RayBoxIntersection.h

#pragma once
 
#include "Math/LinePlaneIntersection.h"
#include "Math/RayTriangleIntersection.h"
 
#include "Foundation/Geometry/Frustum.hpp"
 
#include <glm/vec3.hpp>
 
namespace Cogs
{
  namespace Geometry
  {
    inline bool intersect(const Cogs::Geometry::BoundingBox & box, const glm::vec3 & origin, const glm::vec3 & direction, glm::vec3 & intersection,
      const bool /*usefullviewvolume*/)
    {
      glm::vec3 bounds[2] = {
        box.min,
        box.max
      };
 
      glm::vec3 pointOnRay, ptonbox;
      double sqrmindist = DBL_MAX;
 
      for (int j = 0; j < 2; j++) {
        for (int i = 0; i < 3; i++) {
          glm::vec3 norm(0, 0, 0);
 
          norm[i] = 1.0f;
 
          glm::vec3 hitPoint;
 
          Plane plane;
          plane.normal = norm;
          plane.distance = bounds[j][i];
 
          if (intersect(plane.normal, plane.distance, origin, direction, hitPoint)) {
            int i1 = (i + 1) % 3;
            int i2 = (i + 2) % 3;
 
            double x, y;
 
            double d = distanceToQuad(
              bounds[0][i1], bounds[0][i2],
              bounds[1][i1], bounds[1][i2],
              hitPoint[i1], hitPoint[i2],
              x, y);
 
            if (d <= 0.0f) {
              // Center of ray hit box directly
              intersection = hitPoint;
 
              return true;
            } else if (d < sqrmindist) {
              sqrmindist = d;
              pointOnRay = ptonbox = hitPoint;
 
              ptonbox[i1] = static_cast<float>(x);
              ptonbox[i2] = static_cast<float>(y);
            }
          }
        }
      }
 
      return false;
    }
  }
}