how i can draw mesh topology in sprit kit using swift - graph

Question

I am trying to draw mesh Topology (graph) in sprite kit using swift. I am new for sprite kit . Please give any suggestion or sample code.

Answer 1

So as I mentioned in the comments, I don't know how to make a perfect topography algorithm, however I did come up with something that can replicate you picture.
Basically you add a bunch of plots as SKNodes, then use the .position property to use as the start and end points for a line drawn with CGPath. From that path, you can create a SKShapeNode(path: CGPath).
I also added a custom button in here that uses delegation, but it is completely separate from the actual "guts" of the topography. It's just a button.
// Overly complex way of creating a custom button in SpriteKit:
protocol DrawLinesDelegate: class { func drawLines() }
// Clickable UI element that will draw our lines:
class DrawLinesButton: SKLabelNode {
weak var drawLinesDelegate: DrawLinesDelegate?
init(text: String, drawLinesDelegate: DrawLinesDelegate) {
super.init(fontNamed: "Chalkduster")
self.drawLinesDelegate = drawLinesDelegate
self.text = text
isUserInteractionEnabled = true
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
print(drawLinesDelegate)
drawLinesDelegate?.drawLines()
}
required init?(coder aDecoder: NSCoder) { fatalError("") }
override init() { super.init() }
};
class GameScene: SKScene, DrawLinesDelegate {
var plots = [SKShapeNode]()
// var lines = [SKShapeNode]() // This may be useful in a better algorithm.
var nodesDrawnFrom = [SKShapeNode]()
var drawLinesButton: DrawLinesButton?
func drawLine(from p1: CGPoint, to p2: CGPoint) {
let linePath = CGMutablePath()
linePath.move(to: p1)
linePath.addLine(to: p2)
let line = SKShapeNode(path: linePath)
line.strokeColor = .red
line.lineWidth = 5
// lines.append(line) // Again, may be useful in a better algo.
addChild(line)
}
func drawLines() {
// Remove all lines: // Again again, may be useful in a better algorithm.
/*
for line in lines {
line.removeFromParent()
lines = []
}
*/
// The plot that we will draw from:
var indexNode = SKShapeNode()
// Find indexNode then draw from it:
for plot in plots {
// Find a new node to draw from (the indexNode):
if nodesDrawnFrom.contains(plot) {
continue
} else {
indexNode = plot
}
// Draw lines to every other node (from the indexNode):
for plot in plots {
if plot === indexNode {
continue
} else {
drawLine(from: indexNode.position, to: plot.position)
nodesDrawnFrom.append(indexNode)
}
}
}
}
func addNode(at location: CGPoint) {
let plot = SKShapeNode(circleOfRadius: 50)
plot.name = String(describing: UUID().uuid)
plot.zPosition += 1
plot.position = location
plot.fillColor = .blue
plots.append(plot)
addChild(plot)
}
override func didMove(to view: SKView) {
drawLinesButton = DrawLinesButton(text: "Draw Lines", drawLinesDelegate: self)
drawLinesButton!.position.y = frame.minY + (drawLinesButton!.frame.size.height / 2)
addChild(drawLinesButton!)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let location = touches.first!.location(in: self)
addNode(at: location)
}
}
imperfect algo:
Here you can see that there are multiple lines being drawn from one to another when you had mid-points (that is something blocking a straight line):
You would need to add another entire section to the algorithm to check for this.
Another important thing to note is that SKShapeNode() is very unperformant, and it would be best to transform all of these to SpriteNodes, or to bit-blit the entire scene onto a static texture.
However, having them all as ShapeNodes give you the most flexibility, and is easiest to explain here.