10.4.3 编程实例－太阳系动画
#include <gl/glut.h>
float fEarth = 2.0f; //地球绕太阳的旋转角度
float fMoon = 24.0f; //月球绕地球的旋转角度
void Init()
{
glEnable(GL_DEPTH_TEST); //启用深度测试
glClearColor(0.0f, 0.0f, 0.0f, 0.8f); //背景为黑色
}
void Reshape(int w, int h)
{
if (0 == h)
h = 1;
glViewport(0, 0, w, h); //设置视区尺寸
glMatrixMode(GL_PROJECTION); //指定当前操作投影矩阵堆栈
glLoadIdentity(); //重置投影矩阵
//指定透视投影的观察空间
gluPerspective(45.0f, (float)w / (float)h, 1.0f, 1000.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void Display(void)
{
//清除颜色和深度缓冲区
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW); //指定当前操作模型视图矩阵堆栈
glLoadIdentity(); //重置模型视图矩阵
glTranslatef(0.0f, 0.0f, -500.0f); //将图形沿z轴负向移动
glColor3f(1.0f, 0.0f, 0.0f); //画太阳
glutSolidSphere(50.0f, 20, 20);
glColor3f(0.0f, 0.0f, 1.0f);
glRotatef(23.27,0.0,0.0,1.0); //地球与太阳的黄赤交角
glRotatef(fEarth, 0.0f, 1.0f, 0.0f);
glTranslatef(200.0f, 0.0f, 0.0f);
glutSolidSphere(20.0f, 20, 20); //画地球
glPopMatrix();
glPopMatrix();
glRotatef(6.0f, 1.0f, 1.0f, 1.0f);
glRotatef(fMoon, 0.0f, 1.0f, 0.0f);
glColor3f(1.0f, 1.0f, 0.0f);
glTranslatef(30.0f, 0.0f, 0.0f);
glutSolidSphere(5.0f, 20, 20); //画月球
glLoadIdentity();
glFlush();
glutSwapBuffers();
}
void myIdle(void) //在空闲时调用，达到动画效果
{
fEarth += 0.03f; //增加旋转步长，产生动画效果
if (fEarth > 360.0f)
fEarth = 2.0f;
fMoon += 0.24f;
if (fMoon > 360.0f)
fMoon = 24.0f;
Display();
}
int main(int argc, char *argv[])
{
glutInit(&argc, argv);
//窗口使用RGB颜色，双缓存和深度缓存
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowPosition(100,100);
glutInitWindowSize(600, 400);
glutCreateWindow("太阳系动画");
glutReshapeFunc(Reshape);
glutDisplayFunc(Display);
glutIdleFunc(&myIdle);
Init();
glutMainLoop();
return 0;
}