Building igl statically and moving to the dep scripts

Fixing dep build script on Windows and removing some warnings.

Use bundled igl by default.

Not building with the dependency scripts if not explicitly stated. This way, it will stay in
Fix the libigl patch to include C source files in header only mode.

src/libigl/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