setVertexXY method
Set the XY values of a vertex.
The XY values define the position of the vertex in the local coordinate system of the Display Object.
Implementation
void setVertexXY(int vertex, num x, num y) {
final offset = vertex << 2;
vxList[offset + 0] = x.toDouble();
vxList[offset + 1] = y.toDouble();
}