al_Ray.hpp

#ifndef INCLUDE_AL_RAY_HPP
#define INCLUDE_AL_RAY_HPP
 
/*  Allocore --
  Multimedia / virtual environment application class library
 
  Copyright (C) 2009. AlloSphere Research Group, Media Arts & Technology, UCSB.
  Copyright (C) 2012. The Regents of the University of California.
  All rights reserved.
 
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
 
    Redistributions of source code must retain the above copyright notice,
    this list of conditions and the following disclaimer.
 
    Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
 
    Neither the name of the University of California nor the names of its
    contributors may be used to endorse or promote products derived from
    this software without specific prior written permission.
 
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.
 
 
  File description:
  This is a simple Ray class with some intersection tests
 
  File author(s):
  Tim Wood, 2014, fishuyo@gmail.com
*/
 
#include "al/math/al_Vec.hpp"
 
namespace al {
 
template <class T>
class Ray;
typedef Ray<float> Rayf;
typedef Ray<double> Rayd;
 
template <class T>
class Ray {
 public:
  Vec<3, T> o, d;  // origin and direction of ray
 
  Ray(){};
  Ray(Vec<3, T> origin, Vec<3, T> direction) { set(origin, direction); }
 
  void set(Vec<3, T> origin, Vec<3, T> direction) {
    o.set(origin);
    d.set(direction.normalized());
  }
 
  // return point on ray
  Vec<3, T> operator()(T t) { return o + d * t; }
 
  Vec<3, T>& origin() { return o; }
  Vec<3, T>& direction() { return d; }
 
  T intersectPlane(Vec<3, T> p0, Vec<3, T> n) {
    T den = n.dot(d);
    if (den == 0) return -1;
    return n.dot(p0 - o) / den;
  }
 
  T intersectCircle(Vec<3, T> p0, Vec<3, T> n, T rmax, T rmin = 0.0) {
    T den = n.dot(d);
    if (den == 0) return -1;
    T t = n.dot(p0 - o) / den;
    T r = ((*this)(t)-p0).mag();
    if (r <= rmax && r >= rmin)
      return t;
    else
      return -1;
  }
 
  // intersect sphere
  T intersectSphere(Vec<3, T> cen, T radius) {
    Vec<3, T> o_c = o - cen;
    T A = d.dot(d);
    T B = 2. * (d.dot(o_c));
    T C = (o_c.dot(o_c)) - radius * radius;
    T det = B * B - 4 * A * C;
 
    if (det > 0.) {
      T t1 = (-B - sqrt(det)) / (2. * A);
      if (t1 > 0.) return t1;
      T t2 = (-B + sqrt(det)) / (2. * A);
      if (t2 > 0.) return t2;
 
    } else if (det == 0.) {
      T t = -B / (2. * A);
      if (t > 0.) return t;
    }
    return -1.;  // will be ignoring negative intersections -1 qualifies a miss
  }
 
  bool intersectsSphere(Vec<3, T> cen, T radius) {
    return intersectSphere(cen, radius) > 0.;
  }
 
  T intersectBox(Vec<3, T> cen, Vec<3, T> scl) {
    // courtesy of http://www.cs.utah.edu/~awilliam/box/
    float tmin, tmax, tymin, tymax, tzmin, tzmax;
 
    Vec<3, T> parameters[2];
    Vec<3, T> min = cen - scl / 2;
    Vec<3, T> max = cen + scl / 2;
    parameters[0] = min;
    parameters[1] = max;
 
    Vec<3, T> inv_direction = 1.0 / d;
    int sign[3];
    sign[0] = (inv_direction.x < 0);
    sign[1] = (inv_direction.y < 0);
    sign[2] = (inv_direction.z < 0);
 
    tmin = (parameters[sign[0]].x - o.x) * inv_direction.x;
    tmax = (parameters[1 - sign[0]].x - o.x) * inv_direction.x;
    tymin = (parameters[sign[1]].y - o.y) * inv_direction.y;
    tymax = (parameters[1 - sign[1]].y - o.y) * inv_direction.y;
    if ((tmin > tymax) || (tymin > tmax)) return -1.0;
    if (tymin > tmin) tmin = tymin;
    if (tymax < tmax) tmax = tymax;
    tzmin = (parameters[sign[2]].z - o.z) * inv_direction.z;
    tzmax = (parameters[1 - sign[2]].z - o.z) * inv_direction.z;
    if ((tmin > tzmax) || (tzmin > tmax)) return -1.0;
    if (tzmin > tmin) tmin = tzmin;
    if (tzmax < tmax) tmax = tzmax;
 
    if (tmin < 0.0)
      if (tmax < 0.0)
        return -1.0;
      else
        return tmax;
    else
      return tmin;
  }
 
  bool intersectsBox(Vec<3, T> cen, Vec<3, T> scl) {
    return intersectBox(cen, scl) > 0.0;
  }
 
  // intersect cylinder positioned at origin oriented with Z axis
  T intersectCylinderXY(T radius) {
    T A = d.x * d.x + d.y * d.y;
    T B = 2. * (d.x * o.x + d.y * o.y);
    T C = (o.x * o.x + o.y * o.y) - radius * radius;
    T det = B * B - 4 * A * C;
 
    if (det > 0.) {
      T t1 = (-B - sqrt(det)) / (2. * A);
      if (t1 > 0.) return t1;
      T t2 = (-B + sqrt(det)) / (2. * A);
      if (t2 > 0.) return t2;
 
    } else if (det == 0.) {
      T t = -B / (2. * A);
      if (t > 0.) return t;
    }
    return -1.;  // will be ignoring negative intersections so this is ok for
                 // now
  }
 
  // intersect cylinder positioned at origin oriented with Y axis
  T intersectCylinderXZ(T radius) {
    T A = d.x * d.x + d.z * d.z;
    T B = 2. * (d.x * o.x + d.z * o.z);
    T C = (o.x * o.x + o.z * o.z) - radius * radius;
    T det = B * B - 4 * A * C;
 
    if (det > 0.) {
      T t1 = (-B - sqrt(det)) / (2. * A);
      if (t1 > 0.) return t1;
      T t2 = (-B + sqrt(det)) / (2. * A);
      if (t2 > 0.) return t2;
 
    } else if (det == 0.) {
      T t = -B / (2. * A);
      if (t > 0.) return t;
    }
    return -1.;  // will be ignoring negative intersections so this is ok for
                 // now
  }
 
  // intersect with the capsule shape of the AlloSphere
  // assumes the ray is originating near the center of the sphere
  // check this..
  T intersectAllosphere() {
    T radius = 4.842f;
    T bridgeWidth2 = 2.09f / 2.;
 
    // intersect with bridge cylinder
    T t = intersectCylinderXY(radius);
 
    // if no intersection intersect with appropriate hemisphere
    if (t == -1.) {
      if (d.z < 0.)
        return intersectSphere(Vec<3, T>(0, 0, -bridgeWidth2), radius);
      else
        return intersectSphere(Vec<3, T>(0, 0, bridgeWidth2), radius);
    }
 
    Vec<3, T> p = (*this)(t);
    if (p.z < -bridgeWidth2) {
      return intersectSphere(Vec<3, T>(0, 0, -bridgeWidth2), radius);
    } else if (p.z > bridgeWidth2) {
      return intersectSphere(Vec<3, T>(0, 0, bridgeWidth2), radius);
    } else
      return t;
  }
};
 
}  // namespace al
 
#endif