C++ TileX函数代码示例

	ETileArea(const BaseStation *st, TileIndex tile, TriggerArea ta)
	{
		switch (ta) {
			default: NOT_REACHED();

			case TA_TILE:
				this->tile = tile;
				this->w    = 1;
				this->h    = 1;
				break;

			case TA_PLATFORM: {
				TileIndex start, end;
				Axis axis = GetRailStationAxis(tile);
				TileIndexDiff delta = TileOffsByDiagDir(AxisToDiagDir(axis));

				for (end = tile; IsRailStationTile(end + delta) && IsCompatibleTrainStationTile(end + delta, tile); end += delta) { /* Nothing */ }
				for (start = tile; IsRailStationTile(start - delta) && IsCompatibleTrainStationTile(start - delta, tile); start -= delta) { /* Nothing */ }

				this->tile = start;
				this->w = TileX(end) - TileX(start) + 1;
				this->h = TileY(end) - TileY(start) + 1;
				break;
			}

			case TA_WHOLE:
				st->GetTileArea(this, Station::IsExpected(st) ? STATION_RAIL : STATION_WAYPOINT);
				break;
		}
	}

/**
 * Configure a ViewPort for rendering (a part of) the map into a screenshot.
 * @param t Screenshot type
 * @param [out] vp Result viewport
 */
void SetupScreenshotViewport(ScreenshotType t, ViewPort *vp)
{
	/* Determine world coordinates of screenshot */
	if (t == SC_WORLD) {
		vp->zoom = ZOOM_LVL_WORLD_SCREENSHOT;

		TileIndex north_tile = _settings_game.construction.freeform_edges ? TileXY(1, 1) : TileXY(0, 0);
		TileIndex south_tile = MapSize() - 1;

		/* We need to account for a hill or high building at tile 0,0. */
		int extra_height_top = TilePixelHeight(north_tile) + 150;
		/* If there is a hill at the bottom don't create a large black area. */
		int reclaim_height_bottom = TilePixelHeight(south_tile);

		vp->virtual_left   = RemapCoords(TileX(south_tile) * TILE_SIZE, TileY(north_tile) * TILE_SIZE, 0).x;
		vp->virtual_top    = RemapCoords(TileX(north_tile) * TILE_SIZE, TileY(north_tile) * TILE_SIZE, extra_height_top).y;
		vp->virtual_width  = RemapCoords(TileX(north_tile) * TILE_SIZE, TileY(south_tile) * TILE_SIZE, 0).x                     - vp->virtual_left + 1;
		vp->virtual_height = RemapCoords(TileX(south_tile) * TILE_SIZE, TileY(south_tile) * TILE_SIZE, reclaim_height_bottom).y - vp->virtual_top  + 1;
	} else {
		vp->zoom = (t == SC_ZOOMEDIN) ? _settings_client.gui.zoom_min : ZOOM_LVL_VIEWPORT;

		Window *w = FindWindowById(WC_MAIN_WINDOW, 0);
		vp->virtual_left   = w->viewport->virtual_left;
		vp->virtual_top    = w->viewport->virtual_top;
		vp->virtual_width  = w->viewport->virtual_width;
		vp->virtual_height = w->viewport->virtual_height;
	}

	/* Compute pixel coordinates */
	vp->left = 0;
	vp->top = 0;
	vp->width  = UnScaleByZoom(vp->virtual_width,  vp->zoom);
	vp->height = UnScaleByZoom(vp->virtual_height, vp->zoom);
	vp->overlay = NULL;
}

/**
 * Gets the other end of the aqueduct, if possible.
 * @param tile_from     The begin tile for the aqueduct.
 * @param [out] tile_to The tile till where to show a selection for the aqueduct.
 * @return The other end of the aqueduct, or otherwise a tile in line with the aqueduct to cause the right error message.
 */
static TileIndex GetOtherAqueductEnd(TileIndex tile_from, TileIndex *tile_to = NULL)
{
	int z;
	DiagDirection dir = GetInclinedSlopeDirection(GetTileSlope(tile_from, &z));

