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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# vispy: gallery 2
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
"""
3D brain mesh viewer.
"""
from timeit import default_timer
import numpy as np
from vispy import gloo
from vispy import app
from vispy.util.transforms import perspective, translate, rotate
from vispy.io import load_data_file
brain = np.load(load_data_file('brain/brain.npz', force_download='2014-09-04'))
data = brain['vertex_buffer']
faces = brain['index_buffer']
VERT_SHADER = """
#version 120
uniform mat4 u_model;
uniform mat4 u_view;
uniform mat4 u_projection;
uniform vec4 u_color;
attribute vec3 a_position;
attribute vec3 a_normal;
attribute vec4 a_color;
varying vec3 v_position;
varying vec3 v_normal;
varying vec4 v_color;
void main()
{
v_normal = a_normal;
v_position = a_position;
v_color = a_color * u_color;
gl_Position = u_projection * u_view * u_model * vec4(a_position,1.0);
}
"""
FRAG_SHADER = """
#version 120
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)
// Specular lighting.
vec3 surfaceToCamera = vec3(0.0, 0.0, 1.0) - position;
vec3 K = normalize(normalize(surfaceToLight) + normalize(surfaceToCamera));
float specular = clamp(pow(abs(dot(normal, K)), 40.), 0.0, 1.0);
gl_FragColor = v_color * brightness * vec4(u_light_intensity, 1);
}
"""
class Canvas(app.Canvas):
def __init__(self):
app.Canvas.__init__(self, keys='interactive')
self.size = 800, 600
self.program = gloo.Program(VERT_SHADER, FRAG_SHADER)
self.theta, self.phi = -80, 180
self.translate = 3
self.faces = gloo.IndexBuffer(faces)
self.program.bind(gloo.VertexBuffer(data))
self.program['u_color'] = 1, 1, 1, 1
self.program['u_light_position'] = (1., 1., 1.)
self.program['u_light_intensity'] = (1., 1., 1.)
self.apply_zoom()
gloo.set_state(blend=False, depth_test=True, polygon_offset_fill=True)
self._t0 = default_timer()
self._timer = app.Timer('auto', connect=self.on_timer, start=True)
self.update_matrices()
def update_matrices(self):
self.view = translate((0, 0, -self.translate))
self.model = np.dot(rotate(self.theta, (1, 0, 0)),
rotate(self.phi, (0, 1, 0)))
self.projection = np.eye(4, dtype=np.float32)
self.program['u_model'] = self.model
self.program['u_view'] = self.view
self.program['u_normal'] = np.linalg.inv(np.dot(self.view,
self.model)).T
def on_timer(self, event):
elapsed = default_timer() - self._t0
self.phi = 180 + elapsed * 50.
self.update_matrices()
self.update()
def on_resize(self, event):
self.apply_zoom()
def on_mouse_wheel(self, event):
self.translate += -event.delta[1]/5.
self.translate = max(2, self.translate)
self.update_matrices()
self.update()
def on_draw(self, event):
gloo.clear()
self.program.draw('triangles', indices=self.faces)
def apply_zoom(self):
gloo.set_viewport(0, 0, self.physical_size[0], self.physical_size[1])
self.projection = perspective(45.0, self.size[0] /
float(self.size[1]), 1.0, 20.0)
self.program['u_projection'] = self.projection
if __name__ == '__main__':
c = Canvas()
c.show()
app.run()
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