diff --git a/examples/shader/plasma.kv b/examples/shader/plasma.kv new file mode 100644 index 000000000..f5a58a36a --- /dev/null +++ b/examples/shader/plasma.kv @@ -0,0 +1,9 @@ +#:kivy 1.0 + +: + canvas: + Color: + rgb: 1, 0, 0 + Rectangle: + pos: self.pos + size: self.size diff --git a/examples/shader/plasma.py b/examples/shader/plasma.py new file mode 100644 index 000000000..8a4bf203f --- /dev/null +++ b/examples/shader/plasma.py @@ -0,0 +1,90 @@ +''' +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. +''' + + +from kivy.clock import Clock +from kivy.app import App +from kivy.uix.floatlayout import FloatLayout +from kivy.core.window import Window +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); +} +''' + +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 / 60.) + + 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'] + + +class PlasmaApp(App): + def build(self): + return ShaderWidget(fs=plasma_shader) + +if __name__ == '__main__': + PlasmaApp().run()