Merge newboolean branch into master.

This is for design task T67744, Boolean Redesign.
It adds a choice of solver to the Boolean modifier and the
Intersect (Boolean) and Intersect (Knife) tools.
The 'Fast' choice is the current Bmesh boolean.
The new 'Exact' choice is a more advanced algorithm that supports
overlapping geometry and uses more robust calculations, but is
slower than the Fast choice.
The default with this commit is set to 'Exact'. We can decide before
the 2.91 release whether or not this is the right choice, but this
choice now will get us more testing and feedback on the new code.

1 files changed, 143 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_double2.hh b/source/blender/blenlib/BLI_double2.hh
new file mode 100644
index 00000000000..3466b946e73
--- /dev/null
+++ b/source/blender/blenlib/BLI_double2.hh
@@ -0,0 +1,143 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+/** \file
+ * \ingroup bli
+ */
+
+#include "BLI_double3.hh"
+
+namespace blender {
+
+struct double2 {
+  double x, y;
+
+  double2() = default;
+
+  double2(const double *ptr) : x{ptr[0]}, y{ptr[1]}
+  {
+  }
+
+  double2(double x, double y) : x(x), y(y)
+  {
+  }
+
+  double2(const double3 &other) : x(other.x), y(other.y)
+  {
+  }
+
+  operator double *()
+  {
+    return &x;
+  }
+
+  operator const double *() const
+  {
+    return &x;
+  }
+
+  float length() const
+  {
+    return len_v2_db(*this);
+  }
+
+  friend double2 operator+(const double2 &a, const double2 &b)
+  {
+    return {a.x + b.x, a.y + b.y};
+  }
+
+  friend double2 operator-(const double2 &a, const double2 &b)
+  {
+    return {a.x - b.x, a.y - b.y};
+  }
+
+  friend double2 operator*(const double2 &a, double b)
+  {
+    return {a.x * b, a.y * b};
+  }
+
+  friend double2 operator/(const double2 &a, double b)
+  {
+    BLI_assert(b != 0.0);
+    return {a.x / b, a.y / b};
+  }
+
+  friend double2 operator*(double a, const double2 &b)
+  {
+    return b * a;
+  }
+
+  friend bool operator==(const double2 &a, const double2 &b)
+  {
+    return a.x == b.x && a.y == b.y;
+  }
+
+  friend bool operator!=(const double2 &a, const double2 &b)
+  {
+    return a.x != b.x || a.y != b.y;
+  }
+
+  friend std::ostream &operator<<(std::ostream &stream, const double2 &v)
+  {
+    stream << "(" << v.x << ", " << v.y << ")";
+    return stream;
+  }
+
+  static double dot(const double2 &a, const double2 &b)
+  {
+    return a.x * b.x + a.y * b.y;
+  }
+
+  static double2 interpolate(const double2 &a, const double2 &b, double t)
+  {
+    return a * (1 - t) + b * t;
+  }
+
+  static double2 abs(const double2 &a)
+  {
+    return double2(fabs(a.x), fabs(a.y));
+  }
+
+  static double distance(const double2 &a, const double2 &b)
+  {
+    return (a - b).length();
+  }
+
+  static double distance_squared(const double2 &a, const double2 &b)
+  {
+    return double2::dot(a, b);
+  }
+
+  struct isect_result {
+    enum {
+      LINE_LINE_COLINEAR = -1,
+      LINE_LINE_NONE = 0,
+      LINE_LINE_EXACT = 1,
+      LINE_LINE_CROSS = 2,
+    } kind;
+    double lambda;
+    double mu;
+  };
+
+  static isect_result isect_seg_seg(const double2 &v1,
+                                    const double2 &v2,
+                                    const double2 &v3,
+                                    const double2 &v4);
+};
+
+}  // namespace blender