/**
 * @file llsurfacepatch.h
 * @brief LLSurfacePatch class definition
 *
 * $LicenseInfo:firstyear=2001&license=viewergpl$
 *
 * Copyright (c) 2001-2009, Linden Research, Inc.
 *
 * Second Life Viewer Source Code
 * The source code in this file ("Source Code") is provided by Linden Lab
 * to you under the terms of the GNU General Public License, version 2.0
 * ("GPL"), unless you have obtained a separate licensing agreement
 * ("Other License"), formally executed by you and Linden Lab.  Terms of
 * the GPL can be found in doc/GPL-license.txt in this distribution, or
 * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
 *
 * There are special exceptions to the terms and conditions of the GPL as
 * it is applied to this Source Code. View the full text of the exception
 * in the file doc/FLOSS-exception.txt in this software distribution, or
 * online at
 * http://secondlifegrid.net/programs/open_source/licensing/flossexception
 *
 * By copying, modifying or distributing this software, you acknowledge
 * that you have read and understood your obligations described above,
 * and agree to abide by those obligations.
 *
 * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
 * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
 * COMPLETENESS OR PERFORMANCE.
 * $/LicenseInfo$
 */

#ifndef LL_LLSURFACEPATCH_H
#define LL_LLSURFACEPATCH_H

#include "llpointer.h"
#include "llvector3.h"
#include "llvector3d.h"

#include "llagent.h"
#include "llvosurfacepatch.h"

class LLColor4U;
class LLSurface;
class LLVector2;
class LLViewerRegion;

// A patch should not know about its visibility since that really depends on
// the camera that is looking (or not looking) at it.  So, anything about a
// patch that is specific to a camera should be in the class below.
struct LLPatchVisibilityInfo
{
	LLPatchVisibilityInfo()
	:	mIsVisible(false),
		mDistance(0.f),
		mRenderLevel(0),
		mRenderStride(0)
	{
	}

	F32		mDistance;			// Distance from camera
	S32		mRenderLevel;
	U32		mRenderStride;
	bool	mIsVisible;
};

class LLSurfacePatch
{
	friend class LLSurface;

protected:
	LOG_CLASS(LLSurfacePatch);

public:
	LLSurfacePatch();
	~LLSurfacePatch();

	void connectNeighbor(LLSurfacePatch* neighborp, U32 direction);
	void disconnectNeighbor(LLSurface* surfacep);

	void setNeighborPatch(U32 direction, LLSurfacePatch* neighborp);

	LL_INLINE LLSurfacePatch* getNeighborPatch(U32 direction) const
	{
		return mNeighborPatches[direction];
	}

	bool updateTexture();

	void updateVerticalStats();
	void updateNormals();

	void updateEastEdge();
	void updateNorthEdge();

	void updateCameraDistanceRegion(const LLVector3& pos_region);
	void updateVisibility();
	void updateGL();

	void dirtyZ(); // Dirty the z values of this patch
	LL_INLINE void setHasReceivedData()					{ mHasReceivedData = true; }
	LL_INLINE bool getHasReceivedData() const			{ return mHasReceivedData; }

	F32 getDistance() const;
	LL_INLINE F32 getMaxZ() const						{ return mMaxZ; }
	LL_INLINE F32 getMinZ() const						{ return mMinZ; }
	LL_INLINE F32 getMeanComposition() const			{ return mMeanComposition; }
	LL_INLINE F32 getMinComposition() const				{ return mMinComposition; }
	LL_INLINE F32 getMaxComposition() const				{ return mMaxComposition; }
	LL_INLINE const LLVector3& getCenterRegion() const	{ return mCenterRegion; }
	LL_INLINE const U64& getLastUpdateTime() const		{ return mLastUpdateTime; }
	LL_INLINE LLSurface* getSurface() const				{ return mSurfacep; }

	// get the point at the offset.
	LLVector3 getPointAgent(U32 x,  U32 y) const;

