#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);
glBegin(GL_LINES);
glColor3f(1.0,1.0,1.0);
glVertex2f(-0.8,-0.8);
glColor3f(1.0,0.0,0.0 );
glVertex3f(0.5,0.2,-0.3);
glVertex3f(-0.5,0.4,0.7);
glColor3f(1.0,1.0,1.0);
glVertex3f(0.5,0.2,-0.3);
glEnd(); 
glFlush();
}


int main(int argc,char** argv){
    glutInit(&argc, argv);
    glutInitDisplayMode ( GLUT_RGB );
    glutInitWindowPosition( 300, 100 );
    glutInitWindowSize ( 150, 150 );
    glutCreateWindow ( "Esempio 3" );
    glutDisplayFunc( redraw );
    glutMainLoop ();
}