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

.. only:: html

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

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

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

.. _sphx_glr__gallery_feature_demo_look_at_instanced.py:


Look At (Instanced Mesh)
========================

This example shows how the look_at function can be used with instanced mesh.

.. GENERATED FROM PYTHON SOURCE LINES 7-82



.. image-sg:: /_gallery/feature_demo/images/sphx_glr_look_at_instanced_001.webp
   :alt: look at instanced
   :srcset: /_gallery/feature_demo/images/sphx_glr_look_at_instanced_001.webp
   :class: sphx-glr-single-img





.. code-block:: Python



    from time import perf_counter
    import numpy as np
    import pygfx as gfx
    import pylinalg as la

    scene = gfx.Scene()

    sphere = gfx.Mesh(
        gfx.sphere_geometry(100, 20, 20),
        gfx.MeshPhongMaterial(color="#336699"),
    )
    sphere.receive_shadow = sphere.cast_shadow = True
    scene.add(sphere)

    plane = gfx.Mesh(
        gfx.plane_geometry(4000, 4000),
        gfx.MeshPhongMaterial(color="#336699"),
    )
    plane.local.position = (0, -2500, 0)
    plane.local.rotation = la.quat_from_euler(-np.pi / 2, order="X")
    plane.receive_shadow = True
    scene.add(plane)

    sun = gfx.DirectionalLight()
    sun.local.position = (0, 3000, 0)
    sun.cast_shadow = True
    sun.shadow.camera.depth_range = (1, 6000)
    sun.shadow.camera.width = 4000
    sun.shadow.camera.height = 4000
    scene.add(gfx.AmbientLight())
    scene.add(sun)

    geometry = gfx.cylinder_geometry(10, 0, 100, 12)
    material = gfx.MeshPhongMaterial(color="#336699")
    cones = gfx.Group()

    instance_count = 100
    mesh = gfx.InstancedMesh(geometry, material, instance_count)
    mesh.cast_shadow = mesh.receive_shadow = True

    for i in range(instance_count):
        mesh.set_matrix_at(
            i,
            la.mat_compose(
                np.random.rand(3) * 4000 - 2000, (0, 0, 0, 1), np.random.rand() * 4 + 2
            ),
        )

    scene.add(mesh)

    dummy = gfx.objects.WorldObject()  # dummy object to calculate look_at


    def animate():
        t = perf_counter() / 0.5
        sphere.local.position = (
            np.sin(t * 0.7) * 2000,
            np.cos(t * 0.5) * 2000,
            np.cos(t * 0.3) * 2000,
        )

        for i in range(instance_count):
            m = mesh.get_matrix_at(i)
            dummy.world.matrix = m
            dummy.look_at(sphere.world.position)
            m = dummy.world.matrix
            mesh.set_matrix_at(i, m)


    if __name__ == "__main__":
        disp = gfx.Display()
        disp.before_render = animate
        disp.show(scene)


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

   **Total running time of the script:** (0 minutes 12.349 seconds)


.. _sphx_glr_download__gallery_feature_demo_look_at_instanced.py:

.. only:: html

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

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

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

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

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

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

      :download:`Download zipped: look_at_instanced.zip <look_at_instanced.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#look_at_instanced.py"></iframe>