	/* If the direction isn't right, just return the next tile so the command
	 * complains about the wrong slope instead of the ends not matching up.
	 * Make sure the coordinate is always a valid tile within the map, so we
	 * don't go "off" the map. That would cause the wrong error message. */
	if (!IsValidDiagDirection(dir)) return TILE_ADDXY(tile_from, TileX(tile_from) > 2 ? -1 : 1, 0);

	/* Direction the aqueduct is built to. */
	TileIndexDiff offset = TileOffsByDiagDir(ReverseDiagDir(dir));
	/* The maximum length of the aqueduct. */
	int max_length = min(_settings_game.construction.max_bridge_length, DistanceFromEdgeDir(tile_from, ReverseDiagDir(dir)) - 1);

	TileIndex endtile = tile_from;
	for (int length = 0; IsValidTile(endtile) && TileX(endtile) != 0 && TileY(endtile) != 0; length++) {
		endtile = TILE_ADD(endtile, offset);

		if (length > max_length) break;

		if (GetTileMaxZ(endtile) > z) {
			if (tile_to != NULL) *tile_to = endtile;
			break;
		}
	}

	return endtile;
}

/**
 * Returns the driveable Trackdirs on a tile.
 *
 * One-way-roads are taken into account. Signals are not tested.
 *
 * @param dst_tile The tile of interest.
 * @param src_trackdir The direction the vehicle is currently moving.
 * @param type The transporttype of the vehicle.
 * @param subtype For TRANSPORT_ROAD the compatible RoadTypes of the vehicle.
 * @return The Trackdirs the vehicle can continue moving on.
 */
static TrackdirBits GetDriveableTrackdirBits(TileIndex dst_tile, Trackdir src_trackdir, TransportType type, uint subtype)
{
	TrackdirBits trackdirbits = TrackStatusToTrackdirBits(GetTileTrackStatus(dst_tile, type, subtype));

	if (trackdirbits == 0 && type == TRANSPORT_ROAD && HasBit(subtype, ROADTYPE_TRAM)) {
		/* GetTileTrackStatus() returns 0 for single tram bits.
		 * As we cannot change it there (easily) without breaking something, change it here */
		switch (GetSingleTramBit(dst_tile)) {
			case DIAGDIR_NE:
			case DIAGDIR_SW:
				trackdirbits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
				break;

			case DIAGDIR_NW:
			case DIAGDIR_SE:
				trackdirbits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
				break;

			default: break;
		}
	}

	DEBUG(npf, 4, "Next node: (%d, %d) [%d], possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), dst_tile, trackdirbits);

	/* Select only trackdirs we can reach from our current trackdir */
	trackdirbits &= TrackdirReachesTrackdirs(src_trackdir);

	/* Filter out trackdirs that would make 90 deg turns for trains */
	if (_settings_game.pf.forbid_90_deg && (type == TRANSPORT_RAIL || type == TRANSPORT_WATER)) trackdirbits &= ~TrackdirCrossesTrackdirs(src_trackdir);

	DEBUG(npf, 6, "After filtering: (%d, %d), possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), trackdirbits);

	return trackdirbits;
}

	/** Allocates space for a new tile in the matrix.
	 * @param tile Tile to add.
	 */
	void AllocateStorage(TileIndex tile)
	{
		uint old_left = TileX(this->area.tile) / N;
		uint old_top  = TileY(this->area.tile) / N;
		uint old_w    = this->area.w / N;
		uint old_h    = this->area.h / N;

		/* Add the square the tile is in to the tile area. We do this
		 * by adding top-left and bottom-right of the square. */
		uint grid_x = (TileX(tile) / N) * N;
		uint grid_y = (TileY(tile) / N) * N;
		this->area.Add(TileXY(grid_x, grid_y));
		this->area.Add(TileXY(grid_x + N - 1, grid_y + N - 1));

