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added Vector::refract()

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git-svn-id: svn://anubis/fart/trunk@372 7f9b0f55-74a9-4bce-be96-3c2cd072584d
This commit is contained in:
Josh Holtrop 2010-10-11 15:26:41 +00:00
parent 1eee61002e
commit ed58d2ec7a
1 changed files with 17 additions and 0 deletions
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17
util/Vector.h
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@ -63,6 +63,23 @@ class Vector
return (*this) - target * (2 * dot(target));
}
/*
* from http://www.flipcode.com/archives/
* Reflections_and_Refraction_in_Raytracing.shtml
* target: normal vector of surface
* n1: refraction index of object we're coming from
* n2: refraction index of object we're going into
*/
Vector refract(const Vector & target, double n1, double n2) const
{
const double n = n1 / n2;
const double cosI = dot(target);
const double sinT2 = n * n * (1.0 - cosI * cosI);
if (sinT2 > 1.0)
return Vector(0.0, 0.0, 0.0);
return (*this) * n - target * (n + sqrt(1.0 - sinT2));
}
Vector getPerpendicular() const
{
Vector t = *this;