SpriteKit: suggestions for rounding corners of unconventional grid? - ios

Question

The goal is to round the corners of an unconventional grid similar to the following:
https://s-media-cache-ak0.pinimg.com/564x/50/bc/e0/50bce0cb908913ebc2cf630d635331ef.jpg
https://s-media-cache-ak0.pinimg.com/564x/7e/29/ee/7e29ee80e957ec22bbba630ccefbfaa2.jpg
Instead of a grid with four corners like a conventional grid, these grids have multiple corners in need of rounding.
The brute force approach would be to identify tiles with corners exposed then round those corners either with a different background image or by clipping the corners in code.
Is there a cleaner approach?
The grid is rendered for an iOS app in a SpriteKit SKScene.

Answer 1

This is a really interesting question.You can build your matrix with different approaches but surely you must resolve everytime the changes about the 4 corners in background for each tiles.
Suppose you start with a GameViewController like this (without load SKS files and with anchorPoint equal to zero):
import UIKit
import SpriteKit
class GameViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
guard let view = self.view as! SKView? else { return }
view.ignoresSiblingOrder = true
view.showsFPS = true
view.showsNodeCount = true
let scene = GameScene(size:view.bounds.size)
scene.scaleMode = .resizeFill
scene.anchorPoint = CGPoint.zero
view.presentScene(scene)
}
}
My idea is to build a matrix like this:
import SpriteKit
class GameScene: SKScene {
private var sideTile:CGFloat = 40
private var gridWidthTiles:Int = 5
private var gridHeightTiles:Int = 6
override func didMove(to view: SKView) {
self.drawMatrix()
}
func drawMatrix(){
var index = 1
let matrixPos = CGPoint(x:50,y:150)
for i in 0..<gridHeightTiles {
for j in 0..<gridWidthTiles {
let tile = getTile()
tile.name = "tile\(index)"
addChild(tile)
tile.position = CGPoint(x:matrixPos.x+(sideTile*CGFloat(j)),y:matrixPos.y+(sideTile*CGFloat(i)))
let label = SKLabelNode.init(text: "\(index)")
label.fontSize = 12
label.fontColor = .white
tile.addChild(label)
label.position = CGPoint(x:tile.frame.size.width/2,y:tile.frame.size.height/2)
index += 1
}
}
}
func getTile()->SKShapeNode {
let tile = SKShapeNode(rect: CGRect(x: 0, y: 0, width: sideTile, height: sideTile), cornerRadius: 10)
tile.fillColor = .gray
tile.strokeColor = .gray
return tile
}
}
Output:
Now we can construct a background for each tile of our matrix.
We can made the same tile node but with a different color (maybe more clear than the tile color) and without corner radius. If we split this background in 4 parts we have:
left - bottom background tile
left - top background tile
right - bottom background tile
right - top background tile
Code for a typical background tile:
func getBgTileCorner()->SKShapeNode {
let bgTileCorner = SKShapeNode(rect: CGRect(x: 0, y: 0, width: sideTile/2, height: sideTile/2))
bgTileCorner.fillColor = .lightGray
bgTileCorner.strokeColor = .lightGray
bgTileCorner.lineJoin = .round
bgTileCorner.isAntialiased = false
return bgTileCorner
}
Now with the SKSCropNode we can obtain only the corner using the background tile and the tile:
func getCorner(at angle:String)->SKCropNode {
let cropNode = SKCropNode()
let tile = getTile()
let bgTile = getBgTileCorner()
cropNode.addChild(bgTile)
tile.position = CGPoint.zero
let tileFrame = CGRect(x: 0, y: 0, width: sideTile, height: sideTile)
switch angle {
case "leftBottom": bgTile.position = CGPoint(x:tile.position.x,y:tile.position.y)
case "rightBottom": bgTile.position = CGPoint(x:tile.position.x+tileFrame.size.width/2,y:tile.position.y)
case "leftTop": bgTile.position = CGPoint(x:tile.position.x,y:tile.position.y+tileFrame.size.height/2)
case "rightTop": bgTile.position = CGPoint(x:tile.position.x+tileFrame.size.width/2,y:tile.position.y+tileFrame.size.height/2)
default:break
}
tile.fillColor = self.backgroundColor
tile.strokeColor = self.backgroundColor
tile.lineWidth = 0.0
bgTile.lineWidth = 0.0
tile.blendMode = .replace
cropNode.position = CGPoint.zero
cropNode.addChild(tile)
cropNode.maskNode = bgTile
return cropNode
}
Output for a typical corner:
let corner = getCorner(at: "leftBottom")
addChild(corner)
corner.position = CGPoint(x:50,y:50)
Now we can rebuild the drawMatrix function with the corners for each tile:
func drawMatrix(){
var index = 1
let matrixPos = CGPoint(x:50,y:150)
for i in 0..<gridHeightTiles {
for j in 0..<gridWidthTiles {
let tile = getTile()
tile.name = "tile\(index)"
let bgTileLB = getCorner(at:"leftBottom")
let bgTileRB = getCorner(at:"rightBottom")
let bgTileLT = getCorner(at:"leftTop")
let bgTileRT = getCorner(at:"rightTop")
bgTileLB.name = "bgTileLB\(index)"
bgTileRB.name = "bgTileRB\(index)"
bgTileLT.name = "bgTileLT\(index)"
bgTileRT.name = "bgTileRT\(index)"
addChild(bgTileLB)
addChild(bgTileRB)
addChild(bgTileLT)
addChild(bgTileRT)
addChild(tile)
tile.position = CGPoint(x:matrixPos.x+(sideTile*CGFloat(j)),y:matrixPos.y+(sideTile*CGFloat(i)))
let label = SKLabelNode.init(text: "\(index)")
label.fontSize = 12
label.fontColor = .white
tile.addChild(label)
label.position = CGPoint(x:tile.frame.size.width/2,y:tile.frame.size.height/2)
bgTileLB.position = CGPoint(x:tile.position.x,y:tile.position.y)
bgTileRB.position = CGPoint(x:tile.position.x,y:tile.position.y)
bgTileLT.position = CGPoint(x:tile.position.x,y:tile.position.y)
bgTileRT.position = CGPoint(x:tile.position.x,y:tile.position.y)
index += 1
}
}
}
Output:
Very similar to your screenshots (these are two tile example:)
Now when you want to remove a tile, you can decide what corner you want to remove or leave because for each tile you have also the relative 4 corners :
Output:

