Graphics/PipelinePassList: Add support for attachment proxy

include/Nazara/Graphics/PipelinePassList.hpp

@@ -46,6 +46,7 @@ namespace Nz
 			~PipelinePassList() = default;
 
 			inline std::size_t AddAttachment(FramePassAttachment attachment);
+			inline std::size_t AddAttachmentProxy(std::string name, std::size_t attachmentIndex);
 			inline std::size_t AddPass(std::string name, std::size_t implIndex, ParameterList parameterList = {});
 
 			std::vector<std::unique_ptr<FramePipelinePass>> BuildPasses(FramePipelinePass::PassData& passData) const;
@@ -73,6 +74,12 @@ namespace Nz
 		private:
 			static constexpr std::size_t NoAttachment = std::numeric_limits<std::size_t>::max();
 
+			struct AttachmentProxy
+			{
+				std::string name;
+				std::size_t attachmentIndex;
+			};
+
 			struct Pass
 			{
 				std::size_t depthStencilInput = NoAttachment;
@@ -86,7 +93,7 @@ namespace Nz
 			};
 
 			std::size_t m_finalOutputAttachment;
-			std::vector<FramePassAttachment> m_attachments;
+			std::vector<std::variant<FramePassAttachment, AttachmentProxy>> m_attachments;
 			std::vector<Pass> m_passes;
 	};
 }

include/Nazara/Graphics/PipelinePassList.inl

@@ -15,6 +15,14 @@ namespace Nz
 		return index;
 	}
 
+	inline std::size_t PipelinePassList::AddAttachmentProxy(std::string name, std::size_t attachmentIndex)
+	{
+		std::size_t index = m_attachments.size();
+		m_attachments.emplace_back(AttachmentProxy{ std::move(name), attachmentIndex });
+
+		return index;
+	}
+
 	inline std::size_t PipelinePassList::AddPass(std::string name, std::size_t implIndex, ParameterList parameterList)
 	{
 		std::size_t index = m_passes.size();

src/Nazara/Graphics/Formats/PipelinePassListLoader.cpp

@@ -34,6 +34,27 @@ namespace Nz::Loaders
 							std::string kw = ReadKeyword();
 							if (kw == "attachment")
 								HandleAttachment();
+							else if (kw == "attachmentproxy")
+							{
+								std::string proxyName = ReadString();
+								std::string targetName = ReadString();
+
+								auto it = m_current->attachmentsByName.find(targetName);
+								if (it == m_current->attachmentsByName.end())
+								{
+									NazaraErrorFmt("unknown attachment {}", targetName);
+									throw ResourceLoadingError::DecodingError;
+								}
+
+								if (m_current->attachmentsByName.find(proxyName) != m_current->attachmentsByName.end())
+								{
+									NazaraErrorFmt("attachment {} already exists", proxyName);
+									throw ResourceLoadingError::DecodingError;
+								}
+
+								std::size_t proxyId = m_current->passList->AddAttachmentProxy(proxyName, it->second);
+								m_current->attachmentsByName.emplace(std::move(proxyName), proxyId);
+							}
 							else if (kw == "pass")
 								HandlePass();
 							else if (kw == "output")

src/Nazara/Graphics/PipelinePassList.cpp

@@ -32,9 +32,6 @@ namespace Nz
 		NazaraAssert(m_passes.size() == passes.size(), "pass vector size doesn't match passlist size");
 
 		StackArray<std::size_t> attachmentIndices = NazaraStackArrayNoInit(std::size_t, m_attachments.size());
-		for (std::size_t i = 0; i < m_attachments.size(); ++i)
-			attachmentIndices[i] = frameGraph.AddAttachment(m_attachments[i]);
-
 		auto GetAttachmentIndex = [&](std::size_t attachmentIndex)
 		{
 			if (attachmentIndex == NoAttachment)
@@ -44,6 +41,21 @@ namespace Nz
 			return attachmentIndices[attachmentIndex];
 		};
 
+		for (std::size_t i = 0; i < m_attachments.size(); ++i)
+		{
+			attachmentIndices[i] = std::visit([&](auto&& arg)
+			{
+				using T = std::decay_t<decltype(arg)>;
+				if constexpr (std::is_same_v<T, FramePassAttachment>)
+					return frameGraph.AddAttachment(arg);
+				else if constexpr (std::is_same_v<T, AttachmentProxy>)
+					return frameGraph.AddAttachmentProxy(arg.name, GetAttachmentIndex(arg.attachmentIndex));
+				else
+					static_assert(AlwaysFalse<T>(), "unhandled case");
+
+			}, m_attachments[i]);
+		}
+
 		for (std::size_t passIndex = 0; passIndex < passes.size(); ++passIndex)
 		{
 			const Pass& passData = m_passes[passIndex];