25 lines
700 B
Forth
25 lines
700 B
Forth
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/// tip:"Ensure colorbuffer is alpha clear before calling this one."
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uniform int thickness; /// set:2
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uniform vec4 border_color; /// set:1,1,0,1
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void main() {
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vec4 texel = texture(iChannel0, uv);
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float outline = 0.0;
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if( texel.a == 0.0 ) {
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for( int x = -thickness; x <= thickness; x++ ) {
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for( int y = -thickness;y <= thickness; y++ ) {
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float sample = texture(iChannel0, uv+vec2(float(x)/iWidth, float(y)/iHeight)).a;
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if( sample > 0.0 ) {
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outline = 1.0;
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}
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}
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}
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}
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if( outline == 0.0 )
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discard;
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FRAGCOLOR = vec4(border_color.rgb, outline * border_color.a);
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}
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