gistfile1.txt

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.effectwidget import EffectWidget, EffectBase

Builder.load_string('''
<Root>:
    Widget:
        canvas:
            Color:
                rgba: 1, 1, 1, 1
            Rectangle:
                pos: self.pos
                size: self.size
''')

effect_broken = '''
vec3 hsv2rgb(vec3 c)
{
    vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
    vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
    return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}

float rand(vec2 co){
  return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
}

vec4 effect( vec4 color, sampler2D buf0, vec2 texCoords, vec2 coords )
{
    float number = rand(texCoords + vec2(time, 0.));
    return vec4(hsv2rgb( vec3(number, 1.0, 1.0)), 1.0);
}
'''


class BrokenEffect(EffectBase):
    def __init__(self):
        super(BrokenEffect, self).__init__()
        self.glsl = effect_broken


class Root(EffectWidget):
    def __init__(self):
        super(Root, self).__init__()
        self.effects = [BrokenEffect()]



class BrokenApp(App):
    def build(self):
        return Root()


BrokenApp().run()