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

.. only:: html

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

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

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

.. _sphx_glr__gallery_validation_validate_culling.py:


Culling
=======

Example test to validate winding and culling.

* The rightmost shapes are only lit by a dim ambient light. Other than that:
* The top green shapes should look normal and well lit.
* The bottom yellow shapes should show the backfaces, well lit.
* Hit space to toggle flat shading.

.. GENERATED FROM PYTHON SOURCE LINES 13-113



.. image-sg:: /_gallery/validation/images/sphx_glr_validate_culling_001.webp
   :alt: validate culling
   :srcset: /_gallery/validation/images/sphx_glr_validate_culling_001.webp
   :class: sphx-glr-single-img





.. code-block:: Python



    from rendercanvas.auto import RenderCanvas, loop
    import pygfx as gfx
    import pylinalg as la


    canvas = RenderCanvas(size=(1500, 600))
    renderer = gfx.renderers.WgpuRenderer(canvas)
    scene = gfx.Scene()

    # geometry = gfx.BoxGeometry(1, 1, 1)
    geometry = gfx.torus_knot_geometry(1, 0.3, 256, 20)


    def create_scene(title):
        # Create a green knot shown normally
        material1 = gfx.MeshPhongMaterial(color=(0, 1, 0, 1))
        obj1 = gfx.Mesh(geometry, material1)
        obj1.local.position = (0, 2, 0)
        obj1.material.side = gfx.VisibleSide.front

        # Create a yellow knot for which we show the back
        material2 = gfx.MeshPhongMaterial(color=(1, 1, 0, 1))
        obj2 = gfx.Mesh(geometry, material2)
        obj2.local.position = (0, -2, 0)
        obj2.material.side = gfx.VisibleSide.back

        # Rotate both in a position where the back faces are easier spotted
        rot = la.quat_from_euler((0.71, 1), order="XY")
        obj1.local.rotation = la.quat_mul(rot, obj1.local.rotation)
        obj2.local.rotation = la.quat_mul(rot, obj2.local.rotation)

        t = gfx.Text(
            text=title,
            screen_space=True,
            font_size=20,
            material=gfx.TextMaterial(aa=True),
        )
        t.local.position = (0, 4, 0)
        camera = gfx.OrthographicCamera(4.2, 6)

        amb_light = gfx.AmbientLight(0.2, 2)
        dir_light = gfx.DirectionalLight(1, 2)

        # Compose scene
        scene = gfx.Scene()
        scene.add(obj1, obj2, t, amb_light, camera.add(dir_light))

        return scene


    vp1 = gfx.Viewport(renderer, (0, 0, 300, 600))
    scene1 = create_scene("Regular")

    vp2 = gfx.Viewport(renderer, (300, 0, 300, 600))
    scene2 = create_scene("Flip object")
    scene2.children[0].local.scale_x = -1
    scene2.children[1].local.scale_x = -1

    vp3 = gfx.Viewport(renderer, (600, 0, 300, 600))
    scene3 = create_scene("Rotate camera")
    transform = scene3.children[-1].local
    transform.rotation = la.quat_from_axis_angle((0, 1, 0), 3.141592)

    vp4 = gfx.Viewport(renderer, (900, 0, 300, 600))
    scene4 = create_scene("Flip camera")
    scene4.children[-1].local.scale_z = -1

    vp5 = gfx.Viewport(renderer, (1200, 0, 300, 600))
    scene5 = create_scene("Flip camera, not light")
    scene5.children[-1].local.scale_z = -1
    scene5.add(scene5.children[-1].children[0])  # put light in root
    scene5.add(scene5.children[-2])  # move camera to the end


    @canvas.add_event_handler("key_down")
    def toggle_flat_shading(e):
        if e["key"] == " ":
            for scene in (scene1, scene2, scene3, scene4, scene5):
                for obj in scene.children[:2]:
                    obj.material.flat_shading = not obj.material.flat_shading
            canvas.request_draw()


    def animate():
        vp1.render(scene1, scene1.children[-1])
        vp2.render(scene2, scene2.children[-1])
        vp3.render(scene3, scene3.children[-1])
        vp4.render(scene4, scene4.children[-1])
        vp5.render(scene5, scene5.children[-1])
        renderer.flush()


    canvas.request_draw(animate)


    if __name__ == "__main__":
        print(__doc__)
        loop.run()


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

   **Total running time of the script:** (0 minutes 0.819 seconds)


.. _sphx_glr_download__gallery_validation_validate_culling.py:

.. only:: html

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

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

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

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

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

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: validate_culling.zip <validate_culling.zip>`


.. only:: html

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

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

.. only:: html

    Interactive example
    -------------------

    Try this example in your browser using Pyodide. Might not work with all examples and all devices. Check the output and your browser's console for details.

    .. raw:: html

        <iframe src="./../pyodide.html#validate_culling.py"></iframe>