public FovCone(int range, IntVector2D top, IntVector2D bottom, RiseRun riseRun) : this()
{
this.Range = range;
this.VectorTop = top;
this.VectorBottom = bottom;
this.RiseRun = riseRun;
}
static IntVector2D LogAndEnqueue(Action <FovCone> enqueue, int range, IntVector2D top,
IntVector2D bottom, RiseRun riseRun, int code
)
{
if (top.GT(bottom))
{
var cone = new FovCone(range + 1, top, bottom, riseRun);
#if TraceFOV
TraceFlag.FieldOfView.Trace(false, " EQ: ({0}) code: {1}", cone, code);
#endif
enqueue(cone);
return(bottom);
}
else
{
return(top);
}
}
// This method has two main purposes: (1) it marks points inside the
// portion that are within the radius as in the field of view, and
// (2) it computes which portions of the following column are in the
// field of view, and puts them on a work queue for later processing.
//
// A more sophisticated algorithm would say that a cell is visible if there is
// *any* straight line segment that passes through *any* portion of the origin cell
// and any portion of the target cell, passing through only transparent cells
// along the way. This is the "Permissive Field Of View" algorithm, and it
// is much harder to implement.
//
// Search for transitions from opaque to transparent or
// transparent to opaque and use those to determine what
// portions of the *next* column are visible from the origin.
private static FovCone ComputeFoVForRange(
int observerHeight,
FovCone cone,
Func<ICoordsCanon,bool> isOnBoard,
Func<ICoordsCanon, int> targetHeight,
Func<ICoordsCanon, int> terrainHeight,
Action<ICoordsCanon> setFieldOfView,
FovQueue queue)
{
Action<FovCone> enqueue = queue.Enqueue;
var range = cone.Range;
var topVector = cone.VectorTop;
var topRiseRun = cone.RiseRun;
var bottomVector = cone.VectorBottom;
// track the overlap-cone between adjacent hexes as we move down.
var overlapVector = cone.VectorTop;
var hexX = XFromVector(range, topVector, true);
#if TraceFOV
TraceFlag.FieldOfView.Trace(false, "DQ: ({0}) from {1}", cone, hexX);
#endif
do {
while (overlapVector.GT(bottomVector)) {
var coordsCurrent = HexCoords.NewCanonCoords(hexX,range);
var hexVectorBottom = VectorHexBottom(coordsCurrent);
if (isOnBoard(coordsCurrent)) {
#region Set current hex parameters
var hexVectorTop = VectorHexTop(coordsCurrent);
var hexElevation = targetHeight(coordsCurrent);
var hexHeight = terrainHeight(coordsCurrent);
var hexRiseRun = new RiseRun(hexHeight-observerHeight, range);
#endregion
#region Check visibility of current hex
var riseRun = new RiseRun(hexElevation-observerHeight, GetRange(coordsCurrent));
if ( riseRun >= cone.RiseRun
&& bottomVector.LE(coordsCurrent.Vector) && coordsCurrent.Vector.LE(topVector)
) {
setFieldOfView(coordsCurrent);
#if TraceFOV
TraceFlag.FieldOfView.Trace(false," Set visible: {0} / {1}; {2} >= {3}",
MapCoordsDodecant(coordsCurrent), coordsCurrent.ToString(), riseRun, cone.RiseRun);
#endif
}
#endregion
#region Check hex transition
if (hexRiseRun > topRiseRun) {
topVector = LogAndEnqueue(enqueue, range, topVector, hexVectorTop, topRiseRun, 0);
topRiseRun = hexRiseRun;
} else if (hexRiseRun > cone.RiseRun) {
topVector = LogAndEnqueue(enqueue, range, topVector, overlapVector, topRiseRun, 1);
topRiseRun = hexRiseRun;
} else if (hexRiseRun < cone.RiseRun) {
topVector = LogAndEnqueue(enqueue, range, topVector, overlapVector, topRiseRun, 2);
topRiseRun = cone.RiseRun;
}
#endregion
}
overlapVector = VectorMax(hexVectorBottom, bottomVector);
if (hexVectorBottom.GT(bottomVector)) -- hexX;
}
#region Dequeue next cone
if (queue.Count == 0) {
topVector = LogAndEnqueue(enqueue, range, topVector, bottomVector, topRiseRun, 3);
cone = queue.Dequeue();
break;
} else {
cone = queue.Dequeue();
if(cone.Range != range) {
topVector = LogAndEnqueue(enqueue, range, topVector, bottomVector, topRiseRun, 4);
break;
}
#if TraceFOV
TraceFlag.FieldOfView.Trace(false, "DQ: ({0}) from {1}", cone, hexX);
#endif
}
#endregion
#region Check cone transition
if (cone.RiseRun > topRiseRun) {
topVector = LogAndEnqueue(enqueue, range, topVector, cone.VectorTop, topRiseRun, 5);
topRiseRun = cone.RiseRun;
} else if (cone.RiseRun < topRiseRun) {
topVector = LogAndEnqueue(enqueue, range, topVector, overlapVector, topRiseRun, 6);
topRiseRun = cone.RiseRun; // TODO Why is this commented out?
}
#endregion
overlapVector = topVector;
bottomVector = cone.VectorBottom;
} while(true);
// Pick-up any cone portion at bottom of range still unprocessed
if (topVector.GT(bottomVector))
LogAndEnqueue(enqueue, range, topVector, bottomVector, cone.RiseRun, 7);
return cone;
}