.cpp

@@ -173,12 +173,29 @@ std::optional<SPIRVCompiler::SPIRVCodeVector> SPIRVCompiler::CompileShader(GPUSh
 
 #ifdef __APPLE__
 
-std::optional<std::string> SPIRVCompiler::CompileSPIRVToMSL(std::span<const SPIRVCodeType> spv)
+std::optional<std::string> SPIRVCompiler::CompileSPIRVToMSL(GPUShaderStage stage, std::span<const SPIRVCodeType> spv)
 {
   spirv_cross::CompilerMSL compiler(spv.data(), spv.size());
 
   spirv_cross::CompilerMSL::Options options = compiler.get_msl_options();
   options.pad_fragment_output_components = true;
+
+  if (stage == GPUShaderStage::Fragment)
+  {
+    for (u32 i = 0; i < GPUDevice::MAX_TEXTURE_SAMPLERS; i++)
+    {
+      spirv_cross::MSLResourceBinding rb;
+      rb.stage = spv::ExecutionModelFragment;
+      rb.desc_set = 1;
+      rb.binding = i;
+      rb.count = 1;
+      rb.msl_texture = i;
+      rb.msl_sampler = i;
+      rb.msl_buffer = i;
+      compiler.add_msl_resource_binding(rb);
+    }
+  }
+
   compiler.set_msl_options(options);
 
   std::string msl = compiler.compile();

src/util/spirv_compiler.h

@@ -42,7 +42,7 @@ std::optional<SPIRVCodeVector> CompileShader(GPUShaderStage stage, std::string_v
 #ifdef __APPLE__
 
 // Converts a SPIR-V shader into MSL.
-std::optional<std::string> CompileSPIRVToMSL(std::span<const SPIRVCodeType> spv);
+std::optional<std::string> CompileSPIRVToMSL(GPUShaderStage stage, std::span<const SPIRVCodeType> spv);
 
 #endif