From d679eccb430cce1ab71f835378758d58c171b0e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Leclercq?= <lynix680@gmail.com>
Date: Wed, 7 Jul 2021 21:36:40 +0200
Subject: [PATCH] Shader: Fix struct indexes in case of disabled field

---
 src/Nazara/Shader/Ast/SanitizeVisitor.cpp | 27 ++++++++++++++---------
 src/Nazara/Shader/GlslWriter.cpp          | 23 ++++++++++++++++++-
 src/Nazara/Shader/SpirvConstantCache.cpp  |  3 +++
 src/Nazara/Shader/SpirvWriter.cpp         |  6 +++++
 4 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/src/Nazara/Shader/Ast/SanitizeVisitor.cpp b/src/Nazara/Shader/Ast/SanitizeVisitor.cpp
index a48681575..84a4d8ec4 100644
--- a/src/Nazara/Shader/Ast/SanitizeVisitor.cpp
+++ b/src/Nazara/Shader/Ast/SanitizeVisitor.cpp
@@ -135,21 +135,28 @@ namespace Nz::ShaderAst
 				assert(structIndex < m_context->structs.size());
 				const StructDescription* s = m_context->structs[structIndex];
 
-				auto it = std::find_if(s->members.begin(), s->members.end(), [&](const auto& field)
+				// Retrieve member index (not counting disabled fields)
+				Int32 fieldIndex = 0;
+				const StructDescription::StructMember* fieldPtr = nullptr;
+				for (const auto& field : s->members)
 				{
-					if (field.name != identifier)
-						return false;
-
 					if (field.cond.HasValue() && !field.cond.GetResultingValue())
-						return false;
+						continue;
 
-					return true;
-				});
-				if (it == s->members.end())
+					if (field.name == identifier)
+					{
+						fieldPtr = &field;
+						break;
+					}
+
+					fieldIndex++;
+				}
+
+				if (!fieldPtr)
 					throw AstError{ "unknown field " + identifier };
 
-				accessIndexPtr->indices.push_back(ShaderBuilder::Constant(Int32(std::distance(s->members.begin(), it))));
-				accessIndexPtr->cachedExpressionType = ResolveType(it->type);
+				accessIndexPtr->indices.push_back(ShaderBuilder::Constant(fieldIndex));
+				accessIndexPtr->cachedExpressionType = ResolveType(fieldPtr->type);
 			}
 			else if (IsVectorType(exprType))
 			{
diff --git a/src/Nazara/Shader/GlslWriter.cpp b/src/Nazara/Shader/GlslWriter.cpp
index b28eaec2d..160c606c7 100644
--- a/src/Nazara/Shader/GlslWriter.cpp
+++ b/src/Nazara/Shader/GlslWriter.cpp
@@ -390,8 +390,23 @@ namespace Nz
 		assert((*memberIndices)->GetType() == ShaderAst::NodeType::ConstantExpression);
 		auto& constantValue = static_cast<ShaderAst::ConstantExpression&>(**memberIndices);
 		Int32 index = std::get<Int32>(constantValue.value);
+		assert(index >= 0);
 
-		const auto& member = structDesc->members[index];
+		auto it = structDesc->members.begin();
+		for (; it != structDesc->members.end(); ++it)
+		{
+			const auto& member = *it;
+			if (member.cond.HasValue() && !member.cond.GetResultingValue())
+				continue;
+
+			if (index == 0)
+				break;
+
+			index--;
+		}
+
+		assert(it != structDesc->members.end());
+		const auto& member = *it;
 
 		Append(".");
 		Append(member.name);
@@ -586,6 +601,9 @@ namespace Nz
 		{
 			for (const auto& member : structDesc.members)
 			{
+				if (member.cond.HasValue() && !member.cond.GetResultingValue())
+					continue;
+
 				if (member.builtin.HasValue())
 				{
 					auto it = s_builtinMapping.find(member.builtin.GetResultingValue());
@@ -898,6 +916,9 @@ namespace Nz
 					bool first = true;
 					for (const auto& member : structDesc->members)
 					{
+						if (member.cond.HasValue() && !member.cond.GetResultingValue())
+							continue;
+
 						if (!first)
 							AppendLine();
 
diff --git a/src/Nazara/Shader/SpirvConstantCache.cpp b/src/Nazara/Shader/SpirvConstantCache.cpp
index d569bb22f..4e9699dc9 100644
--- a/src/Nazara/Shader/SpirvConstantCache.cpp
+++ b/src/Nazara/Shader/SpirvConstantCache.cpp
@@ -588,6 +588,9 @@ namespace Nz
 
 		for (const auto& member : structDesc.members)
 		{
+			if (member.cond.HasValue() && !member.cond.GetResultingValue())
+				continue;
+
 			auto& sMembers = sType.members.emplace_back();
 			sMembers.name = member.name;
 			sMembers.type = BuildType(member.type);
diff --git a/src/Nazara/Shader/SpirvWriter.cpp b/src/Nazara/Shader/SpirvWriter.cpp
index 9640c80c4..49fb35d7e 100644
--- a/src/Nazara/Shader/SpirvWriter.cpp
+++ b/src/Nazara/Shader/SpirvWriter.cpp
@@ -218,6 +218,9 @@ namespace Nz
 							std::size_t memberIndex = 0;
 							for (const auto& member : structDesc->members)
 							{
+								if (member.cond.HasValue() && !member.cond.GetResultingValue())
+									continue;
+
 								if (UInt32 varId = HandleEntryInOutType(*entryPointType, funcIndex, member, SpirvStorageClass::Input); varId != 0)
 								{
 									inputs.push_back({
@@ -248,6 +251,9 @@ namespace Nz
 							std::size_t memberIndex = 0;
 							for (const auto& member : structDesc->members)
 							{
+								if (member.cond.HasValue() && !member.cond.GetResultingValue())
+									continue;
+
 								if (UInt32 varId = HandleEntryInOutType(*entryPointType, funcIndex, member, SpirvStorageClass::Output); varId != 0)
 								{
 									outputs.push_back({