Merged branch 'dev_native' into lm_sla_supports_auto

Added igl library files

src/igl/line_segment_in_rectangle.cpp

@@ -0,0 +1,103 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+// 
+// Copyright (C) 2013 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 "line_segment_in_rectangle.h"
+
+IGL_INLINE bool igl::line_segment_in_rectangle(
+  const Eigen::Vector2d & s,
+  const Eigen::Vector2d & d,
+  const Eigen::Vector2d & A,
+  const Eigen::Vector2d & B)
+{
+  using namespace std;
+  using namespace Eigen;
+  // http://stackoverflow.com/a/100165/148668
+  const auto SegmentIntersectRectangle = [](double a_rectangleMinX,
+                                 double a_rectangleMinY,
+                                 double a_rectangleMaxX,
+                                 double a_rectangleMaxY,
+                                 double a_p1x,
+                                 double a_p1y,
+                                 double a_p2x,
+                                 double a_p2y)->bool
+  {
+    // Find min and max X for the segment
+
+    double minX = a_p1x;
+    double maxX = a_p2x;
+
+    if(a_p1x > a_p2x)
+    {
+      minX = a_p2x;
+      maxX = a_p1x;
+    }
+
+    // Find the intersection of the segment's and rectangle's x-projections
+
+    if(maxX > a_rectangleMaxX)
+    {
+      maxX = a_rectangleMaxX;
+    }
+
+    if(minX < a_rectangleMinX)
+    {
+      minX = a_rectangleMinX;
+    }
+
+    if(minX > maxX) // If their projections do not intersect return false
+    {
+      return false;
+    }
+
+    // Find corresponding min and max Y for min and max X we found before
+
+    double minY = a_p1y;
+    double maxY = a_p2y;
+
+    double dx = a_p2x - a_p1x;
+
+    if(fabs(dx) > 0.0000001)
+    {
+      double a = (a_p2y - a_p1y) / dx;
+      double b = a_p1y - a * a_p1x;
+      minY = a * minX + b;
+      maxY = a * maxX + b;
+    }
+
+    if(minY > maxY)
+    {
+      double tmp = maxY;
+      maxY = minY;
+      minY = tmp;
+    }
+
+    // Find the intersection of the segment's and rectangle's y-projections
+
+    if(maxY > a_rectangleMaxY)
+    {
+      maxY = a_rectangleMaxY;
+    }
+
+    if(minY < a_rectangleMinY)
+    {
+      minY = a_rectangleMinY;
+    }
+
+    if(minY > maxY) // If Y-projections do not intersect return false
+    {
+      return false;
+    }
+
+    return true;
+  };
+  const double minX = std::min(A(0),B(0));
+  const double minY = std::min(A(1),B(1));
+  const double maxX = std::max(A(0),B(0));
+  const double maxY = std::max(A(1),B(1));
+  bool ret = SegmentIntersectRectangle(minX,minY,maxX,maxY,s(0),s(1),d(0),d(1));
+  return ret;
+}