.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "_gallery/feature_demo/colormap_channels.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_colormap_channels.py>`
        to download the full example code.

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

.. _sphx_glr__gallery_feature_demo_colormap_channels.py:


Colormap Channels
=================

Example demonstrating colormaps in 4 modes: grayscale, gray+alpha, RGB, RGBA.

.. GENERATED FROM PYTHON SOURCE LINES 7-65



.. image-sg:: /_gallery/feature_demo/images/sphx_glr_colormap_channels_001.webp
   :alt: colormap channels
   :srcset: /_gallery/feature_demo/images/sphx_glr_colormap_channels_001.webp
   :class: sphx-glr-single-img





.. code-block:: Python



    import numpy as np
    import pygfx as gfx
    import pylinalg as la


    group = gfx.Group()


    geometry = gfx.torus_knot_geometry(1, 0.3, 128, 32)
    geometry.texcoords = gfx.Buffer(geometry.texcoords.data[:, 0])

    camera = gfx.OrthographicCamera(16, 3)


    def create_object(tex, xpos):
        material = gfx.MeshPhongMaterial(map=tex)
        obj = gfx.Mesh(geometry, material)
        obj.local.x = xpos
        group.add(obj)


    # === 1-channel colormap: grayscale

    cmap1 = np.array([(1,), (0,), (0,), (1,)], np.float32)
    tex1 = gfx.Texture(cmap1, dim=1)
    create_object(tex1, -6)

    # ==== 2-channel colormap: grayscale + alpha

    cmap2 = np.array([(1, 1), (0, 1), (0, 0), (1, 0)], np.float32)
    tex1 = gfx.Texture(cmap2, dim=1)
    create_object(tex1, -2)

    # === 3-channel colormap: RGB

    cmap3 = np.array([(1, 1, 0), (0, 1, 0), (0, 1, 0), (1, 1, 0)], np.float32)
    tex1 = gfx.Texture(cmap3, dim=1)
    create_object(tex1, +2)

    # === 4-channel colormap: RGBA

    cmap4 = np.array([(1, 1, 0, 1), (0, 1, 0, 1), (0, 1, 0, 0), (1, 1, 0, 0)], np.float32)
    tex1 = gfx.Texture(cmap4, dim=1)
    create_object(tex1, +6)


    def animate():
        rot = la.quat_from_euler((0.0071, 0.01), order="XY")
        for obj in group.children:
            obj.local.rotation = la.quat_mul(rot, obj.local.rotation)


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


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

   **Total running time of the script:** (0 minutes 0.939 seconds)


.. _sphx_glr_download__gallery_feature_demo_colormap_channels.py:

.. only:: html

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

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

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

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

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

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

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