基于OPENGL使用C++实现相机类

应gis for net朋友要求，发布一下以前写的相机类源码，这些代码没有经过优化，很粗糙。而且时间很长了，我根据记忆写了一点简单说明，详细的我也忘记了，见谅。

// Camera.cpp: implementation of the CCamera class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "GLCamera.h"
#include "math.h"
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
//构造函数，初始化视界距离
CGLCamera::CGLCamera()
{
    _ViewFar=10000000.0f;
    _CVM=1.0f;//视角放大系数，小于1时就缩小视角，相当于放大画面，大于1时相当于广角镜头
    this->Init();
}

CGLCamera::~CGLCamera()
{

}
//初始化
GLvoid CGLCamera::Init(GLvoid)
{
    ViewWidth=640;//视口宽度
    ViewHeight=480;//视口高度
    ViewLeft=0;//相对投影面的左边距离
    ViewTop=0;//相对投影面的上边距离
    _LensFocus=50.0f;//镜头焦距，这个是我自己设计的一个参数，3D中的视角不方便理解，用照相机镜头就比较有概念了。
    this->Focus2Angle();//焦距转换为角度。
    _EyePosition.z=10.0;//相机位置的Z坐标
    _EyePosition.w=1.0;//设置为坐标
    _ViewPoint.w=1.0;//设置为坐标，这个是视点的
    //相机方向矢量（单位矢量）
    _Uy.y=1.0;
    _Ux.x=1.0;
    _Uz.z=1.0;

    _ScrewAngle=0.0;//视角扭角，正为向右倾斜，负数为向左倾斜，模拟人头（相机）左右摇摆Z轴角度
    TeleMultiple=10.0f;//最大放大倍数
}
//开拍，实际就是使用参数设置相机位置方向和视点。游戏循环每次绘制前调用一次，就可以使画面得到正确的视图。
GLvoid CGLCamera::Camera(GLvoid)
{
    glMatrixMode(GL_PROJECTION);// 选择投影矩阵

    glViewport(ViewLeft, ViewTop, ViewWidth, ViewHeight);// 设置视口
    glLoadIdentity();// 重置投影矩阵
    
    // 设置视景体
    gluPerspective(
        _ViewAngle*_CVM,//视角参数与系数相乘得到实际视角
        (GLdouble)(ViewWidth-ViewLeft)/
        (GLdouble)(ViewHeight-ViewTop),
        0.5f,
        _ViewFar
        );

    gluLookAt(
        _EyePosition.x,_EyePosition.y,_EyePosition.z,
        _ViewPoint.x,_ViewPoint.y,_ViewPoint.z,
        _Uy.x,_Uy.y,_Uy.z);
}
//变焦，根据不同模式递增/递减视角或按比例放大/缩小视角
GLboolean CGLCamera::Zoom(int Mode,GLdouble Value)
{
    GLboolean tmp;
    switch(Mode)
    {
    case ZOOM_ANGLE:
        _ViewAngle+=Value;
        break;
    case ZOOM_SCALE:
    default:
        _ViewAngle*=Value;
        break;
    }

    tmp= FixViewAngle();
    Angle2Focus();//同步焦距
    return tmp;

}
//限定最大最小视角
GLboolean CGLCamera::FixViewAngle(GLvoid)
{
    if (_ViewAngle<1.0f){_ViewAngle=1.0f;return false;}
    if (_ViewAngle>180){_ViewAngle=180.0f;return false;}
    return true;
}
//角度转焦距
void CGLCamera::Angle2Focus()
{
    _LensFocus=FILM_DIAGONAL/2/tan(_ViewAngle*RAD_UNIT/2);
}
//焦距转角度
void CGLCamera::Focus2Angle()
{
    _ViewAngle=atan(FILM_DIAGONAL/_LensFocus/2.0f)*2/RAD_UNIT;
}
//设置视角
GLboolean CGLCamera::SetViewAngle(GLdouble Value)
{
    GLboolean tmp;
    _ViewAngle=Value;
    tmp= FixViewAngle();
    Angle2Focus();
    return tmp;
}

