Allocate command buffers from pools

src/Nazara/OpenGLRenderer/OpenGLCommandPool.cpp

@@ -3,19 +3,82 @@
 // For conditions of distribution and use, see copyright notice in Config.hpp
 
 #include <Nazara/OpenGLRenderer/OpenGLCommandPool.hpp>
+#include <Nazara/Core/MemoryHelper.hpp>
 #include <Nazara/OpenGLRenderer/OpenGLCommandBuffer.hpp>
 #include <Nazara/OpenGLRenderer/OpenGLCommandBufferBuilder.hpp>
 #include <Nazara/OpenGLRenderer/Debug.hpp>
 
 namespace Nz
 {
-	std::unique_ptr<CommandBuffer> OpenGLCommandPool::BuildCommandBuffer(const std::function<void(CommandBufferBuilder& builder)>& callback)
+	CommandBufferPtr OpenGLCommandPool::BuildCommandBuffer(const std::function<void(CommandBufferBuilder& builder)>& callback)
 	{
-		std::unique_ptr<OpenGLCommandBuffer> commandBuffer = std::make_unique<OpenGLCommandBuffer>();
+		CommandBufferPtr commandBuffer;
+		for (std::size_t i = 0; i < m_commandPools.size(); ++i)
+		{
+			commandBuffer = AllocateFromPool(i);
+			if (commandBuffer)
+				break;
+		}
 
-		OpenGLCommandBufferBuilder builder(*commandBuffer);
+		if (!commandBuffer)
+		{
+			// No allocation could be made, time to allocate a new pool
+			std::size_t newPoolIndex = m_commandPools.size();
+			AllocatePool();
+
+			commandBuffer = AllocateFromPool(newPoolIndex);
+			assert(commandBuffer);
+		}
+
+		OpenGLCommandBufferBuilder builder(static_cast<OpenGLCommandBuffer&>(*commandBuffer.get()));
 		callback(builder);
 
 		return commandBuffer;
 	}
+
+	auto OpenGLCommandPool::AllocatePool() -> CommandPool&
+	{
+		constexpr UInt32 MaxSet = 128;
+
+		CommandPool pool;
+		pool.freeCommands.Resize(MaxSet, true);
+		pool.storage = std::make_unique<CommandPool::BindingStorage[]>(MaxSet);
+
+		return m_commandPools.emplace_back(std::move(pool));
+	}
+
+	CommandBufferPtr OpenGLCommandPool::AllocateFromPool(std::size_t poolIndex)
+	{
+		auto& pool = m_commandPools[poolIndex];
+
+		std::size_t freeBindingId = pool.freeCommands.FindFirst();
+		if (freeBindingId == pool.freeCommands.npos)
+			return {}; //< No free binding in this pool
+
+		pool.freeCommands.Reset(freeBindingId);
+
+		OpenGLCommandBuffer* freeBindingMemory = reinterpret_cast<OpenGLCommandBuffer*>(&pool.storage[freeBindingId]);
+		return CommandBufferPtr(PlacementNew(freeBindingMemory, *this, poolIndex, freeBindingId));
+	}
+
+	void OpenGLCommandPool::Release(CommandBuffer& binding)
+	{
+		OpenGLCommandBuffer& openglBinding = static_cast<OpenGLCommandBuffer&>(binding);
+
+		std::size_t poolIndex = openglBinding.GetPoolIndex();
+		std::size_t bindingIndex = openglBinding.GetBindingIndex();
+
+		assert(poolIndex < m_commandPools.size());
+		auto& pool = m_commandPools[poolIndex];
+		assert(!pool.freeCommands.Test(bindingIndex));
+
+		OpenGLCommandBuffer* bindingMemory = reinterpret_cast<OpenGLCommandBuffer*>(&pool.storage[bindingIndex]);
+		PlacementDestroy(bindingMemory);
+
+		pool.freeCommands.Set(bindingIndex);
+
+		// Try to free pool if it's one of the last one
+		if (poolIndex >= m_commandPools.size() - 1 && poolIndex <= m_commandPools.size())
+			TryToShrink();
+	}
 }