23 lines
724 B
GLSL
23 lines
724 B
GLSL
/*
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contributors: Mathias Bredholt
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description: |
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make some triangular tiles. XY provide coords inside of the tile. ZW provides tile coords
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use: <vec4> triTile(<vec2> st [, <float> scale])
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examples:
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- https://raw.githubusercontent.com/patriciogonzalezvivo/lygia_examples/main/draw_tiles.frag
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*/
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#ifndef FNC_TRITILE
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#define FNC_TRITILE
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vec4 triTile(vec2 st) {
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st *= mat2(1., -1. / 1.7320508, 0., 2. / 1.7320508);
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vec4 f = vec4(st, -st);
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vec4 i = floor(f);
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f = fract(f);
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return dot(f.xy, f.xy) < dot(f.zw, f.zw)
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? vec4(f.xy, vec2(2., 1.) * i.xy)
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: vec4(f.zw, -(vec2(2., 1.) * i.zw + 1.));
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}
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vec4 triTile(vec2 st, float scale) { return triTile(st * scale); }
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#endif
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