VS2012下基于Glut OpenGL绘制椎体示例程序：

这一节在OpneGL绘制椎体，并在单击鼠标右键弹出的菜单里面可以选择打开或关闭：GL_DEPTH_TEST（深度测试）；GL_CULL_FACE（曲面是背面时是否显示）功能；曲面是背面时是采用单色填充还是描边。

显示效果如下所示：



单击鼠标右键弹出菜单效果如下所示：



源代码：

// GlutConeDemo.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include <gl/glut.h>
#include <math.h>

//圆周率宏
#define GL_PI 3.1415f
//获取屏幕的宽度
GLint SCREEN_WIDTH=0;
GLint SCREEN_HEIGHT=0;
//设置程序的窗口大小
GLint windowWidth=400;
GLint windowHeight=300;
//绕x轴旋转角度
GLfloat xRotAngle=0.0f;
//绕y轴旋转角度
GLfloat yRotAngle=0.0f;
//是否打开不显示背面功能
GLint cullFace=0;
//是否打开深度测试功能
GLint depthTest=0;
//背面是采用线条描外框还是使用单色填充　
GLint outLine=0;
//菜单回调函数
void processMenu(int value){
switch(value){
case 1:
depthTest=!depthTest;
break;
case 2:
cullFace=!cullFace;
case 3:
outLine=!outLine;
break;
break;
default:
break;
}
//重新绘制
glutPostRedisplay();
}

//显示回调函数
void renderScreen(void){
GLfloat x,y,z,angle;
GLint i=0;
//把整个窗口清理为当前清理颜色：黑色,清理深度缓冲区
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
//将当前Matrix状态入栈
glPushMatrix();
//坐标系绕x轴旋转xRotAngle
glRotatef(xRotAngle,1.0f,0.0f,0.0f);
//坐标系绕y轴旋转yRotAngle
glRotatef(yRotAngle,0.0f,1.0f,0.0f);
if(depthTest)
glEnable(GL_DEPTH_TEST);//打开深度测试功能
else
glDisable(GL_DEPTH_TEST);//关闭深度测试功能
if(cullFace)
glEnable(GL_CULL_FACE);//打开不显示背面功能
else
glDisable(GL_CULL_FACE);//关闭不显示背面功能
if(outLine)
glPolygonMode(GL_BACK,GL_LINE);//多边形背部使用线条描框
else
glPolygonMode(GL_BACK,GL_FILL);//多边形背部使用单色填充
//进行平滑处理　
glEnable(GL_POINT_SMOOTH);
glHint(GL_POINT_SMOOTH,GL_NICEST);
glEnable(GL_LINE_SMOOTH);
glHint(GL_LINE_SMOOTH,GL_NICEST);
//使用白色绘制坐标系
glColor3f(1.0f,1.0f,1.0f);
//绘制坐标系
glBegin(GL_LINES);
glVertex3f(-80.0f,0.0f,0.0f);
glVertex3f(80.0f,0.0f,0.0f);
glVertex3f(0.0f,-80.0f,0.0f);
glVertex3f(0.0f,80.0f,0.0f);
glVertex3f(0.0f,0.0f,-80.0f);
glVertex3f(0.0f,0.0f,80.0f);
glEnd();

glPushMatrix();
glTranslatef(80.0f,0.0f,0.0f);
glRotatef(90.0f,0.0f,1.0f,0.0f);
glutWireCone(3,6,10,10);
glPopMatrix();

glPushMatrix();
glTranslatef(0.0f,80.0f,0.0f);
glRotatef(-90.0f,1.0f,0.0f,0.0f);
glutWireCone(3,6,10,10);
glPopMatrix();

glPushMatrix();
glTranslatef(0.0f,0.0f,80.0f);
glRotatef(90.0f,0.0f,0.0f,1.0f);
glutWireCone(3,6,10,10);
glPopMatrix();

glBegin(GL_TRIANGLE_FAN);
glVertex3f(0.0f,0.0f,75.0f);
for(angle=0.0f,i=0;i<=6;angle+=(GL_PI/3.0f),i++)
{
x=50*cos(angle);
y=50*sin(angle);
if(i%2==0)
glColor3f(1.0f,0.0f,0.0f);
else
glColor3f(0.0f,1.0f,0.0f);
glVertex3f(x,y,0.0f);
}
glEnd();

glBegin(GL_TRIANGLE_FAN);
glVertex3f(0.0f,0.0f,0.0f);
for(angle=0.0f,i=0;i<=6;angle+=(GL_PI/3.0f),i++)
{
x=50*cos(angle);
y=50*sin(angle);
if(i%2==0)
glColor3f(0.0f,1.0f,0.0f);
else
glColor3f(1.0f,0.0f,0.0f);
glVertex3f(x,y,0.0f);
}
glEnd();

