/**
 * =========================================================================
 * File        : Renderer.h
 * Project     : 0 A.D.
 * Description : higher level interface on top of OpenGL to render basic
 *               objects: terrain, models, sprites, particles etc.
 * =========================================================================
 */

#ifndef INCLUDED_RENDERER
#define INCLUDED_RENDERER

#include "graphics/Camera.h"
#include "lib/ogl.h"
#include "lib/res/handle.h"
#include "ps/Singleton.h"
#include "scripting/ScriptableObject.h"

#include "renderer/Scene.h"

// necessary declarations
class CPatch;
class CMaterial;
class CModel;
class CLightEnv;
class CTexture;

class RenderPathVertexShader;
class WaterManager;
class SkyManager;

// rendering modes
enum ERenderMode { WIREFRAME, SOLID, EDGED_FACES };

// stream flags
#define STREAM_POS 0x01
#define STREAM_NORMAL 0x02
#define STREAM_COLOR 0x04
#define STREAM_UV0 0x08
#define STREAM_UV1 0x10
#define STREAM_UV2 0x20
#define STREAM_UV3 0x40
#define STREAM_POSTOUV0 0x80
#define STREAM_TEXGENTOUV1 0x100

//////////////////////////////////////////////////////////////////////////////////////////
// SVertex3D: simple 3D vertex declaration
struct SVertex3D
{
	float m_Position[3];
	float m_TexCoords[2];
	unsigned int m_Color;
};

//////////////////////////////////////////////////////////////////////////////////////////
// SVertex2D: simple 2D vertex declaration
struct SVertex2D
{
	float m_Position[2];
	float m_TexCoords[2];
	unsigned int m_Color;
};

// access to sole renderer object
#define g_Renderer CRenderer::GetSingleton()

///////////////////////////////////////////////////////////////////////////////////////////
// CRenderer: base renderer class - primary interface to the rendering engine
struct CRendererInternals;

class CRenderer :
	public Singleton<CRenderer>,
	public CJSObject<CRenderer>,
	private SceneCollector
{
public:
	// various enumerations and renderer related constants
	enum { NumAlphaMaps=14 };
	enum { MaxTextureUnits=16 };
	enum Option {
		OPT_NOVBO,
		OPT_NOFRAMEBUFFEROBJECT,
		OPT_SHADOWS,
		OPT_FANCYWATER,
		OPT_LODBIAS
	};

	enum RenderPath {
		// If no rendering path is configured explicitly, the renderer
		// will choose the path when Open() is called.
		RP_DEFAULT,

		// Classic fixed function.
		RP_FIXED,

		// Use (GL 2.0) vertex shaders for T&L when possible.
		RP_VERTEXSHADER
	};

	// stats class - per frame counts of number of draw calls, poly counts etc
	struct Stats {
		// set all stats to zero
		void Reset() { memset(this,0,sizeof(*this)); }
		// add given stats to this stats
		Stats& operator+=(const Stats& rhs) {
			m_Counter++;
			m_DrawCalls+=rhs.m_DrawCalls;
			m_TerrainTris+=rhs.m_TerrainTris;
			m_ModelTris+=rhs.m_ModelTris;
			m_BlendSplats+=rhs.m_BlendSplats;
			return *this;
		}
		// count of the number of stats added together
		size_t m_Counter;
		// number of draw calls per frame - total DrawElements + Begin/End immediate mode loops
		size_t m_DrawCalls;
		// number of terrain triangles drawn
		size_t m_TerrainTris;
		// number of (non-transparent) model triangles drawn
		size_t m_ModelTris;
		// number of splat passes for alphamapping
		size_t m_BlendSplats;
	};

	// renderer options
	struct Options {
		bool m_NoVBO;
		bool m_NoFramebufferObject;
		bool m_Shadows;
		bool m_FancyWater;
		float m_LodBias;
		RenderPath m_RenderPath;
	} m_Options;

	struct Caps {
		bool m_VBO;
		bool m_TextureBorderClamp;
		bool m_GenerateMipmaps;
		bool m_VertexShader;
		bool m_DepthTextureShadows;
		bool m_FramebufferObject;
	};

public:
	// constructor, destructor
	CRenderer();
	~CRenderer();

