// 范例P98.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <gl/glut.h>

static float year=0,day=0;

void display()
{
 glClear(GL_COLOR_BUFFER_BIT);     //清除所有像素
 glColor3f(1.0,1.0,1.0);       //设置画笔白色
 /*在缓存中绘制4对顶点坐标的矩形*/
 
 glPushMatrix();
 glutWireSphere(1.0,20,16);      //绘制太阳
 glRotatef((GLfloat)year,0,1,0);     //绕y轴旋转表示确定公转位置
 glTranslatef(2,0,0);       //平移到公转轨道
 glRotatef((GLfloat)day,0,1,0);     //绕y轴表示自转
 glutWireSphere(0.2,10,8);
 glPopMatrix();
 glutSwapBuffers();          //立即显示出来
}

void init()
{
 glClearColor(0.0,0.0,0.0,0.0);     //用黑色清除背景
 glShadeModel(GL_FLAT);
}
void reshape(int w,int h)
{
 glViewport(0,0,(GLsizei)w,(GLsizei)h);
 glMatrixMode(GL_PROJECTION);
 glLoadIdentity();
 gluPerspective(60,(GLfloat)w/(GLfloat)h,1.0,20.0);
 glMatrixMode(GL_MODELVIEW);
 glLoadIdentity();
 gluLookAt(0,0,5, 0,0,0, 0,1,0);
 glRotatef(45,1,0,0);
}
void spinDisplay(void)
{
 day=day+1;
 year=year+1.0/365;
 if(day>360)
  day-=360;
 if(year>360)
  year-=360;
 glutPostRedisplay();
}
void mouse(int button,int state,int x,int y)
{
 switch(button){
 case GLUT_LEFT_BUTTON:
  if(state==GLUT_DOWN)
   glutIdleFunc(spinDisplay);
  break;
 case GLUT_MIDDLE_BUTTON:
  if(state==GLUT_DOWN)
   glutIdleFunc(0);
  break;
 default:
  break;
 }
}
int main(int argc,char ** argv)
{
 glutInit(&argc,argv);
 glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
 glutInitWindowSize(250,250);     //初始化窗口大小
 glutInitWindowPosition(0,0);    //初始化窗口位置
 glutCreateWindow("hello");      //创建标题为“hello”的窗口
 init();           //调用初始化函数
 glutDisplayFunc(display);      //注册回调函数
 glutReshapeFunc(reshape);
 glutMouseFunc(mouse);
 glutMainLoop();         //进入主循环处理事件
 return 0;
}

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