BansheeEngine/Source/RenderBeast/BsRendererView.h

//********************************** Banshee Engine (www.banshee3d.com) **************************************************//
//**************** Copyright (c) 2016 Marko Pintera ([email protected]). All rights reserved. **********************//
#pragma once

#include "BsRenderBeastPrerequisites.h"
#include "BsPostProcessing.h"
#include "BsObjectRendering.h"
#include "Renderer/BsRenderQueue.h"
#include "BsRendererObject.h"
#include "Math/BsBounds.h"
#include "Math/BsConvexVolume.h"
#include "Renderer/BsLight.h"
#include "BsLightGrid.h"
#include "BsShadowRendering.h"
#include "BsRenderCompositor.h"

namespace bs { namespace ct
{
	struct SceneInfo;
	class RendererLight;

	/** @addtogroup RenderBeast
	 *  @{
	 */

	BS_PARAM_BLOCK_BEGIN(PerCameraParamDef)
		BS_PARAM_BLOCK_ENTRY(Vector3, gViewDir)
		BS_PARAM_BLOCK_ENTRY(Vector3, gViewOrigin)
		BS_PARAM_BLOCK_ENTRY(Matrix4, gMatViewProj)
		BS_PARAM_BLOCK_ENTRY(Matrix4, gMatView)
		BS_PARAM_BLOCK_ENTRY(Matrix4, gMatProj)
		BS_PARAM_BLOCK_ENTRY(Matrix4, gMatInvProj)
		BS_PARAM_BLOCK_ENTRY(Matrix4, gMatInvViewProj)
		BS_PARAM_BLOCK_ENTRY(Matrix4, gMatScreenToWorld)
		BS_PARAM_BLOCK_ENTRY(Matrix4, gNDCToPrevNDC)
		BS_PARAM_BLOCK_ENTRY(Vector2, gDeviceZToWorldZ)
		BS_PARAM_BLOCK_ENTRY(Vector2, gNDCZToWorldZ)
		BS_PARAM_BLOCK_ENTRY(Vector2, gNDCZToDeviceZ)
		BS_PARAM_BLOCK_ENTRY(Vector2, gNearFar)
		BS_PARAM_BLOCK_ENTRY(Vector4I, gViewportRectangle)
		BS_PARAM_BLOCK_ENTRY(Vector4, gClipToUVScaleOffset)
		BS_PARAM_BLOCK_ENTRY(float, gAmbientFactor)
	BS_PARAM_BLOCK_END

	extern PerCameraParamDef gPerCameraParamDef;

	BS_PARAM_BLOCK_BEGIN(SkyboxParamDef)
		BS_PARAM_BLOCK_ENTRY(Color, gClearColor)
	BS_PARAM_BLOCK_END

	extern SkyboxParamDef gSkyboxParamDef;

	/** Shader that renders a skybox using a cubemap or a solid color. */
	class SkyboxMat : public RendererMaterial<SkyboxMat>
	{
		RMAT_DEF("Skybox.bsl");

	public:
		SkyboxMat();

		/** Binds the material for rendering and sets up any global parameters. */
		void bind(const SPtr<GpuParamBlockBuffer>& perCamera);

		/** Updates the skybox texture & solid color used by the material. */
		void setParams(const SPtr<Texture>& texture, const Color& solidColor);

		/** 
		 * Returns the material variation matching the provided parameters.
		 * 
		 * @param[in]	color	When true the material will use a solid color to render a skybox. When false a user
		 *						provided texture will be used instead.
		 */
		static SkyboxMat* getVariation(bool color);
	private:
		GpuParamTexture mSkyTextureParam;
		SPtr<GpuParamBlockBuffer> mParamBuffer;

		static ShaderVariation VAR_Texture;
		static ShaderVariation VAR_Color;
	};

	/** Data shared between RENDERER_VIEW_DESC and RendererViewProperties */
	struct RendererViewData
	{
		RendererViewData();

		Matrix4 viewTransform;
		Matrix4 projTransform;
		Vector3 viewDirection;
		Vector3 viewOrigin;
		bool flipView;
		float nearPlane;
		float farPlane;
		ProjectionType projType;

		/** 
		 * When enabled, renderer extension callbacks will be triggered, allowing other systems to inject their own 
		 * render operations into the view.
		 */
		bool triggerCallbacks : 1;

		/** When enabled, post-processing effects (like tonemapping) will be executed. */
		bool runPostProcessing : 1;

		/** 
		 * Determines if the view is currently rendering reflection probes. This ensures the systems can disable refl.
		 * probe reads in order to prevent incorrect rendering (since probes won't yet have any data).
		 */
		bool renderingReflections : 1;

