OpenGL学习笔记 之三 （简单示例 太阳月亮地球）

#include<glut.h>

// 太阳、地球和月亮
// 假设每个月都是30天
// 一年12个月，共是360天
static int day = 150;//day的变化：从0到359
void myDisplay(void)
{
    glDepthFunc(GL_LEQUAL);//设置深度<=通过,与物体之间的前后有关
    glEnable(GL_DEPTH_TEST);//深度检测
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);//矩阵为投影变换模式
    glLoadIdentity();//获得单位矩阵
    gluPerspective(75,1,1,400000000);//透视变换角度75度，长宽比1：1，最近可视距离1，最远400000000两倍地球公转半径

    glMatrixMode(GL_MODELVIEW);//矩阵为视图模式
    glLoadIdentity();
    gluLookAt(0,-200000000,200000000,0,0,0,0,0,1);//整体布局，视角位（这里是45度倾角），物体位置，z轴正向

    //绘制红色太阳
    glColor3f(1.0f,0.0f,0.0f);
    glutSolidSphere(69600000,20,20);
    //绘制蓝色的地球
    glColor3f(0.0f,0.0f,1.0f);
    glRotatef(day/360.0*360,0.0f,0.0f,-1.0f);
    glTranslatef(150000000,0.0f,0.0f);
    glutSolidSphere(15945000,20,20);
    //绘制黄色的“月亮”
    glColor3f(1.0f,1.0f,0.0f);
    glRotatef(day/30.0*360 - day/360.0*360,0.0f,0.0f,-1);
    glTranslatef(38000000,0.0f,0.0f);
    glutSolidSphere(4345000,20,20);
    glFlush();
}

int main(int argc, char* argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB|GLUT_SINGLE);
    glutInitWindowPosition(100,100);
    glutInitWindowSize(400,400); 
    glutCreateWindow("天体");
    glutDisplayFunc(&myDisplay);
    glutMainLoop();
    return 0;
}

#include<glut.h>

// 太阳、地球和月亮
// 假设每个月都是30天
// 一年12个月，共是360天
static int day = 150; // day的变化：从0到359
void myDisplay(void)
{
    glDepthFunc(GL_LEQUAL);//设置深度<=通过,与物体之间的前后有关
    glEnable(GL_DEPTH_TEST);//深度检测
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);//矩阵为投影变换模式
    glLoadIdentity();//获得单位矩阵
    gluPerspective(75,1,1,400000000);//透视变换角度75度，长宽比1：1，最近可视距离1，最远400000000两倍地球公转半径

    glMatrixMode(GL_MODELVIEW);//矩阵为视图模式
    glLoadIdentity();
    gluLookAt(0,-200000000,200000000,0,0,0,0,0,1);//整体布局，视角位置（这里是45度倾角），物体位置，z轴正向

    //绘制红色太阳
    glColor3f(1.0f,0.0f,0.0f);
    glutSolidSphere(69600000,20,20);
    //绘制蓝色的地球
    glColor3f(0.0f,0.0f,1.0f);
    glRotatef(day/360.0*360,0.0f,0.0f,-1.0f);
    glTranslatef(150000000,0.0f,0.0f);
    glutSolidSphere(15945000,20,20);
    //绘制黄色的“月亮”
    glColor3f(1.0f,1.0f,0.0f);
    glRotatef(day/30.0*360 - day/360.0*360,0.0f,0.0f,-1);
    glTranslatef(38000000,0.0f,0.0f);
    glutSolidSphere(4345000,20,20);
    glFlush();
    glutSwapBuffers();
}
void myIdle()
{
    ++day;
    if(day>=360)
        day = 0;
    myDisplay();
}
int main(int argc, char* argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB|GLUT_DOUBLE);
    glutInitWindowPosition(100,100);
    glutInitWindowSize(450,450); 
    glutCreateWindow("天体");
    glutDisplayFunc(&myDisplay);
    glutIdleFunc(&myIdle);
    glutMainLoop();
    return 0;
}