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# -*- coding: utf-8 -*-
# vispy: gallery 30
# vispy: testskip - because this example sets inactive attributes on Travis
"""
Demo of jump flooding algoritm for EDT using GLSL
Author: Stefan Gustavson (stefan.gustavson@gmail.com)
2010-08-24. This code is in the public domain.
Adapted to `vispy` by Eric Larson <larson.eric.d@gmail.com>.
This version is a vispy-ized translation of jfa_translate.py.
"""
import numpy as np
from os import path as op
import sys
from vispy import app
from vispy.gloo import (Program, FrameBuffer, VertexBuffer, Texture2D,
set_viewport)
from vispy.io import load_data_file, imread
this_dir = op.abspath(op.dirname(__file__))
class Canvas(app.Canvas):
def __init__(self):
self.use_shaders = True
app.Canvas.__init__(self, size=(512, 512), keys='interactive')
# Note: read as bytes, then decode; py2.6 compat
with open(op.join(this_dir, 'vertex_vispy.glsl'), 'rb') as fid:
vert = fid.read().decode('ASCII')
with open(op.join(this_dir, 'fragment_seed.glsl'), 'rb') as f:
frag_seed = f.read().decode('ASCII')
with open(op.join(this_dir, 'fragment_flood.glsl'), 'rb') as f:
frag_flood = f.read().decode('ASCII')
with open(op.join(this_dir, 'fragment_display.glsl'), 'rb') as f:
frag_display = f.read().decode('ASCII')
self.programs = [Program(vert, frag_seed),
Program(vert, frag_flood),
Program(vert, frag_display)]
# Initialize variables
# using two FBs slightly faster than switching on one
self.fbo_to = [FrameBuffer(), FrameBuffer()]
self._setup_textures('shape1.tga')
vtype = np.dtype([('position', 'f4', 2), ('texcoord', 'f4', 2)])
vertices = np.zeros(4, dtype=vtype)
vertices['position'] = [[-1., -1.], [-1., 1.], [1., -1.], [1., 1.]]
vertices['texcoord'] = [[0., 0.], [0., 1.], [1., 0.], [1., 1.]]
vertices = VertexBuffer(vertices)
for program in self.programs:
program.bind(vertices)
self._timer = app.Timer('auto', self.update, start=True)
self.show()
def _setup_textures(self, fname):
data = imread(load_data_file('jfa/' + fname), format='tga')[::-1].copy()
if data.ndim == 3:
data = data[:, :, 0] # Travis gets 2, I get three?
self.texture_size = data.shape[:2]
self.orig_tex = Texture2D(data, format='luminance', wrapping='repeat',
interpolation='nearest')
self.comp_texs = []
data = np.zeros(self.texture_size + (4,), np.float32)
for _ in range(2):
tex = Texture2D(data, format='rgba', wrapping='clamp_to_edge',
interpolation='nearest')
self.comp_texs.append(tex)
self.fbo_to[0].color_buffer = self.comp_texs[0]
self.fbo_to[1].color_buffer = self.comp_texs[1]
for program in self.programs[1:2]:
program['texw'], program['texh'] = self.texture_size
def on_draw(self, event):
if self.use_shaders:
last_rend = 0
self.fbo_to[last_rend].activate()
set_viewport(0, 0, *self.texture_size)
self.programs[0]['texture'] = self.orig_tex
self.programs[0].draw('triangle_strip')
self.fbo_to[last_rend].deactivate()
stepsize = (np.array(self.texture_size) // 2).max()
while stepsize > 0:
self.programs[1]['step'] = stepsize
self.programs[1]['texture'] = self.comp_texs[last_rend]
last_rend = 1 if last_rend == 0 else 0
self.fbo_to[last_rend].activate()
set_viewport(0, 0, *self.texture_size)
self.programs[1].draw('triangle_strip')
self.fbo_to[last_rend].deactivate()
stepsize //= 2
self.programs[2]['texture'] = self.comp_texs[last_rend]
else:
self.programs[2]['texture'] = self.orig_tex
set_viewport(0, 0, *self.physical_size)
self.programs[2].draw('triangle_strip')
def on_key_press(self, event):
if event.key is not None and event.key.name in '1234':
fname = "shape%s.tga" % event.key.name
self._setup_textures(fname)
elif event.key == 'F1':
self.use_shaders = True
elif event.key == 'F2':
self.use_shaders = False
def fun(x):
c.title = 'FPS: %0.1f' % x
if __name__ == '__main__':
c = Canvas()
c.measure_fps(callback=fun)
if sys.flags.interactive != 1:
c.app.run()
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