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Remove optimization for b =~ sqrt(b^2 - 4ac)

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Eryn Wells 2013-09-08 18:46:51 -07:00
parent 6e3f92e47c
commit 11dc22fb8c
1 changed files with 3 additions and 17 deletions
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20
src/object.c
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@ -190,24 +190,10 @@ sphere_does_intersect(Object *obj, Ray ray, float **t)
return 0; return 0;
} }
/*
* Compute most of the quadratic equation as q. Doing this first helps avoid precision errors when
* b =~ sqrt(b^2 - 4ac).
*
* See: http://wiki.cgsociety.org/index.php/Ray_Sphere_Intersection
*/
float q;
float sqrt_discrim = sqrtf(discrim);
if (b < 0) {
q = (-b - sqrt_discrim) / 2.0;
}
else {
q = (-b + sqrt_discrim) / 2.0;
}
// Compute the intersections, the roots of the quadratic equation. Spheres have at most two intersections. // Compute the intersections, the roots of the quadratic equation. Spheres have at most two intersections.
float t0 = q / a; float sqrt_discrim = sqrtf(discrim);
float t1 = c / q; float t0 = (-b - sqrt_discrim) / (2.0 * a);
float t1 = (-b + sqrt_discrim) / (2.0 * a);
// If t[1] is less than t[0], swap them (t[0] will always be the first intersection). // If t[1] is less than t[0], swap them (t[0] will always be the first intersection).
if (t1 < t0) { if (t1 < t0) {