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