SKAction Sequencing and Grouping Animations - swift

Question

I'm doing some death animations for a game, and wanted to ask for some help. I want my monster to disappear in a puff of smoke, but not before it animates a slash effect going across his body.
I have 3 animations that I want to use:
weaponSlash - a line that draws across the monster. Looks like you slashed him with a sword.
smoke - a puff of smoke that slowly expands out
monsterFalling - the monster falls back, startled
What I want to do is play it in this order:
Simultaneously, the slash appears & the monster starts to fall back
About 0.25s into the above animation, I want the cloud to start to appear
When the cloud is about to end (so maybe after 1s) I want the monster to disappear
Remove the smoke, the monster, the sword, etc, and drop some coins on the ground
I started like this, as a test that works somewhat: (ignore the above times for now)
//Cancel any current actions, like a monster attacking
monster.removeAllActions()
//since you can't play 3 animations on one node at the same time, you have to create 3 separate nodes for everything
let slash = SKSpriteNode()
let cloud = SKSpriteNode()
cloud.size = monster.size
slash.size = monster.size
monster.addChild(cloud)
monster.addChild(slash)
//Start the slash animation
slash.run(self.player.currentlyEquippedWeapon.attackAnimation())
//Start the cloud animation (how I get it is elsewhere and not relevant)
cloud.run(cloudAnimation)
//Run the monster death animation, followed by the cleanup/coin dropping
monster.run(SKAction.sequence([monster.deathAnimation(), SKAction.wait(forDuration: 1), postDeathActions]))
The variable PostDeathActions above simply removes the monster node and animates some coins falling.
WHERE I NEED SOME HELP
So the above code doesn't work so great in that the animations all run independently of each other. Based on this, you can see how regardless of whether the slash/cloud finish, the monster will run two actions: him falling back, followed by cleanup, which just removes the monster and spawns the coins. As you can see I tried to delay this by adding a 1s delay but this is all somewhat of a hack since I may have different monsters or attacks, etc, that are faster/slower. I'd rather guarantee that everything finishes before I despawn the monster.
I tried to group this into an SKAction.Run like so:
let preDeath = SKAction.run {
[unowned self] in
monster.run(monster.deathAnimation()
slash.run(self.player.currentlyEquippedWeapon.attackAnimation())
cloud.run(cloudAnimation)
}
but this runs everything at the same time again.
What I want to do is sequence it like this (pseudo code):
let preDeathAnimations = SKAction.Group([slash, cloud, monsterDeathAnimation])
])
SKAction.sequence([preDeathAnimations, postDeathActions])
So this way it'll run all 3 before running cleanup.
Is there a way to do something like this? I know Sequnce/Group need to be run against an SKNode, but I don't have 3 separate ones.
Thanks for your time reading this and any advice you can offer!

Answer 1

This is one idea that I had, but you could use threading + state + onCompletion blocks to take the math out of it. I didn't test it out fully but this general concept should work:
let slash = SKAction.fadeIn(withDuration: 0.5)
let fall = SKAction.fadeOut(withDuration: 0.25)
let puff = SKAction.fadeIn(withDuration: 0.1)
// Put in ALL of the actions from ALL parties that you want to happen prior to puff:
func findLongestTime(from actions: [SKAction]) -> TimeInterval {
var longestTime = TimeInterval(0)
for action in actions {
if action.duration > longestTime { longestTime = action.duration }
}
// Note, if you put a sequence into this function I don't know if it will work right..
// Might need another func like `findDurationOfSequence(_ sequence: SKAction) -> TimeInterval
return longestTime
}
// Note, if you have the monster doing more than falling prior to puff, then you will
// need to subtract those as well:
let monsterActionsPriorToPuff = [fall]
// Add the duration of all monster animations prior to puff:
var MAPTP_duration = TimeInterval(0)
for action in monsterActionsPriorToPuff {
MAPTP_duration += action.duration
}
// Calculate our final wait time, with no negative numbers:
var waitTime = findLongestTime(from: [slash, fall]) - MAPTP_duration
if waitTime < 0 { waitTime = 0 }
let wait = SKAction.wait(forDuration: waitTime)
// Our monster sequence (I forgot to add the disappear, just add after puff)
let monsterSequence = SKAction.sequence([fall, wait, puff])
// Player slashes:
SKSpriteNode().run(slash)
// Monster will wait 0.25 seconds after falling,
// for slash to finish before puffing:
SKSpriteNode().run(monsterSequence)
et me know if this idea isn't working I can try updating it.