Answer 2

Okay, the grid creation process isn't really relative to this. You just need some way of differentiating between a blank spot in the grid and a filled spot. In my example I have a Tile object with a type of .blank or .regular. You need to have all 15 images (you can change the style to whatever you like, although they have to be in the same order and they have to be prefixed with 1..15). It uses bit calculation to figure out which image to use as a background and offsets the background image by 1/2 tile size for x and y. Other than that it is pretty self explanitory. Those background images were my tester images I created when developing this, so feel free to use them.
struct GridPosition {
var col: Int = 0
var row: Int = 0
}
class GameScene: SKScene {
private var backgroundLayer = SKNode()
private var tileLayer = SKNode()
private var gridSize: CGSize = CGSize.zero
private var gridRows: Int = 0
private var gridCols: Int = 0
private var gridBlanks = [Int]()
private var tiles = [[Tile]]()
var tileSize: CGFloat = 150
override func didMove(to view: SKView) {
backgroundLayer.zPosition = 1
addChild(backgroundLayer)
tileLayer.zPosition = 2
addChild(tileLayer)
gridRows = 8
gridCols = 11
gridBlanks = [0,1,3,4,5,6,7,9,10,11,12,13,15,16,17,19,20,21,22,23,31,32,33,36,40,43,56,64,67,69,70,71,72,73,75,77,78,79,82,85,86,87]
createGrid()
createBackgroundTiles()
}
func createGrid() {
for row in 0 ..< gridRows {
var rowContent = [Tile]()
for col in 0 ..< gridCols {
let currentTileLocation: Int = row * gridCols + col
var tile: Tile
if gridBlanks.contains(currentTileLocation) {
tile = Tile(row: row, col: col, type: .blank, tileSize: tileSize)
}
else {
tile = Tile(row: row, col: col, type: .regular, tileSize: tileSize)
}
tile.position = positionInGrid(column: col, row: row)
tile.zPosition = CGFloat(100 + gridRows - row)
tileLayer.addChild(tile)
rowContent.append(tile)
}
tiles.append(rowContent)
}
}
func tileByGridPosition(_ gridPos: GridPosition) -> Tile {
return (tiles[Int(gridPos.row)][Int(gridPos.col)])
}
func positionInGrid(column: Int, row: Int) -> CGPoint {
let startX = 0 - CGFloat(gridCols / 2) * tileSize
let startY = 0 - CGFloat(gridRows / 2) * tileSize + tileSize / 2
return CGPoint(
x: startX + CGFloat(column) * tileSize,
y: startY + CGFloat(row) * tileSize)
}
func createBackgroundTiles() {
for row in 0...gridRows {
for col in 0...gridCols {
let topLeft = (col > 0) && (row < gridRows) && tileByGridPosition(GridPosition(col: col - 1, row: row)).type == .regular
let bottomLeft = (col > 0) && (row > 0) && tileByGridPosition(GridPosition(col: col - 1, row: row - 1)).type == .regular
let topRight = (col < gridCols) && (row < gridRows) && tileByGridPosition(GridPosition(col: col, row: row)).type == .regular
let bottomRight = (col < gridCols) && (row > 0) && tileByGridPosition(GridPosition(col: col, row: row - 1)).type == .regular
// The tiles are named from 0 to 15, according to the bitmask that is made by combining these four values.
let value = Int(NSNumber(value: topLeft)) | Int(NSNumber(value: topRight)) << 1 | Int(NSNumber(value: bottomLeft)) << 2 | Int(NSNumber(value: bottomRight)) << 3
// Values 0 (no tiles)
if value != 0 {
var gridPosition = positionInGrid(column: col, row: row)
gridPosition.x -= tileSize / 2
gridPosition.y -= tileSize / 2
let backgroundNode = SKSpriteNode(imageNamed: ("background_tile_\(value)"))
backgroundNode.size = CGSize(width: tileSize, height: tileSize)
backgroundNode.alpha = 0.8
backgroundNode.position = gridPosition
backgroundNode.zPosition = 1
backgroundLayer.addChild(backgroundNode)
}
}
}
}
}
class Tile: SKSpriteNode {
private var row = 0
private var col = 0
var type: TileType = .blank
init(row: Int, col: Int, type: TileType, tileSize: CGFloat) {
super.init(texture: nil ,color: .clear, size:CGSize(width: tileSize, height: tileSize))
self.type = type
size = self.size
let square = SKSpriteNode(color: type.color, size: size)
square.zPosition = 1
addChild(square)
}
}

