45 lines
1.2 KiB
GLSL
45 lines
1.2 KiB
GLSL
#ifndef UTILS_GLSL_INCLUDED
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#define UTILS_GLSL_INCLUDED
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float signP(float v) { return v >= 0.f ? 1.f : -1.f; }
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vec2 signP(vec2 v) { return vec2(signP(v.x), signP(v.y)); }
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// https://knarkowicz.wordpress.com/2014/04/16/octahedron-normal-vector-encoding/
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// https://www.shadertoy.com/view/Mtfyzl
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vec2 OctWrap( vec2 v )
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{
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return ( 1.0 - abs( v.yx ) ) * signP(v.xy);
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}
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vec2 normalEncode( vec3 n )
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{
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n /= ( abs( n.x ) + abs( n.y ) + abs( n.z ) );
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n.xy = n.z >= 0.0 ? n.xy : OctWrap( n.xy );
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n.xy = n.xy * 0.5 + 0.5;
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return n.xy;
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}
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vec3 normalDecode( vec2 f )
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{
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f = f * 2.0 - 1.0;
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// https://twitter.com/Stubbesaurus/status/937994790553227264
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vec3 n = vec3( f, 1.0 - abs( f.x ) - abs( f.y ) );
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const float t = max( -n.z, 0.f );
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n.xy -= t * signP(n.xy);
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return normalize( n );
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}
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vec2 baryMix(vec2 v1, vec2 v2, vec2 v3, vec2 bary) {
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return v1 * (1. - bary.x - bary.y) + v2 * bary.x + v3 * bary.y;
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}
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vec3 baryMix(vec3 v1, vec3 v2, vec3 v3, vec2 bary) {
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return v1 * (1. - bary.x - bary.y) + v2 * bary.x + v3 * bary.y;
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}
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vec4 baryMix(vec4 v1, vec4 v2, vec4 v3, vec2 bary) {
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return v1 * (1. - bary.x - bary.y) + v2 * bary.x + v3 * bary.y;
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}
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#endif // UTILS_GLSL_INCLUDED
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