GeneralPolygon::operator list<TPPLPoly>()
{
auto isPolygonOutside = [&](const Contour &referencePolygon, const Contour &poly)
{
for(unsigned int p=0; p < referencePolygon.size() ; ++p)
if( !_evenOddRuleAlgorithm( referencePolygon[p], poly) )
return true;
return false;
};
list<TPPLPoly> polys;
for(unsigned int c=0; c < _contours.size() ; ++c)
{
const Contour &contour = _contours[c];
TPPLPoly poly;
poly.Init(contour.size());
for(unsigned int v=0; v < contour.size() ; ++v)
{
TPPLPoint point;
point.x = contour[v].x;
point.y = contour[v].y;
poly[v] = point;
}
// BE CAREFULL!!! not really correct because the polygon could be concave then
// the center of mass could not be inside the polygon
sf::Vector2f centerOfMass(0.0f, 0.0f);
for(unsigned int i=0; i < contour.size() ; ++i)
centerOfMass += contour[i];
centerOfMass *= (1.0f/contour.size());
std::vector<Contour> outsideContours;
for(unsigned int i=0; i < _contours.size() ; ++i)
{
if( i == c )
{
outsideContours.push_back(_contours[i]);
continue;
}
if( isPolygonOutside(_contours[i], contour) )
outsideContours.push_back(_contours[i]);
}
// first test if is a hole or not
if( !_evenOddRuleAlgorithm( centerOfMass, outsideContours ) )
poly.SetHole(true);
else
poly.SetHole(false);
// if it is a hole then it must be in CW order to the algorithm to recognize
// else must be in CCW
if( poly.IsHole() )
poly.SetOrientation(TPPL_CW);// Hole orientation (needed in the algorithm)
else
poly.SetOrientation(TPPL_CCW);// Not a hole orientation (needed in the algorithm)
polys.push_back(poly);
}
return polys;
}