Answer 3

Only thing that comes to mind is when one node touches another node, at that moment in time evaluate the display of said node, as well as change the neighbors that are affected by it.

Answer 4

What we did was lay out the tiles then call this function to round the nodes of exposed tiles.
// Rounds corners of exposed tiles. UIKit inverts coordinates so top is bottom and vice-versa.
fileprivate func roundTileCorners() {
// Get all tiles
var tiles = [TileClass]()
tileLayer.enumerateChildNodes(withName: ".//*") { node, stop in
if node is TileClass {
tiles.append(node as! TileClass)
}
}
// Round corners for each exposed tile
for t in tiles {
// Convert tile's position to root coordinates
let convertedPos = convert(t.position, from: t.parent!)
// Set neighbor positions
var leftNeighborPos = convertedPos
leftNeighborPos.x -= tileWidth
var rightNeighborPos = convertedPos
rightNeighborPos.x += tileWidth
var topNeighborPos = convertedPos
topNeighborPos.y += tileHeight
var bottomNeighborPos = convertedPos
bottomNeighborPos.y -= tileHeight
// Set default value for rounding
var cornersToRound : UIRectCorner?
// No neighbor below & to left? Round bottom left.
if !isTileAtPoint(point: bottomNeighborPos) && !isTileAtPoint(point: leftNeighborPos) {
cornersToRound = cornersToRound?.union(.topLeft) ?? .topLeft
}
// No neighbor below & to right? Round bottom right.
if !isTileAtPoint(point: bottomNeighborPos) && !isTileAtPoint(point: rightNeighborPos) {
cornersToRound = cornersToRound?.union(.topRight) ?? .topRight
}
// No neightbor above & to left? Round top left.
if !isTileAtPoint(point: topNeighborPos) && !isTileAtPoint(point: leftNeighborPos) {
cornersToRound = cornersToRound?.union(.bottomLeft) ?? .bottomLeft
}
// No neighbor above & to right? Round top right.
if !isTileAtPoint(point: topNeighborPos) && !isTileAtPoint(point: rightNeighborPos) {
cornersToRound = cornersToRound?.union(.bottomRight) ?? .bottomRight
}
// Any corners to round?
if cornersToRound != nil {
t.roundCorners(cornersToRound: cornersToRound!)
}
}
}
// Returns true if a tile exists at <point>. Assumes <point> is in root node's coordinates.
fileprivate func isTileAtPoint(point: CGPoint) -> Bool {
return nodes(at: point).contains(where: {$0 is BoardTileNode })
}