ActionBuilder

Caveat developer: As this package is pre-release, the API may change significantly without notice. It has not been tested, so use it at your own risk.

ActionBuilder allows you to write SpriteKit animations in a more succinct, declarative manner. It consists of various structs representing basic animations like Scale and Rotate.

An animation created with ActionBuilder:

let emote =
Sequence {
    Group {
        FadeIn(duration: 0.7)
        Scale(by: 1.5, duration: 0.7)
        Move(to: (0, 30), duration: 0.7)
    }
    Wait(0.5)
    FadeOut(duration: 1)
    Remove()
}

Versus the same animation using Apple’s SpriteKit SKActions:

let emoteAction: SKAction = {
    let fadeIn = SKAction.fadeIn(withDuration: 0.7)
    let grow = SKAction.scale(by: 1.5, duration: 0.7)
    let moveUp = SKAction.moveTo(y: 30, duration: 0.7)
    let appear = SKAction.group([fadeIn, grow, moveUp])
    let wait = SKAction.wait(forDuration: 1)
    let disappear = SKAction.fadeOut(withDuration: 1)
    let remove = SKAction.removeFromParent()
    let emoteAnimation = SKAction.sequence([appear, wait, disappear, remove])
    return emoteAnimation
}()

ActionBuilder allows you to use conditional and looping statements within your animation declaration to make them more flexible and easier to write.

Coordinate animations across multiple nodes with the changeTarget(to:) modifier.

Custom operators included: + will concatenate actions into a sequence, & will group them to run simultaneously, - will reverse reversible actions, and * allows you to repeat an action multiple times.

You can even include SKActions if no equivalent is available in ActionBuilder.

let node = SKNode()
let otherNode = SKNode()

node.run {
    Group {
        
        Sequence {
            for i in 0...9 {
                Colorize(with: UIColor(red: Double(i/10), green: 0.7, blue: 0.7, alpha: 1))
                Wait(0.2)
            }
        }
        .changeTarget(to: otherNode)
        
        Sequence {
            let moveUp = Move(by: (0, 10))
            if Bool.random() {
                moveUp * 2
            } else {
                -moveUp
            }
            
            SKAction.resize(toHeight: 20, duration: 5)
        }
    }
}

See Apple’s documentation: https://developer.apple.com/documentation/spritekit/skaction/action_initializers