VS2012下基于Glut OpenGL绘制虚线示例程序:
在VS2012下使用glut绘制一系列虚线的示例程序,效果如下图所示,按PC的UP,DOWN,LEFT,RIGHT按键可以从不同的角度查看该图形:
glLineStipple用于设置直线的点线模式,其有两个参数
第二个参数PATTERN是一个16进制的数,或者是转换为二进制的16位序列(若不足16位,以0补完)
如glLineStipple (1, 0x0101); /* dotted */
从低位开始(即右侧的1开始),如果是1则绘制像素,0则留空
第一个参数是扩展因子,如上factor设置为2的话,那么将绘制2个像素,14个留空,可以观察下面效果以了解扩展因子,效果如下
源代码:
- // GlutLineStippleDemo.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
- //获取屏幕的宽度与高度
- 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;
- //显示回调函数
- void renderScreen(void){
- GLfloat x,y,z,angle;
- // Stippling factor
- GLint factor = 0;
- // Stipple pattern
- GLushort pattern = 0x0F0F;
- //把整个窗口清理为当前清理颜色:黑色
- glClear(GL_COLOR_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);
- z=0.0f;
- //绘制直线
- for(y=-90.0f;y<=-10.0f;y+=5.0f){
- //设置Stipple Line的factor pattern
- glLineStipple(factor++,pattern);
- //开始绘直线
- glBegin(GL_LINES);
- glVertex3f(-80.0f,y,z);
- glVertex3f(80.0f,y,z);
- //结束绘直线
- glEnd();
- }
- //绘制直线
- pattern=0xF0F0;
- factor=0;
- for(y=10.0f;y<=90.0f;y+=5.0f){
- //设置Stipple Line的factor pattern
- glLineStipple(factor++,pattern);
- //开始绘直线
- glBegin(GL_LINES);
- glVertex3f(-80.0f,y,z);
- glVertex3f(80.0f,y,z);
- //结束绘直线
- 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);
- //使能点虚线
- glEnable(GL_LINE_STIPPLE);
- }
- //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OpenlGL LineStilpple Demo
- glutCreateWindow(“OpenlGL LineStilpple 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);
- //设置窗口大小变化时的回调函数
- 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;
- }