		/* Allocate new storage. */
		T *new_data = CallocT<T>(this->area.w / N * this->area.h / N);

		if (old_w > 0) {
			/* Copy old data if present. */
			uint offs_x = old_left - TileX(this->area.tile) / N;
			uint offs_y = old_top  - TileY(this->area.tile) / N;

			for (uint row = 0; row < old_h; row++) {
				MemCpyT(&new_data[(row + offs_y) * this->area.w / N + offs_x], &this->data[row * old_w], old_w);
			}
		}

		free(this->data);
		this->data = new_data;
	}

static Direction ShipGetNewDirectionFromTiles(TileIndex new_tile, TileIndex old_tile)
{
	uint offs = (TileY(new_tile) - TileY(old_tile) + 1) * 4 +
							TileX(new_tile) - TileX(old_tile) + 1;
	assert(offs < 11 && offs != 3 && offs != 7);
	return _new_vehicle_direction_table[offs];
}

/**
 * Add a single tile to a tile area; enlarge if needed.
 * @param to_add The tile to add
 */
void TileArea::Add(TileIndex to_add)
{
	if (this->tile == INVALID_TILE) {
		this->tile = to_add;
		this->w = 1;
		this->h = 1;
		return;
	}

	uint sx = TileX(this->tile);
	uint sy = TileY(this->tile);
	uint ex = sx + this->w - 1;
	uint ey = sy + this->h - 1;

	uint ax = TileX(to_add);
	uint ay = TileY(to_add);

	sx = min(ax, sx);
	sy = min(ay, sy);
	ex = max(ax, ex);
	ey = max(ay, ey);

	this->tile = TileXY(sx, sy);
	this->w    = ex - sx + 1;
	this->h    = ey - sy + 1;
}

/**
 * Construct the iterator.
 * @param corner1 Tile from where to begin iterating.
 * @param corner2 Tile where to end the iterating.
 */
DiagonalTileIterator::DiagonalTileIterator(TileIndex corner1, TileIndex corner2) : TileIterator(corner2), base_x(TileX(corner2)), base_y(TileY(corner2)), a_cur(0), b_cur(0)
{
	assert(corner1 < MapSize());
	assert(corner2 < MapSize());

	int dist_x = TileX(corner1) - TileX(corner2);
	int dist_y = TileY(corner1) - TileY(corner2);
	this->a_max = dist_x + dist_y;
	this->b_max = dist_y - dist_x;

	/* Unfortunately we can't find a new base and make all a and b positive because
	 * the new base might be a "flattened" corner where there actually is no single
	 * tile. If we try anyway the result is either inaccurate ("one off" half of the
	 * time) or the code gets much more complex;
	 *
	 * We also need to increment here to have equality as marker for the end of a row or
	 * column. Like that it's shorter than having another if/else in operator++
	 */
	if (this->a_max > 0) {
		this->a_max++;
	} else {
		this->a_max--;
	}

	if (this->b_max > 0) {
		this->b_max++;
	} else {
		this->b_max--;
	}
}

static uint NPFSlopeCost(AyStarNode *current)
{
	TileIndex next = current->tile + TileOffsByDiagDir(TrackdirToExitdir(current->direction));

	/* Get center of tiles */
	int x1 = TileX(current->tile) * TILE_SIZE + TILE_SIZE / 2;
	int y1 = TileY(current->tile) * TILE_SIZE + TILE_SIZE / 2;
	int x2 = TileX(next) * TILE_SIZE + TILE_SIZE / 2;
	int y2 = TileY(next) * TILE_SIZE + TILE_SIZE / 2;

	int dx4 = (x2 - x1) / 4;
	int dy4 = (y2 - y1) / 4;

	/* Get the height on both sides of the tile edge.
	 * Avoid testing the height on the tile-center. This will fail for halftile-foundations.
	 */
	int z1 = GetSlopeZ(x1 + dx4, y1 + dy4);
	int z2 = GetSlopeZ(x2 - dx4, y2 - dy4);

	if (z2 - z1 > 1) {
		/* Slope up */
		return _settings_game.pf.npf.npf_rail_slope_penalty;
	}
	return 0;
	/* Should we give a bonus for slope down? Probably not, we
	 * could just substract that bonus from the penalty, because
	 * there is only one level of steepness... */
}

/**
 * Adds all tiles that incident with the north corner of a specific tile to the "tile_table" in a TerraformerState.
 *
 * @param ts TerraformerState.
 * @param tile Tile.
 * @ingroup dirty
 */
static void TerraformAddDirtyTileAround(TerraformerState *ts, TileIndex tile)
{
	/* Make sure all tiles passed to TerraformAddDirtyTile are within [0, MapSize()] */
	if (TileY(tile) >= 1) TerraformAddDirtyTile(ts, tile + TileDiffXY( 0, -1));
	if (TileY(tile) >= 1 && TileX(tile) >= 1) TerraformAddDirtyTile(ts, tile + TileDiffXY(-1, -1));
	if (TileX(tile) >= 1) TerraformAddDirtyTile(ts, tile + TileDiffXY(-1,  0));
	TerraformAddDirtyTile(ts, tile);
}

bool StationRect::AfterRemoveRect(BaseStation *st, TileIndex tile, int w, int h)
{
	assert(PtInExtendedRect(TileX(tile), TileY(tile)));
	assert(PtInExtendedRect(TileX(tile) + w - 1, TileY(tile) + h - 1));

	bool empty = this->AfterRemoveTile(st, tile);
	if (w != 1 || h != 1) empty = empty || AfterRemoveTile(st, TILE_ADDXY(tile, w - 1, h - 1));
	return empty;
}

bool StationRect::AfterRemoveRect(BaseStation *st, TileArea ta)
{
	assert(this->PtInExtendedRect(TileX(ta.tile), TileY(ta.tile)));
	assert(this->PtInExtendedRect(TileX(ta.tile) + ta.w - 1, TileY(ta.tile) + ta.h - 1));

	bool empty = this->AfterRemoveTile(st, ta.tile);
	if (ta.w != 1 || ta.h != 1) empty = empty || this->AfterRemoveTile(st, TILE_ADDXY(ta.tile, ta.w - 1, ta.h - 1));
	return empty;
}

/** A small helper function to initialize the terrain */
static void TgenSetTileHeight(TileIndex tile, int height)
{
	SetTileHeight(tile, height);

	/* Only clear the tiles within the map area. */
	if (TileX(tile) != MapMaxX() && TileY(tile) != MapMaxY() &&
			(!_settings_game.construction.freeform_edges || (TileX(tile) != 0 && TileY(tile) != 0))) {
		MakeClear(tile, CLEAR_GRASS, 3);
	}
}

/**
 * Gets the distance to the edge of the map in given direction.
 * @param tile the tile to get the distance from
 * @param diagdir the direction of interest
 * @return the distance from the edge in tiles
 */
uint DistanceFromEdgeDir(TileIndex tile, DiagDirection dir)
{
	switch (dir) {
		case DIAGDIR_NE: return             TileX(tile) - (_settings_game.construction.freeform_edges ? 1 : 0);
		case DIAGDIR_NW: return             TileY(tile) - (_settings_game.construction.freeform_edges ? 1 : 0);
		case DIAGDIR_SW: return MapMaxX() - TileX(tile) - 1;
		case DIAGDIR_SE: return MapMaxY() - TileY(tile) - 1;
		default: NOT_REACHED();
	}
}

/**
 * Get top height of the tile inside the map.
 * @param t Tile to compute height of
 * @return Maximum height of the tile
 */
int GetTileMaxZ(TileIndex t)
{
	if (TileX(t) == MapMaxX() || TileY(t) == MapMaxY()) return TileHeightOutsideMap(TileX(t), TileY(t));

	int h =         TileHeight(t);                     // N corner
	h = max<int>(h, TileHeight(t + TileDiffXY(1, 0))); // W corner
	h = max<int>(h, TileHeight(t + TileDiffXY(0, 1))); // E corner
	h = max<int>(h, TileHeight(t + TileDiffXY(1, 1))); // S corner

	return h;
}