		/** 
		 * When enabled the alpha channel of the final render target will be populated with an encoded depth value. 
		 * Parameters @p depthEncodeNear and @p depthEncodeFar control which range of the depth buffer to encode.
		 */
		bool encodeDepth : 1;

		/**
		 * Controls at which position to start encoding depth, in view space. Only relevant with @p encodeDepth is enabled.
		 * Depth will be linearly interpolated between this value and @p depthEncodeFar.
		 */
		float depthEncodeNear;

		/**
		 * Controls at which position to stop encoding depth, in view space. Only relevant with @p encodeDepth is enabled.
		 * Depth will be linearly interpolated between @p depthEncodeNear and this value.
		 */
		float depthEncodeFar;

		UINT64 visibleLayers;
		ConvexVolume cullFrustum;
	};

	/** Data shared between RENDERER_VIEW_TARGET_DESC and RendererViewTargetProperties */
	struct RendererViewTargetData
	{
		SPtr<RenderTarget> target;

		Rect2I viewRect;
		Rect2 nrmViewRect;
		UINT32 targetWidth;
		UINT32 targetHeight;
		UINT32 numSamples;

		UINT32 clearFlags;
		Color clearColor;
		float clearDepthValue;
		UINT16 clearStencilValue;
	};

	/** Set of properties describing the output render target used by a renderer view. */
	struct RENDERER_VIEW_TARGET_DESC : RendererViewTargetData
	{ };

	/** Set of properties used describing a specific view that the renderer can render. */
	struct RENDERER_VIEW_DESC : RendererViewData
	{
		RENDERER_VIEW_TARGET_DESC target;

		StateReduction stateReduction;
		Camera* sceneCamera;
	};

	/** Set of properties used describing a specific view that the renderer can render. */
	struct RendererViewProperties : RendererViewData
	{
		RendererViewProperties() {}
		RendererViewProperties(const RENDERER_VIEW_DESC& src);

		Matrix4 viewProjTransform;
		Matrix4 prevViewProjTransform;

		SPtr<RenderTarget> target;
		Rect2I viewRect;
		Rect2 nrmViewRect;
		UINT32 numSamples;
		UINT32 frameIdx;

		UINT32 clearFlags;
		Color clearColor;
		float clearDepthValue;
		UINT16 clearStencilValue;
	};

	/** Information whether certain scene objects are visible in a view, per object type. */
	struct VisibilityInfo
	{
		Vector<bool> renderables;
		Vector<bool> radialLights;
		Vector<bool> spotLights;
		Vector<bool> reflProbes;
	};

	/** Information used for culling an object against a view. */
	struct CullInfo
	{
		CullInfo(const Bounds& bounds, UINT64 layer = -1)
			:bounds(bounds), layer(layer)
		{ }

		Bounds bounds;
		UINT64 layer;
	};

	/**	Renderer information specific to a single render target. */
	struct RendererRenderTarget
	{
		SPtr<RenderTarget> target;
		Vector<Camera*> cameras;
	};

	/** Contains information about a single view into the scene, used by the renderer. */
	class RendererView
	{
	public:
		RendererView();
		RendererView(const RENDERER_VIEW_DESC& desc);

		/** Sets state reduction mode that determines how do render queues group & sort renderables. */
		void setStateReductionMode(StateReduction reductionMode);

		/** Updates the internal camera render settings. */
		void setRenderSettings(const SPtr<RenderSettings>& settings);

		/** Updates the internal information with a new view transform. */
		void setTransform(const Vector3& origin, const Vector3& direction, const Matrix4& view,
						  const Matrix4& proj, const ConvexVolume& worldFrustum);

		/** Updates all internal information with new view information. */
		void setView(const RENDERER_VIEW_DESC& desc);

		/** Returns a structure describing the view. */
		const RendererViewProperties& getProperties() const { return mProperties; }

		/** Returns the scene camera this object is based of. This can be null for manually constructed renderer cameras. */
		Camera* getSceneCamera() const { return mCamera; }

		/** Prepares render targets for rendering. When done call endFrame(). */
		void beginFrame();

		/** Ends rendering and frees any acquired resources. */
		void endFrame();

		/** 
		 * Returns a render queue containing all opaque objects. Make sure to call determineVisible() beforehand if view 
		 * or object transforms changed since the last time it was called.
		 */
		const SPtr<RenderQueue>& getOpaqueQueue() const { return mOpaqueQueue; }
		
