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# ----------------------------------------------------------------------------
# - Open3D: www.open3d.org -
# ----------------------------------------------------------------------------
# Copyright (c) 2018-2024 www.open3d.org
# SPDX-License-Identifier: MIT
# ----------------------------------------------------------------------------
import numpy as np
import open3d as o3d
import open3d.visualization.gui as gui
import open3d.visualization.rendering as rendering
# This example displays a point cloud and if you Ctrl-click on a point
# (Cmd-click on macOS) it will show the coordinates of the point.
# This example illustrates:
# - custom mouse handling on SceneWidget
# - getting a the depth value of a point (OpenGL depth)
# - converting from a window point + OpenGL depth to world coordinate
class ExampleApp:
def __init__(self, cloud):
# We will create a SceneWidget that fills the entire window, and then
# a label in the lower left on top of the SceneWidget to display the
# coordinate.
app = gui.Application.instance
self.window = app.create_window("Open3D - GetCoord Example", 1024, 768)
# Since we want the label on top of the scene, we cannot use a layout,
# so we need to manually layout the window's children.
self.window.set_on_layout(self._on_layout)
self.widget3d = gui.SceneWidget()
self.window.add_child(self.widget3d)
self.info = gui.Label("")
self.info.visible = False
self.window.add_child(self.info)
self.widget3d.scene = rendering.Open3DScene(self.window.renderer)
mat = rendering.MaterialRecord()
mat.shader = "defaultUnlit"
# Point size is in native pixels, but "pixel" means different things to
# different platforms (macOS, in particular), so multiply by Window scale
# factor.
mat.point_size = 3 * self.window.scaling
self.widget3d.scene.add_geometry("Point Cloud", cloud, mat)
bounds = self.widget3d.scene.bounding_box
center = bounds.get_center()
self.widget3d.setup_camera(60, bounds, center)
self.widget3d.look_at(center, center - [0, 0, 3], [0, -1, 0])
self.widget3d.set_on_mouse(self._on_mouse_widget3d)
def _on_layout(self, layout_context):
r = self.window.content_rect
self.widget3d.frame = r
pref = self.info.calc_preferred_size(layout_context,
gui.Widget.Constraints())
self.info.frame = gui.Rect(r.x,
r.get_bottom() - pref.height, pref.width,
pref.height)
def _on_mouse_widget3d(self, event):
# We could override BUTTON_DOWN without a modifier, but that would
# interfere with manipulating the scene.
if event.type == gui.MouseEvent.Type.BUTTON_DOWN and event.is_modifier_down(
gui.KeyModifier.CTRL):
def depth_callback(depth_image):
# Coordinates are expressed in absolute coordinates of the
# window, but to dereference the image correctly we need them
# relative to the origin of the widget. Note that even if the
# scene widget is the only thing in the window, if a menubar
# exists it also takes up space in the window (except on macOS).
x = event.x - self.widget3d.frame.x
y = event.y - self.widget3d.frame.y
# Note that np.asarray() reverses the axes.
depth = np.asarray(depth_image)[y, x]
if depth == 1.0: # clicked on nothing (i.e. the far plane)
text = ""
else:
world = self.widget3d.scene.camera.unproject(
x, y, depth, self.widget3d.frame.width,
self.widget3d.frame.height)
text = "({:.3f}, {:.3f}, {:.3f})".format(
world[0], world[1], world[2])
# This is not called on the main thread, so we need to
# post to the main thread to safely access UI items.
def update_label():
self.info.text = text
self.info.visible = (text != "")
# We are sizing the info label to be exactly the right size,
# so since the text likely changed width, we need to
# re-layout to set the new frame.
self.window.set_needs_layout()
gui.Application.instance.post_to_main_thread(
self.window, update_label)
self.widget3d.scene.scene.render_to_depth_image(depth_callback)
return gui.Widget.EventCallbackResult.HANDLED
return gui.Widget.EventCallbackResult.IGNORED
def main():
app = gui.Application.instance
app.initialize()
# This example will also work with a triangle mesh, or any 3D object.
# If you use a triangle mesh you will probably want to set the material
# shader to "defaultLit" instead of "defaultUnlit".
pcd_data = o3d.data.DemoICPPointClouds()
cloud = o3d.io.read_point_cloud(pcd_data.paths[0])
ex = ExampleApp(cloud)
app.run()
if __name__ == "__main__":
main()
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