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

.. only:: html

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

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

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

.. _sphx_glr_gallery_gloo_multi_texture.py:


Use multiple textures
=====================

We create two textures. One that shows a red, green and blue band in
the horizontal direction and one that does the same in the vertical
direction. In the fragment shader the colors from both textures are
added.

.. GENERATED FROM PYTHON SOURCE LINES 14-92



.. image-sg:: /gallery/gloo/images/sphx_glr_multi_texture_001.png
   :alt: multi texture
   :srcset: /gallery/gloo/images/sphx_glr_multi_texture_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    import numpy as np

    from vispy import gloo
    from vispy import app


    # Images to be displayed
    W, H = 30, 30
    im1 = np.zeros((W, H, 3), np.float32)
    im2 = np.zeros((W, H, 3), np.float32)
    im1[:10, :, 0] = 1.0
    im1[10:20, :, 1] = 1.0
    im1[20:, :, 2] = 1.0
    im2[:, :10, 0] = 1.0
    im2[:, 10:20, 1] = 1.0
    im1[:, 20:, 2] = 1.0

    # A simple texture quad
    data = np.zeros(4, dtype=[('a_position', np.float32, 2),
                              ('a_texcoord', np.float32, 2)])
    data['a_position'] = np.array([[-1, -1], [+1, -1], [-1, +1], [+1, +1]])
    data['a_texcoord'] = np.array([[1, 0], [1, 1.2], [0, 0], [0, 1.2]])


    VERT_SHADER = """
    attribute vec2 a_position;
    attribute vec2 a_texcoord;
    varying vec2 v_texcoord;

    void main (void)
    {
        v_texcoord = a_texcoord;
        gl_Position = vec4(a_position, 0.0, 1.0);
    }
    """

    FRAG_SHADER = """
    uniform sampler2D u_tex1;
    uniform sampler2D u_tex2;
    varying vec2 v_texcoord;

    void main()
    {
        vec3 clr1 = texture2D(u_tex1, v_texcoord).rgb;
        vec3 clr2 = texture2D(u_tex2, v_texcoord).rgb;
        gl_FragColor.rgb = clr1 + clr2;
        gl_FragColor.a = 1.0;
    }
    """


    class Canvas(app.Canvas):

        def __init__(self):
            app.Canvas.__init__(self, size=(500, 500), keys='interactive')

            self.program = gloo.Program(VERT_SHADER, FRAG_SHADER)
            self.program['u_tex1'] = gloo.Texture2D(im1, interpolation='linear')
            self.program['u_tex2'] = gloo.Texture2D(im2, interpolation='linear')
            self.program.bind(gloo.VertexBuffer(data))

            gloo.set_clear_color('white')

            self.show()

        def on_resize(self, event):
            width, height = event.physical_size
            gloo.set_viewport(0, 0, width, height)

        def on_draw(self, event):
            gloo.clear(color=True, depth=True)
            self.program.draw('triangle_strip')


    if __name__ == '__main__':
        canvas = Canvas()
        app.run()


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

   **Total running time of the script:** (0 minutes 0.461 seconds)


.. _sphx_glr_download_gallery_gloo_multi_texture.py:

.. only:: html

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

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

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

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

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


.. only:: html

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

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