Open Graphics Library初步_摄影机_GLUT

直接把代码弄进来，课上如果能讲到的话……

#include <gl/glut.h>
#include <math.h>

const float PI = 3.1416;
float ax = 0.0f;
float ay = 0.0f;
float az = 0.0f;
double et1 = 0.0;
double et2 = 0.0;
double d = 500.0;

int mx = 0;
int my = 0;

void Drawing_Box(){
    
    glPushMatrix();
    glPolygonMode(GL_BACK,GL_LINE);
    glTranslatef(0.0f, 0.0f, 100.0f);
    glRotatef(ax, 1.0f, 0.0f, 0.0f);
    glRotatef(ay, 0.0f, 1.0f, 0.0f);
    glRotatef(az, 0.0f, 0.0f, 1.0f);

    glColor3f( 1.0f, 0.0f, 0.0f );
    // 正方体
    glutSolidCube(100);

/*    
    glBegin( GL_QUADS );
        glColor3f(1.0f,0.0f,0.0f);
        glVertex3f(100.0f,100.0f,-100.0f);
        glVertex3f(-100.0f,100.0f,-100.0f);
        glVertex3f(-100.0f,-100.0f,-100.0f);
        glVertex3f(100.0f,-100.0f,-100.0f);
        
        glColor3f(0.0f,1.0f,0.0f);
        glVertex3f(100.0f,-100.0f,100.0f);
        glVertex3f(-100.0f,-100.0f,100.0f);
        glVertex3f(-100.0f,100.0f,100.0f);
        glVertex3f(100.0f,100.0f,100.0f);
    glEnd();
*/    
    glPopMatrix();
    
    // 地面
    glPushMatrix();
    glBegin( GL_QUADS );
    glColor3f( 1.0f, 1.0f, 1.0f );
    glVertex3f(100.0f,100.0f,0.0f);
    glVertex3f(-100.0f,100.0f,0.0f);
    glVertex3f(-100.0f,-100.0f,0.0f);
    glColor3f( 0.5f, 0.5f, 1.0f );
    glVertex3f(100.0f,-100.0f,0.0f);    
    glEnd();
    glPopMatrix();
}

void Drawing(){
    glPushMatrix();
    glTranslatef(0.0f, 0.0f, 0.0f);
    glRotatef(ax, 1.0f, 0.0f, 0.0f);
    glRotatef(ay, 0.0f, 1.0f, 0.0f);
    glRotatef(az, 0.0f, 0.0f, 1.0f);
    glBegin( GL_LINES );{
        for(float t=.0f; t<=PI; t+=.1f){
            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(cosf(t)*100.0f,sinf(t)*100.0f,0.0f);
            glVertex3f(0,0,0);
            
            glColor3f(0.0f, 1.0f, 0.0f);
            glVertex3f(0.0f,cosf(t)*100.0f,sinf(t)*100.0f);
            glVertex3f(0,0,0);
            
            glColor3f(0.0f, 0.0f, 1.0f);
            glVertex3f(sinf(t)*100.0f,0.0f,cosf(t)*100.0f);
            glVertex3f(0,0,0);
        }
    }glEnd();
    glPopMatrix();
}

void SetEye()
{
    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();
    double eyex;
    double eyey;
    double eyez;
    double upx;
    double upy;
    double et2b = 90.0 - et2;
    double et1b = -et1;
    eyex = d * sin(et2b) * cos(et1b);
    eyey = d * sin(et2b) * sin(et1b);
    double temp = cos(et2b);
    eyez = d * temp;

    upx = - eyex * (eyez>0?1:-1);
    upy = eyey / upx * eyex;
    gluLookAt(eyex,eyey,eyez, 0,0,0, upx,upy,0);
}

void OnReshape(int w, int h){    
    
    double ar = (double)w/(double)h;
    glViewport(0, 0, w, h);
    glMatrixMode( GL_PROJECTION );
    glLoadIdentity();

/*        
    if(w>=h){
        glOrtho(-300*ar, 300*ar, -300, 300, 0, 600);
    }else{
        glOrtho(-300, 300, -300/ar, 300/ar, 0, 600);
    }

*/

    gluPerspective( 60.0f, ar, 1, 800 );
    /*
    if(w>=h){
        glFrustum(-ar*50.0f, ar*50.0f, -50.0f, 50.0f, 50, 800);
    }else{
        glFrustum(-50.0f, 50.0f, -50.0f/ar, 50.0f/ar, 50, 800);
    }
*/

    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();
    gluLookAt(200,-400,500, 0,0,100, -1,2,0);
    
    GLfloat ambientLight[] = {.3f, .3f, .3f, 1.0f};
    GLfloat diffuseLight[] = {.7f, .7f, .7f, 1.0f};
    glEnable(GL_DEPTH_TEST);
    glFrontFace(GL_CCW);
    glEnable(GL_CULL_FACE);
    glEnable(GL_LIGHTING);
    glLightfv(GL_LIGHT0, GL_AMBIENT, ambientLight);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseLight);
    glEnable(GL_LIGHT0);
    glEnable(GL_COLOR_MATERIAL);
    glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
    glClearColor( 0.0f, 0.0f, 0.0f, 1.0f );
    glEnable(GL_NORMALIZE);
}

void OnDisplay(){
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    SetEye();
    Drawing_Box();
    glutSwapBuffers();
}

void OnTimer(int flag){
    ax += 0.42f;
    ay += 0.5f;
    az += 0.1f;
    //et1 += 0.005f;
    //et2 = PI / 3;
    OnDisplay();
    glutTimerFunc(10, OnTimer, 101);
}

void OnMouse(int button, int state, int x, int y){
    if(button == GLUT_DOWN){
        mx = x;
        my = y;
    }
}

void OnMotion(int x, int y){
    et1 += (double)(x - mx)/100.0;
    et2 += (double)(y - my)/100.0;
    mx = x;
    my = y;
}

int main(int argc, char* argv[]){
    glutInit(&argc, argv);
    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
    glutInitWindowPosition(0,0);
    glutInitWindowSize(800,600);
    glutCreateWindow("窗口标题");
    glutDisplayFunc(OnDisplay);
    glutReshapeFunc(OnReshape);
    glutTimerFunc(10, OnTimer, 101);
    glutMouseFunc(OnMouse);
    glutMotionFunc(OnMotion);
    glutMainLoop();
    return 0;
}