.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/scene/mesh_shading.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_gallery_scene_mesh_shading.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_gallery_scene_mesh_shading.py:


Shading a Mesh
==============

Show mesh filter usage for shading (lighting) a mesh and displaying a wireframe.

.. GENERATED FROM PYTHON SOURCE LINES 13-120



.. image-sg:: /gallery/scene/images/sphx_glr_mesh_shading_001.png
   :alt: mesh shading
   :srcset: /gallery/scene/images/sphx_glr_mesh_shading_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    import argparse

    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


    parser = argparse.ArgumentParser()
    default_mesh = load_data_file('orig/triceratops.obj.gz')
    parser.add_argument('--mesh', default=default_mesh)
    parser.add_argument('--shininess', default=100)
    parser.add_argument('--wireframe-width', default=1)
    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`.
    mesh = Mesh(vertices, faces, color=(.5, .7, .5, 1))
    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(width=args.wireframe_width)
    # Note: For convenience, this `ShadingFilter` would be created automatically by
    # the `MeshVisual with, e.g. `mesh = MeshVisual(..., shading='smooth')`. It is
    # created manually here for demonstration purposes.
    shading_filter = ShadingFilter(shininess=args.shininess)
    # The wireframe filter is attached before the shading filter otherwise the
    # wireframe is not shaded.
    mesh.attach(wireframe_filter)
    mesh.attach(shading_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_states = (
        dict(shading=None),
        dict(shading='flat'),
        dict(shading='smooth'),
    )
    shading_state_index = shading_states.index(
        dict(shading=shading_filter.shading))

    wireframe_states = (
        dict(wireframe_only=False, faces_only=False,),
        dict(wireframe_only=True, faces_only=False,),
        dict(wireframe_only=False, faces_only=True,),
    )
    wireframe_state_index = wireframe_states.index(dict(
        wireframe_only=wireframe_filter.wireframe_only,
        faces_only=wireframe_filter.faces_only,
    ))


    def cycle_state(states, index):
        new_index = (index + 1) % len(states)
        return states[new_index], new_index


    @canvas.events.key_press.connect
    def on_key_press(event):
        global shading_state_index
        global wireframe_state_index
        if event.key == 's':
            state, shading_state_index = cycle_state(shading_states,
                                                     shading_state_index)
            for attr, value in state.items():
                setattr(shading_filter, attr, value)
            mesh.update()
        elif event.key == 'w':
            wireframe_filter.enabled = not wireframe_filter.enabled
            mesh.update()
        elif event.key == 'f':
            state, wireframe_state_index = cycle_state(wireframe_states,
                                                       wireframe_state_index)
            for attr, value in state.items():
                setattr(wireframe_filter, attr, value)
            mesh.update()


    canvas.show()


    if __name__ == "__main__":
        app.run()


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.948 seconds)


.. _sphx_glr_download_gallery_scene_mesh_shading.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: mesh_shading.ipynb <mesh_shading.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: mesh_shading.py <mesh_shading.py>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_