Really cruddy iOS particle system to demo emissionLongitude

SFSViewController.m

//
//  SFSViewController.m
//  AmazingParticleSpinner
//
//  Created by Thomas Dimson on 9/15/12.
//  Copyright (c) 2012 Thomas Dimson. All rights reserved.
//

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

@implementation SFSViewController {
    __weak UILabel *_angleLabel;
    __weak CAEmitterLayer *_emitterLayer;
}

- (void)viewDidLoad
{
    [super viewDidLoad];


    CAEmitterLayer *emitterLayer = [CAEmitterLayer layer];
    emitterLayer.emitterPosition = self.view.center;
    _emitterLayer = emitterLayer;
    [self.view.layer addSublayer:emitterLayer];
    
    CAEmitterCell *funnyEmitterCell = [CAEmitterCell emitterCell];
    funnyEmitterCell.contents = (id)[UIImage imageNamed:@"funny.jpg"].CGImage;
    funnyEmitterCell.birthRate = 10.0;
    funnyEmitterCell.velocity = 200.0;
    funnyEmitterCell.lifetime = 5.0;
    funnyEmitterCell.scale = 0.1;
    funnyEmitterCell.name = @"funny";
    emitterLayer.emitterCells = [NSArray arrayWithObject:funnyEmitterCell];
    [self bumpAngle];
    
    UILabel *angleLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 20, 100, 30)];
    angleLabel.backgroundColor = [UIColor clearColor];
    [self.view addSubview:angleLabel];
    _angleLabel = angleLabel;
}

- (void) bumpAngle {
    NSNumber *emissionLongitude = [_emitterLayer valueForKeyPath:@"emitterCells.funny.emissionLongitude"];
    NSNumber *nextLongitude = [NSNumber numberWithFloat:[emissionLongitude floatValue] + 0.02];
    [_emitterLayer setValue:nextLongitude forKeyPath:@"emitterCells.funny.emissionLongitude"];
    _angleLabel.text = [NSString stringWithFormat:@"%.0f degrees", [nextLongitude floatValue] * 180 / M_PI];
   [self performSelector:@selector(bumpAngle) withObject:nil afterDelay:0.1];
}


@end