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

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

.. _sphx_glr_gallery_gloo_lighted_cube.py:


Show a rotating cube with lighting
==================================

.. GENERATED FROM PYTHON SOURCE LINES 13-162







.. code-block:: Python


    import numpy as np

    from vispy import gloo, app
    from vispy.gloo import Program, VertexBuffer, IndexBuffer
    from vispy.util.transforms import perspective, translate, rotate
    from vispy.geometry import create_cube


    vertex = """
    uniform mat4 u_model;
    uniform mat4 u_view;
    uniform mat4 u_projection;
    uniform vec4 u_color;

    attribute vec3 position;
    attribute vec2 texcoord;
    attribute vec3 normal;
    attribute vec4 color;

    varying vec3 v_position;
    varying vec3 v_normal;
    varying vec4 v_color;

    void main()
    {
        v_normal = normal;
        v_position = position;
        v_color = color * u_color;
        gl_Position = u_projection * u_view * u_model * vec4(position,1.0);
    }
    """

    fragment = """
    uniform mat4 u_model;
    uniform mat4 u_view;
    uniform mat4 u_normal;

    uniform vec3 u_light_intensity;
    uniform vec3 u_light_position;

    varying vec3 v_position;
    varying vec3 v_normal;
    varying vec4 v_color;

    void main()
    {
        // Calculate normal in world coordinates
        vec3 normal = normalize(u_normal * vec4(v_normal,1.0)).xyz;

        // Calculate the location of this fragment (pixel) in world coordinates
        vec3 position = vec3(u_view*u_model * vec4(v_position, 1));

        // Calculate the vector from this pixels surface to the light source
        vec3 surfaceToLight = u_light_position - position;

        // Calculate the cosine of the angle of incidence (brightness)
        float brightness = dot(normal, surfaceToLight) /
                          (length(surfaceToLight) * length(normal));
        brightness = max(min(brightness,1.0),0.0);

        // Calculate final color of the pixel, based on:
        // 1. The angle of incidence: brightness
        // 2. The color/intensities of the light: light.intensities
        // 3. The texture and texture coord: texture(tex, fragTexCoord)

        gl_FragColor = v_color * brightness * vec4(u_light_intensity, 1);
    }
    """


    class Canvas(app.Canvas):
        def __init__(self):
            app.Canvas.__init__(self, size=(512, 512), title='Lighted cube',
                                keys='interactive')
            self.timer = app.Timer('auto', self.on_timer)

            # Build cube data
            V, F, outline = create_cube()
            vertices = VertexBuffer(V)
            self.faces = IndexBuffer(F)
            self.outline = IndexBuffer(outline)

            # Build view, model, projection & normal
            # --------------------------------------
            self.view = translate((0, 0, -5))
            model = np.eye(4, dtype=np.float32)
            normal = np.array(np.matrix(np.dot(self.view, model)).I.T)

            # Build program
            # --------------------------------------
            self.program = Program(vertex, fragment)
            self.program.bind(vertices)
            self.program["u_light_position"] = 2, 2, 2
            self.program["u_light_intensity"] = 1, 1, 1
            self.program["u_model"] = model
            self.program["u_view"] = self.view
            self.program["u_normal"] = normal
            self.phi, self.theta = 0, 0

            self.activate_zoom()

            # OpenGL initialization
            # --------------------------------------
            gloo.set_state(clear_color=(0.30, 0.30, 0.35, 1.00), depth_test=True,
                           polygon_offset=(1, 1),
                           blend_func=('src_alpha', 'one_minus_src_alpha'),
                           line_width=0.75)
            self.timer.start()

            self.show()

        def on_draw(self, event):
            gloo.clear(color=True, depth=True)
            # program.draw(gl.GL_TRIANGLES, indices)

            # Filled cube
            gloo.set_state(blend=False, depth_test=True, polygon_offset_fill=True)
            self.program['u_color'] = 1, 1, 1, 1
            self.program.draw('triangles', self.faces)

            # Outlined cube
            gloo.set_state(polygon_offset_fill=False, blend=True, depth_mask=False)
            self.program['u_color'] = 0, 0, 0, 1
            self.program.draw('lines', self.outline)
            gloo.set_state(depth_mask=True)

        def on_resize(self, event):
            self.activate_zoom()

        def activate_zoom(self):
            gloo.set_viewport(0, 0, *self.physical_size)
            projection = perspective(45.0, self.size[0] / float(self.size[1]),
                                     2.0, 10.0)
            self.program['u_projection'] = projection

        def on_timer(self, event):
            self.theta += .5
            self.phi += .5
            model = np.dot(rotate(self.theta, (0, 0, 1)),
                           rotate(self.phi, (0, 1, 0)))
            normal = np.linalg.inv(np.dot(self.view, model)).T
            self.program['u_model'] = model
            self.program['u_normal'] = normal
            self.update()

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


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

   **Total running time of the script:** (0 minutes 0.246 seconds)


.. _sphx_glr_download_gallery_gloo_lighted_cube.py:

.. only:: html

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

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

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

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

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


.. only:: html

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

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