/** 
 * @file llviewercamera.h
 * @brief LLViewerCamera class header file
 *
 * Copyright (c) 2002-2007, 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://secondlife.com/developers/opensource/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://secondlife.com/developers/opensource/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.
 */

#ifndef LL_LLVIEWERCAMERA_H
#define LL_LLVIEWERCAMERA_H

#include "llcamera.h"
#include "lltimer.h"
#include "llstat.h"
#include "m4math.h"

class LLCoordGL;
class LLViewerObject;

// This rotation matrix moves the default OpenGL reference frame 
// (-Z at, Y up) to Cory's favorite reference frame (X at, Z up)
const F32 OGL_TO_CFR_ROTATION[16] = {  0.f,  0.f, -1.f,  0.f, 	// -Z becomes X
									  -1.f,  0.f,  0.f,  0.f, 	// -X becomes Y
									   0.f,  1.f,  0.f,  0.f,	//  Y becomes Z
									   0.f,  0.f,  0.f,  1.f };

class LLViewerCamera : public LLCamera
{
public:
	LLViewerCamera();

//	const LLVector3 &getPositionAgent() const;
//	const LLVector3d &getPositionGlobal() const;

	void updateCameraLocation(const LLVector3 &center,
								const LLVector3 &up_direction,
								const LLVector3 &point_of_interest);

	static void updateFrustumPlanes(LLCamera& camera, BOOL ortho = FALSE);
	void setPerspective(BOOL for_selection, S32 x, S32 y_from_bot, S32 width, S32 height, BOOL limit_select_distance, F32 z_near = 0, F32 z_far = 0);

	const LLMatrix4 &getProjection() const;
	const LLMatrix4 &getModelview() const;

	// Warning!  These assume the current global matrices are correct
	void projectScreenToPosAgent(const S32 screen_x, const S32 screen_y, LLVector3* pos_agent ) const;
	BOOL projectPosAgentToScreen(const LLVector3 &pos_agent, LLCoordGL &out_point, const BOOL clamp = TRUE) const;
	BOOL projectPosAgentToScreenEdge(const LLVector3 &pos_agent, LLCoordGL &out_point) const;


	LLStat *getVelocityStat() { return &mVelocityStat; }
	LLStat *getAngularVelocityStat() { return &mAngularVelocityStat; }

	void getPixelVectors(const LLVector3 &pos_agent, LLVector3 &up, LLVector3 &right);
	LLVector3 roundToPixel(const LLVector3 &pos_agent);

	void setDefaultFOV(F32 fov) { mCameraFOVDefault = fov; }
	F32 getDefaultFOV() { return mCameraFOVDefault; }

	BOOL cameraUnderWater() const;

	const LLVector3 &getPointOfInterest() { return mLastPointOfInterest; }
	BOOL areVertsVisible(LLViewerObject* volumep, BOOL all_verts);
	F32 getPixelMeterRatio() const				{ return mPixelMeterRatio; }
	S32 getScreenPixelArea() const				{ return mScreenPixelArea; }

	void setZoomParameters(F32 factor, S16 subregion) { mZoomFactor = factor; mZoomSubregion = subregion; }
	F32 getZoomFactor() { return mZoomFactor; }                             
	S16 getZoomSubRegion() { return mZoomSubregion; } 

protected:
	void calcProjection(const F32 far_distance) const;

	LLStat mVelocityStat;
	LLStat mAngularVelocityStat;
	mutable LLMatrix4	mProjectionMatrix;	// Cache of perspective matrix
	mutable LLMatrix4	mModelviewMatrix;
	F32					mCameraFOVDefault;
	LLVector3			mLastPointOfInterest;
	F32					mPixelMeterRatio; // Divide by distance from camera to get pixels per meter at that distance.
	S32					mScreenPixelArea; // Pixel area of entire window
	F32					mZoomFactor;
	S16					mZoomSubregion;

public:
	static BOOL sDisableCameraConstraints;
	F64		mGLProjectionMatrix[16];
	
};

extern LLViewerCamera *gCamera;
extern F64 gGLModelView[16];
extern F64 gGLProjection[16];
extern S32 gGLViewport[4];

#endif // LL_LLVIEWERCAMERA_H