Week 15 , 自動旋轉

#include <Gl/glut.h>
float a=0; //a is the alpha weight 內插比重
float angle[20]={0,90,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
float angleOld[20]={0,90,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
float angleNew[20]={90,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
void display()
{
     glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
     glPushMatrix();
       glRotatef(angle[0],0,0,1);//用現在的角度angle來轉動
       glutSolidTeapot(0.3);
       glPopMatrix();
     
       glPushMatrix();
       glTranslatef(0.5,0,0);
       glRotatef(angle[1],0,0,1);//用現在的角度angle來轉動
       glutSolidTeapot(0.3);
       glPopMatrix();
     
       glutSwapBuffers();
}

void readNext()
{
     a+=0.1;
     for(int i=0;i<20;i++) angle[i] =angleOld[i]*(1-a) + angleNew[i]*a;
}

void timer(int t)
{
     glutTimerFunc(10,timer,0);//幾ms後開始,0ms開始播放(立即播放)
     readNext();
     glutPostRedisplay();
}

void keyboard(unsigned char key, int x ,int y)
{
     if(key=='r'){
     readNext();
      }
      else if(key=='p'){
           glutTimerFunc(0,timer,0);//幾ms後開始, 0ms後開始播(立即播放)
           }
      glutPostRedisplay();
}

int main()
{
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);
    glutCreateWindow("Week 15");
   
    glutKeyboardFunc(keyboard);
    glutDisplayFunc(display);
    glutMainLoop();
}