正方体每个面都不一样

要让正方体每个面的颜色都不一样，可以在绘制每个面前先设置不同的颜色。OpenGL 中可以使用 glBegin(GL_POLYGON) 和 glEnd() 来绘制多边形，例如正方体的每个面就是一个由四个顶点组成的矩形，可以使用 glBegin(GL_POLYGON) 和 glEnd() 来绘制。完整代码如下：

#include "stdafx.h"
#include <stdio.h>
#include <glut.h>

void init(void) {
    glClearColor(0.0,0.0,0.0,0.0);
    glShadeModel(GL_FLAT);
}

void myReshape(int w, int h) {
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum(-1.0,1.0,-1.0,1.0,1.5,20.0);
    glMatrixMode(GL_MODELVIEW);
}

void display(void) {
    glClear(GL_COLOR_BUFFER_BIT);
    
    // 绘制紫色茶壶
    glColor3f(1.0,0.0,1.0);
    glLoadIdentity();
    gluLookAt(5.0,4.0,5.0,0.0,0.0,0.0,0.0,1.0,0.0);
    glScalef(2.0,2.0,2.0);
    glutWireTeapot(1);
    
    // 绘制彩色正方体
    glLoadIdentity();
    gluLookAt(5.0,4.0,5.0,2.0,2.0,0.0,0.0,1.0,0.0);
    glScalef(2.5,2.5,2.5);
    
    // 绘制前面（红色）
    glBegin(GL_POLYGON);
    glColor3f(1.0, 0.0, 0.0);
    glVertex3f(-0.5, -0.5, 0.5);
    glVertex3f(0.5, -0.5, 0.5);
    glVertex3f(0.5, 0.5, 0.5);
    glVertex3f(-0.5, 0.5, 0.5);
    glEnd();
    
    // 绘制后面（黄色）
    glBegin(GL_POLYGON);
    glColor3f(1.0, 1.0, 0.0);
    glVertex3f(-0.5, -0.5, -0.5);
    glVertex3f(0.5, -0.5, -0.5);
    glVertex3f(0.5, 0.5, -0.5);
    glVertex3f(-0.5, 0.5, -0.5);
    glEnd();
    
    // 绘制左面（绿色）
    glBegin(GL_POLYGON);
    glColor3f(0.0, 1.0, 0.0);
    glVertex3f(-0.5, -0.5, -0.5);
    glVertex3f(-0.5, -0.5, 0.5);
    glVertex3f(-0.5, 0.5, 0.5);
    glVertex3f(-0.5, 0.5, -0.5);
    glEnd();
    
    // 绘制右面（蓝色）
    glBegin(GL_POLYGON);
    glColor3f(0.0, 0.0, 1.0);
    glVertex3f(0.5, -0.5, -0.5);
    glVertex3f(0.5, -0.5, 0.5);
    glVertex3f(0.5, 0.5, 0.5);
    glVertex3f(0.5, 0.5, -0.5);
    glEnd();
    
    // 绘制上面（白色）
    glBegin(GL_POLYGON);
    glColor3f(1.0, 1.0, 1.0);
    glVertex3f(-0.5, 0.5, -0.5);
    glVertex3f(0.5, 0.5, -0.5);
    glVertex3f(0.5, 0.5, 0.5);
    glVertex3f(-0.5, 0.5, 0.5);
    glEnd();
    
    // 绘制下面（黑色）
    glBegin(GL_POLYGON);
    glColor3f(0.0, 0.0, 0.0);
    glVertex3f(-0.5, -0.5, -0.5);
    glVertex3f(0.5, -0.5, -0.5);
    glVertex3f(0.5, -0.5, 0.5);
    glVertex3f(-0.5, -0.5, 0.5);
    glEnd();
    
    glFlush();
}

void main(int argc, char **argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
    glutInitWindowSize(500,500);
    glutInitWindowPosition(100,100);
    glutCreateWindow("3D Cube");
    init();
    glutReshapeFunc(myReshape);
    glutDisplayFunc(display);
    glutMainLoop();
}