public static DoublePoint ContinuousIsoStaggeredScreenToMapMapper(double screenX, double screenY)
{
// get the normalized grid coordinate as integer.
// this roughly tells us the cell we are in.
// Note: Grid coordinates are 1-unit based,
// as opposed to the 4-unit based view coordinates
//
// For Iso-Staggered maps the grid mapper already returns the (almost) correct
// coordinates for the central tile.
// We still have to check whether the coordinate given is
// in one of the corner regions.
var cgrid = ContinuousGridScreenToMapMapper(screenX, screenY);
var ngrid = MapCoordinate.Normalize(cgrid);
// offsets within the tile are not scaled.
var dx = cgrid.X - ngrid.X;
var dy = cgrid.Y - ngrid.Y;
// In Staggered maps, the underlying map is stretched on the y-axis
// compared to normal grids. On the y-axis one map-grid-cell of 1
// moves the position by 2.
ngrid = ngrid.WithY(ngrid.Y * 2);
if (Math.Abs(dx) > 0.5 - Math.Abs(dy))
{
// This is one of the corner regions.
var direction = Compute(dx, dy);
staggeredNavigator.NavigateTo(direction, ngrid, out MapCoordinate result);
var d = (0.5 - Math.Abs(dx));
double rdx = -Math.Sign(dx) * d;
double rdy = -Math.Sign(dy) * (0.5 - Math.Abs(dy));
return(new DoublePoint(result.X + rdx, result.Y + rdy));
}
return(new DoublePoint(ngrid.X + dx, ngrid.Y + dy));
}
public static MapCoordinate IsoStaggeredScreenToMapMapper(double screenX, double screenY)
{
var r = ContinuousIsoStaggeredScreenToMapMapper(screenX, screenY);
return(MapCoordinate.Normalize(r));
}
