SpriteKit particle emitter change color

Question

I have created a particle effect using the editor and now I'd like to change particleColor in code. I have set particleColorSequence to nil (otherwise I the colors would come from the color ramp in the editor and not my code) and particleColorBlendFactor is set to 1.0. I assign a random color to particleColor in the update method with the hopes that it will change each time through the loop. It does choose a random color the first time through, but then the color never varies. Can someone please explain why?

Global

let emitter = SKEmitterNode(fileNamed: "squares.sks")
let colors = [SKColor.red, SKColor.green, SKColor.blue]

didMove(to view:)

emitter?.particleColorBlendFactor = 1.0
emitter?.particleColorSequence = nil
addChild(emitter!)

update(_ currentTime:)

let random = Int(arc4random_uniform(UInt32(self.colors.count)))
emitter?.particleColor = colors[random]

pbodsk pbodsk · Accepted Answer · 2017-04-18T07:14:34

This hardly counts as an answer but I couldn't fit it all into a comment so...please bear with me.

The good news is that your code seems to work!

I tried creating a new Sprite Kit project and pasted your code into that so I ended up with a GameScene class of type SKScene looking like this:

import SpriteKit
import GameplayKit

class GameScene: SKScene {
 
    let emitter = SKEmitterNode(fileNamed: "squares.sks")
    let colors = [SKColor.red, SKColor.green, SKColor.blue]
    var lastUpdateTime: TimeInterval?

    override func didMove(to view: SKView) {
        emitter?.particleColorBlendFactor = 1.0
        emitter?.particleColorSequence = nil
        addChild(emitter!)
    }

    override func update(_ currentTime: TimeInterval) {
        var delta = TimeInterval()
        if let last = lastUpdateTime {
            delta = currentTime - last
        } else {
            delta = currentTime
        }
        if delta > 1.0 {
            lastUpdateTime = currentTime
            let random = Int(arc4random_uniform(UInt32(self.colors.count)))
            emitter?.particleColor = colors[random]
        }
    }
}

And then I created a new SKEmitterNode from the template (I used fire...just to chose something) and named it squares.sks.

When I run that, I can see this:

So...where does that leave us?

I'm thinking there must be something different in your setup. If you try to create a new example project like mine, are you able to get it to work?

Yeah...hardly an answer I know, but think of it as a reassurance that you are on the right path at least :)

SpriteKit particle emitter change color

1 Answers

So...where does that leave us?