	// open up the renderer: performs any necessary initialisation
	bool Open(int width,int height,int depth);

	// resize renderer view
	void Resize(int width,int height);

	// set/get boolean renderer option
	void SetOptionBool(enum Option opt,bool value);
	bool GetOptionBool(enum Option opt) const;
	// set/get RGBA color renderer option
// 	void SetOptionColor(enum Option opt,const RGBAColor& value);
	void SetOptionFloat(enum Option opt, float val);
// 	const RGBAColor& GetOptionColor(enum Option opt) const;
	void SetRenderPath(RenderPath rp);
	RenderPath GetRenderPath() const { return m_Options.m_RenderPath; }
	static CStr GetRenderPathName(RenderPath rp);
	static RenderPath GetRenderPathByName(const CStr& name);

	// return view width
	int GetWidth() const { return m_Width; }
	// return view height
	int GetHeight() const { return m_Height; }
	// return view aspect ratio
	float GetAspect() const { return float(m_Width)/float(m_Height); }

	// signal frame start
	void BeginFrame();
	// signal frame end
	void EndFrame();

	// set color used to clear screen in BeginFrame()
	void SetClearColor(u32 color);

	// return current frame counter
	int GetFrameCounter() const { return m_FrameCounter; }

	/**
	 * Set up the camera used for rendering the next scene; this includes
	 * setting OpenGL state like viewport, projection and modelview matrices.
	 *
	 * @param viewCamera this camera determines the eye position for rendering
	 * @param cullCamera this camera determines the frustum for culling in the renderer and
	 * for shadow calculations
	 */
	void SetSceneCamera(const CCamera& viewCamera, const CCamera& cullCamera);

	// set the viewport
	void SetViewport(const SViewPort &);

	/**
	 * Render the given scene immediately.
	 * @param scene a Scene object describing what should be rendered.
	 */
	void RenderScene(Scene* scene);

	// basic primitive rendering operations in 2 and 3D; handy for debugging stuff, but also useful in
	// editor tools (eg for highlighting specific terrain patches)
	// note:
	//		* all 3D vertices specified in world space
	//		* primitive operations rendered immediatedly, never batched
	//		* primitives rendered in current material (set via SetMaterial)
// 	void RenderLine(const SVertex2D* vertices);
// 	void RenderLineLoop(int len,const SVertex2D* vertices);
// 	void RenderTri(const SVertex2D* vertices);
// 	void RenderQuad(const SVertex2D* vertices);
// 	void RenderLine(const SVertex3D* vertices);
// 	void RenderLineLoop(int len,const SVertex3D* vertices);
// 	void RenderTri(const SVertex3D* vertices);
// 	void RenderQuad(const SVertex3D* vertices);

	// set the current lighting environment; (note: the passed pointer is just copied to a variable within the renderer,
	// so the lightenv passed must be scoped such that it is not destructed until after the renderer is no longer rendering)
	void SetLightEnv(CLightEnv* lightenv) {
		m_LightEnv=lightenv;
	}

	// set the mode to render subsequent terrain patches
	void SetTerrainRenderMode(ERenderMode mode) { m_TerrainRenderMode=mode; }
	// get the mode to render subsequent terrain patches
	ERenderMode GetTerrainRenderMode() const { return m_TerrainRenderMode; }

	// set the mode to render subsequent models
	void SetModelRenderMode(ERenderMode mode) { m_ModelRenderMode=mode; }
	// get the mode to render subsequent models
	ERenderMode GetModelRenderMode() const { return m_ModelRenderMode; }

