Show a rotating cube with an outline

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

fragment = """
varying vec4 v_color;
void main()
{
    gl_FragColor = v_color;
}
"""


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

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

        # Build program
        # --------------------------------------
        self.program = Program(vertex, fragment)
        self.program.bind(vertices)

        # Build view, model, projection & normal
        # --------------------------------------
        view = translate((0, 0, -5))
        model = np.eye(4, dtype=np.float32)

        self.program['u_model'] = model
        self.program['u_view'] = view
        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), line_width=0.75,
                       blend_func=('src_alpha', 'one_minus_src_alpha'))
        self.timer.start()

        self.show()

    def on_draw(self, event):
        gloo.clear(color=True, depth=True)

        # 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(blend=True, depth_mask=False, polygon_offset_fill=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
        self.program['u_model'] = np.dot(rotate(self.theta, (0, 0, 1)),
                                         rotate(self.phi, (0, 1, 0)))
        self.update()

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