使用glBegin(GL_QUADS)绘制六个侧面来组成一个立方体;并使用glFrontFace(GL_CW)、glFrontFace(GL_CCW)来设置每个面的正面;使用glColor3ub来设置立方体每六个顶点的颜色。单击鼠标右键可以在弹出的菜单里面选择是否显示坐标轴以及是正视图还是透视视图。按键盘的UP、DOWN、LEFT、RIGHT按键可以从不同的角度查看该颜色立方体。
源代码:
// GlutColorCubeDemo.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;
//受支持的点大小范围
GLfloat sizes[2];
//受支持的点大小增量
GLfloat step;
//最大的投影矩阵堆栈深度
GLint iMaxProjectionStackDepth;
//最大的模型视图矩阵堆栈深度
GLint iMaxModeviewStackDepth;
//最大的纹理矩阵堆栈深度
GLint iMaxTextureStackDepth;
GLint iCoordinateaxis=2;//是否显示坐标轴
GLint iProjectionMode=1;//投影模式
void changSize(GLint w,GLint h);
//菜单回调函数
void processMenu(int value){
switch(value){
case 1:
iCoordinateaxis=1;
break;
case 2:
iCoordinateaxis=2;
break;
case 3:
iProjectionMode=1;
//强制调用窗口大小变化回调函数,更改投影模式为正交投影
changSize(glutGet(GLUT_WINDOW_WIDTH),glutGet(GLUT_WINDOW_HEIGHT));
break;
case 4:
iProjectionMode=2;
//强制调用窗口大小变化回调函数,更改投影模式为透视投影
changSize(glutGet(GLUT_WINDOW_WIDTH),glutGet(GLUT_WINDOW_HEIGHT));
break;
default:
break;
}
//重新绘制
glutPostRedisplay();
}
//显示回调函数
void renderScreen(void){
//将窗口颜色清理为黑色
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
//把整个窗口清理为当前清理颜色:黑色;清除深度缓冲区。
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);
//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);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
/*
if(2==iProjectionMode){
glTranslatef(0.0f,0.0f,-200.0f);
}*/
if(1==iCoordinateaxis){
glColor3f(1.0f,1.0f,1.0f);
glBegin(GL_LINES);
glVertex3f(-90.0f,00.0f,0.0f);
glVertex3f(90.0f,0.0f,0.0f);
glVertex3f(0.0f,-90.0f,0.0f);
glVertex3f(0.0f,90.0f,0.0f);
glVertex3f(0.0f,0.0f,-90.0f);
glVertex3f(0.0f,0.0f,90.0f);
glEnd();
glPushMatrix();
glTranslatef(90.0f,0.0f,0.0f);
glRotatef(90.0f,0.0f,1.0f,0.0f);
glutSolidCone(3,6,10,10);
glPopMatrix();
glPushMatrix();
glTranslatef(0.0f,90.0f,0.0f);
glRotatef(-90.0f,1.0f,0.0f,0.0f);
glutSolidCone(3,6,10,10);
glPopMatrix();
glPushMatrix();
glTranslatef(0.0f,0.0f,90.0f);
glRotatef(70.0f,0.0f,0.0f,1.0f);
glutSolidCone(3,6,10,10);
glPopMatrix();
}
// Draw six quads
glFrontFace(GL_CW);
glBegin(GL_QUADS);
// Front Face
// White
glColor3ub((GLubyte) 255, (GLubyte)255, (GLubyte)255);
glVertex3f(50.0f,50.0f,50.0f);
// Yellow
glColor3ub((GLubyte) 255, (GLubyte)255, (GLubyte)0);
glVertex3f(50.0f,0.0f,50.0f);
// Red
glColor3ub((GLubyte) 255, (GLubyte)0, (GLubyte)0);
glVertex3f(0.0f,0.0f,50.0f);
// Magenta
glColor3ub((GLubyte) 255, (GLubyte)0, (GLubyte)255);
glVertex3f(0.0f,50.0f,50.0f);
// Top Face
// Cyan
glColor3f(0.0f, 1.0f, 1.0f);
glVertex3f(50.0f,50.0f,0.0f);
// White
glColor3f(1.0f, 1.0f, 1.0f);
glVertex3f(50.0f,50.0f,50.0f);
// Magenta
glColor3f(1.0f, 0.0f, 1.0f);
glVertex3f(0.0f,50.0f,50.0f);
// Blue
glColor3f(0.0f, 0.0f, 1.0f);
glVertex3f(0.0f,50.0f,0.0f);
// Right face
// White
glColor3f(1.0f, 1.0f, 1.0f);
glVertex3f(50.0f,50.0f,50.0f);
// Cyan
glColor3f(0.0f, 1.0f, 1.0f);
glVertex3f(50.0f,50.0f,0.0f);
// Green
glColor3f(0.0f, 1.0f, 0.0f);
glVertex3f(50.0f,0.0f,0.0f);
// Yellow
glColor3f(1.0f, 1.0f, 0.0f);
glVertex3f(50.0f,0.0f,50.0f);
glEnd();
glFrontFace(GL_CCW);
glBegin(GL_QUADS);
// Bottom Face
// Green
glColor3f(0.0f, 1.0f, 0.0f);
glVertex3f(50.0f,0.0f,0.0f);
// Yellow
glColor3f(1.0f, 1.0f, 0.0f);
glVertex3f(50.0f,0.0f,50.0f);
// Red
glColor3f(1.0f, 0.0f, 0.0f);
glVertex3f(0.0f,0.0f,50.0f);
// Black
glColor3f(0.0f, 0.0f, 0.0f);
glVertex3f(0.0f,0.0f,0.0f);
