timer

用timer當計時器會比Idle更好
因問Idle會忽快忽慢

#include <GL/glut.h>
float angle=0;
void timer(int t)
{
     glutTimerFunc(10, timer, 1);
     angle+=1;
     glutPostRedisplay();
}
void display()
{
    glEnable(GL_DEPTH_TEST);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glPushMatrix();
       glRotatef(angle,0,1,0);
       glutSolidTeapot(0.5);
    glPopMatrix();
    glFlush();
}
int main(int argc,char**argv)
{
    glutInit(&argc,argv);
    glutCreateWindow("3D");
    glutDisplayFunc(display);
    glutTimerFunc(10, timer, 0);
    glutMainLoop();
}



憤怒的茶壺

#include <GL/glut.h>
#include <math.h>
float angle=0, potX=0, potY=0, potVX=0, potVY=0;
int potState=0;
void timer(int t)
{
     glutTimerFunc(10, timer, 1);
     angle+=1;
     if(potState==0) potY=0.5*sin(angle/180.0*3.14);
     if(potState==2){ potX+=potVX; potY+=potVY; }
     glutPostRedisplay();
}
void display()
{
    glEnable(GL_DEPTH_TEST);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glutSolidTeapot(0.01);
    glPushMatrix();
       glTranslatef(potX, potY, 0);
       glRotatef(angle,0,1,0);
       glutSolidTeapot(0.01);
    glPopMatrix();
    glFlush();
}
void motion(int x, int y)
{
    if(potState==1){potX=(x-350)/350.0; potY=-(y-350)/350.0;}
}
void mouse(int button, int state, int x ,int y)
{
    if(state==GLUT_DOWN){ potState=1;}
    else if(state==GLUT_UP){potState=2; potVX=-(x-350)/3500.0 ; potVY=(y-350)/3500.0;}
}
int main(int argc,char**argv)
{
    glutInit(&argc,argv);
    glutCreateWindow("3D");
    glutReshapeWindow(700,700);
    glutDisplayFunc(display);
    glutTimerFunc(10, timer, 0);
    glutMouseFunc(mouse);
    glutMotionFunc(motion);
    glutMainLoop();
}