22 lines
685 B
HLSL
22 lines
685 B
HLSL
/*
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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: <float4> triTile(<float2> st [, <float> scale])
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*/
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#ifndef FNC_TRITILE
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#define FNC_TRITILE
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float4 triTile(float2 st) {
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st = mult(float2x2( 1.0, -1.0 / 1.7320508,
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0.0, 2.0 / 1.7320508), st);
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float4 f = float4(st, -st);
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float4 i = floor(f);
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f = frac(f);
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return dot(f.xy, f.xy) < dot(f.zw, f.zw)
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? float4(f.xy, float2(2., 1.) * i.xy)
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: float4(f.zw, -(float2(2., 1.) * i.zw + 1.));
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}
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float4 triTile(float2 st, float scale) { return triTile(st * scale); }
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#endif
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