// Left face
// Magenta
glColor3f(1.0f, 0.0f, 1.0f);
glVertex3f(0.0f,50.0f,50.0f);
// Blue
glColor3f(0.0f, 0.0f, 1.0f);
glVertex3f(0.0f,50.0f,0.0f);
// Black
glColor3f(0.0f, 0.0f, 0.0f);
glVertex3f(0.0f,0.0f,0.0f);
// Red
glColor3f(1.0f, 0.0f, 0.0f);
glVertex3f(0.0f,0.0f,50.0f);
// Back Face
// Cyan
glColor3f(0.0f, 1.0f, 1.0f);
glVertex3f(50.0f,50.0f,0.0f);
// Green
glColor3f(0.0f, 1.0f, 0.0f);
glVertex3f(50.0f,0.0f,0.0f);
// Black
glColor3f(0.0f, 0.0f, 0.0f);
glVertex3f(0.0f,0.0f,0.0f);
// Blue
glColor3f(0.0f, 0.0f, 1.0f);
glVertex3f(0.0f,50.0f,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){
glEnable(GL_DEPTH_TEST); //使能深度测试
//glFrontFace(GL_CCW); //多边形逆时针方向为正面
glEnable(GL_CULL_FACE); //不显示背面
//glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);//背面正面均使用线填充
glPolygonMode(GL_FRONT,GL_FILL);//背面正面均使用线填充
glPolygonMode(GL_BACK,GL_LINE);//背面正面均使用线填充
glShadeModel(GL_SMOOTH);
//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(1.0f,1.0f,0.0f);
//使能深度测试
glEnable(GL_DEPTH_TEST);
//获取受支持的点大小范围
glGetFloatv(GL_POINT_SIZE_RANGE,sizes);
//获取受支持的点大小增量
glGetFloatv(GL_POINT_SIZE_GRANULARITY,&step);
//获取最大的投影矩阵堆栈深度
glGetIntegerv( GL_MAX_PROJECTION_STACK_DEPTH,&iMaxProjectionStackDepth);
//获取最大的模型视图矩阵堆栈深度
glGetIntegerv( GL_MAX_MODELVIEW_STACK_DEPTH,&iMaxModeviewStackDepth);
//获取最大的纹理矩阵堆栈深度
glGetIntegerv( GL_MAX_TEXTURE_STACK_DEPTH,&iMaxTextureStackDepth);
printf("point size range:%f-%f\n",sizes[0],sizes[1]);
printf("point step:%f\n",step);
printf("iMaxProjectionStackDepth=%d\n",iMaxProjectionStackDepth);
printf("iMaxModeviewStackDepth=%d\n",iMaxModeviewStackDepth);
printf("iMaxTextureStackDepth=%d\n",iMaxTextureStackDepth);
}
//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(1==iProjectionMode){
printf("glOrtho\n");
if(w<h)
glOrtho(-coordinatesize,coordinatesize,-coordinatesize/ratio,coordinatesize/ratio,-coordinatesize,coordinatesize);
else
glOrtho(-coordinatesize*ratio,coordinatesize*ratio,-coordinatesize,coordinatesize,-coordinatesize,coordinatesize);
//当前矩阵设置为模型视图矩阵
glMatrixMode(GL_MODELVIEW);
//重置当前指定的矩阵为单位矩阵
glLoadIdentity();
}
else{
printf("gluPerspective\n");
gluPerspective(60,ratio,10.0f,500.0f);
//当前矩阵设置为模型视图矩阵
glMatrixMode(GL_MODELVIEW);
//重置当前指定的矩阵为单位矩阵
glLoadIdentity();
glTranslatef(0.0f,0.0f,-200.0f);
}
}
//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();
}
void timerFunc(int value)
{
glutPostRedisplay();
glutTimerFunc(10, timerFunc, 1);
}
int main(int argc, char* argv[])
{
//菜单
GLint iMainMenu;
GLint iCoordinateaxisMenu;
GLint iOrthoOrPerspectMenu;
//初始化glut
glutInit(&argc,argv);
//使用双缓冲区、深度缓冲区。
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 LoadMatrix Demo
glutCreateWindow("OpenGL color cube Demo");
//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);
//菜单回调函数
iCoordinateaxisMenu=glutCreateMenu(processMenu);
//添加菜单
glutAddMenuEntry("Display coordinate axis",1);
glutAddMenuEntry("Don't dispaly coordinate axis",2);
iOrthoOrPerspectMenu=glutCreateMenu(processMenu);
glutAddMenuEntry("Ortho",3);
glutAddMenuEntry("Perspect",4);
iMainMenu=glutCreateMenu(processMenu);
glutAddSubMenu("Whether Display coordinate axis",iCoordinateaxisMenu);
glutAddSubMenu("Ortho Or Perspect",iOrthoOrPerspectMenu);
//将菜单榜定到鼠标右键上
glutAttachMenu(GLUT_RIGHT_BUTTON);
glutTimerFunc(10,timerFunc, 1);
//设置全局渲染参数
setupRederingState();
glutMainLoop();
return 0;
}