/// <summary>
/// Combines two polygons into one CSG object. Polygons p1 and p2 are treated as top and
/// bottom of a tube segment with p1 and p2 as the profile. <b>Note:</b> both polygons must have the
/// same number of vertices. This method does not guarantee intersection-free CSGs. It is in the
/// responsibility of the caller to ensure that the orientation of p1 and p2 allow for
/// intersection-free combination of both.
/// </summary>
/// <param name="p1">first polygon</param>
/// <param name="p2">second polygon</param>
/// <param name="bottom">defines whether to close the bottom of the tube</param>
/// <param name="top">defines whether to close the top of the tube</param>
/// <returns>List of polygons</returns>
///
public static List <Polygon> combine(Polygon p1, Polygon p2, bool bottom, bool top)
{
List <Polygon> newPolygons = new List <Polygon>();
if (p1.vertices.Count != p2.vertices.Count)
{
throw new Exception("Polygons must have the same number of vertices");
}
int numVertices = p1.vertices.Count;
if (bottom)
{
newPolygons.Add(p1.flipped());
}
for (int i = 0; i < numVertices; i++)
{
int nexti = (i + 1) % numVertices;
IVector3d bottomV1 = p1.vertices[i].pos;
IVector3d topV1 = p2.vertices[i].pos;
IVector3d bottomV2 = p1.vertices[nexti].pos;
IVector3d topV2 = p2.vertices[nexti].pos;
List <IVector3d> pPoints;
pPoints = new List <IVector3d> {
bottomV2, topV2, topV1
};
newPolygons.Add(Polygon.fromPoints(pPoints, p1.getStorage()));
pPoints = new List <IVector3d> {
bottomV2, topV1, bottomV1
};
newPolygons.Add(Polygon.fromPoints(pPoints, p1.getStorage()));
}
if (top)
{
newPolygons.Add(p2);
}
return(newPolygons);
}
private static CSG extrude(IVector3d dir, Polygon polygon1)
{
List <Polygon> newPolygons = new List <Polygon>();
if (dir.z() < 0)
{
throw new ArgumentException("z < 0 currently not supported for extrude: " + dir);
}
newPolygons.AddRange(PolygonUtil.concaveToConvex(polygon1));
Polygon polygon2 = polygon1.translated(dir);
int numvertices = polygon1.vertices.Count;
for (int i = 0; i < numvertices; i++)
{
int nexti = (i + 1) % numvertices;
IVector3d bottomV1 = polygon1.vertices[i].pos;
IVector3d topV1 = polygon2.vertices[i].pos;
IVector3d bottomV2 = polygon1.vertices[nexti].pos;
IVector3d topV2 = polygon2.vertices[nexti].pos;
List <IVector3d> pPoints = new List <IVector3d> {
bottomV2, topV2, topV1, bottomV1
};
newPolygons.Add(Polygon.fromPoints(pPoints, polygon1.getStorage()));
}
polygon2 = polygon2.flipped();
List <Polygon> topPolygons = PolygonUtil.concaveToConvex(polygon2);
newPolygons.AddRange(topPolygons);
return(CSG.fromPolygons(newPolygons));
}
private static List <Polygon> extrude(IVector3d dir, Polygon polygon1, bool top, bool bottom)
{
List <Polygon> newPolygons = new List <Polygon>();
if (bottom)
{
newPolygons.AddRange(PolygonUtil.concaveToConvex(polygon1));
}
Polygon polygon2 = polygon1.translated(dir);
Transform rot = Transform.unity();
IVector3d a = polygon2.getPlane().getNormal().normalized();
IVector3d b = dir.normalized();
IVector3d c = a.crossed(b);
double l = c.magnitude(); // sine of angle
if (l > 1e-9)
{
IVector3d axis = c.times(1.0 / l);
double angle = a.angle(b);
double sx = 0;
double sy = 0;
double sz = 0;
int n = polygon2.vertices.Count;
foreach (Vertex v in polygon2.vertices)
{
sx += v.pos.x();
sy += v.pos.y();
sz += v.pos.z();
}
IVector3d center = Vector3d.xyz(sx / n, sy / n, sz / n);
rot = rot.rot(center, axis, angle * Math.PI / 180.0);
foreach (Vertex v in polygon2.vertices)
{
v.pos = rot.transform(v.pos);
}
}
int numvertices = polygon1.vertices.Count;
for (int i = 0; i < numvertices; i++)
{
int nexti = (i + 1) % numvertices;
IVector3d bottomV1 = polygon1.vertices[i].pos;
IVector3d topV1 = polygon2.vertices[i].pos;
IVector3d bottomV2 = polygon1.vertices[nexti].pos;
IVector3d topV2 = polygon2.vertices[nexti].pos;
List <IVector3d> pPoints = new List <IVector3d> {
bottomV2, topV2, topV1, bottomV1
};
newPolygons.Add(Polygon.fromPoints(pPoints, polygon1.getStorage()));
}
polygon2 = polygon2.flipped();
List <Polygon> topPolygons = PolygonUtil.concaveToConvex(polygon2);
if (top)
{
newPolygons.AddRange(topPolygons);
}
return(newPolygons);
}