From 90ab0e9438b0a547e8e9b932cbd8d3c145102255 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Leclercq?= <lynix680@gmail.com>
Date: Mon, 13 Dec 2021 23:44:34 +0100
Subject: [PATCH] Graphics/FramePass: Add SetReadInput method

---
 examples/DeferredShading/main.cpp     | 12 +++---------
 include/Nazara/Graphics/FramePass.hpp |  5 +++--
 include/Nazara/Graphics/FramePass.inl |  6 ++++++
 src/Nazara/Graphics/FrameGraph.cpp    |  7 +++++--
 4 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/examples/DeferredShading/main.cpp b/examples/DeferredShading/main.cpp
index 5a70d7913..9e843ca9e 100644
--- a/examples/DeferredShading/main.cpp
+++ b/examples/DeferredShading/main.cpp
@@ -672,10 +672,7 @@ int main()
 			Nz::PixelFormat::RGBA16F
 		});
 
-		bloomOutput = graph.AddAttachment({
-			"Backbuffer",
-			Nz::PixelFormat::RGBA16F
-		});
+		bloomOutput = graph.AddAttachmentProxy("Bloom output", lightOutput);
 
 		unsigned int bloomSize = 50'000;
 		bloomBrightOutput = graph.AddAttachment({
@@ -889,11 +886,6 @@ int main()
 			builder.SetViewport(renderArea);
 			builder.BindVertexBuffer(0, *fullscreenVertexBuffer);
 
-			// Blit light output
-			builder.BindPipeline(*Nz::Graphics::Instance()->GetBlitPipeline(false));
-			builder.BindShaderBinding(0, *bloomBlitBinding);
-			builder.Draw(3);
-
 			// Blend bloom
 			builder.BindPipeline(*bloomBlendPipeline);
 			for (std::size_t i = 0; i < BloomSubdivisionCount; ++i)
@@ -909,6 +901,8 @@ int main()
 		});
 
 		bloomBlendPass.AddInput(lightOutput);
+		bloomBlendPass.SetReadInput(0, false);
+
 		for (std::size_t i = 0; i < BloomSubdivisionCount; ++i)
 			bloomBlendPass.AddInput(bloomTextures[i * 2 + 1]);
 
diff --git a/include/Nazara/Graphics/FramePass.hpp b/include/Nazara/Graphics/FramePass.hpp
index bf9b81fb7..06cf6a521 100644
--- a/include/Nazara/Graphics/FramePass.hpp
+++ b/include/Nazara/Graphics/FramePass.hpp
@@ -61,10 +61,10 @@ namespace Nz
 			inline void SetCommandCallback(CommandCallback callback);
 			inline void SetClearColor(std::size_t outputIndex, const std::optional<Color>& color);
 			inline void SetDepthStencilClear(float depth, UInt32 stencil);
-			inline void SetExecutionCallback(ExecutionCallback callback);
-
 			inline void SetDepthStencilInput(std::size_t attachmentId);
 			inline void SetDepthStencilOutput(std::size_t attachmentId);
+			inline void SetExecutionCallback(ExecutionCallback callback);
+			inline void SetReadInput(std::size_t inputIndex, bool doesRead);
 
 			FramePass& operator=(const FramePass&) = delete;
 			FramePass& operator=(FramePass&&) noexcept = default;
@@ -80,6 +80,7 @@ namespace Nz
 			struct Input
 			{
 				std::size_t attachmentId;
+				bool doesRead = true;
 			};
 
 			struct Output
diff --git a/include/Nazara/Graphics/FramePass.inl b/include/Nazara/Graphics/FramePass.inl
index 8a27e0f11..3a38bfab2 100644
--- a/include/Nazara/Graphics/FramePass.inl
+++ b/include/Nazara/Graphics/FramePass.inl
@@ -126,6 +126,12 @@ namespace Nz
 		m_executionCallback = std::move(callback);
 	}
 
+	inline void FramePass::SetReadInput(std::size_t inputIndex, bool doesRead)
+	{
+		assert(inputIndex < m_inputs.size());
+		m_inputs[inputIndex].doesRead = doesRead;
+	}
+
 	inline void FramePass::SetDepthStencilInput(std::size_t attachmentId)
 	{
 		m_depthStencilInput = attachmentId;
diff --git a/src/Nazara/Graphics/FrameGraph.cpp b/src/Nazara/Graphics/FrameGraph.cpp
index 0ebb3887d..8cc1a4fc2 100644
--- a/src/Nazara/Graphics/FrameGraph.cpp
+++ b/src/Nazara/Graphics/FrameGraph.cpp
@@ -658,7 +658,7 @@ namespace Nz
 			std::vector<RenderPass::SubpassDescription> subpassesDesc;
 			std::vector<RenderPass::SubpassDependency> subpassesDeps;
 
-			auto RegisterColorInput = [&](const FramePass::Input& input, PhysicalPassData::Subpass& subpass)
+			auto RegisterColorInputRead = [&](const FramePass::Input& input, PhysicalPassData::Subpass& subpass)
 			{
 				std::size_t textureId = Retrieve(m_pending.attachmentToTextures, input.attachmentId);
 
@@ -769,7 +769,10 @@ namespace Nz
 				colorAttachments.reserve(subpassOutputs.size());
 
 				for (const auto& input : subpassInputs)
-					RegisterColorInput(input, subpass);
+				{
+					if (input.doesRead)
+						RegisterColorInputRead(input, subpass);
+				}
 
 				for (const auto& output : subpassOutputs)
 				{