intersect.h
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上传日期:2022-07-26
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- // intersect.h
- //
- // Copyright (C) 2002, Chris Laurel <claurel@shatters.net>
- //
- // Intersection calculation for various geometric objects.
- //
- // This program is free software; you can redistribute it and/or
- // modify it under the terms of the GNU General Public License
- // as published by the Free Software Foundation; either version 2
- // of the License, or (at your option) any later version.
- #ifndef _CELMATH_INTERSECT_H_
- #define _CELMATH_INTERSECT_H_
- #include "ray.h"
- #include "sphere.h"
- #include "ellipsoid.h"
- template<class T> bool testIntersection(const Ray3<T>& ray,
- const Sphere<T>& sphere,
- T& distance)
- {
- Vector3<T> diff = ray.origin - sphere.center;
- T s = (T) 1.0 / square(sphere.radius);
- T a = ray.direction * ray.direction * s;
- T b = ray.direction * diff * s;
- T c = diff * diff * s - (T) 1.0;
- T disc = b * b - a * c;
- if (disc < 0.0)
- return false;
- disc = (T) sqrt(disc);
- T sol0 = (-b + disc) / a;
- T sol1 = (-b - disc) / a;
- if (sol0 > 0)
- {
- if (sol0 < sol1 || sol1 < 0)
- distance = sol0;
- else
- distance = sol1;
- return true;
- }
- else if (sol1 > 0)
- {
- distance = sol1;
- return true;
- }
- else
- {
- return false;
- }
- }
- template<class T> bool testIntersection(const Ray3<T>& ray,
- const Sphere<T>& sphere,
- T& distanceToTester,
- T& cosAngleToCenter)
- {
- if (testIntersection(ray, sphere, distanceToTester))
- {
- cosAngleToCenter = (sphere.center - ray.origin)*ray.direction/(sphere.center - ray.origin).length();
- return true;
- }
- return false;
- }
- template<class T> bool testIntersection(const Ray3<T>& ray,
- const Ellipsoid<T>& e,
- T& distance)
- {
- Vector3<T> diff = ray.origin - e.center;
- Vector3<T> s((T) 1.0 / square(e.axes.x),
- (T) 1.0 / square(e.axes.y),
- (T) 1.0 / square(e.axes.z));
- Vector3<T> sdir(ray.direction.x * s.x,
- ray.direction.y * s.y,
- ray.direction.z * s.z);
- Vector3<T> sdiff(diff.x * s.x, diff.y * s.y, diff.z * s.z);
- T a = ray.direction * sdir;
- T b = ray.direction * sdiff;
- T c = diff * sdiff - (T) 1.0;
- T disc = b * b - a * c;
- if (disc < 0.0)
- return false;
- disc = (T) sqrt(disc);
- T sol0 = (-b + disc) / a;
- T sol1 = (-b - disc) / a;
- if (sol0 > 0)
- {
- if (sol0 < sol1 || sol1 < 0)
- distance = sol0;
- else
- distance = sol1;
- return true;
- }
- else if (sol1 > 0)
- {
- distance = sol1;
- return true;
- }
- else
- {
- return false;
- }
- }
- template<class T> bool testIntersection(const Ray3<T>& ray,
- const Ellipsoid<T>& ellipsoid,
- T& distanceToTester,
- T& cosAngleToCenter)
- {
- if (testIntersection(ray, ellipsoid, distanceToTester))
- {
- cosAngleToCenter = (ellipsoid.center - ray.origin)*ray.direction/(ellipsoid.center - ray.origin).length();
- return true;
- }
- return false;
- }
- #endif // _CELMATH_INTERSECT_H_