基于CAEmitterLayer的雨天、下雪、火焰、烟花粒子效果demo

基于CAEmitterLayer的雨天、下雪、火焰、烟花粒子效果demo

demo源码地址：

CAEmitterLayer是继承自CALayer的layer类,拥有众多属性ios下雪下雨的，其中此demo用到的属性有：

emitterCells：是拿来与CAEmitterLayer关联显示粒子效果的，是CAEmitterCell的实例化对象，必须有值；

emitterPosition：粒子排放位置，默认值是(0, 0)；

emitterShape：粒子排放形状ios下雪下雨的，默认值是kCAEmitterLayerPoint；

emitterSize：粒子排放的大小，取决于emitterShape，可忽略；

emitterMode：粒子排放模式，默认值是kCAEmitterLayerVolume；

renderMode：粒子渲染方式，默认值是kCAEmitterLayerUnordered.

CAEmitterCell继承自NSObject且遵守一定协议的类，拥有众多属性，其中此demo用到的属性有：

birthRate：粒子每秒产生个数；

lifetime：粒子的生命周期；

emissionRange:粒子排放的范围；

velocity：粒子的速率；

velocityRange：粒子速度变化值；

alphaSpeed：粒子生命周期内色彩差异速度；

contents：CAEmitterCell的内容，是CGImageRef类型。

核心代码

// 下雨、下雪

/**

* 设置emitterLayer的属性

*/

- (void)initEmitterLayerProperties {

self.emitterLayer.emitterSize = self.frame.size;

self.emitterLayer.emitterPosition = CGPointMake(self.frame.origin.x, self.frame.origin.y);

}

/**

* 设置emitterCell的属性并与emitterLayer关联显示效果

*

* @param weather 天气名称

*/

- (void)showWeather:(NSString *)weather {

CAEmitterCell *emitterCell = [CAEmitterCell emitterCell];

emitterCell.birthRate = 20.f;

emitterCell.lifetime = 100.f;

emitterCell.velocity = 10.f;

emitterCell.velocityRange = 3.f;

emitterCell.yAcceleration = 5.f;

emitterCell.emissionRange = 6 * M_2_PI;

emitterCell.contents = (__bridge id _Nullable)([UIImage imageNamed:weather].CGImage);

self.emitterLayer.emitterCells = @[emitterCell];

}

// 火焰

/**

* 设置emitterLayer的属性

*/

- (void)initEmitterLayerProperties {

self.emitterLayer.emitterSize = self.frame.size;

self.emitterLayer.emitterPosition = CGPointMake(self.frame.origin.x, self.frame.origin.y);

self.emitterLayer.emitterMode = kCAEmitterLayerPoints;

self.emitterLayer.renderMode = kCAEmitterLayerBackToFront;

}

/**

* 设置emitterCell的属性并与emitterLayer关联显示效果

*/

- (void)show {

CAEmitterCell *emitterCell = [CAEmitterCell emitterCell];

emitterCell.birthRate = 200.f;

emitterCell.lifetime = 10.f;

emitterCell.velocity = 10.f;

emitterCell.velocityRange = 15.f;

emitterCell.emissionRange = 2 * M_PI;

emitterCell.alphaSpeed -= 0.5f;

emitterCell.contents = (__bridge id _Nullable)([UIImage imageNamed:@"fire_selected"].CGImage);

self.emitterLayer.emitterCells = @[emitterCell];

}

// 烟花

/**

* 设置emitterLayer的属性

*/

- (void)initEmitterLayerProperties {

self.emitterLayer.emitterSize = self.frame.size;

self.emitterLayer.emitterPosition = CGPointMake(self.frame.origin.x, self.frame.origin.y);

self.emitterLayer.emitterMode = kCAEmitterLayerPoints;

self.emitterLayer.renderMode = kCAEmitterLayerBackToFront;

}

/**

* 设置emitterCell的属性并与emitterLayer关联显示效果

*/

- (void)show {

CAEmitterCell *emitterCell = [CAEmitterCell emitterCell];

emitterCell.birthRate = 50.f;

emitterCell.lifetime = 6.f;

emitterCell.velocity = 50.f;

emitterCell.velocityRange = 100.f;

emitterCell.emissionRange = 2 * M_PI;

emitterCell.alphaSpeed -= 0.5f;

emitterCell.contents = (__bridge id _Nullable)([UIImage imageNamed:@"fireworks_selected"].CGImage);

self.emitterLayer.emitterCells = @[emitterCell];

}

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