/// <summary>Gets a Field-of-View for this board synchronously.</summary>
public static IFov GetFieldOfView(this IFovBoard <IHex> @this, HexCoords origin, FovTargetMode targetMode, int heightOfMan, int hexesPerMile)
{
Traces.FieldOfView.Trace("GetFieldOfView");
var fov = new ArrayFieldOfView(@this);
if (@this.IsPassable(origin))
{
ShadowCasting.ComputeFieldOfView(origin, @this, targetMode, coords => fov[coords] = true, heightOfMan, hexesPerMile);
}
return(fov);
}
/// <summary>Gets a Field-of-View for this board synchronously.</summary>
public static IShadingMask GetFieldOfView(this IFovBoard @this, HexCoords origin, int fovRadius, FovTargetMode targetMode, int heightOfMan, int hexesPerMile)
{
Tracing.FieldOfView.Trace("GetFieldOfView");
var fov = new ArrayFieldOfView(@this);
if (@this.IsOverseeable(origin))
{
ShadowCasting.ComputeFieldOfView(@this, origin, fovRadius, targetMode, coords => fov[coords] = true, heightOfMan, hexesPerMile);
}
return(fov);
}
/// <summary>Calculate Field-of-View from a specified TargetMode, assuming a spherical earth
/// and height measured in feet if <code>hexesPerMile</code> is not equal 0.</summary>
/// <param name="coordsObserver">Cordinates of observer;s hex.</param>
/// <param name="board">A reference to an IFovBoard {IHex} instance.</param>
/// <param name="targetMode">TargetMode value for determining target visibility.</param>
/// <param name="setFieldOfView">Sets a hex as visible in the Field-of-View.</param>
/// <param name="defaultHeight">Height used for observer and target when targetMode = EqualHeights/</param>
/// <param name="hexesPerMile">Number of hexes per mile (ie 1/4000 of planet radius).</param>
/// <remarks>Adjusts visibility for curvature of the Earth. This is the only version of
/// ComputeFieldOfView that is <b>not</b> scale invariant for height, and assumes that height
/// is measured in feet.
/// </remarks>
/// <a href="http://mathcentral.uregina.ca/qq/database/QQ.09.02/shirley3.html">Hidden by the Curvature of the Earth</a>
public static void ComputeFieldOfView(
HexCoords coordsObserver,
IFovBoard <IHex> board,
FovTargetMode targetMode,
Action <HexCoords> setFieldOfView,
int defaultHeight,
int hexesPerMile
)
{
int CalculationHeightUnits = UseMetric ? 5 // convert metres to cm for greater precision
: 12; // convert feet to inches for greater precision
Func <HexCoords, int> elevationTarget;
int elevationObserver;
switch (targetMode)
{
case FovTargetMode.TargetHeightEqualZero:
elevationTarget = coords => board.ElevationGroundASL(coords);
elevationObserver = board.ElevationObserverASL(coordsObserver);
break;
default:
case FovTargetMode.TargetHeightEqualActual:
elevationTarget = coords => board.ElevationTargetASL(coords);
elevationObserver = board.ElevationObserverASL(coordsObserver);
break;
case FovTargetMode.EqualHeights:
elevationTarget = coords => board.ElevationGroundASL(coords) + defaultHeight;
elevationObserver = elevationTarget(coordsObserver);
break;
}
Func <HexCoords, int> deltaHeight = GetDeltaHeight(coordsObserver, hexesPerMile, CalculationHeightUnits);
ShadowCasting.ComputeFieldOfView(
coordsObserver,
board.FovRadius - 1,
elevationObserver * CalculationHeightUnits,
board.IsOnboard,
coords => elevationTarget(coords) * CalculationHeightUnits - deltaHeight(coords),
(coords, hexside) => board.ElevationHexsideASL(coords, hexside) * CalculationHeightUnits - deltaHeight(coords),
setFieldOfView
);
}
