#include<GL/glut.h>
#include<GL/gl.h>
#include<GL/glu.h>


void redraw(){
	glClearColor(0.0,0.0,0.0,1.0);
	glClear(GL_COLOR_BUFFER_BIT);
	GLfloat y;
	GLint factor=1;
	//GLushort pattern=0x5555;
	GLushort pattern=0x00FF;
	glEnable(GL_LINE_STIPPLE);
	for(y=-0.9f;y<0.9f;y+=0.2f){
		glLineStipple(factor,pattern);
		glBegin(GL_LINES);
			glVertex2f(-0.8f,y);
			glVertex2f(0.8f,y);
		glEnd();
		factor++;
	}
	glFlush();
}


int main(int argc,char** argv){
    glutInit(&argc, argv);
    glutInitDisplayMode ( GLUT_RGB );
    glutInitWindowPosition( 300, 100 );
    glutInitWindowSize ( 150, 150 );
    glutCreateWindow ( "Esempio 7" );
    glutDisplayFunc( redraw );
    glutMainLoop ();
}