getting GKObstacleGraph to work with SKTileMapNode - sprite-kit

Question

I'm currently working in Xcode 8, using Swift 3 and the new SKTileMapNode from SpritKit to make a 2D dungeon crawler type of game.
I'm have trouble getting GKObstacleGraph to work with the tilemap. Please help!
I tried to loop through all the tiles within the obstacle layer of the tilemap and create a polygon for each tile and store it in the GKObstacleGraph. Each tile in obstacle layer is a wall tile. The map looks like some type of dungeon crawler, so the wall is all over the places.
I have something like below:
for row in 0..<tileMapNode.numberOfRows {
for column in 0..<tileMapNode.numberOfColumns {
let tile = tileMapNode.tileDefinition(atColumn: column, row: row)
let tileCenter = tileMapName.centerOfTile(atColumn: column, row: row)
//find 4 corners of each tile from its center
let bottomLeft = float2(CGPointMake(tileCenter.x - tile.size.width/2, tileCenter.y - tile.size.height/2))
let bottomRight = float2(CGPointMake((tileCenter.x - tile.size.width/2, tileCenter.y + tile.size.height/2))
let topRight = float2(CGPointMake((tileCenter.x + tile.size.width/2, tileCenter.y + tile.size.height/2))
let topLeft = float2(CGPointMake((tileCenter.x - tile.size.width/2, tileCenter.y + tile.size.height/2))
var vertices = [topLeft , bottomLeft , bottomRight , topRight ]
let obstacle = GKPolygonObstacle(points: &vertices, count: 4)
obstacleGraph.add(obstacle)
}
}
However, when i run the app it shows that there are over 80000 nodes, way too many pathfinding pathes.
Any help would be appreciated.

Answer 1

I'm not certain that GKObstacleGraph is the right choice of graph here. According to the GameplayKit documentation:
For example, you can design a level with the SpriteKit Scene Editor in Xcode and use physics bodies to mark regions that the player (or other game entities) cannot pass through, then use the obstaclesFromNodePhysicsBodies: method to generate GKPolygonObstacle objects marking impassable regions.
The function obstaclesFromNodePhysicsBodies is used like this to extract obstacles and create the graph;
let obstacles = SKNode.obstaclesFromNodePhysicsBodies(self.children)
graph = GKObstacleGraph(obstacles: obstacles, bufferRadius: 0.0)
For a SKTilemapNode representing a cartesian grid, the GKGridGraph seems the likely choice.