BansheeEngine/BansheeCore/Include/BsHardwareBufferManager.h

#pragma once

#include "BsCorePrerequisites.h"
#include "BsModule.h"
#include "BsVertexBuffer.h"
#include "BsIndexBuffer.h"
#include "BsVertexDeclaration.h"

namespace BansheeEngine 
{
	/** @cond INTERNAL */
	/** @addtogroup RenderAPI
	 *  @{
	 */

	/**
	 * Handles creation of various hardware buffers.
	 *
	 * @note	Sim thread only.
	 */
	class BS_CORE_EXPORT HardwareBufferManager : public Module<HardwareBufferManager>
	{
    public:
        HardwareBufferManager();
        virtual ~HardwareBufferManager();

		/**
		 * Creates a new vertex buffer used for holding number of vertices and other per-vertex data. Buffer can be bound 
		 * to the pipeline and its data can be passed to the active vertex GPU program.
		 *
		 * @param[in]	vertexSize	Size of a single vertex in the buffer, in bytes.
		 * @param[in]	numVerts	Number of vertices the buffer can hold.
		 * @param[in]	usage		Usage that tells the hardware how will be buffer be used. 
		 * @param[in]	streamOut	If true the buffer will be usable for streaming out data from the GPU.
		 */
		virtual VertexBufferPtr createVertexBuffer(UINT32 vertexSize, UINT32 numVerts, GpuBufferUsage usage, bool streamOut = false);

		/**
		 * Creates a new index buffer that holds indices referencing vertices in a vertex buffer. Indices are interpreted 
		 * by the pipeline and vertices are drawn in the order specified in the index buffer.
		 *
		 * @param[in]	itype		Index type, determines size of an index.
		 * @param[in]	numIndexes	Number of indexes can buffer can hold.
		 * @param[in]	usage		Usage that tells the hardware how will be buffer be used. 
		 */
		virtual IndexBufferPtr createIndexBuffer(IndexType itype, UINT32 numIndexes, GpuBufferUsage usage);

		/**
		 * Creates an GPU parameter block that you can use for setting parameters for GPU programs. Parameter blocks may be
		 * used for sharing parameter data between multiple GPU programs, requiring you to update only one buffer for all of
		 * them, potentially improving performance.
		 *
		 * @param[in]	size	Size of the parameter buffer in bytes.
		 * @param[in]	usage	Usage that tells the hardware how will be buffer be used. 
		 */
		virtual GpuParamBlockBufferPtr createGpuParamBlockBuffer(UINT32 size, GpuParamBlockUsage usage = GPBU_DYNAMIC);

		/**
		 * Creates a generic buffer that can be passed as a parameter to a GPU program. This type of buffer can hold various 
		 * type of data and can be used for various purposes. See "GpuBufferType" for explanation of different buffer types.
		 *
		 * @param[in]	elementCount  	Number of elements in the buffer. 
		 * @param[in]	elementSize   	Size of each individual element in the buffer, in bytes.
		 * @param[in]	type		  	Type of the buffer.
		 * @param[in]	usage		  	Usage that tells the hardware how will be buffer be used. 
		 * @param[in]	randomGpuWrite	(optional) Allows the GPU to write to the resource.
		 * @param[in]	useCounter	  	(optional) Binds a counter that can be used from a GPU program on the buffer.
		 *
		 * @note	
		 * Be aware that due to some render API restrictions some of these settings cannot be used together, and if so you 
		 * will receive an assert in debug mode.
		 */
		virtual GpuBufferPtr createGpuBuffer(UINT32 elementCount, UINT32 elementSize, 
			GpuBufferType type, GpuBufferUsage usage, bool randomGpuWrite = false, bool useCounter = false);

		/** Creates a new vertex declaration from a list of vertex elements. */
		virtual VertexDeclarationPtr createVertexDeclaration(const List<VertexElement>& elements);
	};

	/**
	 * Handles creation of various hardware buffers.
	 *
	 * @note	Core thread only.
	 */
	class BS_CORE_EXPORT HardwareBufferCoreManager : public Module<HardwareBufferCoreManager>
	{
    public:
		virtual ~HardwareBufferCoreManager() { }

		/** @copydoc HardwareBufferManager::createVertexBuffer */
		virtual SPtr<VertexBufferCore> createVertexBuffer(UINT32 vertexSize, UINT32 numVerts, GpuBufferUsage usage, bool streamOut = false);

		/** @copydoc HardwareBufferManager::createIndexBuffer */
		virtual SPtr<IndexBufferCore> createIndexBuffer(IndexType itype, UINT32 numIndexes, GpuBufferUsage usage);

		/** @copydoc HardwareBufferManager::createVertexDeclaration */
		virtual SPtr<VertexDeclarationCore> createVertexDeclaration(const List<VertexElement>& elements);

		/** @copydoc HardwareBufferManager::createGpuParamBlockBuffer */
		virtual SPtr<GpuParamBlockBufferCore> createGpuParamBlockBuffer(UINT32 size, GpuParamBlockUsage usage = GPBU_DYNAMIC);

		/** @copydoc HardwareBufferManager::createGpuBuffer */
		virtual SPtr<GpuBufferCore> createGpuBuffer(UINT32 elementCount, UINT32 elementSize, 
			GpuBufferType type, GpuBufferUsage usage, bool randomGpuWrite = false, bool useCounter = false);

	protected:
		friend class IndexBuffer;
		friend class VertexBuffer;
		friend class VertexDeclaration;
		friend class GpuParamBlockBuffer;
		friend class GpuBuffer;

		/** @copydoc createVertexBuffer */
		virtual SPtr<VertexBufferCore> createVertexBufferInternal(UINT32 vertexSize, UINT32 numVerts, GpuBufferUsage usage, bool streamOut = false) = 0;

		/** @copydoc createIndexBuffer */
		virtual SPtr<IndexBufferCore> createIndexBufferInternal(IndexType itype, UINT32 numIndexes, GpuBufferUsage usage) = 0;

		/** @copydoc createGpuParamBlockBuffer */
		virtual SPtr<GpuParamBlockBufferCore> createGpuParamBlockBufferInternal(UINT32 size, GpuParamBlockUsage usage = GPBU_DYNAMIC) = 0;

		/** @copydoc createGpuBuffer */
		virtual SPtr<GpuBufferCore> createGpuBufferInternal(UINT32 elementCount, UINT32 elementSize,
			GpuBufferType type, GpuBufferUsage usage, bool randomGpuWrite = false, bool useCounter = false) = 0;

		/** @copydoc createVertexDeclaration */
		virtual SPtr<VertexDeclarationCore> createVertexDeclarationInternal(const List<VertexElement>& elements);
	};

	/** @} */
	/** @endcond */
}