opengl 太阳系模拟

#include <GL/glut.h>
#include <stdlib.h>

static int year = 0, day = 0;//公转和自转分别转动角度，静态变量，所有函数都可以用

void init(void) 
{
   glClearColor (0.0, 0.0, 0.0, 0.0);//清屏
   glShadeModel (GL_FLAT);//设置的着色模式
}

void display(void)
{
   glClear (GL_COLOR_BUFFER_BIT);//清颜色缓存

//太阳
   glColor3f(1.0f, 0.0f, 0.0f);//红色
   glPushMatrix();//压栈
   glutWireSphere(1.0,20,16); /* draw sun *///   线框体 半径 1.0   20，16是经度纬度线框的个数
  

//行星
   glColor3f(1.0f, 0.0f, 1.0f);//平红色
   glPushMatrix();//压栈
   glRotatef ((GLfloat) year, 0.0, 1.0, 0.0);
   glTranslatef (-2.0, 0.0, 0.0);//xyz,在x方向平移2.0
   glRotatef ((GLfloat) day, 1.0, 1.0, 1.0);
   glutWireSphere(0.2, 10, 8); //1
   glPopMatrix();//弹出

   glColor3f(0.0f, 1.0f, 1.0f);//情色
    glPushMatrix();//压栈
	glRotatef ((GLfloat) year, 0.0, 1.0, 0.0);
   glTranslatef (2.0, 0.0, 0.0);
   glRotatef ((GLfloat) day, 0.0, 1.0, 0.0);
   glutWireSphere(0.5, 10, 8); //2
   glPopMatrix();//弹出

   glColor3f(0.0f, 0.0f, 1.0f);//蓝色
   glPushMatrix();//压栈
   glRotatef ((GLfloat) year, 0.0, 1.0, 0.0);
   glTranslatef (3.5, 0.0, 0.0);
   glRotatef ((GLfloat) day, 0.0, 1.0, 0.0);
   glutWireSphere(0.3, 10, 8); //3
   glPopMatrix();//弹出 

   glColor3f(1.0f, 1.0f, 0.0f);//黄色
   glPushMatrix();//压栈
   glRotatef ((GLfloat) year, 0.0, 1.0, 0.0);
    glTranslatef (-3.5, 0.0, 0.0);
   glRotatef ((GLfloat) day, 0.0, 1.0, 0.0);
   glutWireSphere(0.3, 10, 8); //4
   glPopMatrix();//弹出

    glColor3f(0.0f, 1.0f, 0.0f);//绿色
   glPushMatrix();//压栈
   glRotatef ((GLfloat) year, 0.0, 1.0, 0.0);
    glTranslatef (5.0, 0.0, 0.0);
   glRotatef ((GLfloat) day, 0.0, 1.0, 0.0);
   glutWireSphere(0.3, 10, 8); //5

 glColor3f(1.0f, 1.0f, 0.0f);//黄色
   glPushMatrix();//压栈
   glRotatef ((GLfloat) year, 1.0, 1.0, 0.0);
    glTranslatef (0.0, 2.0, 0.0);
   glRotatef ((GLfloat) day, 0.0, 1.0, 0.0);
   glutWireSphere(0.3, 10, 8); //5.1
   glPopMatrix();//弹出


   glutSwapBuffers();
}

void reshape (int w, int h)//框口发生改变时候//从下往上看
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h); //设定的显示窗口
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();//投影矩阵为单位矩阵
   gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);//设定投影变换，台锥体
   glMatrixMode(GL_MODELVIEW);//后续要操作的矩阵为模型视图矩阵
   glLoadIdentity();//将模型视图矩阵为单位阵
   gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);//设定视点（观测点）
}

void keyboard (unsigned char key, int x, int y)//按到键盘的key值，
{
   switch (key) {
      case 'd':
         day = (day + 10) % 360;//逆时针转10度
         glutPostRedisplay();
         break;
      case 'D':
         day = (day - 10) % 360; //顺时针转10度
         glutPostRedisplay();
         break;
      case 'y':
         year = (year + 5) % 360; 
         glutPostRedisplay();
         break;
      case 'Y':
         year = (year - 5) % 360;
         glutPostRedisplay();
         break;
      case 27:
         exit(0);
         break;
      default:
         break;
   }
}

int main(int argc, char** argv)
{
   glutInit(&argc, argv);//初始化窗口
   glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);//两个模式
   glutInitWindowSize (500, 500); 
   glutInitWindowPosition (100, 100);
   glutCreateWindow (argv[0]);
   init ();//清屏之类的
   glutDisplayFunc(display); 
   glutReshapeFunc(reshape);
   glutKeyboardFunc(keyboard);//事件处理函数，键盘按下去，执行的一个函数
   glutMainLoop();
   return 0;
}