此实例在opengl编程指南中有,这里具体说明一下
static int year= 0,day=0;
void Init()
{
glClearColor(0.0,0.0,0.0,0.0);
glShadeModel(GL_FLAT);
}
void reshape(int w,int h)
{
glViewport(0,0,(GLsizei)w,(GLsizei)h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(40,(GLfloat)w/(GLfloat)h,1,20);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0.0,0.0,5.0,0.0,0.0,0.0,0.0,1.0,0.0); //以前犯过的一个错,把此句加载投影模式下了,怎么都看不到模型
//这个应该是模型视图变换
}
void keyboard(unsigned char key,int x,int y)
{
switch (key) {
case 'd':
day = (day+10)/360; //这边的360当然是一个圆周了
glutPostRedisplay();
break;
case 'D':
day = (day-10)%360;
glutPostRedisplay();
break;
case 'y':
year = (year+5)%360;
glutPostRedisplay();
break;
case 'Y':
year = (year-5)%360;
glutPostRedisplay();
break;
default:
break;
}
}
void display()
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glColor3f(1,1,1);
glPushMatrix();
glutWireSphere(1.0,22,16);
glRotatef((GLfloat)year,0.0,1.0,0.0);
glTranslatef(2.0,0.0,0.0); //公转和自传的区别,就是此句代码
glRotatef((GLfloat)day,0.0,1.0,0.0);
glutWireSphere(0.3,10,8);
glPopMatrix();
glutSwapBuffers();
}
int main(int argc,char** argv)
{
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH);
glutInitWindowSize(640,480);
glutInitWindowPosition(100,100);
glutCreateWindow("Maya Camera");
Init();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutMainLoop();
return 0;
}