BansheeEngine/BansheeCore/Include/BsPass.h

#pragma once

#include "BsCorePrerequisites.h"
#include "BsColor.h"
#include "BsIReflectable.h"
#include "BsCoreObject.h"

namespace BansheeEngine
{
	/**
	 * @brief	Descriptor structure used for initializing a shader pass.
	 */
	struct PASS_DESC
	{
		BlendStatePtr blendState;
		RasterizerStatePtr rasterizerState;
		DepthStencilStatePtr depthStencilState;
		UINT32 stencilRefValue;

		GpuProgramPtr vertexProgram;
		GpuProgramPtr fragmentProgram;
		GpuProgramPtr geometryProgram;
		GpuProgramPtr hullProgram;
		GpuProgramPtr domainProgram;
		GpuProgramPtr computeProgram;
	};

	/**
	 * @brief	Descriptor structure used for initializing a core thread
	 *			variant of a shader pass.
	 */
	struct PASS_DESC_CORE
	{
		SPtr<BlendStateCore> blendState;
		SPtr<RasterizerStateCore> rasterizerState;
		SPtr<DepthStencilStateCore> depthStencilState;
		UINT32 stencilRefValue;

		SPtr<GpuProgramCore> vertexProgram;
		SPtr<GpuProgramCore> fragmentProgram;
		SPtr<GpuProgramCore> geometryProgram;
		SPtr<GpuProgramCore> hullProgram;
		SPtr<GpuProgramCore> domainProgram;
		SPtr<GpuProgramCore> computeProgram;
	};

	/**
	 * @brief	Contains all data used by a pass, templated
	 *			so it may contain both core and sim thread data.
	 */
	template<bool Core>
	struct TPassTypes
	{ };

	template<>
	struct TPassTypes < false >
	{
		typedef BlendStatePtr BlendStateType;
		typedef RasterizerStatePtr RasterizerStateType;
		typedef DepthStencilStatePtr DepthStencilStateType;
		typedef GpuProgramPtr GpuProgramType;
		typedef PASS_DESC PassDescType;
	};

	template<>
	struct TPassTypes < true >
	{
		typedef SPtr<BlendStateCore> BlendStateType;
		typedef SPtr<RasterizerStateCore> RasterizerStateType;
		typedef SPtr<DepthStencilStateCore> DepthStencilStateType;
		typedef SPtr<GpuProgramCore> GpuProgramType;
		typedef PASS_DESC_CORE PassDescType;
	};

	/**
	 * @brief	Class defining a single pass of a technique (of a material), i.e.
	 * 			a single rendering call.
	 *
	 *			Pass may contain multiple GPU programs (vertex, fragment, geometry, etc.), and
	 *			a set of pipeline states (blend, rasterizer, etc.).
	 *
	 * @note	Templated so it can be used for both core and non-core versions of a pass.
	 */
	template<bool Core>
	class BS_CORE_EXPORT TPass
    {
    public:
		typedef typename TPassTypes<Core>::BlendStateType BlendStateType;
		typedef typename TPassTypes<Core>::RasterizerStateType RasterizerStateType;
		typedef typename TPassTypes<Core>::DepthStencilStateType DepthStencilStateType;
		typedef typename TPassTypes<Core>::GpuProgramType GpuProgramType;
		typedef typename TPassTypes<Core>::PassDescType PassDescType;

		virtual ~TPass() { }

        bool hasVertexProgram() const { return mData.vertexProgram != nullptr; }
		bool hasFragmentProgram() const { return mData.fragmentProgram != nullptr; }
		bool hasGeometryProgram() const { return mData.geometryProgram != nullptr; }
		bool hasHullProgram() const { return mData.hullProgram != nullptr; }
		bool hasDomainProgram() const { return mData.domainProgram != nullptr; }
		bool hasComputeProgram() const { return mData.computeProgram != nullptr; }

		/**
		 * @brief	Returns true if this pass has some element of transparency.
		 */
		bool hasBlending() const;

		BlendStateType getBlendState() const { return mData.blendState; }
		RasterizerStateType getRasterizerState() const { return mData.rasterizerState; }
		DepthStencilStateType getDepthStencilState() const { return mData.depthStencilState; }

		/**
		 * @brief	Gets the stencil reference value that is used when performing operations using the
		 * 			stencil buffer.
		 */
		UINT32 getStencilRefValue() const { return mData.stencilRefValue; }

		const GpuProgramType& getVertexProgram() const { return mData.vertexProgram; }
		const GpuProgramType& getFragmentProgram() const { return mData.fragmentProgram; }
		const GpuProgramType& getGeometryProgram() const { return mData.geometryProgram; }
		const GpuProgramType& getHullProgram(void) const { return mData.hullProgram; }
		const GpuProgramType& getDomainProgram(void) const { return mData.domainProgram; }
		const GpuProgramType& getComputeProgram(void) const { return mData.computeProgram; }

	protected:
		TPass();
		TPass(const PassDescType& desc);

		PassDescType mData;
    };

	/**
	 * @copydoc	PassBase
	 *
	 * @note	Core thread.
	 */
	class BS_CORE_EXPORT PassCore : public CoreObjectCore, public TPass<true>
    {
    public:
		virtual ~PassCore() { }

		/**
		 * @brief	Creates a new empty pass.
		 */
		static SPtr<PassCore> create(const PASS_DESC_CORE& desc);

	protected:
		friend class Pass;
		friend class TechniqueCore;

		PassCore() { }
		PassCore(const PASS_DESC_CORE& desc);

		/**
		 * @copydoc	CoreObjectCore::syncToCore
		 */
		void syncToCore(const CoreSyncData& data) override;
    };

	/**
	 * @copydoc	PassBase
	 *
	 * @note	Sim thread.
	 */
	class BS_CORE_EXPORT Pass : public IReflectable, public CoreObject, public TPass<false>
    {
    public:
		virtual ~Pass() { }

		/**
		 * @brief	Retrieves an implementation of a pass usable only from the
		 *			core thread.
		 */
		SPtr<PassCore> getCore() const;

		/**
		 * @brief	Creates a new empty pass.
		 */
		static PassPtr create(const PASS_DESC& desc);

	protected:
		friend class Technique;

		Pass() { }
		Pass(const PASS_DESC& desc);

		/**
		 * @copydoc	CoreObject::syncToCore
		 */
		CoreSyncData syncToCore(FrameAlloc* allocator) override;

		/**
		 * @copydoc	CoreObject::createCore
		 */
		SPtr<CoreObjectCore> createCore() const override;

		/**
		 * @copydoc	CoreObject::syncToCore
		 */
		void getCoreDependencies(FrameVector<SPtr<CoreObject>>& dependencies) override;

		/**
		 * @brief	Creates a new empty pass but doesn't initialize it.
		 */
		static PassPtr createEmpty();

		/************************************************************************/
		/* 								RTTI		                     		*/
		/************************************************************************/
	public:
		friend class PassRTTI;
		static RTTITypeBase* getRTTIStatic();
		virtual RTTITypeBase* getRTTI() const override;
    };
}