kivy/examples/shader/plasma.py

'''
Plasma Shader
=============

This shader example have been taken from http://www.iquilezles.org/apps/shadertoy/
with some adapation.

This might become a Kivy widget when experimentation will be done.
'''

print 'SETUP KIVY >>'
from kivy.logger import Logger
import logging
Logger.setLevel(logging.TRACE)

from kivy.config import Config
Config.remove_option('input', 'default')
Config.remove_option('input', 'mactouch')
Config.set('graphics', 'fullscreen', 'auto')
print 'SETUP KIVY << done'


from kivy.clock import Clock
from kivy.app import App
from kivy.uix.floatlayout import FloatLayout
from kivy.core.window import Window
#Window.clearcolor = None
from kivy.graphics import RenderContext
from kivy.properties import StringProperty

# This header must be not changed, it contain the minimum information from Kivy.
header = '''
#ifdef GL_ES
precision highp float;
#endif

/* Outputs from the vertex shader */
varying vec4 frag_color;
varying vec2 tex_coord0;

/* uniform texture samplers */
uniform sampler2D texture0;
'''

# Plasma shader
plasma_shader = header + '''
uniform vec2 resolution;
uniform float time;

void main(void)
{
//   float x = gl_FragCoord.x;
//   float y = gl_FragCoord.y;
//   float mov0 = x+y+cos(sin(time)*2.)*100.+sin(x/100.)*1000.;
//   float mov1 = y / resolution.y / 0.2 + time;
//   float mov2 = x / resolution.x / 0.2;
//   float c1 = abs(sin(mov1+time)/2.+mov2/2.-mov1-mov2+time);
//   float c2 = abs(sin(c1+sin(mov0/1000.+time)+sin(y/40.+time)+sin((x+y)/100.)*3.));
//   float c3 = abs(sin(c2+cos(mov1+mov2+c2)+cos(mov2)+sin(x/1000.)));
//   gl_FragColor = vec4( c1,c2,c3,1.0);
   gl_FragColor = vec4(1.0, 1.0, 0., 1.0);
}
'''

class ShaderWidget(FloatLayout):

    # property to set the source code for fragment shader
    fs = StringProperty(None)

    def __init__(self, **kwargs):
        # Instead of using Canvas, we will use a RenderContext,
        # and change the default shader used.
        self.canvas = RenderContext()

        # call the constructor of parent
        # if they are any graphics object, they will be added on our new canvas
        super(ShaderWidget, self).__init__(**kwargs)

        # We'll update our glsl variables in a clock
        Clock.schedule_interval(self.update_glsl, 1.)

    def on_fs(self, instance, value):
        # set the fragment shader to our source code
        shader = self.canvas.shader
        old_value = shader.fs
        shader.fs = value
        if not shader.success:
            shader.fs = old_value
            raise Exception('failed')

    def update_glsl(self, *largs):
        self.canvas['time'] = Clock.get_boottime()
        self.canvas['resolution'] = map(float, self.size)
        # This is needed for the default vertex shader.
        self.canvas['projection_mat'] = Window.render_context['projection_mat']
        # print self.canvas['projection_mat']


class PlasmaApp(App):
    def build(self):
        return ShaderWidget(fs=plasma_shader)

if __name__ == '__main__':
    PlasmaApp().run()