Merged branch 'dev_native' into lm_sla_supports_auto

Added igl library files

src/igl/ray_box_intersect.cpp

@@ -0,0 +1,149 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+// 
+// Copyright (C) 2016 Alec Jacobson <alecjacobson@gmail.com>
+// 
+// This Source Code Form is subject to the terms of the Mozilla Public License 
+// v. 2.0. If a copy of the MPL was not distributed with this file, You can 
+// obtain one at http://mozilla.org/MPL/2.0/.
+#include "ray_box_intersect.h"
+#include <vector>
+
+template <
+  typename Derivedsource,
+  typename Deriveddir,
+  typename Scalar>
+IGL_INLINE bool igl::ray_box_intersect(
+  const Eigen::MatrixBase<Derivedsource> & origin,
+  const Eigen::MatrixBase<Deriveddir> & dir,
+  const Eigen::AlignedBox<Scalar,3> & box,
+  const Scalar & t0,
+  const Scalar & t1,
+  Scalar & tmin,
+  Scalar & tmax)
+{
+#ifdef false
+  // https://github.com/RMonica/basic_next_best_view/blob/master/src/RayTracer.cpp
+  const auto & intersectRayBox = [](
+    const Eigen::Vector3f& rayo,
+    const Eigen::Vector3f& rayd,
+    const Eigen::Vector3f& bmin,
+    const Eigen::Vector3f& bmax, 
+    float & tnear,
+    float & tfar
+    )->bool
+  {
+    Eigen::Vector3f bnear;
+    Eigen::Vector3f bfar;
+    // Checks for intersection testing on each direction coordinate
+    // Computes 
+    float t1, t2;
+    tnear = -1e+6f, tfar = 1e+6f; //, tCube;
+    bool intersectFlag = true;
+    for (int i = 0; i < 3; ++i) {
+  //    std::cout << "coordinate " << i << ": bmin " << bmin(i) << ", bmax " << bmax(i) << std::endl; 
+      assert(bmin(i) <= bmax(i));
+      if (::fabs(rayd(i)) < 1e-6) {   // Ray parallel to axis i-th
+        if (rayo(i) < bmin(i) || rayo(i) > bmax(i)) {
+          intersectFlag = false;
+        }
+      }
+      else {
+        // Finds the nearest and the farthest vertices of the box from the ray origin
+        if (::fabs(bmin(i) - rayo(i)) < ::fabs(bmax(i) - rayo(i))) {
+          bnear(i) = bmin(i);
+          bfar(i) = bmax(i);
+        }
+        else {
+          bnear(i) = bmax(i);
+          bfar(i) = bmin(i);
+        }
+  //      std::cout << "  bnear " << bnear(i) << ", bfar " << bfar(i) << std::endl;
+        // Finds the distance parameters t1 and t2 of the two ray-box intersections:
+        // t1 must be the closest to the ray origin rayo. 
+        t1 = (bnear(i) - rayo(i)) / rayd(i);
+        t2 = (bfar(i) - rayo(i)) / rayd(i);
+        if (t1 > t2) {
+          std::swap(t1,t2);
+        } 
+        // The two intersection values are used to saturate tnear and tfar
+        if (t1 > tnear) {
+          tnear = t1;
+        }
+        if (t2 < tfar) {
+          tfar = t2;
+        }
+  //      std::cout << "  t1 " << t1 << ", t2 " << t2 << ", tnear " << tnear << ", tfar " << tfar 
+  //        << "  tnear > tfar? " << (tnear > tfar) << ", tfar < 0? " << (tfar < 0) << std::endl;
+        if(tnear > tfar) {
+          intersectFlag = false;
+        }
+        if(tfar < 0) {
+        intersectFlag = false;
+        }
+      }
+    }
+    // Checks whether intersection occurs or not
+    return intersectFlag;
+  };
+  float tmin_f, tmax_f;
+  bool ret = intersectRayBox(
+      origin.   template cast<float>(),
+      dir.      template cast<float>(),
+      box.min().template cast<float>(),
+      box.max().template cast<float>(),
+      tmin_f,
+      tmax_f);
+  tmin = tmin_f;
+  tmax = tmax_f;
+  return ret;
+#else
+  using namespace Eigen;
+  // This should be precomputed and provided as input
+  typedef Matrix<Scalar,1,3>  RowVector3S;
+  const RowVector3S inv_dir( 1./dir(0),1./dir(1),1./dir(2));
+  const std::vector<bool> sign = { inv_dir(0)<0, inv_dir(1)<0, inv_dir(2)<0};
+  // http://people.csail.mit.edu/amy/papers/box-jgt.pdf
+  // "An Efficient and Robust Ray–Box Intersection Algorithm"
+  Scalar tymin, tymax, tzmin, tzmax;
+  std::vector<RowVector3S> bounds = {box.min(),box.max()};
+  tmin = ( bounds[sign[0]](0)   - origin(0)) * inv_dir(0);
+  tmax = ( bounds[1-sign[0]](0) - origin(0)) * inv_dir(0);
+  tymin = (bounds[sign[1]](1)   - origin(1)) * inv_dir(1);
+  tymax = (bounds[1-sign[1]](1) - origin(1)) * inv_dir(1);
+  if ( (tmin > tymax) || (tymin > tmax) )
+  {
+    return false;
+  }
+  if (tymin > tmin)
+  {
+    tmin = tymin;
+  }
+  if (tymax < tmax)
+  {
+    tmax = tymax;
+  }
+  tzmin = (bounds[sign[2]](2) - origin(2))   * inv_dir(2);
+  tzmax = (bounds[1-sign[2]](2) - origin(2)) * inv_dir(2);
+  if ( (tmin > tzmax) || (tzmin > tmax) )
+  {
+    return false;
+  }
+  if (tzmin > tmin)
+  {
+    tmin = tzmin;
+  }
+  if (tzmax < tmax)
+  {
+    tmax = tzmax;
+  }
+  if(!( (tmin < t1) && (tmax > t0) ))
+  {
+    return false;
+  }
+  return true;
+#endif
+}
+
+#ifdef IGL_STATIC_LIBRARY
+template bool igl::ray_box_intersect<Eigen::Matrix<double, 1, 3, 1, 1, 3>, Eigen::Matrix<double, 1, 3, 1, 1, 3>, double>(Eigen::MatrixBase<Eigen::Matrix<double, 1, 3, 1, 1, 3> > const&, Eigen::MatrixBase<Eigen::Matrix<double, 1, 3, 1, 1, 3> > const&, Eigen::AlignedBox<double, 3> const&, double const&, double const&, double&, double&);
+#endif