how to set duration for individual SKTextures in animation

Question

I am trying to set duration for individual SKTextures in an animation. Below the armsAtlas texture atlas. I would like to set the upTexture to last between 1-4 seconds randomly followed by the downTexture to last between 0.3 - 1 second. How can I set these duration ranges for the individual textures?

let armsAtlas = SKTextureAtlas(named: "arms")
let downTexture = armsAtlas.textureNamed("down")
let upTexture = armsAtlas.textureNamed("up")

Answer 1

You can use SKAction sequence and it's waitForDuration:withRange: method, like this:

//By default, the sprite is initialized with downTexture
let sprite = SKSpriteNode(texture: downTexture)
sprite.position = CGPoint(x: 200, y: 200)
addChild(sprite)
let sequence = SKAction.sequence([

    SKAction.runBlock({NSLog("Up texture set")}), //Added just for debugging to print a current time
    SKAction.setTexture(upTexture),
    SKAction.waitForDuration(2.5, withRange: 3.0),  //Wait between 1.0 and 4.0 seconds
    SKAction.runBlock({NSLog("Down texture set")}),
    SKAction.setTexture(downTexture),
    SKAction.waitForDuration(0.65, withRange: 0.7),//Wait between 0.3 and 1.0 seconds
    ])

let action = SKAction.repeatActionForever(sequence)

sprite.runAction(action, withKey: "aKey")

What this code does, is that it creates a sprite, initialize it with downTexture by default and:

• swap texture to upTexture immediately
• waits between 1 and 4 seconds
• swap texture to downTexture
• waits between 0.3 and 1 seconds
• repeats all this forever

If you want to stop this action, you can access it like this:

if sprite.actionForKey("aKey") != nil {
            removeActionForKey("aKey")
}

Answer 2

There are lots of ways to do this.

You could use SKAction delay to swap randomly between them...

func setTexture(texture: SKTexture, delay: NSTimeInterval, range: NSTimeInterval) -> SKAction {
    let textureAction = SKAction.setTexture(texture)
    let delayAction = SKAction.waitForDuration(delay, withRange: range)
    return SKAction.sequence([delayAction, textureAction])
}

No set up the action to switch between the two...

let downAction = setTexture(downTexture, delay: 0.65, range: 0.35)
let upAction = setTexture(upTexture, delay: 2.5, range: 1.5)
let sequenceAction = SKAction.sequence([downAction, upAction])
let repeatAction = SKAction.repeatActionForever(sequenceAction)

yourTexturedSprite.runAction(repeatAction)