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

下面是一个使用OpenGL、Open3D和Python实现鼠标拖动画矩形框选出点云数据的感兴趣区域的代码示例：

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

# 定义点云数据
pcd = o3d.io.read_point_cloud("pointcloud.ply")

# 定义全局变量
window_width = 800
window_height = 600
mouse_pressed = False
start_x, start_y = 0, 0
end_x, end_y = 0, 0
selected_points = []

def draw_rect(x1, y1, x2, y2):
    # 绘制矩形框选区域
    glColor3f(1.0, 1.0, 1.0)
    glLineWidth(2.0)
    glBegin(GL_LINE_LOOP)
    glVertex2i(x1, y1)
    glVertex2i(x2, y1)
    glVertex2i(x2, y2)
    glVertex2i(x1, y2)
    glEnd()

def display():
    # 显示函数
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glPointSize(2)
    glBegin(GL_POINTS)
    for i in range(len(pcd.points)):
        glVertex3f(pcd.points[i][0], pcd.points[i][1], pcd.points[i][2])
    glEnd()
    draw_rect(start_x, start_y, end_x, end_y)
    glutSwapBuffers()

def reshape(width, height):
    # 窗口大小变化回调函数
    glViewport(0, 0, width, height)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluPerspective(60.0, float(width)/float(height), 0.1, 1000.0)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity()
    gluLookAt(0.0, 0.0, 10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0)

def mouse(button, state, x, y):
    # 鼠标事件回调函数
    global mouse_pressed, start_x, start_y, end_x, end_y, selected_points
    if button == GLUT_LEFT_BUTTON and state == GLUT_DOWN:
        mouse_pressed = True
        start_x, start_y = x, y
        end_x, end_y = x, y
    elif button == GLUT_LEFT_BUTTON and state == GLUT_UP:
        mouse_pressed = False
        selected_points = []
        # 将选中的点云数据加入selected_points列表
        for i in range(len(pcd.points)):
            if pcd.points[i][0] > min(start_x, end_x) and pcd.points[i][0] < max(start_x, end_x) and \
               pcd.points[i][1] > min(window_height - start_y, window_height - end_y) and pcd.points[i][1] < max(window_height - start_y, window_height - end_y):
                selected_points.append(i)
    elif button == GLUT_RIGHT_BUTTON and state == GLUT_DOWN:
        # 右键清空选择
        selected_points = []

def motion(x, y):
    # 鼠标移动事件回调函数
    global end_x, end_y
    end_x, end_y = x, y

def main():
    glutInit()
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)
    glutInitWindowSize(window_width, window_height)
    glutCreateWindow(b"OpenGL Python")
    glutDisplayFunc(display)
    glutReshapeFunc(reshape)
    glutMouseFunc(mouse)
    glutMotionFunc(motion)
    glEnable(GL_DEPTH_TEST)
    glClearColor(0.0, 0.0, 0.0, 0.0)
    glutMainLoop()

if __name__ == '__main__':
    main()

在这个示例代码中，我们首先使用Open3D库读取点云数据，然后使用OpenGL和PyOpenGL库进行可视化。我们定义了全局变量`selected_points`，用于保存框选后的点云数据。当鼠标左键按下时，我们记录下起始位置`start_x`和`start_y`，并在`motion`函数中更新结束位置`end_x`和`end_y`。当鼠标左键释放时，我们遍历所有点云数据，将在矩形框选区域内的点加入`selected_points`列表中。当鼠标右键按下时，我们清空`selected_points`列表。

注意，在矩形框选区域内的点的判断中，我们使用了OpenGL坐标系，而不是窗口坐标系。OpenGL坐标系的原点在窗口中心，x轴向右，y轴向上。因此，当判断点在矩形框选区域内时，需要将y坐标转换为窗口坐标系下的坐标。