const GLfloat factor = 0.1f;


void display()
{
	GLfloat x;
	glClear(GL_COLOR_BUFFER_BIT);
	glBegin(GL_LINES);
	glVertex2f(-1.0, 0.0);
	glVertex2f(1.0, 0.0);
	glVertex2f(0.0, -1.0);
	glVertex2f(0.0, 1.0);
	glEnd();

	glBegin(GL_LINE_STRIP);
	for (x = -1.0/factor; x < 1.0/factor; x+=0.01)
	{
		glVertex2f(x*factor, sin(x)*factor);
	}
	glEnd();
	glFlush();
}


int main(int argc, char **argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
	glutInitWindowPosition(100, 100);
	glutInitWindowSize(500, 200);
	glutCreateWindow("opengl 3d view");
	//init();
	glutDisplayFunc(display);
	glutMainLoop();

	return 0;
}

一、当factor=0.1时

二、当factor=0.3时