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# -*- coding: utf-8 -*-
# vispy: gallery 2000
# -----------------------------------------------------------------------------
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
# -----------------------------------------------------------------------------
# Author: Nicolas P .Rougier
# Date: 06/03/2014
# Abstract: GPU computing using the framebuffer
# Keywords: framebuffer, GPU computing, reaction-diffusion
# -----------------------------------------------------------------------------
from __future__ import division
import numpy as np
from vispy.gloo import (Program, FrameBuffer, RenderBuffer, set_viewport,
clear, set_state)
from vispy import app
render_vertex = """
attribute vec2 position;
attribute vec2 texcoord;
varying vec2 v_texcoord;
void main()
{
gl_Position = vec4(position, 0.0, 1.0);
v_texcoord = texcoord;
}
"""
render_fragment = """
uniform int pingpong;
uniform sampler2D texture;
varying vec2 v_texcoord;
void main()
{
float v;
if( pingpong == 0 )
v = texture2D(texture, v_texcoord).r;
else
v = texture2D(texture, v_texcoord).b;
gl_FragColor = vec4(1.0-v, 1.0-v, 1.0-v, 1.0);
}
"""
compute_vertex = """
attribute vec2 position;
attribute vec2 texcoord;
varying vec2 v_texcoord;
void main()
{
gl_Position = vec4(position, 0.0, 1.0);
v_texcoord = texcoord;
}
"""
compute_fragment = """
uniform int pingpong;
uniform sampler2D texture; // U,V:= r,g, other channels ignored
uniform sampler2D params; // rU,rV,f,k := r,g,b,a
uniform float dx; // horizontal distance between texels
uniform float dy; // vertical distance between texels
uniform float dd; // unit of distance
uniform float dt; // unit of time
varying vec2 v_texcoord;
void main(void)
{
float center = -(4.0+4.0/sqrt(2.0)); // -1 * other weights
float diag = 1.0/sqrt(2.0); // weight for diagonals
vec2 p = v_texcoord; // center coordinates
vec2 c,l;
if( pingpong == 0 ) {
c = texture2D(texture, p).rg; // central value
// Compute Laplacian
l = ( texture2D(texture, p + vec2(-dx,-dy)).rg
+ texture2D(texture, p + vec2( dx,-dy)).rg
+ texture2D(texture, p + vec2(-dx, dy)).rg
+ texture2D(texture, p + vec2( dx, dy)).rg) * diag
+ texture2D(texture, p + vec2(-dx, 0.0)).rg
+ texture2D(texture, p + vec2( dx, 0.0)).rg
+ texture2D(texture, p + vec2(0.0,-dy)).rg
+ texture2D(texture, p + vec2(0.0, dy)).rg
+ c * center;
} else {
c = texture2D(texture, p).ba; // central value
// Compute Laplacian
l = ( texture2D(texture, p + vec2(-dx,-dy)).ba
+ texture2D(texture, p + vec2( dx,-dy)).ba
+ texture2D(texture, p + vec2(-dx, dy)).ba
+ texture2D(texture, p + vec2( dx, dy)).ba) * diag
+ texture2D(texture, p + vec2(-dx, 0.0)).ba
+ texture2D(texture, p + vec2( dx, 0.0)).ba
+ texture2D(texture, p + vec2(0.0,-dy)).ba
+ texture2D(texture, p + vec2(0.0, dy)).ba
+ c * center;
}
float u = c.r; // compute some temporary
float v = c.g; // values which might save
float lu = l.r; // a few GPU cycles
float lv = l.g;
float uvv = u * v * v;
vec4 q = texture2D(params, p).rgba;
float ru = q.r; // rate of diffusion of U
float rv = q.g; // rate of diffusion of V
