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ios - 当 CAEmitterLayer 的 CAEmitter Cells 的生命周期结束时,你如何移除它——而不是重复直到你从 super 层中移除它

转载 作者:可可西里 更新时间:2023-11-01 05:47:03 25 4
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我正在以稍微改变的方式使用通用代码(来自 iOS Fireworks 演示)。我在 UIView 的子类中有以下内容。我想要的是让烟花出现在用户触摸(不是用力)的地方,并在 CAEmitterLayer/CAEmitterCells“生命周期”的长度内播放。相反,当我将它添加到 addSublayer 时,这会立即开始——就像我确信它的意思一样。但是,我想以稍微不同的方式使用它。有没有一种方法可以更改它,以便有一个带有完成 block 的 CATransaction(到 removeFromSuperlayer)或类似的东西?欢迎任何想法。

 #import "FireworksView.h"

@implementation FireworksView

- (void)launchFirework{

//Load the spark image for the particle

CAEmitterLayer *mortor = [CAEmitterLayer layer];
mortor.emitterPosition = CGPointMake(self.bounds.size.width/2, self.bounds.size.height*(.75));
mortor.renderMode = kCAEmitterLayerAdditive;

//Invisible particle representing the rocket before the explosion
CAEmitterCell *rocket = [CAEmitterCell emitterCell];
rocket.emissionLongitude = -M_PI / 2;
rocket.emissionLatitude = 0;
rocket.lifetime = 1.6;
rocket.birthRate = 1;
rocket.velocity = 400;
rocket.velocityRange = 100;
rocket.yAcceleration = 250;
rocket.emissionRange = M_PI / 4;
rocket.color = CGColorCreateCopy([UIColor colorWithRed:.5 green:.5 blue:.5 alpha:.5].CGColor);
rocket.redRange = 0.5;
rocket.greenRange = 0.5;
rocket.blueRange = 0.5;

//Name the cell so that it can be animated later using keypath
[rocket setName:@"rocket"];

//Flare particles emitted from the rocket as it flys
CAEmitterCell *flare = [CAEmitterCell emitterCell];
flare.contents = (id)[UIImage imageNamed:@"tspark.png"].CGImage;
flare.emissionLongitude = (4 * M_PI) / 2;
flare.scale = 0.4;
flare.velocity = 100;
flare.birthRate = 45;
flare.lifetime = 1.5;
flare.yAcceleration = 350;
flare.emissionRange = M_PI / 7;
flare.alphaSpeed = -0.7;
flare.scaleSpeed = -0.1;
flare.scaleRange = 0.1;
flare.beginTime = 0.01;
flare.duration = 0.7;

//The particles that make up the explosion
CAEmitterCell *firework = [CAEmitterCell emitterCell];
firework.contents = (id)[UIImage imageNamed:@"tspark.png"].CGImage;
firework.birthRate = 9999;
firework.scale = 0.6;
firework.velocity = 130;
firework.lifetime = 2;
firework.alphaSpeed = -0.2;
firework.yAcceleration = 80;
firework.beginTime = 1.5;
firework.duration = 0.1;
firework.emissionRange = 2 * M_PI;
firework.scaleSpeed = -0.1;
firework.spin = 2;

//Name the cell so that it can be animated later using keypath
[firework setName:@"firework"];

//preSpark is an invisible particle used to later emit the spark
CAEmitterCell *preSpark = [CAEmitterCell emitterCell];
preSpark.birthRate = 80;
preSpark.velocity = firework.velocity * 0.70;
preSpark.lifetime = 1.7;
preSpark.yAcceleration = firework.yAcceleration * 0.85;
preSpark.beginTime = firework.beginTime - 0.2;
preSpark.emissionRange = firework.emissionRange;
preSpark.greenSpeed = 100;
preSpark.blueSpeed = 100;
preSpark.redSpeed = 100;

//Name the cell so that it can be animated later using keypath
[preSpark setName:@"preSpark"];

//The 'sparkle' at the end of a firework
CAEmitterCell *spark = [CAEmitterCell emitterCell];
spark.contents = (id)[UIImage imageNamed:@"tspark.png"].CGImage;
spark.lifetime = 0.05;
spark.yAcceleration = 250;
spark.beginTime = 0.8;
spark.scale = 0.4;
spark.birthRate = 10;

preSpark.emitterCells = [NSArray arrayWithObjects:spark, nil];
rocket.emitterCells = [NSArray arrayWithObjects:flare, firework, preSpark, nil];
mortor.emitterCells = [NSArray arrayWithObjects:rocket, nil];

[self.layer addSublayer:mortor];
}

最佳答案

答案是,使用 CAEmitter,没有办法——委托(delegate)等——在循环结束时停止发射器。您唯一可以做的就是在您认为应该删除它时从图层中优雅地删除它。

关于ios - 当 CAEmitterLayer 的 CAEmitter Cells 的生命周期结束时,你如何移除它——而不是重复直到你从 super 层中移除它,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9643370/

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