我想创造一个像烟花一样的效果。我知道我可以使用 CAEmitterCell。我尝试下载一些示例,但我仍在 iOS 5.0 中使用此功能
有人知道如何使用 CAEmitterCell 创建烟花效果的好教程吗?
我需要创建如下内容:
所有粒子都从中心(红色圆圈)向绿色圆圈方向移动。红圈这是初始点,将有一些 CGPoint 值。
我找到了这个解决方案:
这就是 DWFParticleView.h 文件的外观
#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
这就是 DWFParticleView.m 的外观
#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
这是在屏幕上一键点击的方法,例如显示我们的效果
- (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];
}
我在这里找到的材料:雷