float f = q.b; // some coupling parameter
float k = q.a; // another coupling parameter
float du = ru * lu / dd - uvv + f * (1.0 - u); // Gray-Scott equation
float dv = rv * lv / dd + uvv - (f + k) * v; // diffusion+-reaction
u += du * dt;
v += dv * dt;
if( pingpong == 1 ) {
gl_FragColor = vec4(clamp(u, 0.0, 1.0), clamp(v, 0.0, 1.0), c);
} else {
gl_FragColor = vec4(c, clamp(u, 0.0, 1.0), clamp(v, 0.0, 1.0));
}
}
"""
class Canvas(app.Canvas):
def __init__(self):
app.Canvas.__init__(self, title='Grayscott Reaction-Diffusion',
size=(512, 512), keys='interactive')
self.scale = 4
self.comp_size = self.size
comp_w, comp_h = self.comp_size
dt = 1.0
dd = 1.5
species = {
# name : [r_u, r_v, f, k]
'Bacteria 1': [0.16, 0.08, 0.035, 0.065],
'Bacteria 2': [0.14, 0.06, 0.035, 0.065],
'Coral': [0.16, 0.08, 0.060, 0.062],
'Fingerprint': [0.19, 0.05, 0.060, 0.062],
'Spirals': [0.10, 0.10, 0.018, 0.050],
'Spirals Dense': [0.12, 0.08, 0.020, 0.050],
'Spirals Fast': [0.10, 0.16, 0.020, 0.050],
'Unstable': [0.16, 0.08, 0.020, 0.055],
'Worms 1': [0.16, 0.08, 0.050, 0.065],
'Worms 2': [0.16, 0.08, 0.054, 0.063],
'Zebrafish': [0.16, 0.08, 0.035, 0.060]
}
P = np.zeros((comp_h, comp_w, 4), dtype=np.float32)
P[:, :] = species['Unstable']
UV = np.zeros((comp_h, comp_w, 4), dtype=np.float32)
UV[:, :, 0] = 1.0
r = 32
UV[comp_h // 2 - r:comp_h // 2 + r,
comp_w // 2 - r:comp_w // 2 + r, 0] = 0.50
UV[comp_h // 2 - r:comp_h // 2 + r,
comp_w // 2 - r:comp_w // 2 + r, 1] = 0.25
UV += np.random.uniform(0.0, 0.01, (comp_h, comp_w, 4))
UV[:, :, 2] = UV[:, :, 0]
UV[:, :, 3] = UV[:, :, 1]
self.pingpong = 1
self.compute = Program(compute_vertex, compute_fragment, 4)
self.compute["params"] = P
self.compute["texture"] = UV
self.compute["position"] = [(-1, -1), (-1, +1), (+1, -1), (+1, +1)]
self.compute["texcoord"] = [(0, 0), (0, 1), (1, 0), (1, 1)]
self.compute['dt'] = dt
self.compute['dx'] = 1.0 / comp_w
self.compute['dy'] = 1.0 / comp_h
self.compute['dd'] = dd
self.compute['pingpong'] = self.pingpong
self.render = Program(render_vertex, render_fragment, 4)
self.render["position"] = [(-1, -1), (-1, +1), (+1, -1), (+1, +1)]
self.render["texcoord"] = [(0, 0), (0, 1), (1, 0), (1, 1)]
self.render["texture"] = self.compute["texture"]
self.render['pingpong'] = self.pingpong
self.fbo = FrameBuffer(self.compute["texture"],
RenderBuffer(self.comp_size))
set_state(depth_test=False, clear_color='black')
self._timer = app.Timer('auto', connect=self.update, start=True)
self.show()
def on_draw(self, event):
with self.fbo:
set_viewport(0, 0, *self.comp_size)
self.compute["texture"].interpolation = 'nearest'
self.compute.draw('triangle_strip')
clear(color=True)
set_viewport(0, 0, *self.physical_size)
self.render["texture"].interpolation = 'linear'
self.render.draw('triangle_strip')
self.pingpong = 1 - self.pingpong
self.compute["pingpong"] = self.pingpong
self.render["pingpong"] = self.pingpong
def on_resize(self, event):
set_viewport(0, 0, *self.physical_size)
if __name__ == '__main__':
canvas = Canvas()
app.run()
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