from directshowbaseShowBase import ShowBasefrom panda3dcore import Point3 LineSegsclass MyAppShowBase def __init__self ShowBase__init__self # 已知的平面的4个点坐标 p1 = Point30 0 0

from direct.showbase.ShowBase import ShowBase from panda3d.core import Point3, LineSegs

class MyApp(ShowBase): def init(self): ShowBase.init(self)

    # 已知的平面的4个点坐标
    p1 = Point3(0, 0, 0)
    p2 = Point3(2, 0, 0)
    p3 = Point3(2, 0, 2)
    p4 = Point3(0, 0, 2)

    # 创建LineSegs对象并设置颜色和宽度
    lines = LineSegs()
    lines.set_color(1, 0, 0, 1)
    lines.set_thickness(2)

    # 从p1开始绘制线段
    lines.move_to(p1)
    lines.draw_to(p2)
    lines.draw_to(p3)
    lines.draw_to(p4)
    lines.draw_to(p1)

    # 创建NodePath并将其附加到场景图中
    node = lines.create()
    np = self.render.attach_new_node(node)

    # 计算平面法向量
    v1 = p2 - p1
    v2 = p3 - p1
    normal = v1.cross(v2).normalized()
    print("平面法向量:", normal)

    # 沿着法向量方向拉伸出长方体
    dist = 1
    p1_ext = p1 + normal * dist
    p2_ext = p2 + normal * dist
    p3_ext = p3 + normal * dist
    p4_ext = p4 + normal * dist
    p5_ext = p1 - normal * dist
    p6_ext = p2 - normal * dist
    p7_ext = p3 - normal * dist
    p8_ext = p4 - normal * dist

    # 创建LineSegs对象并设置颜色和宽度
    lines = LineSegs()
    lines.set_color(0, 1, 0, 1)
    lines.set_thickness(2)

    # 绘制长方体的12条边
    lines.move_to(p1_ext)
    lines.draw_to(p2_ext)
    lines.draw_to(p3_ext)
    lines.draw_to(p4_ext)
    lines.draw_to(p1_ext)
    lines.move_to(p5_ext)
    lines.draw_to(p6_ext)
    lines.draw_to(p7_ext)
    lines.draw_to(p8_ext)
    lines.draw_to(p5_ext)
    lines.move_to(p1_ext)
    lines.draw_to(p5_ext)
    lines.move_to(p2_ext)
    lines.draw_to(p6_ext)
    lines.move_to(p3_ext)
    lines.draw_to(p7_ext)
    lines.move_to(p4_ext)
    lines.draw_to(p8_ext)

    # 创建NodePath并将其附加到场景图中
    node = lines.create()
    np = self.render.attach_new_node(node