//恢复压入栈的Matrix
glPopMatrix();
//交换两个缓冲区的指针
glutSwapBuffers();
}
//设置Redering State
void setupRederingState(void){
//设置清理颜色为黑色
glClearColor(0.0f,0.0,0.0,1.0f);
//设置绘画颜色为绿色
glColor3f(0.0f,1.0f,0.0f);
//改变正反面
//glFrontFace(GL_CW);
//单色填充模式
glShadeModel(GL_FLAT);
}
//窗口大小变化回调函数
void changSize(GLint w,GLint h){
//横宽比率
GLfloat ratio;
//设置坐标系为x(-100.0f,100.0f)、y(-100.0f,100.0f)、z(-100.0f,100.0f)
GLfloat coordinatesize=100.0f;
//窗口宽高为零直接返回
if((w==0)||(h==0))
return;
//设置视口和窗口大小一致
glViewport(0,0,w,h);
//对投影矩阵应用随后的矩阵操作
glMatrixMode(GL_PROJECTION);
//重置当前指定的矩阵为单位矩阵　
glLoadIdentity();
ratio=(GLfloat)w/(GLfloat)h;
//正交投影
if(w<h)
glOrtho(-coordinatesize,coordinatesize,-coordinatesize/ratio,coordinatesize/ratio,-coordinatesize,coordinatesize);
else
glOrtho(-coordinatesize*ratio,coordinatesize*ratio,-coordinatesize,coordinatesize,-coordinatesize,coordinatesize);
//对模型视图矩阵堆栈应用随后的矩阵操作
glMatrixMode(GL_MODELVIEW);
//重置当前指定的矩阵为单位矩阵　
glLoadIdentity();
}

//按键输入处理回调函数
void specialKey(int key,int x,int y){

if(key==GLUT_KEY_UP){
xRotAngle-=5.0f;
}
else if(key==GLUT_KEY_DOWN){
xRotAngle+=5.0f;
}
else if(key==GLUT_KEY_LEFT){
yRotAngle-=5.0f;
}
else if(key==GLUT_KEY_RIGHT){
yRotAngle+=5.0f;
}
//重新绘制
glutPostRedisplay();
}

int main(int argc, char* argv[])
{
//初始化glut
glutInit(&argc,argv);
//使用双缓冲区模式
glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH);
//获取系统的宽像素
SCREEN_WIDTH=glutGet(GLUT_SCREEN_WIDTH);
//获取系统的高像素
SCREEN_HEIGHT=glutGet(GLUT_SCREEN_HEIGHT);
//创建窗口，窗口名字为OpenGL BackAndFront Demo
glutCreateWindow("OpenGL Cone Demo");
//菜单回调函数
glutCreateMenu(processMenu);
//添加菜单
glutAddMenuEntry("Toggle depth test",1);
glutAddMenuEntry("Toggle cull face",2);
glutAddMenuEntry("Toggle back outline",3);
//将菜单榜定到鼠标右键上
glutAttachMenu(GLUT_RIGHT_BUTTON);
//设置窗口大小
glutReshapeWindow(windowWidth,windowHeight);
//窗口居中显示
glutPositionWindow((SCREEN_WIDTH-windowWidth)/2,(SCREEN_HEIGHT-windowHeight)/2);
//窗口大小变化时的处理函数
glutReshapeFunc(changSize);
//设置显示回调函数
glutDisplayFunc(renderScreen);
//设置按键输入处理回调函数
glutSpecialFunc(specialKey);
//设置全局渲染参数
setupRederingState();
glutMainLoop();
return 0;
}