static public IEnumerable <Triangle> Triangles(this ITriangulableShape shape)
{
using (IEnumerator <Vector2> enumerator = shape.TriangulationVertices().GetEnumerator())
{
if (!enumerator.MoveNext())
{
yield break;
}
var triangle = new Triangle();
triangle.P0 = enumerator.Current;
enumerator.MoveNext();
triangle.P1 = enumerator.Current;
enumerator.MoveNext();
triangle.P2 = enumerator.Current;
yield return(triangle);
if (shape.StripTriangulation)
{
while (enumerator.MoveNext())
{
triangle = new Triangle
{
P0 = triangle.P2,
P1 = triangle.P1,
P2 = enumerator.Current
};
yield return(triangle);
}
}
while (enumerator.MoveNext())
{
triangle = new Triangle();
triangle.P0 = enumerator.Current;
enumerator.MoveNext();
triangle.P1 = enumerator.Current;
enumerator.MoveNext();
triangle.P2 = enumerator.Current;
yield return(triangle);
}
}
}
static public ITriangulableShape InverseTransform(this ITransformer transformer, ITriangulableShape shape)
{
Vector2[] vertices = shape.Vertices.Select(transformer.InverseTransform).ToArray();
Segment[] edges = shape.Edges.Select(transformer.InverseTransform).ToArray();
return(new IndexedShape(vertices, edges, shape.TriangulationIndices?.ToArray(), shape.StripTriangulation));
}
static public IEnumerable <Vector2> TriangulationVertices(this ITriangulableShape shape)
{
return(shape.TriangulationIndices?.Select(shape.GetIndexedVertex) ?? shape.Vertices);
}