一.直线的点画模式：即并不完全填充所有像素来画一条直线，而是用点画的形式，间隔地画一条直线
首先启用点画模式：
glEnable(GL_LINE_STIPPLE);
然后自定义创建自己的点画模式
glLineStipple(GLlint factor,GLushort pattern);
其中第一个参数factor为乘法因子，第二个参数pattern为自定义的点画模式:一个16位的值，每个位表示线段的一部分状态为打开或者关闭,采用16进制，例如：0x5555
直线点画的实例程序：
// STIPPLE.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include<GL\glut.h>
void Init()
{
glClearColor(0.0f,0.0f,0.0f,0.0f); } void MyDisplay()
{
glClear(GL_COLOR_BUFFER_BIT); GLint factor=;
GLushort pattern=0x5555;
GLfloat y;
glEnable(GL_LINE_STIPPLE); glColor3f(0.0,1.0f,0.0f); for ( y = -80.0f; y < 80.0f; y+=20.0f)
{
glLineStipple(factor,pattern);
glBegin(GL_LINES);
glVertex2f(-80.0f,y);
glVertex2f(80.0,y);
factor++;
glEnd(); } glutSwapBuffers(); }
void ChangeSize(int w,int h)
{
if (h==)
{
h=;
}
glViewport(,,w,h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w<=h)
{
gluOrtho2D(-100.0,100.0,-100.0*(GLfloat)h/(GLfloat)w,100.0*(GLfloat)h/(GLfloat)w);
}
else
{
gluOrtho2D(-100.0*(GLfloat)w/(GLfloat)h,100.0*(GLfloat)w/(GLfloat)h,-100.0,100.0);
}
glMatrixMode(GL_MODELVIEW);
glLoadIdentity(); }
int main(int argc, char ** argv)
{
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_RGB|GLUT_DOUBLE);
glutInitWindowPosition(,);
glutInitWindowSize(,);
glutCreateWindow("Line_STIPPLE"); Init();
glutDisplayFunc(MyDisplay);
glutReshapeFunc(ChangeSize); glutMainLoop(); }