axmol/external/poly2tri/common/shapes.cc

/*
 * Poly2Tri Copyright (c) 2009-2018, Poly2Tri Contributors
 * https://github.com/jhasse/poly2tri
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * * Neither the name of Poly2Tri nor the names of its contributors may be
 *   used to endorse or promote products derived from this software without specific
 *   prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "shapes.h"

#include <cassert>
#include <iostream>

namespace p2t {

std::ostream& operator<<(std::ostream& out, const Point& point) {
  return out << point.x << "," << point.y;
}

Triangle::Triangle(Point& a, Point& b, Point& c)
{
  points_[0] = &a; points_[1] = &b; points_[2] = &c;
  neighbors_[0] = nullptr; neighbors_[1] = nullptr; neighbors_[2] = nullptr;
  constrained_edge[0] = constrained_edge[1] = constrained_edge[2] = false;
  delaunay_edge[0] = delaunay_edge[1] = delaunay_edge[2] = false;
  interior_ = false;
}

// Update neighbor pointers
void Triangle::MarkNeighbor(Point* p1, Point* p2, Triangle* t)
{
  if ((p1 == points_[2] && p2 == points_[1]) || (p1 == points_[1] && p2 == points_[2]))
    neighbors_[0] = t;
  else if ((p1 == points_[0] && p2 == points_[2]) || (p1 == points_[2] && p2 == points_[0]))
    neighbors_[1] = t;
  else if ((p1 == points_[0] && p2 == points_[1]) || (p1 == points_[1] && p2 == points_[0]))
    neighbors_[2] = t;
  else
    assert(0);
}

// Exhaustive search to update neighbor pointers
void Triangle::MarkNeighbor(Triangle& t)
{
  if (t.Contains(points_[1], points_[2])) {
    neighbors_[0] = &t;
    t.MarkNeighbor(points_[1], points_[2], this);
  } else if (t.Contains(points_[0], points_[2])) {
    neighbors_[1] = &t;
    t.MarkNeighbor(points_[0], points_[2], this);
  } else if (t.Contains(points_[0], points_[1])) {
    neighbors_[2] = &t;
    t.MarkNeighbor(points_[0], points_[1], this);
  }
}

/**
 * Clears all references to all other triangles and points
 */
void Triangle::Clear()
{
    Triangle *t;
    for( int i=0; i<3; i++ )
    {
        t = neighbors_[i];
        if( t != nullptr )
        {
            t->ClearNeighbor( this );
        }
    }
    ClearNeighbors();
    points_[0]=points_[1]=points_[2] = nullptr;
}

void Triangle::ClearNeighbor(const Triangle *triangle )
{
    if( neighbors_[0] == triangle )
    {
        neighbors_[0] = nullptr;
    }
    else if( neighbors_[1] == triangle )
    {
        neighbors_[1] = nullptr;
    }
    else
    {
        neighbors_[2] = nullptr;
    }
}

void Triangle::ClearNeighbors()
{
  neighbors_[0] = nullptr;
  neighbors_[1] = nullptr;
  neighbors_[2] = nullptr;
}

void Triangle::ClearDelunayEdges()
{
  delaunay_edge[0] = delaunay_edge[1] = delaunay_edge[2] = false;
}

Point* Triangle::OppositePoint(Triangle& t, const Point& p)
{
  Point *cw = t.PointCW(p);
  return PointCW(*cw);
}

// Legalized triangle by rotating clockwise around point(0)
void Triangle::Legalize(Point& point)
{
  points_[1] = points_[0];
  points_[0] = points_[2];
  points_[2] = &point;
}

// Legalize triagnle by rotating clockwise around oPoint
void Triangle::Legalize(Point& opoint, Point& npoint)
{
  if (&opoint == points_[0]) {
    points_[1] = points_[0];
    points_[0] = points_[2];
    points_[2] = &npoint;
  } else if (&opoint == points_[1]) {
    points_[2] = points_[1];
    points_[1] = points_[0];
    points_[0] = &npoint;
  } else if (&opoint == points_[2]) {
    points_[0] = points_[2];
    points_[2] = points_[1];
    points_[1] = &npoint;
  } else {
    assert(0);
  }
}

int Triangle::Index(const Point* p)
{
  if (p == points_[0]) {
    return 0;
  } else if (p == points_[1]) {
    return 1;
  } else if (p == points_[2]) {
    return 2;
  }
  assert(0);
  return -1;
}

int Triangle::EdgeIndex(const Point* p1, const Point* p2)
{
  if (points_[0] == p1) {
    if (points_[1] == p2) {
      return 2;
    } else if (points_[2] == p2) {
      return 1;
    }
  } else if (points_[1] == p1) {
    if (points_[2] == p2) {
      return 0;
    } else if (points_[0] == p2) {
      return 2;
    }
  } else if (points_[2] == p1) {
    if (points_[0] == p2) {
      return 1;
    } else if (points_[1] == p2) {
      return 0;
    }
  }
  return -1;
}

void Triangle::MarkConstrainedEdge(int index)
{
  constrained_edge[index] = true;
}

void Triangle::MarkConstrainedEdge(Edge& edge)
{
  MarkConstrainedEdge(edge.p, edge.q);
}

// Mark edge as constrained
void Triangle::MarkConstrainedEdge(Point* p, Point* q)
{
  if ((q == points_[0] && p == points_[1]) || (q == points_[1] && p == points_[0])) {
    constrained_edge[2] = true;
  } else if ((q == points_[0] && p == points_[2]) || (q == points_[2] && p == points_[0])) {
    constrained_edge[1] = true;
  } else if ((q == points_[1] && p == points_[2]) || (q == points_[2] && p == points_[1])) {
    constrained_edge[0] = true;
  }
}