		/** 
		 * Returns a render queue containing all transparent objects. Make sure to call determineVisible() beforehand if 
		 * view or object transforms changed since the last time it was called.
		 */
		const SPtr<RenderQueue>& getTransparentQueue() const { return mTransparentQueue; }

		/** Returns the compositor in charge of rendering for this view. */
		const RenderCompositor& getCompositor() const { return mCompositor; }

		/**
		 * Populates view render queues by determining visible renderable objects. 
		 *
		 * @param[in]	renderables			A set of renderable objects to iterate over and determine visibility for.
		 * @param[in]	cullInfos			A set of world bounds & other information relevant for culling the provided
		 *									renderable objects. Must be the same size as the @p renderables array.
		 * @param[out]	visibility			Output parameter that will have the true bit set for any visible renderable
		 *									object. If the bit for an object is already set to true, the method will never
		 *									change it to false which allows the same bitfield to be provided to multiple
		 *									renderer views. Must be the same size as the @p renderables array.
		 *									
		 *									As a side-effect, per-view visibility data is also calculated and can be
		 *									retrieved by calling getVisibilityMask().
		 */
		void determineVisible(const Vector<RendererObject*>& renderables, const Vector<CullInfo>& cullInfos,
			Vector<bool>* visibility = nullptr);

		/**
		 * Calculates the visibility masks for all the lights of the provided type.
		 * 
		 * @param[in]	lights				A set of lights to determine visibility for.
		 * @param[in]	bounds				Bounding sphere for each provided light. Must be the same size as the @p lights
		 *									array.
		 * @param[in]	type				Type of all the lights in the @p lights array.
		 * @param[out]	visibility			Output parameter that will have the true bit set for any visible light. If the
		 *									bit for a light is already set to true, the method will never change it to false
		 *									which allows the same bitfield to be provided to multiple renderer views. Must
		 *									be the same size as the @p lights array.
		 *									
		 *									As a side-effect, per-view visibility data is also calculated and can be
		 *									retrieved by calling getVisibilityMask().
		 */
		void determineVisible(const Vector<RendererLight>& lights, const Vector<Sphere>& bounds, LightType type, 
			Vector<bool>* visibility = nullptr);

		/**
		 * Culls the provided set of bounds against the current frustum and outputs a set of visibility flags determining
		 * which entry is or isn't visible by this view. Both inputs must be arrays of the same size.
		 */
		void calculateVisibility(const Vector<CullInfo>& cullInfos, Vector<bool>& visibility) const;

		/**
		 * Culls the provided set of bounds against the current frustum and outputs a set of visibility flags determining
		 * which entry is or isn't visible by this view. Both inputs must be arrays of the same size.
		 */
		void calculateVisibility(const Vector<Sphere>& bounds, Vector<bool>& visibility) const;

		/**
		 * Culls the provided set of bounds against the current frustum and outputs a set of visibility flags determining
		 * which entry is or isn't visible by this view. Both inputs must be arrays of the same size.
		 */
		void calculateVisibility(const Vector<AABox>& bounds, Vector<bool>& visibility) const;

		/** Returns the visibility mask calculated with the last call to determineVisible(). */
		const VisibilityInfo& getVisibilityMasks() const { return mVisibility; }

		/** Returns per-view settings that control rendering. */
		const RenderSettings& getRenderSettings() const { return *mRenderSettings; }

		/**
		 * Retrieves a hash value that is updated whenever render settings change. This can be used by external systems
		 * to detect when they need to update.
		 */
		UINT64 getRenderSettingsHash() const { return mRenderSettingsHash; }

		/** Updates the GPU buffer containing per-view information, with the latest internal data. */
		void updatePerViewBuffer();

		/** Returns a buffer that stores per-view parameters. */
		SPtr<GpuParamBlockBuffer> getPerViewBuffer() const { return mParamBuffer; }

		/** 
		 * Returns information about visible lights, in the form of a light grid, used for forward rendering. Only valid
		 * after a call to updateLightGrid().
		 */
		const LightGrid& getLightGrid() const { return mLightGrid; }

		/** Updates the light grid used for forward rendering. */
		void updateLightGrid(const VisibleLightData& visibleLightData, const VisibleReflProbeData& visibleReflProbeData);

		/**
		 * Returns a value that can be used for transforming x, y coordinates from NDC into UV coordinates that can be used
		 * for sampling a texture projected on the view.
		 *
		 * @return	Returns two 2D values that can be used to transform the coordinate as such: UV = NDC * xy + zw.
		 */
		Vector4 getNDCToUV() const;

		/** Returns an index of this view within the parent view group. */
		UINT32 getViewIdx() const { return mViewIdx; }