GLdouble CGLCamera::GetViewAngle()
{
    return _ViewAngle;
}
//设置镜头焦距
GLboolean CGLCamera::SetLens(GLdouble Value)
{
    _LensFocus=Value;
    Focus2Angle();
    return FixViewAngle();
}

GLdouble CGLCamera::GetLens()
{
    return _LensFocus;
}


//设置相机位置（坐标对象）
GLvoid CGLCamera::SetPosition(CVector p)
{
    CVector t;
    _EyePosition=p;
    this->FixUV();

}
//设置相机位置（坐标分量）
GLvoid CGLCamera::SetPosition(GLdouble x,GLdouble y,GLdouble z )
{
    CVector v;
    v.x=x;
    v.y=y;
    v.z=z;
    v.w=1.0;
    SetPosition(v);
}
//设置视点（坐标对象）
GLvoid CGLCamera::SetViewPoint(CVector p)
{
    p.w=1.0;
    _ViewPoint=p;
    FixUV();
}

//设置视点（坐标分量）
GLvoid CGLCamera::SetViewPoint(GLdouble x,GLdouble y,GLdouble z)
{
    CVector t;
    t.x=x;
    t.y=y;
    t.z=z;
    SetViewPoint(t);
}
//相机与视点一起平移（平移矢量分量）
GLvoid CGLCamera::Transfer(GLdouble Vx,GLdouble Vy,GLdouble Vz)
{
    
    CVector t;
    this->FixUV();
    t=_Ux*Vx+_Uy*Vy+_Uz*Vz;
    _M.SetTransfer(t.x,t.y,t.z);
    _EyePosition=_M.Transform(_EyePosition);
    _ViewPoint=_M.Transform(_ViewPoint);

}
//相机与视点一起平移（平移矢量对象）
GLvoid CGLCamera::Transfer(CVector V)
{
    Transfer(V.x,V.y,V.z);
}
//设置扭角
GLvoid CGLCamera::SetScrewAngle(GLdouble Value)
{
    _ScrewAngle=Value;
    
    _Uy.Clear();
    _Uy.y=1.0;
    FixUV();
    _M.SetRotateAngle(Value,_Uz);
    _Uy=_M.Transform(_Uy);
    _Ux=_M.Transform(_Ux);
    
}

GLdouble CGLCamera::GetScrewAngle()
{
    return _ScrewAngle;
}

//望远镜效果，当主程序接收到望远镜按键后循环调用此函数，产生逐步变焦效果，释放按键后立刻恢复到50MM标准镜效果。Switch参数就是按键按下标志
//如果望远镜按键按住不放，递减放大系数，步进值0.1,直到系数达到TeleMultiple的倒数位置并锁定在0.1,就是视角缩小到当前视角参数_ViewAngle的1/10,画面放大当前设定值的10倍。
GLvoid CGLCamera::Telescope(GLboolean Switch)
{
    if (Switch)
    {
        if (_LensFocus!=50.0f)
        {
            _LensFocus=50.0f;
            this->Focus2Angle();
        }
        if (_CVM>(1/TeleMultiple))_CVM-=0.1f;
    }
    else
        _CVM=1.0f;
}


//环视效果（水平旋转角和垂直旋转角）
GLvoid CGLCamera::LookAround(GLdouble HAngle, GLdouble VAngle)
{
    CVector v;
    if (HAngle!=0.0)
    {
    v=_ViewPoint-_EyePosition;
    _M.SetRotateAngle(HAngle,_Uy);
    _ViewPoint=_M.Transform(v)+_EyePosition;
    this->FixUV();
    }
    if (VAngle!=0.0)
    {
    v=_ViewPoint-_EyePosition;
    _M.SetRotateAngle(VAngle,_Ux);
    _ViewPoint=_M.Transform(v)+_EyePosition;
    this->FixUV();
    }
    
