From 17a6c4168ea67011f13efb9c831e7636f7830538 Mon Sep 17 00:00:00 2001
From: Philip Rebohle <philip.rebohle@tu-dortmund.de>
Date: Sun, 15 Sep 2019 14:56:23 +0200
Subject: [PATCH] [dxbc] Implement stencil ref export from fragment shaders

This is an optional feature in D3D11.3, but easy enough to support.
---
 src/d3d11/d3d11_device.cpp |  3 ++-
 src/dxbc/dxbc_compiler.cpp | 17 +++++++++++++++++
 src/dxbc/dxbc_compiler.h   |  1 +
 src/dxbc/dxbc_enums.h      |  1 +
 4 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/d3d11/d3d11_device.cpp b/src/d3d11/d3d11_device.cpp
index 4a6f4145..6679ac7d 100644
--- a/src/d3d11/d3d11_device.cpp
+++ b/src/d3d11/d3d11_device.cpp
@@ -1367,10 +1367,11 @@ namespace dxvk {
         if (FeatureSupportDataSize != sizeof(D3D11_FEATURE_DATA_D3D11_OPTIONS2))
           return E_INVALIDARG;
 
+        const auto& extensions = m_dxvkDevice->extensions();
         const auto& features = m_dxvkDevice->features();
 
         auto info = static_cast<D3D11_FEATURE_DATA_D3D11_OPTIONS2*>(pFeatureSupportData);
-        info->PSSpecifiedStencilRefSupported = FALSE; // TODO
+        info->PSSpecifiedStencilRefSupported = extensions.extShaderStencilExport;
         info->TypedUAVLoadAdditionalFormats  = features.core.features.shaderStorageImageReadWithoutFormat;
         info->ROVsSupported                  = FALSE;
         info->ConservativeRasterizationTier  = D3D11_CONSERVATIVE_RASTERIZATION_NOT_SUPPORTED;
diff --git a/src/dxbc/dxbc_compiler.cpp b/src/dxbc/dxbc_compiler.cpp
index ffd0c0ad..911f2527 100644
--- a/src/dxbc/dxbc_compiler.cpp
+++ b/src/dxbc/dxbc_compiler.cpp
@@ -554,6 +554,18 @@ namespace dxvk {
           "oDepth");
       } break;
       
+      case DxbcOperandType::OutputStencilRef: {
+        m_module.enableExtension("SPV_EXT_shader_stencil_export");
+        m_module.enableCapability(spv::CapabilityStencilExportEXT);
+        m_module.setExecutionMode(m_entryPointId,
+          spv::ExecutionModeStencilRefReplacingEXT);
+        m_ps.builtinStencilRef = emitNewBuiltinVariable({
+          { DxbcScalarType::Sint32, 1, 0 },
+          spv::StorageClassOutput },
+          spv::BuiltInFragStencilRefEXT,
+          "oStencilRef");
+      } break;
+
       case DxbcOperandType::OutputDepthGe: {
         m_module.setExecutionMode(m_entryPointId, spv::ExecutionModeDepthReplacing);
         m_module.setExecutionMode(m_entryPointId, spv::ExecutionModeDepthGreater);
@@ -4860,6 +4872,11 @@ namespace dxvk {
           { DxbcScalarType::Float32, 1 },
           m_ps.builtinDepth };
       
+      case DxbcOperandType::OutputStencilRef:
+        return DxbcRegisterPointer {
+          { DxbcScalarType::Sint32, 1 },
+          m_ps.builtinStencilRef };
+
       case DxbcOperandType::InputPrimitiveId:
         return DxbcRegisterPointer {
           { DxbcScalarType::Uint32, 1 },
diff --git a/src/dxbc/dxbc_compiler.h b/src/dxbc/dxbc_compiler.h
index e7a6eaeb..39e9743f 100644
--- a/src/dxbc/dxbc_compiler.h
+++ b/src/dxbc/dxbc_compiler.h
@@ -171,6 +171,7 @@ namespace dxvk {
     
     uint32_t builtinFragCoord     = 0;
     uint32_t builtinDepth         = 0;
+    uint32_t builtinStencilRef    = 0;
     uint32_t builtinIsFrontFace   = 0;
     uint32_t builtinSampleId      = 0;
     uint32_t builtinSampleMaskIn  = 0;
diff --git a/src/dxbc/dxbc_enums.h b/src/dxbc/dxbc_enums.h
index 27610e46..5ecd10bd 100644
--- a/src/dxbc/dxbc_enums.h
+++ b/src/dxbc/dxbc_enums.h
@@ -288,6 +288,7 @@ namespace dxvk {
     OutputDepthGe           = 38,
     OutputDepthLe           = 39,
     CycleCounter            = 40,
+    OutputStencilRef        = 41,
   };