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# -*- coding: utf-8 -*-
# -----------------------------------------------------------------------------
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
# -----------------------------------------------------------------------------
from __future__ import division
import numpy as np
from vispy import app
from vispy.gloo import VertexBuffer
from vispy.visuals import Visual
from vispy.visuals.transforms import STTransform
class MarkerVisual(Visual):
# My full vertex shader, with just a `transform` hook.
VERTEX_SHADER = """
#version 120
attribute vec2 a_position;
attribute vec3 a_color;
attribute float a_size;
varying vec4 v_fg_color;
varying vec4 v_bg_color;
varying float v_radius;
varying float v_linewidth;
varying float v_antialias;
void main (void) {
v_radius = a_size;
v_linewidth = 1.0;
v_antialias = 1.0;
v_fg_color = vec4(0.0,0.0,0.0,0.5);
v_bg_color = vec4(a_color, 1.0);
gl_Position = $transform(vec4(a_position,0,1));
gl_PointSize = 2.0*(v_radius + v_linewidth + 1.5*v_antialias);
}
"""
FRAGMENT_SHADER = """
#version 120
varying vec4 v_fg_color;
varying vec4 v_bg_color;
varying float v_radius;
varying float v_linewidth;
varying float v_antialias;
void main()
{
float size = 2.0*(v_radius + v_linewidth + 1.5*v_antialias);
float t = v_linewidth/2.0-v_antialias;
float r = length((gl_PointCoord.xy - vec2(0.5,0.5))*size);
float d = abs(r - v_radius) - t;
if( d < 0.0 )
gl_FragColor = v_fg_color;
else
{
float alpha = d/v_antialias;
alpha = exp(-alpha*alpha);
if (r > v_radius)
gl_FragColor = vec4(v_fg_color.rgb, alpha*v_fg_color.a);
else
gl_FragColor = mix(v_bg_color, v_fg_color, alpha);
}
}
"""
def __init__(self, pos=None, color=None, size=None):
Visual.__init__(self, self.VERTEX_SHADER, self.FRAGMENT_SHADER)
self._pos = pos
self._color = color
self._size = size
self.set_gl_state(blend=True,
blend_func=('src_alpha', 'one_minus_src_alpha'))
self._draw_mode = 'points'
def _prepare_transforms(self, view=None):
view.view_program.vert['transform'] = view.transforms.get_transform()
def _prepare_draw(self, view):
# attributes / uniforms are not available until program is built
self.shared_program['a_position'] = VertexBuffer(self._pos)
self.shared_program['a_color'] = VertexBuffer(self._color)
self.shared_program['a_size'] = VertexBuffer(self._size)
class Canvas(app.Canvas):
def __init__(self):
app.Canvas.__init__(self, keys='interactive')
ps = self.pixel_scale
n = 10000
pos = 0.25 * np.random.randn(n, 2).astype(np.float32)
color = np.random.uniform(0, 1, (n, 3)).astype(np.float32)
size = np.random.uniform(2*ps, 12*ps, (n, 1)).astype(np.float32)
self.points = MarkerVisual(pos=pos, color=color, size=size)
w, h = self.size
self.points.transform = STTransform(scale=(w / 2., h / 2.),
translate=(w / 2., h / 2.))
def on_mouse_move(self, event):
if event.is_dragging:
dxy = event.pos - event.last_event.pos
button = event.press_event.button
if button == 1:
self.points.transform.move(dxy)
elif button == 2:
center = event.press_event.pos
self.points.transform.zoom(np.exp(dxy * (0.01, -0.01)), center)
self.update()
def on_resize(self, event):
vp = (0, 0, self.physical_size[0], self.physical_size[1])
self.context.set_viewport(*vp)
self.points.transforms.configure(canvas=self, viewport=vp)
def on_draw(self, event):
self.context.clear('white')
self.points.draw()
if __name__ == '__main__':
c = Canvas()
c.show()
app.run()
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