BansheeEngine/CamelotCore/Include/BsGPUProfiler.h

#pragma once

#include "CmPrerequisites.h"
#include "CmModule.h"
#include "BsProfilerFwd.h"

namespace BansheeEngine
{
	/**
	 * @brief	Profiler report containing information about GPU sampling data 
	 *			from a single frame.
	 */
	struct GPUProfilerReport
	{
		/**
		 * @brief	Contains various profiler statistics about a single GPU profiling sample
		 */
		struct Sample
		{
			String name; /**< Name of the sample for easier identification. */
			float timeMs; /**< Time in milliseconds it took to execute the sampled block. */

			UINT32 numDrawCalls; /**< Number of draw calls that happened. */
			UINT32 numRenderTargetChanges; /**< How many times was render target changed. */
			UINT32 numPresents; /**< How many times did a buffer swap happen on a double buffered render target. */
			UINT32 numClears; /**< How many times was render target cleared. */

			UINT32 numVertices; /**< Total number of vertices sent to the GPU. */
			UINT32 numTriangles; /**< Total number of triangles sent to the GPU. */
			UINT32 numDrawnSamples; /**< Number of samples drawn by the GPU. */

			UINT32 numBlendStateChanges; /**< How many times did the blend state change. */
			UINT32 numRasterizerStateChanges; /**< How many times did the rasterizer state change. */
			UINT32 numDepthStencilStateChanges; /**< How many times did the depth stencil state change. */
			
			UINT32 numTextureBinds; /**< How many times was a texture bound. */
			UINT32 numSamplerBinds; /**< How many times was a sampler bound. */
			UINT32 numVertexBufferBinds; /**< How many times was a vertex buffer bound. */
			UINT32 numIndexBufferBinds; /**< How many times was an index buffer bound. */
			UINT32 numGpuParamBufferBinds; /**< How many times was an GPU parameter buffer bound. */
			UINT32 numGpuProgramBinds; /**< How many times was a GPU program bound. */

			UINT32 numResourceWrites; /**< How many times were GPU resources written to. */
			UINT32 numResourceReads; /**< How many times were GPU resources read from. */

			UINT32 numObjectsCreated; /**< How many GPU objects were created. */
			UINT32 numObjectsDestroyed; /**< How many GPU objects were destroyed. */
		};

		Sample frameSample; /**< Sample containing data for entire frame. */
		Vector<Sample> samples;
	};

	/**
	 * @brief	Profiler that measures time and amount of various GPU operations.
	 *
	 * @note	Sim thread only. However most operations will be queued on the core thread or
	 *			on the GPU itself so the results will not be immediately available.
	 */
	class CM_EXPORT GPUProfiler : public Module<GPUProfiler>
	{
		/**
		 * @brief	Signals a start of a new frame. Every frame will generate a separate profiling report.
		 *			This call must be followed by "endFrame", and any sampling operations must happen between
		 *			beginFrame and endFrame.
		 */
		void beginFrame();

		/**
		 * @brief	Signals an end of the currently sampled frame. Results of the sampling will be available
		 *			once getNumAvailableReports increments. This may take a while as the sampling is scheduled on
		 *			the core thread and on the GPU.
		 */
		void endFrame();

		/**
		 * @brief	Begins sample measurement. Must be followed by endSample.
		 *
		 * @param	name	Unique name for the sample you can later use to find the sampling data.
		 *
		 * @note	Must be called between beginFrame/endFrame calls.
		 */
		void beginSample(const ProfilerString& name);

		/**
		 * @brief	Ends sample measurement.
		 *
		 * @param	name	Unique name for the sample.
		 *
		 * @note	Unique name is primarily needed to more easily identify mismatched
		 * 			begin/end sample pairs. Otherwise the name in beginSample would be enough.
		 *			Must be called between beginFrame/endFrame calls.
		 */
		void endSample(const ProfilerString& name);

		/**
		 * @brief	Returns number of profiling reports that are ready but haven't been
		 *			retrieved yet. 
		 *
		 * @note	There is an internal limit of maximum number of available reports, where oldest ones will
		 *			get deleted so make sure to call this often if you don't want to miss some.
		 */
		UINT32 getNumAvailableReports();

		/**
		 * @brief	Gets the oldest report available and removes it from the internal list.
		 *			Throws an exception if no reports are available.
		 */
		const GPUProfilerReport& getNextReport();
	};
}