OpenGL编程指南10：组合运动示例1—创建太阳系模型

1.程序代码：

#include <vgl.h>
static int year =0, day =0;

void init(void)
{
glClearColor(0.0,0.0,1.0,0.0);  //清除背景底色
glShadeModel(GL_FLAT);
}
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(0.5,0.5,0.5);         //相当于画笔

glPushMatrix();
glRotatef((GLfloat)year, 0.0, 1.0, 0.0);
glutWireSphere(1,30,24);        //sun: radius  longtitude  latitude
glPopMatrix();

glPushMatrix();
glRotatef((GLfloat)year,-1,1,0);
glTranslatef(3.0, 0.0, 0.0);
glTranslatef(0.0, 3.0, 0.0);
glRotatef((GLfloat)day, -1.0, 1.0, 0.0);
glutWireSphere(0.3,10,8);
glPopMatrix();

glPushMatrix();
glRotatef((GLfloat)year,1,1,0);
glTranslatef(2.0,0.0,0.0);
glTranslatef(0.0,-2.0,0.0);
glRotatef((GLfloat)day,1,1,0);
glutWireSphere(0.3,10,8);
glPopMatrix();

glutSwapBuffers();
}

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(0.0,0.0,6.0,
0.0,0.0,0.0,
0.0,1.0,0.0 );
}
void keyboard(unsigned char key, int x,int y)
{
switch(key){
case 'd':  day = (day+10) %360;
glutPostRedisplay();
break;
case 'D':  day = (day-10) %360;
glutPostRedisplay();
break;
case 'y':  year = (year+5) %360;
glutPostRedisplay();
break;
case 'Y':  year = (year-5) %360;
glutPostRedisplay();
break;
default:
break;
}
}
int main(int argc, char** argv)
{
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
glutInitWindowSize(400,400);
glutInitWindowPosition(200,200);
glutCreateWindow(argv[0]);
init();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutMainLoop();
return 0;
}

2.说出结果