forked from cgvr/DeltaVR
57 lines
2.2 KiB
HLSL
57 lines
2.2 KiB
HLSL
// The MIT License
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// Copyright © 2016 Inigo Quilez
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// Permission is hereby granted, free of charge, to any person obtaining a copy of this software
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// and associated documentation files (the "Software"), to deal in the Software without restriction,
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// including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
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//subject to the following conditions: The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS",
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// WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
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// OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
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// CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
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// OR OTHER DEALINGS IN THE SOFTWARE.
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//
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// From https://www.shadertoy.com/view/Xt3SzX
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// Compute a ray capsule intersection
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float capIntersect( float3 ro, float3 rd, float3 pa, float3 pb, float r )
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{
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float3 ba = pb - pa;
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float3 oa = ro - pa;
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float baba = dot(ba,ba);
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float bard = dot(ba,rd);
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float baoa = dot(ba,oa);
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float rdoa = dot(rd,oa);
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float oaoa = dot(oa,oa);
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float a = baba - bard*bard;
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float b = baba*rdoa - baoa*bard;
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float c = baba*oaoa - baoa*baoa - r*r*baba;
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float h = b*b - a*c;
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if( h>=0.0 )
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{
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float t = (-b-sqrt(h))/a;
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float y = baoa + t*bard;
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// body
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if( y>0.0 && y<baba ) return t;
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// caps
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float3 oc = (y<=0.0) ? oa : ro - pb;
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b = dot(rd,oc);
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c = dot(oc,oc) - r*r;
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h = b*b - c;
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if( h>0.0 ) return -b - sqrt(h);
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}
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return -1.0;
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}
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// Compute capsule normal given a position
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float3 capNormal( float3 pos, float3 a, float3 b, float r )
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{
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float3 ba = b - a;
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float3 pa = pos - a;
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float h = clamp(dot(pa,ba)/dot(ba,ba),0.0,1.0);
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return (pa - h*ba)/r;
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}
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