32 lines
933 B
HLSL
32 lines
933 B
HLSL
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#ifndef NORMALCOMPRESSION_INCLUDE
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#define NORMALCOMPRESSION_INCLUDE
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float2 octWrap( float2 v )
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{
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return ( 1.0 - abs( v.yx ) ) * ( v.xy >= 0.0 ? 1.0 : -1.0 );
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}
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// use octahedral encoding to reduce to 2 coords, then pack them as two 16 bit values in a 32 bit float.
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float encode( float3 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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uint nx = (uint)(n.x * 0xffff);
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uint ny = (uint)(n.y * 0xffff);
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return asfloat((nx << 16) | (ny & 0xffff));
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}
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// unpack 32 bit float into two 16 bit ones, then use octahedral decoding.
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float3 decode( float k )
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{
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uint d = asuint(k);
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float2 f = float2((d >> 16) / 65535.0, (d & 0xffff) / 65535.0) * 2.0 - 1.0;
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float3 n = float3( f.x, f.y, 1.0 - abs( f.x ) - abs( f.y ) );
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float t = saturate( -n.z );
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n.xy += n.xy >= 0.0 ? -t : t;
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return normalize( n );
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}
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#endif
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