	// try and load the given texture
	bool LoadTexture(CTexture* texture,int wrapflags);
	// set the given unit to reference the given texture; pass a null texture to disable texturing on any unit;
	// active texture unit always set to given unit on exit
	void SetTexture(int unit,CTexture* texture);
	// bind a GL texture object to active unit
	void BindTexture(int unit,GLuint tex);
	// query transparency of given texture
	bool IsTextureTransparent(CTexture* texture);

	// load the default set of alphamaps.
	// return a negative error code if anything along the way fails.
	// called via delay-load mechanism.
	int LoadAlphaMaps();
	void UnloadAlphaMaps();

	// return stats accumulated for current frame
	const Stats& GetStats() { return m_Stats; }

	// return the current light environment
	const CLightEnv &GetLightEnv() { return *m_LightEnv; }

	// return the current view camera
	const CCamera& GetViewCamera() const { return m_ViewCamera; }
	// return the current cull camera
	const CCamera& GetCullCamera() const { return m_CullCamera; }

	// get the current OpenGL model-view-projection matrix into the given float[]
	CMatrix3D GetModelViewProjectionMatrix();

	/**
	 * GetWaterManager: Return the renderer's water manager.
	 *
	 * @return the WaterManager object used by the renderer
	 */
	WaterManager* GetWaterManager() { return m_WaterManager; }

	/**
	 * GetSkyManager: Return the renderer's sky manager.
	 *
	 * @return the SkyManager object used by the renderer
	 */
	SkyManager* GetSkyManager() { return m_SkyManager; }

	/**
	 * SetFastPlayerColor: Tell the renderer which path to take for
	 * player colored models. Both paths should provide the same visual
	 * quality, however the slow path runs on older hardware using multi-pass.
	 *
	 * @param fast true if the fast path should be used from now on. If fast
	 * is true but the OpenGL implementation does not support it, a warning
	 * is printed and the slow path is used instead.
	 */
	void SetFastPlayerColor(bool fast);

	/**
	 * GetCapabilities: Return which OpenGL capabilities are available and enabled.
	 *
	 * @return capabilities structure
	 */
	const Caps& GetCapabilities() const { return m_Caps; }

	bool GetDisableCopyShadow() const { return m_DisableCopyShadow; }

	static void ScriptingInit();

protected:
	friend struct CRendererInternals;
	friend class CVertexBuffer;
	friend class CPatchRData;
	friend class FixedFunctionModelRenderer;
	friend class ModelRenderer;
	friend class PolygonSortModelRenderer;
	friend class SortModelRenderer;
	friend class RenderPathVertexShader;
	friend class HWLightingModelRenderer;
	friend class InstancingModelRenderer;
	friend class TerrainRenderer;

	// scripting
	// TODO: Perhaps we could have a version of AddLocalProperty for function-driven
	// properties? Then we could hide these function in the private implementation class.
	jsval JSI_GetFastPlayerColor(JSContext*);
	void JSI_SetFastPlayerColor(JSContext* ctx, jsval newval);
	jsval JSI_GetRenderPath(JSContext*);
	void JSI_SetRenderPath(JSContext* ctx, jsval newval);
	jsval JSI_GetUseDepthTexture(JSContext*);
	void JSI_SetUseDepthTexture(JSContext* ctx, jsval newval);
	jsval JSI_GetDepthTextureBits(JSContext*);
	void JSI_SetDepthTextureBits(JSContext* ctx, jsval newval);
	jsval JSI_GetSky(JSContext*);
	void JSI_SetSky(JSContext* ctx, jsval newval);

	//BEGIN: Implementation of SceneCollector
	void Submit(CPatch* patch);
	void SubmitNonRecursive(CModel* model);
	//END: Implementation of SceneCollector

	// render any batched objects
	void RenderSubmissions();

	// patch rendering stuff
	void RenderPatches();

	// model rendering stuff
	void RenderModels();
	void RenderTransparentModels();

	// shadow rendering stuff
	void RenderShadowMap();

	// render water reflection and refraction textures
	void RenderReflections();
	void RenderRefractions();

	// debugging
	void DisplayFrustum();

