ProjectArcade

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#ifdef GL_ES
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precision mediump float;
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precision mediump int;
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#endif
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attribute vec4 a_position;
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attribute vec2 a_texcoord0;
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uniform vec2 u_texelDelta;
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varying vec4 v_texcoord0;
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varying vec4 v_texcoord1;
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varying vec4 v_texcoord2;
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varying vec4 v_texcoord3;
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varying vec4 v_texcoord4;
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varying vec4 v_texcoord5;
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varying vec4 v_texcoord6;
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float scaleoffset = 0.8; //edge detection offset
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void main()
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{
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  float x = u_texelDelta.x*scaleoffset;
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  float y = u_texelDelta.y*scaleoffset;
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  vec2 dg1 = vec2( x,y);
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  vec2 dg2 = vec2(-x,y);
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  vec2 dx  = vec2(x,0.0);
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  vec2 dy  = vec2(0.0,y);
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  gl_Position = a_position;
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  v_texcoord0=a_texcoord0.xyxy;
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  v_texcoord1.xy = v_texcoord0.xy - dy;
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  v_texcoord2.xy = v_texcoord0.xy + dy;
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  v_texcoord3.xy = v_texcoord0.xy - dx;
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  v_texcoord4.xy = v_texcoord0.xy + dx;
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  v_texcoord5.xy = v_texcoord0.xy - dg1;
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  v_texcoord6.xy = v_texcoord0.xy + dg1;
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  v_texcoord1.zw = v_texcoord0.xy - dg2;
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  v_texcoord2.zw = v_texcoord0.xy + dg2;
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}
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