Psychedelic smoke CAEmitterLayer particle effect

SFSSmokeScreen.m

#import "SFSSmokeScreen.h"
#import <QuartzCore/QuartzCore.h>

@implementation SFSSmokeScreen {
    __weak CAEmitterLayer*smokeEmitter;
}

-(id)initWithFrame:(CGRect)frame emitterFrame:(CGRect)emitterFrame{
   if ((self = [super initWithFrame:frame])) {
       self.backgroundColor = [UIColor clearColor];
       smokeEmitter = (CAEmitterLayer*)self.layer;
       smokeEmitter.emitterPosition = CGPointMake(emitterFrame.origin.x + emitterFrame.size.width / 2,
                                                 emitterFrame.origin.y + emitterFrame.size.height / 2);
       smokeEmitter.emitterSize = emitterFrame.size;
       smokeEmitter.emitterShape = kCAEmitterLayerRectangle;

       CAEmitterCell*smokeCell = [CAEmitterCell emitterCell];
       smokeCell.contents = (__bridge id)[[UIImage imageNamed:@"SmokeParticle.png"] CGImage];
       [smokeCell setName:@"smokeCell"];

       smokeCell.birthRate = 150;
       smokeCell.lifetime = 1.0;
       smokeCell.lifetimeRange = 0.5;
       smokeCell.color = [[UIColor colorWithRed:0.6 green:0.6 blue:0.6 alpha:1.0] CGColor];
       smokeCell.redRange = 1.0;
       smokeCell.redSpeed = 0.5;
       smokeCell.blueRange = 1.0;
       smokeCell.blueSpeed = 0.5;
       smokeCell.greenRange = 1.0;
       smokeCell.greenSpeed = 0.5;
       smokeCell.alphaSpeed = -0.2;

       smokeCell.velocity = 50;
       smokeCell.velocityRange = 20;
       smokeCell.yAcceleration = -100;
       smokeCell.emissionLongitude = -M_PI / 2;
       smokeCell.emissionRange = M_PI / 4;

       smokeCell.scale = 1.0;
       smokeCell.scaleSpeed = 1.0;
       smokeCell.scaleRange = 1.0;

       smokeEmitter.emitterCells = [NSArray arrayWithObject:smokeCell];
   }
    return self;
    
}

+ (Class) layerClass {
    return [CAEmitterLayer class];
}

- (void) stopEmitting {
    smokeEmitter.birthRate = 0.0;
}


@end