// The point counter-clockwise to given point
Point* Triangle::PointCW(const Point& point)
{
  if (&point == points_[0]) {
    return points_[2];
  } else if (&point == points_[1]) {
    return points_[0];
  } else if (&point == points_[2]) {
    return points_[1];
  }
  assert(0);
  return nullptr;
}

// The point counter-clockwise to given point
Point* Triangle::PointCCW(const Point& point)
{
  if (&point == points_[0]) {
    return points_[1];
  } else if (&point == points_[1]) {
    return points_[2];
  } else if (&point == points_[2]) {
    return points_[0];
  }
  assert(0);
  return nullptr;
}

// The neighbor clockwise to given point
Triangle* Triangle::NeighborCW(const Point& point)
{
  if (&point == points_[0]) {
    return neighbors_[1];
  } else if (&point == points_[1]) {
    return neighbors_[2];
  }
  return neighbors_[0];
}

// The neighbor counter-clockwise to given point
Triangle* Triangle::NeighborCCW(const Point& point)
{
  if (&point == points_[0]) {
    return neighbors_[2];
  } else if (&point == points_[1]) {
    return neighbors_[0];
  }
  return neighbors_[1];
}

bool Triangle::GetConstrainedEdgeCCW(const Point& p)
{
  if (&p == points_[0]) {
    return constrained_edge[2];
  } else if (&p == points_[1]) {
    return constrained_edge[0];
  }
  return constrained_edge[1];
}

bool Triangle::GetConstrainedEdgeCW(const Point& p)
{
  if (&p == points_[0]) {
    return constrained_edge[1];
  } else if (&p == points_[1]) {
    return constrained_edge[2];
  }
  return constrained_edge[0];
}

void Triangle::SetConstrainedEdgeCCW(const Point& p, bool ce)
{
  if (&p == points_[0]) {
    constrained_edge[2] = ce;
  } else if (&p == points_[1]) {
    constrained_edge[0] = ce;
  } else {
    constrained_edge[1] = ce;
  }
}

void Triangle::SetConstrainedEdgeCW(const Point& p, bool ce)
{
  if (&p == points_[0]) {
    constrained_edge[1] = ce;
  } else if (&p == points_[1]) {
    constrained_edge[2] = ce;
  } else {
    constrained_edge[0] = ce;
  }
}

bool Triangle::GetDelunayEdgeCCW(const Point& p)
{
  if (&p == points_[0]) {
    return delaunay_edge[2];
  } else if (&p == points_[1]) {
    return delaunay_edge[0];
  }
  return delaunay_edge[1];
}

bool Triangle::GetDelunayEdgeCW(const Point& p)
{
  if (&p == points_[0]) {
    return delaunay_edge[1];
  } else if (&p == points_[1]) {
    return delaunay_edge[2];
  }
  return delaunay_edge[0];
}

void Triangle::SetDelunayEdgeCCW(const Point& p, bool e)
{
  if (&p == points_[0]) {
    delaunay_edge[2] = e;
  } else if (&p == points_[1]) {
    delaunay_edge[0] = e;
  } else {
    delaunay_edge[1] = e;
  }
}

void Triangle::SetDelunayEdgeCW(const Point& p, bool e)
{
  if (&p == points_[0]) {
    delaunay_edge[1] = e;
  } else if (&p == points_[1]) {
    delaunay_edge[2] = e;
  } else {
    delaunay_edge[0] = e;
  }
}

// The neighbor across to given point
Triangle& Triangle::NeighborAcross(const Point& opoint)
{
  Triangle* neighbor = nullptr;
  if (&opoint == points_[0]) {
    neighbor = neighbors_[0];
  } else if (&opoint == points_[1]) {
    neighbor = neighbors_[1];
  } else {
    neighbor = neighbors_[2];
  }
  if (neighbor == nullptr) {
      throw std::runtime_error("NeighborAcross - null neighbor");
  }
  return *neighbor;
}

void Triangle::DebugPrint()
{
  std::cout << *points_[0] << " " << *points_[1] << " " << *points_[2] << std::endl;
}

bool Triangle::CircumcicleContains(const Point& point) const
{
  assert(IsCounterClockwise());
  const double dx = points_[0]->x - point.x;
  const double dy = points_[0]->y - point.y;
  const double ex = points_[1]->x - point.x;
  const double ey = points_[1]->y - point.y;
  const double fx = points_[2]->x - point.x;
  const double fy = points_[2]->y - point.y;

  const double ap = dx * dx + dy * dy;
  const double bp = ex * ex + ey * ey;
  const double cp = fx * fx + fy * fy;

  return (dx * (fy * bp - cp * ey) - dy * (fx * bp - cp * ex) + ap * (fx * ey - fy * ex)) < 0;
}

bool Triangle::IsCounterClockwise() const
{
  return (points_[1]->x - points_[0]->x) * (points_[2]->y - points_[0]->y) -
             (points_[2]->x - points_[0]->x) * (points_[1]->y - points_[0]->y) >
         0;
}

bool IsDelaunay(const std::vector<p2t::Triangle*>& triangles)
{
  for (const auto triangle : triangles) {
    for (const auto other : triangles) {
      if (triangle == other) {
        continue;
      }
      for (int i = 0; i < 3; ++i) {
        if (triangle->CircumcicleContains(*other->GetPoint(i))) {
          return false;
        }
      }
    }
  }
  return true;
}

}