glBegin(GL_POLYGON);
for (int j = 0; j <= n ; ++j) {
glVertex2f(c1.x + R1 * sin(2 * Pi / n * j), c1.y + R1 * cos(2 * Pi / n * j));
}
glEnd();
glBegin(GL_POLYGON);
for (int j = 0; j <= n ; ++j) {
glVertex2f(c2.x + R2 * sin(2 * Pi / n * j), c2.y + R2 * cos(2 * Pi / n * j));
}
glEnd();
c1,c2就是两个圆的圆心坐标了,R1,R2是两个圆的半径,用GL_POLYGON模式画图,取一个n值就行了