19 lines
582 B
Forth
19 lines
582 B
Forth
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uniform int thickness = 2;
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uniform vec4 border_color = vec4(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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FRAGCOLOR = mix(texel, border_color, outline * border_color.a);
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}
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