Question

我使用以下代码定期生成SKNode。有没有办法使这些SKNode的生成周期随机。具体来说，如何使以下代码中的“delayFish”成为一个随机延迟的动作？

[self removeActionForKey:@"fishSpawn"];
SKAction* spawnFish = [SKAction performSelector:@selector(spawnLittleFishes) onTarget:self];
SKAction* delayFish = [SKAction waitForDuration:3.0/_moving.speed];
SKAction* spawnThenDelayFish = [SKAction sequence:@[spawnFish, delayFish]];
SKAction* spawnThenDelayFishForever = [SKAction repeatActionForever:spawnThenDelayFish];
[self runAction:spawnThenDelayFishForever withKey:@"fishSpawn"];

Answer 1

<强> ObjC：

首先设定平均延迟和范围......

#define kAverageDelay    2.0
#define kDelayRange      1.0     // vary by plus or minus 0.5 seconds

然后将您的delayFish操作更改为此...

SKAction* delayFish = [SKAction waitForDuration:kAverageDelay withRange:kDelayRange];

<强>夫特：

首先设定平均延迟和范围......

let averageDelay:TimeInterval = 2.0
let delayRange:TimeInterval = 1.0     // vary by plus or minus 0.5 seconds

然后将您的delayFish操作更改为此...

let delayFish = SKAction.wait(forDuration:averageDelay, withRange:delayRange)

Answer 2

插入随机浮点而不是固定浮点数。

在你的情况下是这样的：

double value = ((double)arc4random() / ARC4RANDOM_MAX) 
   * (maxValue - minValue)
   + minValue;

SKAction* delayFish = [SKAction waitForDuration:value/_moving.speed];

我明白了。在您的情况下，这不会起作用，因为repeatActionForever将使用最后创建的随机值运行。永远。也许试试这个。我不确定这是否有效：

SKAction* delayFish = [SKAction waitForDuration: (((double)arc4random() / ARC4RANDOM_MAX) * (maxValue - minValue)+ minValue)/_moving.speed];

我建议将随机值设为自己的方法。

-(double) getRandomValue(){
    return (((double)arc4random() / ARC4RANDOM_MAX) * (maxValue - minValue)+ minValue);
}

编辑：

以下是类似问题的链接。也许这可能有所帮助。遗憾！

SKAction *randomXMovement = [SKAction runBlock:^(void){
    NSInteger xMovement = arc4random() % 20;
    NSInteger leftOrRight = arc4random() % 2;
    if (leftOrRight == 1) {
        xMovement *= -1;
    }
    SKAction *moveX = [SKAction moveByX:xMovement y:0 duration:1.0];
    [aSprite runAction:moveX];
}];

SKAction *wait = [SKAction waitForDuration:1.0];
SKAction *sequence = [SKAction sequence:@[randomXMovement, wait]];
SKAction *repeat = [SKAction repeatActionForever:sequence];
[aSprite runAction: repeat];

来源：SKAction: How to Animate Random Repeated Actions

SKAction：如何在节点生成中生成随机延迟

2 个答案: