Question

我试图为我的iOS spritekit游戏创建一个盾牌加电，而不是刷新当前的盾牌，它在顶部堆叠另一个盾牌。我的代码：

    -(void)didMoveToView:(SKView *)view {
               ...
    self.shieldIsActive = NO;
               ...
}
    -(void)didBeginContact:(SKPhysicsContact *)contact{
               ...
   else if (firstBody.categoryBitMask == CollisionCategoryLaser | firstBody.categoryBitMask == CollisionCategoryPlasmaShot |firstBody.categoryBitMask == CollisionCategoryProjectile && secondBody.categoryBitMask == CollisionCategoryShieldIcon){
        // Projectile OR Plasma Shot Or Laser hits Shield Icon
        ShieldIconNode *shieldIcon = (ShieldIconNode *)secondBody.node;
        ShieldNode *shield = [ShieldNode shieldAtPosition:CGPointMake(CGRectGetMidX(self.frame)+4, CGRectGetMidY(self.frame)-210)];
        [shieldIcon removeFromParent];
        if (firstBody.categoryBitMask == CollisionCategoryProjectile){
            ProjectileNode *projectile = (ProjectileNode *)firstBody.node;
            [projectile removeFromParent];
        }
        if (!self.shieldIsActive){
            [self addChild:shield];
            self.shieldIsActive = YES;
        }
        // Remove shield after a period of time. BUG: Adds multiple shields if one is already active
        if (self.shieldIsActive){
            SKAction *wait = [SKAction waitForDuration:ShieldTimer];
            [self runAction:wait completion:^{[shield removeFromParent];}];
            self.shieldIsActive = NO;

               ...
    }

Answer 1

让我们取代这个条件：

else if (firstBody.categoryBitMask == CollisionCategoryLaser | firstBody.categoryBitMask == CollisionCategoryPlasmaShot |firstBody.categoryBitMask == CollisionCategoryProjectile && secondBody.categoryBitMask == CollisionCategoryShieldIcon){

由此：

else if ((firstBody.categoryBitMask == CollisionCategoryLaser || firstBody.categoryBitMask == CollisionCategoryPlasmaShot || firstBody.categoryBitMask == CollisionCategoryProjectile ) && secondBody.categoryBitMask == CollisionCategoryShieldIcon){

请注意，对于OR运算符，使用||代替|。

Answer 2

正如Domsware指出的那样，在第一个|语句中，需要用逻辑||（以及添加的相应括号）替换按位if。奇怪的是，由于|运算符的优先级低于==运算符，因此您的if语句可能已按预期工作。

另外，你应该考虑隐藏/显示盾牌，而不是像Whirlwind建议的那样添加/移除盾牌。

那说了一些想法......

if (!self.shieldIsActive)和if (self.shieldIsActive)的条件始终为true（除非shieldIsActive设置在代码中的其他位置），这可能会导致多个屏蔽一次一幕
将self.shieldIsAction = NO移动到操作的完成块将解决此问题

和一些代码......

    if (!self.shieldIsActive){
        ShieldNode *shield = [ShieldNode shieldAtPosition:CGPointMake(CGRectGetMidX(self.frame)+4, CGRectGetMidY(self.frame)-210)];
        [self addChild:shield];
        self.shieldIsActive = YES;
        SKAction *wait = [SKAction waitForDuration:ShieldTimer];
        [self runAction:wait completion:^{
            [shield removeFromParent];
            self.shieldIsActive = NO;
        }];
    }

防止sprite节点＆＃34;堆叠＆＃34;在彼此之上？

2 个答案: