Method GetLimitedMap

internal/mapper/mapper.go:574–796

BFS Crawls from the center position as though the players POV So it won't follow locked rooms, secrets, etc.

(centerRoomId int, c Config)

// BFS Crawls from the center position as though the players POV
// So it won't follow locked rooms, secrets, etc.
func (r *mapper) GetLimitedMap(centerRoomId int, c Config) mapRender {

	if c.ZoomLevel < 0 {
		c.ZoomLevel = 0
	}
	c.ZoomLevel++
	// Minimum effective zoom of 2 ensures that rooms 1 coordinate unit apart
	// always have at least 1 connector cell between them, making rooms that are
	// N units apart visually distinguishable from rooms that are 1 unit apart.
	if c.ZoomLevel < 2 {
		c.ZoomLevel = 2
	}

	out := newMapRender(c.Width, c.Height)

	centerX, centerY := c.Width>>1, c.Height>>1

	// Start drawing from the center of the output canvas
	dstPos := positionDelta{
		x: centerX,
		y: centerY,
		z: 0,
	}

	node := r.crawledRooms[centerRoomId]
	if node == nil {
		return out
	}

	r.crawlQueue = make([]crawlRoom, 0, 20) // pre-allocate 20 capacity

	drawX, drawY := 0, 0

	// Special additional crawl tracker.
	// This is because we're doing a unique crawl right now, independent of the "global crawl"
	tmpCrawledTracker := map[int]struct{}{}

	//var lastNode *mapNode = nil
	r.crawlQueue = append(r.crawlQueue, crawlRoom{RoomId: node.RoomId, Pos: dstPos})

	var symbol rune
	var legend string

	for len(r.crawlQueue) > 0 {

		roomNow := r.crawlQueue[0]
		r.crawlQueue = r.crawlQueue[1:]

		if _, ok := tmpCrawledTracker[roomNow.RoomId]; ok {
			continue
		}

		dstPos = roomNow.Pos

		node := r.getMapNode(roomNow.RoomId)
		if node == nil {
			continue
		}