Renderer: Fix MRT support

src/Nazara/OpenGLRenderer/OpenGLCommandBuffer.cpp

@@ -3,6 +3,7 @@
 // For conditions of distribution and use, see copyright notice in Config.hpp
 
 #include <Nazara/OpenGLRenderer/OpenGLCommandBuffer.hpp>
+#include <Nazara/Core/StackArray.hpp>
 #include <Nazara/OpenGLRenderer/OpenGLCommandPool.hpp>
 #include <Nazara/OpenGLRenderer/OpenGLVaoCache.hpp>
 #include <Nazara/OpenGLRenderer/Wrapper/Context.hpp>
@@ -57,6 +58,10 @@ 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);
+
 		for (const auto& commandVariant : m_commands)
 		{
 			std::visit([&](auto&& command)
@@ -103,6 +108,10 @@ namespace Nz
 					if (command.framebuffer->GetType() == OpenGLFramebuffer::Type::FBO)
 					{
 						std::size_t colorBufferCount = command.framebuffer->GetColorBufferCount();
+						assert(colorBufferCount <= fboDrawBuffers.size());
+
+						context->glDrawBuffers(GLsizei(colorBufferCount), fboDrawBuffers.data());
+
 						for (std::size_t i = 0; i < colorBufferCount; ++i)
 						{
 							Nz::Color color = command.clearValues[i].color;
@@ -115,6 +124,9 @@ namespace Nz
 					}
 					else
 					{
+						GLenum buffer = GL_BACK;
+						context->glDrawBuffers(1, &buffer);
+
 						Nz::Color color = command.clearValues[0].color;
 						context->glClearColor(color.r / 255.f, color.g / 255.f, color.b / 255.f, color.a / 255.f);
 						context->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

src/Nazara/VulkanRenderer/VulkanCommandBufferBuilder.cpp

@@ -85,6 +85,7 @@ namespace Nz
 		m_commandBuffer.BeginRenderPass(beginInfo);
 
 		m_currentRenderPass = &vkRenderPass;
+		m_currentSubpassIndex = 0;
 	}
 
 	void VulkanCommandBufferBuilder::BindIndexBuffer(Nz::AbstractBuffer* indexBuffer, UInt64 offset)
@@ -101,7 +102,7 @@ namespace Nz
 
 		const VulkanRenderPipeline& vkBinding = static_cast<const VulkanRenderPipeline&>(pipeline);
 
-		m_commandBuffer.BindPipeline(VK_PIPELINE_BIND_POINT_GRAPHICS, vkBinding.Get(m_currentRenderPass->GetRenderPass()));
+		m_commandBuffer.BindPipeline(VK_PIPELINE_BIND_POINT_GRAPHICS, vkBinding.Get(*m_currentRenderPass, m_currentSubpassIndex));
 	}
 
 	void VulkanCommandBufferBuilder::BindShaderBinding(const ShaderBinding& binding)
@@ -160,6 +161,7 @@ namespace Nz
 	void VulkanCommandBufferBuilder::NextSubpass()
 	{
 		m_commandBuffer.NextSubpass();
+		m_currentSubpassIndex++;
 	}
 
 	void VulkanCommandBufferBuilder::PreTransferBarrier()

src/Nazara/VulkanRenderer/VulkanRenderPipeline.cpp

@@ -19,20 +19,31 @@ namespace Nz
 		m_pipelineCreateInfo = BuildCreateInfo(m_pipelineInfo);
 	}
 
-	VkPipeline VulkanRenderPipeline::Get(const Vk::RenderPass& renderPass) const
+	VkPipeline VulkanRenderPipeline::Get(const VulkanRenderPass& renderPass, std::size_t subpassIndex) const
 	{
-		if (auto it = m_pipelines.find(renderPass); it != m_pipelines.end())
+		const Vk::RenderPass& renderPassHandle = renderPass.GetRenderPass();
+
+		// Use color attachment count as a key
+		const auto& subpasses = renderPass.GetSubpassDescriptions();
+		assert(subpassIndex < subpasses.size());
+
+		std::size_t colorAttachmentCount = subpasses[subpassIndex].colorAttachment.size();
+
+		std::pair<VkRenderPass, std::size_t> key = { renderPassHandle, colorAttachmentCount };
+
+		if (auto it = m_pipelines.find(key); it != m_pipelines.end())
 			return it->second;
 
-		// Copy create info to make Get re-entrant
+		UpdateCreateInfo(colorAttachmentCount);
+
 		VkGraphicsPipelineCreateInfo pipelineCreateInfo = m_pipelineCreateInfo.pipelineInfo;
-		pipelineCreateInfo.renderPass = renderPass;
+		pipelineCreateInfo.renderPass = renderPassHandle;
 
 		Vk::Pipeline newPipeline;
 		if (!newPipeline.CreateGraphics(*m_device, pipelineCreateInfo))
 			return VK_NULL_HANDLE;
 
-		auto it = m_pipelines.emplace(renderPass, std::move(newPipeline)).first;
+		auto it = m_pipelines.emplace(key, std::move(newPipeline)).first;
 		return it->second;
 	}
 
@@ -269,4 +280,20 @@ namespace Nz
 
 		return createInfo;
 	}
+
+	void VulkanRenderPipeline::UpdateCreateInfo(std::size_t colorBufferCount) const
+	{
+		// TODO: Add support for independent blend
+		std::size_t previousSize = m_pipelineCreateInfo.colorBlendAttachmentState.size();
+		if (previousSize < colorBufferCount)
+		{
+			assert(!m_pipelineCreateInfo.colorBlendAttachmentState.empty());
+
+			m_pipelineCreateInfo.colorBlendAttachmentState.resize(colorBufferCount);
+			for (std::size_t i = previousSize; i < colorBufferCount; ++i)
+				m_pipelineCreateInfo.colorBlendAttachmentState[i] = m_pipelineCreateInfo.colorBlendAttachmentState.front();
+		}
+
+		m_pipelineCreateInfo.stateData->colorBlendState = BuildColorBlendInfo(m_pipelineInfo, m_pipelineCreateInfo.colorBlendAttachmentState);
+	}
 }