ios 烟花 火焰 雨水 雪花等特效属性

CAEmitterLayer *snowEmitter = [CAEmitterLayer layer];
  //例子发射位置
  snowEmitter.emitterPosition = CGPointMake(120,20);
  //发射源的尺寸大小
  snowEmitter.emitterSize = CGSizeMake(self.view.bounds.size.width * 20, 20);
  //发射模式
  snowEmitter.emitterMode = kCAEmitterLayerSurface;
  //发射源的形状
  snowEmitter.emitterShape = kCAEmitterLayerLine;
  
  //创建雪花类型的粒子
  CAEmitterCell *snowflake = [CAEmitterCell emitterCell];
  //粒子的名字
  snowflake.name = @"snow";
  //粒子参数的速度乘数因子
  snowflake.birthRate = 1.0;
  snowflake.lifetime = 120.0;
  //粒子速度
  snowflake.velocity =10.0;
  //粒子的速度范围
  snowflake.velocityRange = 10;
  //粒子y方向的加速度分量
  snowflake.yAcceleration = 2;
  //周围发射角度
  snowflake.emissionRange = 0.5 * M_PI;
  //子旋转角度范围
  snowflake.spinRange = 0.25 * M_PI;
  snowflake.contents = (id)[[UIImage imageNamed:@"DazFlake"] CGImage];
  //设置雪花形状的粒子的颜色
  snowflake.color = [[UIColor colorWithRed:0.200 green:0.258 blue:0.543 alpha:1.000] CGColor];
  
  //创建星星形状的粒子
  CAEmitterCell *snowflake1 = [CAEmitterCell emitterCell];
  //粒子的名字
  snowflake1.name = @"snow";
  //粒子参数的速度乘数因子
  snowflake1.birthRate = 1.0;
  snowflake1.lifetime = 120.0;
  //粒子速度
  snowflake1.velocity =10.0;
  //粒子的速度范围
  snowflake1.velocityRange = 10;
  //粒子y方向的加速度分量
  snowflake1.yAcceleration = 2;
  //周围发射角度
  snowflake1.emissionRange = 0.5 * M_PI;
  //子旋转角度范围
  snowflake1.spinRange = 0.25 * M_PI;
  //粒子的内容和内容的颜色
  snowflake1.contents = (id)[[UIImage imageNamed:@"DazStarOutline"] CGImage];
  snowflake1.color = [[UIColor colorWithRed:0.600 green:0.658 blue:0.743 alpha:1.000] CGColor];
  
  snowEmitter.shadowOpacity = 1.0;
  snowEmitter.shadowRadius = 0.0;
  snowEmitter.shadowOffset = CGSizeMake(0.0, 1.0);
  //粒子边缘的颜色
  snowEmitter.shadowColor = [[UIColor redColor] CGColor];
  
  snowEmitter.emitterCells = [NSArray arrayWithObjects:snowflake,snowflake1,nil];
  [self.view.layer insertSublayer:snowEmitter atIndex:0];
  // Do any additional setup after loading the view