// Start the Transport.
func (t *Transport) start() {
dialer := &net.Dialer{Timeout: t.DialTimeout}
t.transport = &http.Transport{
Dial: dialer.Dial,
Proxy: t.Proxy,
TLSClientConfig: t.TLSClientConfig,
DisableKeepAlives: t.DisableKeepAlives,
DisableCompression: t.DisableCompression,
MaxIdleConnsPerHost: t.MaxIdleConnsPerHost,
ResponseHeaderTimeout: t.ResponseHeaderTimeout,
}
t.closeMonitor = make(chan bool)
t.pq = pqueue.New(16)
go t.monitor()
}
// FindPath finds a path
// Returns a slice of points which consists the starting point up to the end point inclusively
func (p *Pathfinder) FindPath(startX int, startY int, endX int, endY int) ([]*Point, error) {
// No acceptable tiles were set
if len(p.acceptableTiles) == 0 {
return nil, errors.New("You can't find a path without first calling SetAcceptableTiles()")
}
// No grid was set
if p.collisionGrid == nil {
return nil, errors.New("You can't find a path without first calling SetGrid()")
}
// Start or endpoint outside of scope
if startX < 0 || startY < 0 || endX < 0 || endX < 0 ||
startX > len(p.collisionGrid[0])-1 || startY > len(p.collisionGrid)-1 ||
endX > len(p.collisionGrid[0])-1 || endY > len(p.collisionGrid)-1 {
return nil, errors.New("You can't find a path without first calling SetGrid()")
}
// Start and end are the same tile
if startX == endX && startY == endY {
return make([]*Point, 0), nil
}
// End point is not an acceptable tile
endTile := p.collisionGrid[endY][endX]
isAcceptable := false
for i := 0; i < len(p.acceptableTiles); i++ {
if endTile == p.acceptableTiles[i] {
isAcceptable = true
break
}
}
if isAcceptable == false {
return make([]*Point, 0), nil
}
p.startX = startX
p.startY = startY
p.endX = endX
p.endY = endY
// TODO is there a more memory-efficient way to do this ?
p.openList = pqueue.New(len(p.collisionGrid[0]) * len(p.collisionGrid))
p.coordinateToNode = make(map[string]*node)
n := newNode(p.startX, p.startY, p.endX, p.endY, nil, straightCost)
p.coordinateToNode[getHashKeyForPoint(startX, startY)] = n
item := &pqueue.Item{Value: n, Priority: int64(n.bestGuessDistance() * costPrecision)}
p.openList.Push(item)
for {
if p.openList.Len() == 0 {
return nil, errors.New("path not found")
}
item, _ := p.openList.PeekAndShift(math.MaxInt64)
parent := item.Value.(*node)
var sn searchNodes
if parent.y > 0 {
sn = append(sn, newSearchNode(0, -1, p.endX, p.endY, straightCost*p.getTileCost(parent.x, parent.y-1), parent))
}
if parent.x < len(p.collisionGrid[0])-1 {
sn = append(sn, newSearchNode(1, 0, p.endX, p.endY, straightCost*p.getTileCost(parent.x+1, parent.y), parent))
}
if parent.y < len(p.collisionGrid)-1 {
sn = append(sn, newSearchNode(0, 1, p.endX, p.endY, straightCost*p.getTileCost(parent.x, parent.y+1), parent))
}
if parent.x > 0 {
sn = append(sn, newSearchNode(-1, 0, p.endX, p.endY, straightCost*p.getTileCost(parent.x-1, parent.y), parent))
}
if p.diagonalsEnabled {
if parent.x > 0 && parent.y > 0 {
if p.allowCornerCutting ||
(isTileWalkable(p.collisionGrid, p.acceptableTiles, parent.x, parent.y-1) &&
isTileWalkable(p.collisionGrid, p.acceptableTiles, parent.x-1, parent.y)) {
sn = append(sn, newSearchNode(-1, -1, p.endX, p.endY, diagonalCost*p.getTileCost(parent.x-1, parent.y-1), parent))
}
}
if parent.x < len(p.collisionGrid[0])-1 && parent.y < len(p.collisionGrid)-1 {
if p.allowCornerCutting ||
(isTileWalkable(p.collisionGrid, p.acceptableTiles, parent.x, parent.y+1) &&
isTileWalkable(p.collisionGrid, p.acceptableTiles, parent.x+1, parent.y)) {
sn = append(sn, newSearchNode(1, 1, p.endX, p.endY, diagonalCost*p.getTileCost(parent.x+1, parent.y+1), parent))
}
}
if parent.x < len(p.collisionGrid[0])-1 && parent.y > 0 {
if p.allowCornerCutting ||
(isTileWalkable(p.collisionGrid, p.acceptableTiles, parent.x, parent.y-1) &&
isTileWalkable(p.collisionGrid, p.acceptableTiles, parent.x+1, parent.y)) {
sn = append(sn, newSearchNode(1, -1, p.endX, p.endY, diagonalCost*p.getTileCost(parent.x+1, parent.y-1), parent))
}
}
if parent.x > 0 && parent.y < len(p.collisionGrid)-1 {
if p.allowCornerCutting ||
(isTileWalkable(p.collisionGrid, p.acceptableTiles, parent.x, parent.y+1) &&
isTileWalkable(p.collisionGrid, p.acceptableTiles, parent.x-1, parent.y)) {
sn = append(sn, newSearchNode(-1, 1, p.endX, p.endY, diagonalCost*p.getTileCost(parent.x-1, parent.y+1), parent))
}
}
}
// First sort all of the potential nodes we could search by their cost + heuristic distance
sort.Sort(sn)
// Search all of the adjacent nodes
for i := 0; i < len(sn); i++ {
adjacentCoordinateX := sn[i].parent.x + sn[i].x
adjacentCoordinateY := sn[i].parent.y + sn[i].y
hashKey := getHashKeyForPoint(adjacentCoordinateX, adjacentCoordinateY)
_, exists := p.additionalPointsToAvoid[hashKey]
if !exists {
if sn[i].endX == adjacentCoordinateX && sn[i].endY == adjacentCoordinateY {
var path []*Point
path = append(path, &Point{X: adjacentCoordinateX, Y: adjacentCoordinateY}, &Point{X: sn[i].parent.x, Y: sn[i].parent.y})
parent := sn[i].parent
for {
parent = parent.parent
if parent == nil {
break
}
path = append(path, &Point{X: parent.x, Y: parent.y})
}
// Reverse path slice
for i := len(path)/2 - 1; i >= 0; i-- {
opp := len(path) - 1 - i
path[i], path[opp] = path[opp], path[i]
}
return path, nil
}
if isTileWalkable(p.collisionGrid, p.acceptableTiles, adjacentCoordinateX, adjacentCoordinateY) {
existingNode, exists := p.coordinateToNode[hashKey]
if exists {
if sn[i].parent.costSoFar+sn[i].cost < existingNode.costSoFar {
existingNode.costSoFar = sn[i].parent.costSoFar + sn[i].cost
existingNode.parent = sn[i].parent
}
} else {
n := newNode(adjacentCoordinateX, adjacentCoordinateY, p.endX, p.endY, sn[i].parent, sn[i].cost)
p.coordinateToNode[hashKey] = n
item := &pqueue.Item{Value: n, Priority: int64(n.bestGuessDistance() * costPrecision)}
p.openList.Push(item)
}
}
}
}
}
return nil, errors.New("path not found")
}