openGL+open3d+python 鼠标拖动画矩形框选出点云数据的感兴趣区域代码

以下是一个基于Open3D和PyOpenGL的示例代码，演示如何使用鼠标拖动矩形框来选择点云数据的感兴趣区域：

import open3d as o3d
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import numpy as np

# 用于存储点云数据的全局变量
pcd = None

# 定义矩形框的起点和终点坐标
start_x, start_y, end_x, end_y = 0, 0, 0, 0

# OpenGL 窗口宽度和高度
window_width, window_height = 640, 480

def init():
    # 初始化窗口和 OpenGL 环境
    glutInit()
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)
    glutInitWindowSize(window_width, window_height)
    glutCreateWindow("Select Point Cloud ROI")

    # 注册回调函数
    glutDisplayFunc(display)
    glutKeyboardFunc(keyboard)
    glutMouseFunc(mouse)
    glutMotionFunc(motion)

    # 设置 OpenGL 渲染模式和深度测试
    glShadeModel(GL_SMOOTH)
    glEnable(GL_DEPTH_TEST)

def display():
    global pcd
    # 清除屏幕和深度缓存
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    
    # 如果有点云数据就显示
    if pcd is not None:
        # 设置 OpenGL 投影矩阵
        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()
        gluPerspective(45, window_width / window_height, 0.1, 100.0)
        glMatrixMode(GL_MODELVIEW)
        
        # 设置 OpenGL 模型视图矩阵
        glLoadIdentity()
        gluLookAt(0, 0, 3, 0, 0, 0, 0, 1, 0)
        
        # 绘制点云数据
        glColor3f(1.0, 1.0, 1.0)
        glBegin(GL_POINTS)
        for point in np.asarray(pcd.points):
            glVertex3f(point[0], point[1], point[2])
        glEnd()

        # 绘制矩形框
        if start_x != end_x and start_y != end_y:
            glColor3f(0.0, 1.0, 0.0)
            glLineWidth(2)
            glBegin(GL_LINE_LOOP)
            glVertex3f(start_x, start_y, 0)
            glVertex3f(end_x, start_y, 0)
            glVertex3f(end_x, end_y, 0)
            glVertex3f(start_x, end_y, 0)
            glEnd()
        
    glutSwapBuffers()

def keyboard(key, x, y):
    # 按下 ESC 键退出程序
    if key == chr(27):
        sys.exit(0)

def mouse(button, state, x, y):
    global start_x, start_y, end_x, end_y, pcd
    if button == GLUT_LEFT_BUTTON:
        if state == GLUT_DOWN:
            start_x, start_y = x, y
        elif state == GLUT_UP:
            # 使用 Open3D 进行点云数据截取
            bbox = o3d.geometry.AxisAlignedBoundingBox.from_points(
                pcd.select_down_sample(np.array([[start_x, start_y], [end_x, end_y]])).points)
            pcd_crop = pcd.crop(bbox)

            # 显示裁剪后的点云数据
            global window_width, window_height
            window_width, window_height = 640, 480
            pcd = pcd_crop
            glutReshapeWindow(window_width, window_height)

def motion(x, y):
    global end_x, end_y
    end_x, end_y = x, y
    glutPostRedisplay()

if __name__ == '__main__':
    # 读取点云数据
    pcd = o3d.io.read_point_cloud("point_cloud.pcd")

    # 初始化 OpenGL 窗口和环境
    init()

    # 进入 OpenGL 主循环
    glutMainLoop()

在代码中，我们使用了 `o3d.geometry.AxisAlignedBoundingBox.from_points()` 函数将矩形框转换为 Open3D 中的 AxisAlignedBoundingBox 对象，并使用 `pcd.crop()` 函数对原始点云数据进行截取操作，得到裁剪后的点云数据。裁剪后的点云数据将替代原始点云数据，并在窗口中显示。