按住按钮时发射弹丸

Question

我想在我的游戏中做的是在按住射击按钮的同时不断发射射弹。我一直在使用的是简单的 touchesBegan 和 touchesMoved（仅调用 touchesBegan）解决方案。所以我遇到的问题是：如果你按住按钮你只会发射一次，但是如果你在按住它的同时稍微移动触摸点（调用touchesMoved方法），你将一次发射多个弹丸。

我需要帮助的是：如何在按住按钮的同时不断发射这些射弹，就像您在 Touch Down 类方法中所做的那样？希望我所要求的是可能的。

Answer 1

您可以使用 touchesBegan 和 touchesEnded 函数来跟踪按下按钮的时间。然后使用SKScene的update功能，延迟发射弹丸。

逻辑是在按下按钮时将布尔值 shooting 设置为 true。 shooting 在 touchesEnded 中设置为 false。这样我们就可以跟踪触摸。然后在 update 函数中，如果 shooting 变量为真，则发射弹丸。

在Objective C

//GameScene.h

@property (nonatomic,strong) SKSpriteNode *shootButton;

//GameScene.m

BOOL shooting = false;
CFTimeInterval lastShootingTime = 0;
CFTimeInterval delayBetweenShots = 0.5;

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    CGPoint location = [touch locationInNode:self];

    if  ([self nodeAtPoint:location] == self.shootButton)
    {
        shooting = true;
        NSLog(@"start shooting");
    }

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    CGPoint location = [touch locationInNode:self];

    if  ([self nodeAtPoint:location] == self.shootButton)
    {
        shooting = false;
        NSLog(@"stop shooting");
    }
}


-(void)shoot
{
    // Projectile code
    NSLog(@"shooting");
}

-(void)update:(NSTimeInterval)currentTime {

    if (shooting)
    {
        NSTimeInterval delay = currentTime - lastShootingTime;
        if (delay >= delayBetweenShots) {
            [self shoot];
            lastShootingTime = currentTime;
        }
    }
}

在Swift

var shootButton : SKSpriteNode!

var shooting = false
var lastShootingTime : CFTimeInterval = 0
var delayBetweenShots : CFTimeInterval = 0.5

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
    let touch: AnyObject? = touches.anyObject()
    if let location = touch?.locationInNode(self)
    {
        if self.nodeAtPoint(location) == shootButton
        {
            self.shooting = true
            println("start shooting")
        }
    }
}

override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
    let touch: AnyObject? = touches.anyObject()
    if let location = touch?.locationInNode(self)
    {
        if self.nodeAtPoint(location) == shootButton
        {
            self.shooting = false
            println("stop shooting")
        }
    }
}

func shoot()
{
    // Projectile code
    println("shooting")
}

override func update(currentTime: NSTimeInterval) {

    if shooting
    {
        let delay = currentTime - lastShootingTime
        if delay >= delayBetweenShots {
            shoot()
            lastShootingTime = currentTime
        }
    }
}

您可以调整 delayBetweenShots 变量来改变触发的速度。

按住按钮时发射弹丸

shoot projectiles while button is held

objective-c

sprite-kit