eg: dotted/dashed Using glLineStiple(GLint factor,GLushort pattern)

// Lstipple.c
// OpenGL SuperBible, Chapter 4
// Demonstrates line stippling
// Program by Richard S. Wright Jr.

#define FREEGLUT_STATIC
#include <GL/glut.h>


// Define a constant for the value of PI
#define GL_PI 3.1415f

// Rotation amounts
static GLfloat xRot = 0.0f;
static GLfloat yRot = 0.0f;


// Called to draw scene
void RenderScene(void)
	{
	GLfloat y;					// Storeage for varying Y coordinate
	GLint factor = 1;			// Stippling factor
	GLushort pattern = 0x55ff;	// Stipple pattern
	

	// Clear the window with current clearing color
	glClear(GL_COLOR_BUFFER_BIT);

	// Save matrix state and do the rotation
	glPushMatrix();
	glRotatef(xRot, 1.0f, 0.0f, 0.0f);
	glRotatef(yRot, 0.0f, 1.0f, 0.0f);

	// Enable Stippling
	glEnable(GL_LINE_STIPPLE);

	// Step up Y axis 20 units at a time	
	for(y = -90.0f; y < 90.0f; y += 20.0f)
		{
		// Reset the repeat factor and pattern
		glLineStipple(factor,pattern);

		// Draw the line
		glBegin(GL_LINES);
			glVertex2f(-80.0f, y);
			glVertex2f(80.0f, y);	
		glEnd();

		factor++;
		}


	// Restore transformations
	glPopMatrix();

	// Flush drawing commands
	glutSwapBuffers();
	}

// This function does any needed initialization on the rendering
// context. 
void SetupRC()
	{
	// Black background
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f );

	// Set drawing color to green
	glColor3f(0.0f, 1.0f, 0.0f);
	}

void SpecialKeys(int key, int x, int y)
	{
	if(key == GLUT_KEY_UP)
		xRot-= 5.0f;

	if(key == GLUT_KEY_DOWN)
		xRot += 5.0f;

	if(key == GLUT_KEY_LEFT)
		yRot -= 5.0f;

	if(key == GLUT_KEY_RIGHT)
		yRot += 5.0f;

	if(xRot > 356.0f)
	{
		xRot = 0.0f;
		printf("here 1\n");
	}

	if(xRot < -1.0f)
	{
		xRot = 355.0f;
		printf("here 2\n");
	}

	if(key > 356.0f)
		yRot = 0.0f;

	if(key < -1.0f)
		yRot = 355.0f;

	// Refresh the Window
	glutPostRedisplay();
	}


void ChangeSize(int w, int h)
	{
	GLfloat nRange = 100.0f;

	// Prevent a divide by zero
	if(h == 0)
		h = 1;

	// Set Viewport to window dimensions
    glViewport(0, 0, w, h);

	// Reset coordinate system
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();

	// Establish clipping volume (left, right, bottom, top, near, far)
    if (w <= h) 
		glOrtho (-nRange, nRange, -nRange*h/w, nRange*h/w, -nRange, nRange);
    else 
		glOrtho (-nRange*w/h, nRange*w/h, -nRange, nRange, -nRange, nRange);

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	}

int main(int argc, char* argv[])
	{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutCreateWindow("Stippled Line Example");
	glutReshapeFunc(ChangeSize);
	glutSpecialFunc(SpecialKeys);
	glutDisplayFunc(RenderScene);
	SetupRC();
	glutMainLoop();

	return 0;
	}

　　glLineStipple(GLint factor,GLushort pattern)中参数的含义：

　　pattern是由1或0组成的16位序列，“1”代表绘制这个像素，“0”代表不绘制这个像素。结合factor，“1”代表连续绘制factor个像素，“0”代表不绘制连续factor个像素。如此，重复pattern。

　　举个例子：0xffff:默认值，代表直线；0x5555:dotted;0x00ff:dashed;0x1c47:dash/dot/dash..

　　注意：LineStipple的绘制pattern与实际绘制的顺序是相反的，比如上面这个例子，pattern=0x55ff，实际绘制是这个顺序：“1111 1111 1010 1010”。原因：在内部，OpenGL通过左移pattern来操作pattern以获取下一个掩码值是更加快速的。OpenGL的设计目标就是实现高性能的图形，因此它常常使用类似的技巧。

有图为证：