my code is:
Code :
void display() {
 
 
 
			glColor3f(1.0f, 0.0f, 0.0f);
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	// Clear The Screen And The Depth Buffer
 
			glMatrixMode(GL_MODELVIEW);
            glLoadIdentity();
            gluLookAt(0, 0, 1.2, 0, 0, 0, 0, 1, 0);
			glRotatef(30,0,0,1);
			glBegin(GL_TRIANGLES);					// Start Drawing The Pyramid
            glColor3f(0.0f, 1.0f, 0.0f);			// Red
 
			glVertex3f(-1.0f, 1.0f, 0.0f);			// Top Of Triangle (Front)
            glVertex3f(-1.0f, -1.0f, 0.0f);			// Left Of Triangle (Front)
            glVertex3f(1.0f, -1.0f, 0.0f);			// Right Of Triangle (Front)
 
 
            glVertex3f(-1.0f, 1.0f, 0.0f);			// Top Of Triangle (Right)
            glVertex3f(1.0f, -1.0f, 0.0f);			// Left Of Triangle (Right)
            glVertex3f(1.0f, 1.0f, 0.0f);
            glEnd();
			  glFlush();
			glutSwapBuffers();
}
void init(void)
{
  /* Setup cube vertex data. */
 
 
  /* Use depth buffering for hidden surface elimination. */
	glDisable( GL_DEPTH_TEST ) ;
	glClearColor( 1.0, 1.0, 1.0, 0.0 ) ; // white
	glClear( GL_COLOR_BUFFER_BIT ) ;
	float mulval = 0.01 ; // you might want to change this
 
	glEnable( GL_BLEND ) ;
	glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ; // works fine, except cracks
	//glBlendFunc( GL_SRC_ALPHA_SATURATE, GL_ONE ) ; // works only on black background...
	glPolygonMode( GL_FRONT, GL_FILL ) ;
	glEnable( GL_POLYGON_SMOOTH ) ;
	glHint( GL_POLYGON_SMOOTH_HINT, GL_NICEST ) ;
}
int main(int argc, char** argv) {
 
  // Use a single buffered window in RGB mode (as opposed to a double-buffered
  // window or color-index mode).
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_RGB  |GLUT_DEPTH | GLUT_STENCIL);
 
  // Position window at (80,80)-(480,380) and give it a title.
  glutInitWindowPosition(80, 80);
  glutInitWindowSize(800, 600);
  glutCreateWindow("A Simple Triangle");
 
  // Tell GLUT that whenever the main window needs to be repainted that it
  // should call the function display().
  glutDisplayFunc(display);
  glutReshapeFunc(reshape);
  // Tell GLUT to start reading and processing events.  This function
  // never returns; the program only exits when the user closes the main
  // window or kills the process.
  init();
  glutMainLoop();
  return 0;
}
and result is:
Attachment 1266

what is the line between of triangle? i want to remove it!!