pointcloud-Pan.py


from vispy import app, gloo, visuals, scene, io


vertex_shader = """
varying vec4 color;
void main() {
    vec4 visual_pos = vec4($position, 1);
    vec4 doc_pos = $visual_to_doc(visual_pos);
    gl_Position = $doc_to_render(doc_pos);

    vec4 visual_pos2 = $doc_to_visual(doc_pos + vec4(0, 0, -1, 0));
    vec4 view_direction = (visual_pos2 / visual_pos2.w) - visual_pos;
    view_direction = vec4(normalize(view_direction.xyz), 0);

    color = vec4(view_direction.rgb, 1);
}
"""

fragment_shader = """
varying vec4 color;
void main() {
    gl_FragColor = color;
}
"""


class MyMeshVisual(visuals.Visual):
    """
    """

    def __init__(self):
        visuals.Visual.__init__(self)

        # Create an interesting mesh shape for demonstration.
        fname = io.load_data_file('orig/triceratops.obj.gz')
        vertices, faces, normals, tex = io.read_mesh(fname)

        self._ibo = gloo.IndexBuffer(faces)

        self.program = visuals.shaders.ModularProgram(vertex_shader,
                                                      fragment_shader)
        self.program.vert['position'] = gloo.VertexBuffer(vertices)
        #self.program.vert['normal'] = gloo.VertexBuffer(normals)

    def draw(self, transforms):
        # Note we use the "additive" GL blending settings so that we do not
        # have to sort the mesh triangles back-to-front before each draw.
        gloo.set_state('additive', cull_face=False)

        self.program.vert['visual_to_doc'] = transforms.visual_to_document
        imap = transforms.visual_to_document.inverse
        self.program.vert['doc_to_visual'] = imap
        self.program.vert['doc_to_render'] = (
            transforms.framebuffer_to_render *
            transforms.document_to_framebuffer)

        # Finally, draw the triangles.
        self.program.draw('triangles', self._ibo)


# Auto-generate a Visual+Node class for use in the scenegraph.
MyMesh = scene.visuals.create_visual_node(MyMeshVisual)


# Finally we will test the visual by displaying in a scene.

canvas = scene.SceneCanvas(keys='interactive', show=True)

# Add a ViewBox to let the user zoom/rotate
view = canvas.central_widget.add_view()
view.camera = 'turntable'
view.camera.fov = 50
view.camera.distance = 2

mesh = MyMesh(parent=view.scene)
mesh.transform = visuals.transforms.AffineTransform()
#mesh.transform.translate([-25, -25, -25])
mesh.transform.rotate(90, (1, 0, 0))

axis = scene.visuals.XYZAxis(parent=view.scene)

# ..and optionally start the event loop
if __name__ == '__main__':
    import sys
    if sys.flags.interactive != 1:
        app.run()