From ccf77ac4596ac7db0df978f0c5b1fbf71eb9001b Mon Sep 17 00:00:00 2001
From: SirLynix <lynix680@gmail.com>
Date: Tue, 6 Dec 2022 07:49:41 +0100
Subject: [PATCH] OpenGLRenderer: Setup draw buffers only once

---
 .../Nazara/OpenGLRenderer/Wrapper/Framebuffer.hpp |  1 +
 .../Nazara/OpenGLRenderer/Wrapper/Framebuffer.inl |  9 +++++++++
 src/Nazara/OpenGLRenderer/OpenGLCommandBuffer.cpp |  8 +-------
 .../OpenGLRenderer/OpenGLFboFramebuffer.cpp       | 15 +++++++++++++++
 4 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/include/Nazara/OpenGLRenderer/Wrapper/Framebuffer.hpp b/include/Nazara/OpenGLRenderer/Wrapper/Framebuffer.hpp
index cb6f6e2b9..c59e639e8 100644
--- a/include/Nazara/OpenGLRenderer/Wrapper/Framebuffer.hpp
+++ b/include/Nazara/OpenGLRenderer/Wrapper/Framebuffer.hpp
@@ -24,6 +24,7 @@ namespace Nz::GL
 
 			inline GLenum Check() const;
 
+			inline void DrawBuffers(GLsizei n, const GLenum* bufs);
 			inline void Renderbuffer(GLenum attachment, GLenum renderbuffer);
 			inline void Texture2D(GLenum attachment, GLenum textarget, GLuint texture, GLint level = 0);
 
diff --git a/include/Nazara/OpenGLRenderer/Wrapper/Framebuffer.inl b/include/Nazara/OpenGLRenderer/Wrapper/Framebuffer.inl
index be740fe01..171f3eab8 100644
--- a/include/Nazara/OpenGLRenderer/Wrapper/Framebuffer.inl
+++ b/include/Nazara/OpenGLRenderer/Wrapper/Framebuffer.inl
@@ -17,6 +17,15 @@ namespace Nz::GL
 		return context.glCheckFramebufferStatus(target);
 	}
 
+	inline void Framebuffer::DrawBuffers(GLsizei n, const GLenum* bufs)
+	{
+		assert(m_objectId);
+
+		const Context& context = EnsureContext();
+		context.BindFramebuffer(FramebufferTarget::Draw, m_objectId);
+		context.glDrawBuffers(n, bufs);
+	}
+
 	inline void Framebuffer::Renderbuffer(GLenum attachment, GLenum renderbuffer)
 	{
 		assert(m_objectId);
diff --git a/src/Nazara/OpenGLRenderer/OpenGLCommandBuffer.cpp b/src/Nazara/OpenGLRenderer/OpenGLCommandBuffer.cpp
index 8ae6db26d..16a88089c 100644
--- a/src/Nazara/OpenGLRenderer/OpenGLCommandBuffer.cpp
+++ b/src/Nazara/OpenGLRenderer/OpenGLCommandBuffer.cpp
@@ -61,10 +61,6 @@ namespace Nz
 	{
 		const GL::Context* context = GL::Context::GetCurrentContext();
 
-		StackArray<GLenum> fboDrawBuffers = NazaraStackArrayNoInit(GLenum, m_maxColorBufferCount);
-		for (std::size_t i = 0; i < m_maxColorBufferCount; ++i)
-			fboDrawBuffers[i] = GLenum(GL_COLOR_ATTACHMENT0 + i);
-
 		StackArray<std::size_t> colorIndexes = NazaraStackArrayNoInit(std::size_t, m_maxColorBufferCount);
 
 		for (const auto& commandVariant : m_commands)
@@ -129,7 +125,7 @@ namespace Nz
 					context = GL::Context::GetCurrentContext();
 
 					std::size_t colorBufferCount = command.framebuffer->GetColorBufferCount();
-					assert(colorBufferCount <= fboDrawBuffers.size());
+					assert(colorBufferCount <= colorIndexes.size());
 
 					colorIndexes.fill(0);
 					std::size_t colorIndex = 0;
@@ -175,8 +171,6 @@ namespace Nz
 					{
 						const OpenGLFboFramebuffer& fboFramebuffer = static_cast<const OpenGLFboFramebuffer&>(*command.framebuffer);
 
-						context->glDrawBuffers(GLsizei(colorBufferCount), fboDrawBuffers.data());
-
 						invalidateAttachments = NazaraStackVector(GLenum, colorBufferCount + 1);
 
 						for (std::size_t i = 0; i < colorBufferCount; ++i)
diff --git a/src/Nazara/OpenGLRenderer/OpenGLFboFramebuffer.cpp b/src/Nazara/OpenGLRenderer/OpenGLFboFramebuffer.cpp
index 7a39bd502..c99e5250e 100644
--- a/src/Nazara/OpenGLRenderer/OpenGLFboFramebuffer.cpp
+++ b/src/Nazara/OpenGLRenderer/OpenGLFboFramebuffer.cpp
@@ -5,6 +5,7 @@
 #include <Nazara/OpenGLRenderer/OpenGLFboFramebuffer.hpp>
 #include <Nazara/OpenGLRenderer/OpenGLRenderPass.hpp>
 #include <Nazara/OpenGLRenderer/OpenGLTexture.hpp>
+#include <Nazara/Utils/StackArray.hpp>
 #include <stdexcept>
 #include <Nazara/OpenGLRenderer/Debug.hpp>
 
@@ -85,6 +86,20 @@ namespace Nz
 			throw std::runtime_error("invalid framebuffer: 0x" + NumberToString(status, 16));
 
 		m_colorAttachmentCount = colorAttachmentCount;
+
+		if (m_colorAttachmentCount > 0)
+		{
+			StackArray<GLenum> fboDrawBuffers = NazaraStackArrayNoInit(GLenum, m_colorAttachmentCount);
+			for (std::size_t i = 0; i < m_colorAttachmentCount; ++i)
+				fboDrawBuffers[i] = GLenum(GL_COLOR_ATTACHMENT0 + i);
+
+			m_framebuffer.DrawBuffers(SafeCast<GLsizei>(m_colorAttachmentCount), fboDrawBuffers.data());
+		}
+		else
+		{
+			GLenum buffer = GL_NONE;
+			m_framebuffer.DrawBuffers(1, &buffer);
+		}
 	}
 
 	void OpenGLFboFramebuffer::Activate() const