.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "gallery/scene/face_picking.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note :ref:`Go to the end ` to download the full example code. .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_scene_face_picking.py: Picking Faces from a Mesh ========================= Demonstrates how to identify (pick) individual faces on a mesh. Arguments: * --mesh - Path to a mesh file (OBJ/OBJ.GZ) [optional] Controls: * p - Toggle face picking view - shows the colors encoding face ID * r - Clear painted faces * s - Cycle shading modes (None, 'flat', 'smooth') * w - Toggle wireframe .. GENERATED FROM PYTHON SOURCE LINES 22-150 .. image-sg:: /gallery/scene/images/sphx_glr_face_picking_001.png :alt: face picking :srcset: /gallery/scene/images/sphx_glr_face_picking_001.png :class: sphx-glr-single-img .. code-block:: Python import argparse import itertools import time import numpy as np from vispy import app, scene from vispy.io import read_mesh, load_data_file from vispy.scene.visuals import Mesh from vispy.scene import transforms from vispy.visuals.filters import ShadingFilter, WireframeFilter, FacePickingFilter parser = argparse.ArgumentParser() default_mesh = load_data_file('orig/triceratops.obj.gz') parser.add_argument('--mesh', default=default_mesh) args, _ = parser.parse_known_args() vertices, faces, _normals, _texcoords = read_mesh(args.mesh) canvas = scene.SceneCanvas(keys='interactive', bgcolor='white') view = canvas.central_widget.add_view() view.camera = 'arcball' view.camera.depth_value = 1e3 # Create a colored `MeshVisual`. face_colors = np.tile((0.5, 0.0, 0.5, 1.0), (len(faces), 1)) mesh = Mesh( vertices, faces, face_colors=face_colors.copy() ) mesh.transform = transforms.MatrixTransform() mesh.transform.rotate(90, (1, 0, 0)) mesh.transform.rotate(-45, (0, 0, 1)) view.add(mesh) # Use filters to affect the rendering of the mesh. wireframe_filter = WireframeFilter() shading_filter = ShadingFilter() face_picking_filter = FacePickingFilter() mesh.attach(wireframe_filter) mesh.attach(shading_filter) mesh.attach(face_picking_filter) def attach_headlight(view): light_dir = (0, 1, 0, 0) shading_filter.light_dir = light_dir[:3] initial_light_dir = view.camera.transform.imap(light_dir) @view.scene.transform.changed.connect def on_transform_change(event): transform = view.camera.transform shading_filter.light_dir = transform.map(initial_light_dir)[:3] attach_headlight(view) shading = itertools.cycle(("flat", "smooth", None)) shading_filter.shading = next(shading) throttle = time.monotonic() @canvas.events.mouse_move.connect def on_mouse_move(event): global throttle # throttle mouse events to 50ms if time.monotonic() - throttle < 0.05: return throttle = time.monotonic() # adjust the event position for hidpi screens render_size = tuple(d * canvas.pixel_scale for d in canvas.size) x_pos = event.pos[0] * canvas.pixel_scale y_pos = render_size[1] - (event.pos[1] * canvas.pixel_scale) # render a small patch around the mouse cursor restore_state = not face_picking_filter.enabled face_picking_filter.enabled = True mesh.update_gl_state(blend=False) picking_render = canvas.render( region=(x_pos - 1, y_pos - 1, 3, 3), size=(3, 3), bgcolor=(0, 0, 0, 0), alpha=True, ) if restore_state: face_picking_filter.enabled = False mesh.update_gl_state(blend=not face_picking_filter.enabled) # unpack the face index from the color in the center pixel face_idx = (picking_render.view(np.uint32) - 1)[1, 1, 0] if face_idx > 0 and face_idx < len(face_colors): # this may be less safe, but it's faster than set_data mesh.mesh_data._face_colors_indexed_by_faces[face_idx] = (0, 1, 0, 1) mesh.mesh_data_changed() @canvas.events.key_press.connect def on_key_press(event): if event.key == 'p': face_picking_filter.enabled = not face_picking_filter.enabled mesh.update_gl_state(blend=not face_picking_filter.enabled) mesh.update() if event.key == 'r': mesh.set_data(vertices, faces, face_colors=face_colors) if event.key == 's': shading_filter.shading = next(shading) mesh.update() if event.key == 'w': wireframe_filter.enabled = not wireframe_filter.enabled mesh.update() canvas.show() if __name__ == "__main__": print(__doc__) app.run() .. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 0.988 seconds) .. _sphx_glr_download_gallery_scene_face_picking.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: face_picking.ipynb ` .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: face_picking.py ` .. container:: sphx-glr-download sphx-glr-download-zip :download:`Download zipped: face_picking.zip ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_