	LLVector2 getTexCoords(U32 x, U32 y) const;

	void calcNormal(U32 x, U32 y, U32 stride);
	const LLVector3& getNormal(U32 x, U32 y) const;

	void eval(U32 x, U32 y, U32 stride, LLVector3* vertex, LLVector3* normal,
			  LLVector2* tex0, LLVector2* tex1);

	LL_INLINE LLVector3 getOriginAgent() const			{ return gAgent.getPosAgentFromGlobal(mOriginGlobal); }
	LL_INLINE const LLVector3d& getOriginGlobal() const	{ return mOriginGlobal; }
	void setOriginGlobal(const LLVector3d& origin_global);

	// connectivity -- each LLPatch points at 5 neighbors (or NULL)
	// +---+---+---+
	// |   | 2 | 5 |
	// +---+---+---+
	// | 3 | 0 | 1 |
	// +---+---+---+
	// | 6 | 4 |   |
	// +---+---+---+

	LL_INLINE bool getVisible() const					{ return mVisInfo.mIsVisible; }
	LL_INLINE U32 getRenderStride() const				{ return mVisInfo.mRenderStride; }
	LL_INLINE S32 getRenderLevel() const				{ return mVisInfo.mRenderLevel; }

	void setSurface(LLSurface* surfacep);
	LL_INLINE void setDataZ(F32* data_z)				{ mDataZ = data_z; }
	LL_INLINE void setDataNorm(LLVector3* data_norm)	{ mDataNorm = data_norm; }
	LL_INLINE F32* getDataZ() const						{ return mDataZ; }

	void dirty();	// Mark this surface patch as dirty...
	LL_INLINE void clearDirty()							{ mDirty = false; }

	LL_INLINE void clearVObj()							{ mVObjp = NULL; }

	// *HACK: used to signal that the patches have all been reloaded, and that
	// a minium delay should be insreted before any other attempt. HB
	static void allPatchesReloaded();
	// Use to set the auto-reload delay, clamp it and cache it, when the
	// corresponding debug setting is changed or the viewer started. HB
	static void setAutoReloadDelay(U32 delay);

	static bool needsPatchesReload()					{ return sNeedsPatchesReload; }

private:
	void updateCompositionStats(LLViewerRegion* regionp);

protected:
	// Pointer to the LLVOSurfacePatch object which is used in the new renderer.
	LLPointer<LLVOSurfacePatch>	mVObjp;

	LLSurface*					mSurfacep;	// Pointer to "parent" surface

	// Time patch was last updated
	U64							mLastUpdateTime;

	// Pointers to beginnings of patch data fields
	LLVector3d					mOriginGlobal;
	LLVector3					mOriginRegion;

	U32							mDataOffset;
	LLVector3*					mDataNorm;
	F32*						mDataZ;

	// Height field stats
	LLVector3					mCenterRegion; // Center in region-local coords
	F32							mMinZ;
	F32							mMaxZ;
	F32							mMeanZ;
	F32							mRadius;

	F32							mMinComposition;
	F32							mMaxComposition;
	F32							mMeanComposition;

	F32							mFirstFailureTime;

	LLSurfacePatch*				mNeighborPatches[8];
	// Which normals are invalid
	bool						mNormalsInvalid[9];

	// This bitmap is non-zero if patch is on at least one edge of LLSurface
	// that is "connected" to another LLSurface.
	U8							mConnectedEdge;

	// All of the camera-dependent stuff should be in its own class...
	LLPatchVisibilityInfo		mVisInfo;

	bool						mDirty;
	bool						mDirtyZStats;
	bool						mHeightsGenerated;

	// Has the patch EVER received height data ?
	bool						mHasReceivedData;
	// Does the surface texture need to be updated ?
	bool						mSTexUpdate;

	// *HACK: used to ask auto-reload of failed patch textures.
	static F32					sAutoReloadDelay;
	static F32					sNextAllowedReloadTime;
	static bool					sNeedsPatchesReload;
};

extern const U32 gDirOpposite[];

#endif // LL_LLSURFACEPATCH_H