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

.. only:: html

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

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

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

.. _sphx_glr__gallery_mesh_surface_earth.py:


Earth sphere animation
======================

Example showing how to create a sphere with an image of the Earth and rotate it around its 23.44° axis of rotation
with respect to the ecliptic (the xz plane in the visualization).

.. GENERATED FROM PYTHON SOURCE LINES 9-95



.. image-sg:: /_gallery/mesh/images/sphx_glr_surface_earth_001.webp
   :alt: surface earth
   :srcset: /_gallery/mesh/images/sphx_glr_surface_earth_001.webp
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    /opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:400: RuntimeWarning: divide by zero encountered in divide
      screen_full = (ndc_full[:, :2] / ndc_full[:, 3:4]) * half_canvas_size
    /opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:400: RuntimeWarning: invalid value encountered in divide
      screen_full = (ndc_full[:, :2] / ndc_full[:, 3:4]) * half_canvas_size
    /opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:412: RuntimeWarning: invalid value encountered in divide
      screen_sel = (ndc_sel[:, :2] / ndc_sel[:, 3:4]) * half_canvas_size
    /home/runner/work/fastplotlib/fastplotlib/fastplotlib/graphics/features/_base.py:18: UserWarning: casting int64 array to float32
      warn(f"casting {array.dtype} array to float32")







|

.. code-block:: Python


    # test_example = false

    import fastplotlib as fpl
    import numpy as np
    import imageio.v3 as iio
    import pylinalg as la


    figure = fpl.Figure(size=(700, 560), cameras="3d", controller_types="orbit")

    # create a sphere from spherical coordinates
    # see this for reference: https://mathworld.wolfram.com/SphericalCoordinates.html
    # phi and theta are swapped in this example w.r.t. the wolfram alpha description
    radius = 10
    nx = 101
    phi = np.linspace(0, np.pi * 2, num=nx, dtype=np.float32)
    ny = 51
    theta = np.linspace(0, np.pi, num=ny, dtype=np.float32)

    phi_grid, theta_grid = np.meshgrid(phi, theta)

    # convert to cartesian coordinates
    theta_grid_sin = np.sin(theta_grid)
    x = radius * np.cos(phi_grid) * theta_grid_sin * -1
    y = radius * np.cos(theta_grid)
    z = radius * np.sin(phi_grid) * theta_grid_sin

    # get texture coords to map the image onto the mesh positions
    u = phi_grid / (np.pi * 2)
    v = 1 - (theta_grid / np.pi)
    texcoords = np.dstack([u, v]).reshape(-1, 2)

    # get an image of the earth from nasa
    image = iio.imread(
        "https://svs.gsfc.nasa.gov/vis/a000000/a003600/a003615/flat_earth_Largest_still.0330.jpg"
    )
    # images coordinate systems are typically inverted in y, so flip the image
    image = np.ascontiguousarray(np.flipud(image))

    # create a sphere
    sphere = figure[0, 0].add_surface(
        np.dstack([x, y, z]),
        mode="phong",
        colors="magenta",
        cmap=image,
        mapcoords=texcoords,
    )

    # display xz plane as a grid
    figure[0, 0].axes.grids.xz.visible = True
    figure.show()

    # view from top right angle
    figure[0, 0].camera.show_object(sphere.world_object, (-0.5, -0.25, -1), up=(0, 1, 0))
    figure[0, 0].camera.zoom = 1.25

    # create quaternion for 23.44 degrees axial tilt
    axial_tilt = la.quat_from_euler((np.radians(23.44), 0), order="XY")

    # a line to indicate the axial tilt
    figure[0, 0].add_line(
        np.array([[0, -20, 0], [0, 20, 0]]), rotation=axial_tilt, colors="magenta"
    )

    rot = 1


    def rotate():
        # rotate by 1 degree
        global rot
        rot += 1
        rot_quat = la.quat_from_euler((0, np.radians(rot)), order="XY")

        # apply rotation w.r.t. axial tilt
        sphere.rotation = la.quat_mul(axial_tilt, rot_quat)


    figure[0, 0].add_animations(rotate)


    # NOTE: fpl.loop.run() should not be used for interactive sessions
    # See the "JupyterLab and IPython" section in the user guide
    if __name__ == "__main__":
        print(__doc__)
        fpl.loop.run()


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

   **Total running time of the script:** (0 minutes 29.909 seconds)


.. _sphx_glr_download__gallery_mesh_surface_earth.py:

.. only:: html

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

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

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

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

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


.. only:: html

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

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