mirror of https://github.com/kivy/kivy.git
103 lines
2.5 KiB
Python
103 lines
2.5 KiB
Python
'''
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Rotated Shader
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=============
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This shader example is a modified version of plasma.py that shows how to
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rotate areas of fragment shaders bounded by vertex_instructions.
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'''
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from kivy.app import App
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from kivy.clock import Clock
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from kivy.factory import Factory
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from kivy.graphics import RenderContext
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from kivy.properties import StringProperty
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from kivy.uix.widget import Widget
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# imported early for side effects needed for Shader
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import kivy.core.window
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shared_code = '''
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$HEADER$
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uniform float time;
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vec4 tex(void)
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{
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return frag_color * texture2D(texture0, tex_coord0);
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}
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float plasmaFunc(float n1, float n2, float n3, float n4)
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{
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vec4 fPos = frag_modelview_mat * gl_FragCoord;
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return abs(sin(
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sin(sin(fPos.x / n1) + time) +
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sin(fPos.y / n2 + time) +
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n4 * sin((fPos.x + fPos.y) / n3)));
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}
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'''
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plasma_shader = shared_code + '''
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void main(void)
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{
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float green = plasmaFunc(40., 30., 100., 3.5);
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gl_FragColor = vec4(1.0, green, 1.0, 1.0) * tex();
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}
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'''
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plasma_shader2 = shared_code + '''
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void main(void)
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{
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float red = plasmaFunc(30., 20., 10., .5);
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gl_FragColor = vec4(red, 1.0, 1.0, 1.0) * tex();
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}
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'''
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class ShaderWidget(Widget):
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# property to set the source code for fragment shader
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fs = StringProperty(None)
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def __init__(self, **kwargs):
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# Instead of using Canvas, we will use a RenderContext,
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# and change the default fragment shader used.
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self.canvas = RenderContext(use_parent_projection=True,
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use_parent_modelview=True,
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use_parent_frag_modelview=True)
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# call the constructor of parent
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# if they are any graphics object, they will be added on our new canvas
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super(ShaderWidget, self).__init__(**kwargs)
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# We'll update our glsl variables in a clock
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Clock.schedule_interval(self.update_glsl, 1 / 60.)
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def update_glsl(self, *largs):
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self.canvas['time'] = Clock.get_boottime()
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def on_fs(self, instance, value):
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# set the fragment shader to our source code
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shader = self.canvas.shader
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old_value = shader.fs
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shader.fs = value
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if not shader.success:
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shader.fs = old_value
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raise Exception('failed')
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class RotatedApp(App):
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def build(self):
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main_widget = Factory.MainWidget()
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main_widget.fs = plasma_shader
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main_widget.mini.fs = plasma_shader2
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return main_widget
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if __name__ == '__main__':
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RotatedApp().run()
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