}
//这个函数是用来绘制三维十字线的，只是为了调试观察用。
GLvoid CGLCamera::DrawUV()
{
CVector t;
    glBegin(GL_LINES);
/*
        glColor3f(1.0f,1.0f,0.0f);
        glVertex3f(_ViewPoint.x,_ViewPoint.y,_ViewPoint.z);
        t=_Ux+_ViewPoint;
        glVertex3f(t.x,t.y,t.z);
    
        glColor3f(0.0f,1.0f,0.0f);
        t=_Uy+_ViewPoint;
        glVertex3f(_ViewPoint.x,_ViewPoint.y,_ViewPoint.z);
        glVertex3f(t.x,t.y,t.z);
*/
        glColor3f(1.0f,1.0f,0.0f);
        glVertex3f(0,0,0);
        t=_Ux;
        glVertex3f(t.x,t.y,t.z);
    
        glColor3f(0.0f,1.0f,0.0f);
        t=_Uy;
        glVertex3f(0,0,0);
        glVertex3f(t.x,t.y,t.z);

        glColor3f(0.0f,1.0f,1.0f);
        t=_Uz;
        glVertex3f(0,0,0);
        glVertex3f(t.x,t.y,t.z);

        glEnd();

}

GLvoid CGLCamera::FixUV(GLvoid)
{
    CVector t;
    t=_EyePosition-_ViewPoint;
    _Uz=t.UnitOperation();

    _Ux=_Uy.GetCrossMultiply(_Uz);
    _Ux=_Ux.UnitOperation();

    _Uy=_Uz.GetCrossMultiply(_Ux);
    _Uy=_Uy.UnitOperation();
}

忘了还有头文件。

// CGLCamera.h: interface for the CGLCamera class.
//
//////////////////////////////////////////////////////////////////////

#if !defined(AFX_GLCAMERA_H__D5CC9BD0_034C_40DD_AD7F_3604B8B70E29__INCLUDED_)
#define AFX_GLCAMERA_H__D5CC9BD0_034C_40DD_AD7F_3604B8B70E29__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#define ZOOM_ANGLE 0
#define ZOOM_SCALE 1


#define FILM_DIAGONAL 43.267

class CGLCamera 
{
    
public:
    GLvoid DrawUV();//绘制局部坐标的单位矢量
    GLvoid LookAround(GLdouble HAngle,GLdouble VAngle);//环视
    GLvoid Telescope(GLboolean Switch);//望远镜效果开/关
    GLvoid Init(GLvoid);//初始化
    //设置视点
    GLvoid SetViewPoint(GLdouble x,GLdouble y,GLdouble z );
    GLvoid SetViewPoint(CVector p);
    //设置位置
    GLvoid SetPosition(CVector p);
    GLvoid SetPosition(GLdouble x,GLdouble y,GLdouble z );
    //平移
    GLvoid Transfer(GLdouble Vx,GLdouble Vy,GLdouble Vz);
    GLvoid Transfer(CVector V);
    //视角
    GLdouble GetViewAngle(void);
    GLboolean SetViewAngle(GLdouble Value);
    //扭角，以垂直于画面的轴旋转角
    GLdouble GetScrewAngle(void);
    GLvoid SetScrewAngle(GLdouble Value);
    //焦距
    GLdouble GetLens(void);
    GLboolean SetLens(GLdouble Value);

    
    GLsizei ViewLeft;
    GLsizei ViewTop;
    GLsizei ViewHeight;
    GLsizei ViewWidth;
    //开拍
    GLvoid Camera(GLvoid);
    GLdouble TeleMultiple;//望远倍数
    
    //变焦
    GLboolean Zoom(int Mode,GLdouble Value);
    
    CGLCamera();
    virtual ~CGLCamera();

    CVector _EyePosition,_ViewPoint;
    CVector _Ux,_Uy,_Uz;
private:
    GLvoid FixUV(GLvoid);
    void Focus2Angle(void);
    void Angle2Focus(void);
    GLboolean FixViewAngle(GLvoid);
    GLdouble _ViewAngle,_CVM;
    GLdouble _LensFocus;
    GLdouble _ScrewAngle;
    GLdouble _ViewFar;    
    GLdouble _LookLength,_LookVAngle,_LookHAngle;
    
    
    CMatrix _M;

};


#endif // !defined(AFX_GLCAMERA_H__D5CC9BD0_034C_40DD_AD7F_3604B8B70E29__INCLUDED_)