		/** Assigns a view index to the view. To be called by the parent view group when the view is added to it. */
		void _setViewIdx(UINT32 viewIdx) { mViewIdx = viewIdx; }

		/**
		 * Extracts the necessary values from the projection matrix that allow you to transform device Z value (range [0, 1]
		 * into view Z value.
		 * 
		 * @param[in]	projMatrix	Projection matrix that was used to create the device Z value to transform.
		 * @return					Returns two values that can be used to transform device z to view z using this formula:
		 * 							z = (deviceZ + y) * x.
		 */
		static Vector2 getDeviceZToViewZ(const Matrix4& projMatrix);

		/**
		 * Extracts the necessary values from the projection matrix that allow you to transform NDC Z value (range depending
		 * on render API) into view Z value.
		 * 
		 * @param[in]	projMatrix	Projection matrix that was used to create the NDC Z value to transform.
		 * @return					Returns two values that can be used to transform NDC z to view z using this formula:
		 * 							z = (NDCZ + y) * x.
		 */
		static Vector2 getNDCZToViewZ(const Matrix4& projMatrix);

		/** 
		 * Returns a value that can be used for tranforming a depth value in NDC, to a depth value in device Z ([0, 1] 
		 * range using this formula: (NDCZ + y) * x. 
		 */
		static Vector2 getNDCZToDeviceZ();
	private:
		RendererViewProperties mProperties;
		RENDERER_VIEW_TARGET_DESC mTargetDesc;
		Camera* mCamera;

		SPtr<RenderQueue> mOpaqueQueue;
		SPtr<RenderQueue> mTransparentQueue;

		RenderCompositor mCompositor;
		SPtr<RenderSettings> mRenderSettings;
		UINT32 mRenderSettingsHash;

		SPtr<GpuParamBlockBuffer> mParamBuffer;
		VisibilityInfo mVisibility;
		LightGrid mLightGrid;
		UINT32 mViewIdx;
	};

	/** Contains one or multiple RendererView%s that are in some way related. */
	class RendererViewGroup
	{
	public:
		RendererViewGroup();
		RendererViewGroup(RendererView** views, UINT32 numViews, UINT32 shadowMapSize);

		/** 
		 * Updates the internal list of views. This is more efficient than always constructing a new instance of this class
		 * when views change, as internal buffers don't need to be re-allocated.
		 */
		void setViews(RendererView** views, UINT32 numViews);

		/** Returns a view at the specified index. Index must be less than the value returned by getNumViews(). */
		RendererView* getView(UINT32 idx) const { return mViews[idx]; }

		/** Returns the total number of views in the group. */
		UINT32 getNumViews() const { return (UINT32)mViews.size(); }

		/** 
		 * Returns information about visibility of various scene objects, from the perspective of all the views in the 
		 * group (visibility will be true if the object is visible from any of the views. determineVisibility() must be
		 * called whenever the scene or view information changes (usually every frame). 
		 */
		const VisibilityInfo& getVisibilityInfo() const { return mVisibility; }

		/**
		 * Returns information about lights visible from this group of views. Only valid after a call to 
		 * determineVisibility().
		 */
		const VisibleLightData& getVisibleLightData() const { return mVisibleLightData; }

		/**
		 * Returns information about refl. probes visible from this group of views. Only valid after a call to 
		 * determineVisibility().
		 */
		const VisibleReflProbeData& getVisibleReflProbeData() const { return mVisibleReflProbeData; }

		/** Returns the object responsible for rendering shadows for this view group. */
		ShadowRendering& getShadowRenderer() { return mShadowRenderer; }

		/** Returns the object responsible for rendering shadows for this view group. */
		const ShadowRendering& getShadowRenderer() const { return mShadowRenderer; }

		/** 
		 * Updates visibility information for the provided scene objects, from the perspective of all views in this group,
		 * and updates the render queues of each individual view. Use getVisibilityInfo() to retrieve the calculated
		 * visibility information.
		 */
		void determineVisibility(const SceneInfo& sceneInfo);

	private:
		Vector<RendererView*> mViews;
		VisibilityInfo mVisibility;

		VisibleLightData mVisibleLightData;
		VisibleReflProbeData mVisibleReflProbeData;

		// Note: Ideally we would want to keep this global, so all views share it. This way each view group renders its
		// own set of shadows, but there might be shadows that are shared, and therefore we could avoid rendering them
		// multiple times. Since non-primary view groups are used for pre-processing tasks exclusively (at the moment) 
		// this isn't an issue right now.
		ShadowRendering mShadowRenderer;
	};

	/** @} */
}}