Open Radar

 
Summary:
When using a SKEmitterNode in iOS 9.0, particles are not being emitted (or rendered to the screen) when the emitter's particleAction is a SKAction that uses the method 'animateWithTextures: timePerFrame'.

This works as expected in iOS 8.

The attached sample project contains a segmented control that allows you to see:
 - a single node with a single static texture (works on iOS 8 and iOS 9),
 - a single node with an animating texture (works on iOS 8 and iOS 9),
 - a particle emitter, emitting particles with a single static texture (works on iOS 8 and iOS 9),
 - a particle emitter, emitting particles with animated textures (works on iOS 8, DOES NOT work on iOS 9).

Running the app on an iOS 8 device / simulator and selecting the option 'Emitter - Animating' will allow you to see the final desired outcome of a confetti like effect. Basically falling particles that are animating through a series of textures to give a 3D rotating effect as they fall.

The following code is from a single animating node that works as expected in iOS 9.

    self.spriteAnimation = [SKAction animateWithTextures:self.textureArray timePerFrame:(kAnimationDuration/self.textureArray.count)];
    [self.confettiNodeAnimating runAction:[SKAction repeatActionForever:self.spriteAnimation]];


However the following code fails to produce emitted particles with animating textures on iOS 9.0:

    self.spriteAnimation = [SKAction animateWithTextures:self.textureArray timePerFrame:(kAnimationDuration/self.textureArray.count)];
    self.confettiEmitterAnimating.particleAction = [SKAction repeatActionForever:self.spriteAnimation];


This leads me to believe there is an issue with using animated textures in conjunction with the emitter's particleAction.

Steps to Reproduce:
1. Open provided example app on iOS 8 device or simulator.
2. Use the segmented control to view all nodes / emitters.
3. Notice how all segments selections produce either a single node or particle emitter (static or animating through textures).
4. Open the provided app on iOS 9 device or simulator.
5. Use the segmented control to view all nodes / emitters.
6. Notice how the 'Emitter - Animating' does not render any particles to the screen.
7. Notice that the 'Emitter - Static' will render particles to the screen, but will stop rendering if the user selects another option and then re-selects 'Emitter - Static'.

Expected Results:
Expected to see the animated particles being emitted in both iOS 8 and iOS 9 when selecting the 'Emitter - Animating' option in the provided example project (SpriteKitAnimationSample).

Actual Results:
Animated particles are not emitted / rendered to the screen when built for iOS 9.

Version:
Xcode Version 7.0 beta 6 (7A192o) - iOS 9.0 (13A4325c)

Configuration:
iPhone 6 Plus - Model A1524