/**
* Function performing a search around a center tile and going outward, thus in circle.
* Although it really is a square search...
* Every tile will be tested by means of the callback function proc,
* which will determine if yes or no the given tile meets criteria of search.
* @param tile to start the search from. Upon completion, it will return the tile matching the search
* @param size: number of tiles per side of the desired search area
* @param proc: callback testing function pointer.
* @param user_data to be passed to the callback function. Depends on the implementation
* @return result of the search
* @pre proc != NULL
* @pre size > 0
*/
public static bool CircularTileSearch <T>(ref TileIndex tile, uint size, TestTileOnSearchProc <T> proc, T userData)
{
if (proc == null)
{
throw new ArgumentNullException(nameof(proc));
}
if (size <= 0)
{
throw new ArgumentOutOfRangeException(nameof(size), "Must be greater than zero");
}
if (size % 2 == 1)
{
/* If the length of the side is uneven, the center has to be checked
* separately, as the pattern of uneven sides requires to go around the center */
if (proc(ref tile, userData))
{
return(true);
}
/* If tile test is not successful, get one tile up,
* ready for a test in first circle around center tile */
tile = TILE_ADD(tile, (uint)(int)TileOffsByDir(Direction.DIR_N));
return(CircularTileSearch(ref tile, size / 2, 1, 1, proc, userData));
}
else
{
return(CircularTileSearch(ref tile, size / 2, 0, 0, proc, userData));
}
}
/**
* Generalized circular search allowing for rectangles and a hole.
* Function performing a search around a center rectangle and going outward.
* The center rectangle is left out from the search. To do a rectangular search
* without a hole, set either h or w to zero.
* Every tile will be tested by means of the callback function proc,
* which will determine if yes or no the given tile meets criteria of search.
* @param tile to start the search from. Upon completion, it will return the tile matching the search.
* This tile should be directly north of the hole (if any).
* @param radius How many tiles to search outwards. Note: This is a radius and thus different
* from the size parameter of the other CircularTileSearch function, which is a diameter.
* @param w the width of the inner rectangle
* @param h the height of the inner rectangle
* @param proc callback testing function pointer.
* @param user_data to be passed to the callback function. Depends on the implementation
* @return result of the search
* @pre proc != NULL
* @pre radius > 0
*/
public static bool CircularTileSearch <T>(ref TileIndex tile, uint radius, uint w, uint h, TestTileOnSearchProc <T> proc,
T userData)
{
if (proc == null)
{
throw new ArgumentNullException(nameof(proc));
}
if (radius <= 0)
{
throw new ArgumentOutOfRangeException(nameof(radius), "Must be greater than zero");
}
uint x = TileX(tile) + w + 1;
uint y = TileY(tile);
uint[] extent = new uint[(int)DiagDirection.DIAGDIR_END] {
w, h, w, h
};
for (uint n = 0; n < radius; n++)
{
for (var dir = (int)DiagDirection.DIAGDIR_BEGIN; dir < (int)DiagDirection.DIAGDIR_END; dir++)
{
/* Is the tile within the map? */
for (uint j = extent[dir] + n * 2 + 1; j != 0; j--)
{
if (x < MapSizeX() && y < MapSizeY())
{
TileIndex t = TileXY(x, y);
/* Is the callback successful? */
if (proc(ref t, userData))
{
/* Stop the search */
tile = t;
return(true);
}
}
/* Step to the next 'neighbour' in the circular line */
x += (uint)_tileoffs_by_diagdir[dir].x;
y += (uint)_tileoffs_by_diagdir[dir].y;
}
}
/* Jump to next circle to test */
x += (uint)_tileoffs_by_dir[(int)Direction.DIR_W].x;
y += (uint)_tileoffs_by_dir[(int)Direction.DIR_W].y;
}
tile = TileConstants.INVALID_TILE;
return(false);
}
