iOS CAEmitterCell firework effect - ios

Question

I'm wanna create an effect like firework. I know that I can use for it CAEmitterCell. I tried to download few examples, but I still in progress with this feature in iOS 5.0
Anybody know good tutorial how to create firework effect using CAEmitterCell?
I need to create something like below:
All particles are going from the center (red circle) in direction to green circles. Red circle this is initial point that will have some CGPoint value.

Answer 1

I have found this solution:
it's how DWFParticleView.h file looks
#import <UIKit/UIKit.h>
#interface DWFParticleView : UIView
#property (nonatomic) CGFloat time;
-(void)configurateEmmiter;
-(void)setEmitterPositionFromTouch: (UITouch*)t;
-(void)setIsEmitting:(BOOL)isEmitting andPoint:(CGPoint)point;
#end
this is how looks DWFParticleView.m
#import "DWFParticleView.h"
#import <QuartzCore/QuartzCore.h>
#implementation DWFParticleView
{
CAEmitterLayer* fireEmitter; //1
}
-(void)configurateEmmiter
{
//set ref to the layer
fireEmitter = (CAEmitterLayer*)self.layer; //2
//configure the emitter layer
fireEmitter.emitterPosition = CGPointMake(50, 50);
fireEmitter.emitterSize = CGSizeMake(5, 5);
CAEmitterCell* fire = [CAEmitterCell emitterCell];
fire.birthRate = 0;
fire.lifetime = 2.0;
fire.lifetimeRange = 0.5;
//fire.color = [[UIColor colorWithRed:0.8 green:0.4 blue:0.2 alpha:0.6] CGColor];
fire.contents = (id)[[UIImage imageNamed:#"star_icon.png"] CGImage];
[fire setName:#"fire"];
fire.velocity = 80;
fire.velocityRange = 20;
fire.emissionRange = M_PI * 2.0f;
fire.scaleSpeed = 0.1;
fire.spin = 0.5;
//add the cell to the layer and we're done
fireEmitter.emitterCells = [NSArray arrayWithObject:fire];
fireEmitter.renderMode = kCAEmitterLayerAdditive;
}
+ (Class) layerClass {
return [CAEmitterLayer class];
}
-(void)setEmitterPositionFromTouch: (UITouch*)t
{
//change the emitter's position
fireEmitter.emitterPosition = [t locationInView:self];
}
-(void)setIsEmitting:(BOOL)isEmitting andPoint:(CGPoint)point
{
fireEmitter.emitterPosition = point;
//turn on/off the emitting of particles
[fireEmitter setValue:[NSNumber numberWithInt:isEmitting?50:0]
forKeyPath:#"emitterCells.fire.birthRate"];
[self performSelector:#selector(decayStep) withObject:nil afterDelay:self.time];
}
- (void)decayStep {
[fireEmitter setValue:[NSNumber numberWithInt:0]
forKeyPath:#"emitterCells.fire.birthRate"];
}
#end
this is method one tap on screen for example that shows our effect
- (void)tap {
DWFParticleView *fireView = [[DWFParticleView alloc] init];
fireView.time = 0.3;
[fireView setUserInteractionEnabled:NO];
[fireView configurateEmmiter];
[fireView setFrame:CGRectMake(0, 0, 0, 0)];
[fireView setBackgroundColor:[UIColor redColor]];
[self.view addSubview:fireView];
}
the material I have found here: ray