	// enable oblique frustum clipping with the given clip plane
	void SetObliqueFrustumClipping(const CVector4D& clipPlane, int sign);

	// RENDERER DATA:
	/// Private data that is not needed by inline functions
	CRendererInternals* m;
	// view width
	int m_Width;
	// view height
	int	m_Height;
	// view depth (bpp)
	int	m_Depth;
	// frame counter
	int m_FrameCounter;
	// current terrain rendering mode
	ERenderMode m_TerrainRenderMode;
	// current model rendering mode
	ERenderMode m_ModelRenderMode;

	/**
	 * m_ViewCamera: determines the eye position for rendering
	 *
	 * @see CGameView::m_ViewCamera
	 */
	CCamera m_ViewCamera;

	/**
	 * m_CullCamera: determines the frustum for culling and shadowmap calculations
	 *
	 * @see CGameView::m_ViewCamera
	 */
	CCamera m_CullCamera;

	// color used to clear screen in BeginFrame
	float m_ClearColor[4];
	// current lighting setup
	CLightEnv* m_LightEnv;
	// ogl_tex handle of composite alpha map (all the alpha maps packed into one texture)
	Handle m_hCompositeAlphaMap;
	// coordinates of each (untransformed) alpha map within the packed texture
	struct {
		float u0,u1,v0,v1;
	} m_AlphaMapCoords[NumAlphaMaps];
	// card capabilities
	Caps m_Caps;
	// build card cap bits
	void EnumCaps();
	// per-frame renderer stats
	Stats m_Stats;
	// active textures on each unit
	GLuint m_ActiveTextures[MaxTextureUnits];

	// Additional state that is only available when the vertex shader
	// render path is used (according to m_Options.m_RenderPath)
	RenderPathVertexShader* m_VertexShader;

	/// If false, use a multipass fallback for player colors.
	bool m_FastPlayerColor;

	/**
	 * m_WaterManager: the WaterManager object used for water textures and settings
	 * (e.g. water color, water height)
	 */
	WaterManager* m_WaterManager;

	/**
	 * m_SkyManager: the SkyManager object used for sky textures and settings
	 */
	SkyManager* m_SkyManager;

	/**
	 * m_SortAllTransparent: If true, all transparent models are
	 * rendered using the TransparencyRenderer which performs sorting.
	 *
	 * Otherwise, transparent models are rendered using the faster
	 * batching renderer when possible.
	 */
	bool m_SortAllTransparent;

	/**
	 * m_DisplayFrustum: Render the cull frustum and other data that may be interesting
	 * to evaluate culling and shadow map calculations
	 *
	 * Can be controlled from JS via renderer.displayFrustum
	 */
	bool m_DisplayFrustum;

	/**
	 * m_DisableCopyShadow: For debugging purpose:
	 * Disable copying of shadow data into the shadow texture (when EXT_fbo is not available)
	 */
	bool m_DisableCopyShadow;

public:
	/**
	 * m_ShadowZBias: Z bias used when rendering shadows into a depth texture.
	 * This can be used to control shadowing artifacts.
	 *
	 * Can be accessed via JS as renderer.shadowZBias
	 * ShadowMap uses this for matrix calculation.
	 */
	float m_ShadowZBias;

	/**
	 * m_ShadowMapSize: Size of shadow map, or 0 for default. Typically slow but useful
	 * for high-quality rendering. Changes don't take effect until the shadow map
	 * is regenerated.
	 *
	 * Can be accessed via JS as renderer.shadowMapSize
	 */
	int m_ShadowMapSize;

	/**
	 * m_SkipSubmit: Disable the actual submission of rendering commands to OpenGL.
	 * All state setup is still performed as usual.
	 *
	 * Can be accessed via JS as renderer.skipSubmit
	 */
	bool m_SkipSubmit;

	/**
	 * m_RenderTerritories: 
	 * Turn territory boundary rendering on or off.
	 */
	bool m_RenderTerritories;
};


#endif