From d52376a65f37fcbbb67428b917fd3819436b6dfb Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Tue, 2 May 2023 20:29:38 -0700
Subject: Various dxc/fxc compatibility fixes. (#2863)

* Various dxc/fxc compatibility fixes.

* Cleanup.

* Fix test cases.

* Fix comments.

---------

Co-authored-by: Yong He <yhe@nvidia.com>
---
 source/slang/slang-emit-glsl.cpp | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

(limited to 'source/slang/slang-emit-glsl.cpp')

diff --git a/source/slang/slang-emit-glsl.cpp b/source/slang/slang-emit-glsl.cpp
index 0abd78137..bc170dadc 100644
--- a/source/slang/slang-emit-glsl.cpp
+++ b/source/slang/slang-emit-glsl.cpp
@@ -339,16 +339,25 @@ void GLSLSourceEmitter::_emitGLSLParameterGroup(IRGlobalParam* varDecl, IRUnifor
     m_writer->emit("_S");
     m_writer->emit(m_uniqueIDCounter++);
 
-    m_writer->emit("\n{\n");
-    m_writer->indent();
 
     auto elementType = type->getElementType();
-
-    emitType(elementType, "_data");
-    m_writer->emit(";\n");
-
-    m_writer->dedent();
-    m_writer->emit("} ");
+    auto structType = as<IRStructType>(elementType);
+    if (!as<IRGLSLShaderStorageBufferType>(type) && structType)
+    {
+        // We need to emit the fields of the struct as individual variables
+        // in the constant buffer.
+        //
+        emitStructDeclarationsBlock(structType, true);
+    }
+    else
+    {
+        m_writer->emit("\n{\n");
+        m_writer->indent();
+        emitType(elementType, "_data");
+        m_writer->emit(";\n");
+        m_writer->dedent();
+        m_writer->emit("} ");
+    }
 
     m_writer->emit(getName(varDecl));
 
@@ -794,7 +803,7 @@ void GLSLSourceEmitter::_maybeEmitGLSLBuiltin(IRGlobalParam* var, UnownedStringS
         m_writer->emit("out");
         m_writer->emit(" ");
         m_writer->emit(elementTypeName);
-        emitStructDeclarationsBlock(elementType);
+        emitStructDeclarationsBlock(elementType, false);
         m_writer->emit(" ");
         m_writer->emit(name);
         emitArrayBrackets(arrayType);
@@ -1157,7 +1166,7 @@ void GLSLSourceEmitter::_emitGLSLPerVertexVaryingFragmentInput(IRGlobalParam* pa
     //
     _emitType(type, &arrayDeclarator);
 
-    emitSemantics(param);
+    emitSemantics(param, false);
 
     emitLayoutSemantics(param);
 
@@ -2372,6 +2381,17 @@ void GLSLSourceEmitter::emitInterpolationModifiersImpl(IRInst* varInst, IRType*
     }
 }
 
+void GLSLSourceEmitter::emitPackOffsetModifier(IRInst* varInst, IRType* valueType, IRPackOffsetDecoration* decoration)
+{
+    SLANG_UNUSED(varInst);
+    SLANG_UNUSED(valueType);
+
+    _requireGLSLExtension(UnownedStringSlice::fromLiteral("GL_ARB_enhanced_layouts"));
+    m_writer->emit("layout(offset = ");
+    m_writer->emit(decoration->getRegisterOffset()->getValue() * 16 + decoration->getComponentOffset()->getValue() * 4);
+    m_writer->emit(")\n");
+}
+
 void GLSLSourceEmitter::emitMeshOutputModifiersImpl(IRInst* varInst)
 {
     if(varInst->findDecoration<IRGLSLPrimitivesRateDecoration>())
-- 
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