精灵工具包删除特定节点

Question

我正在尝试创建一个角色永远向右奔跑的游戏（游戏是横向的）。地上有角色可以跳过的尖刺。目前，我正在以几乎类似检查点的样式创建一组新的（并且有点随机）尖峰，一旦角色达到一定距离，就会创建下一组随机组织的尖峰，并且检查点距离被推回等等.除了尖刺，我还有一个单独但非常相似的类似检查点的系统，用于创建构成地面的瓷砖。 这是我的那部分代码，'endlessX' 和 'endlessGroundX' 是检查点值：

- (void) didSimulatePhysics {
if (player.position.x > endlessX) {
    int random = player.position.x + self.frame.size.width;
    [self createSpike:random];
    endlessX += self.frame.size.width/2.2 + arc4random_uniform(30);
}
if (player.position.x + self.frame.size.width > endlessGroundX) {
    [self createGround:endlessGroundX];
    endlessGroundX += tile1.frame.size.width;
}
    [self centerOnNode: player];
 }

createSpike 和 createGround 方法的参数只是 SKSpriteNodes 的“x”值。 我目前拥有它，因为角色本身是移动的，而尖峰和瓷砖是静止的。这就是我创建角色的方式：

-(void) createPlayer {

player = [SKSpriteNode spriteNodeWithImageNamed:@"base"];
player.position = CGPointMake(self.frame.size.width/2, self.frame.size.height/2);
player.name = @"player";
player.zPosition = 60;
player.xScale = 0.8;
player.yScale = 0.8;
player.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:player.frame.size.height/2];
player.physicsBody.mass = 1;
player.physicsBody.linearDamping = 0.0;
player.physicsBody.angularDamping = 0.0;
player.physicsBody.friction = 0.0;
player.physicsBody.restitution = 0.0;
player.physicsBody.allowsRotation = NO;
player.physicsBody.dynamic = YES;
player.physicsBody.velocity = CGVectorMake(400, 0);
player.physicsBody.categoryBitMask = playerCategory;
player.physicsBody.collisionBitMask = wallCategory;
player.physicsBody.contactTestBitMask = wallCategory | spikeCategory;
[myWorld addChild:player];
  }

这样，角色将永远不会因摩擦或任何其他类似的力而失去任何动能。然后，我使用苹果在他们的冒险游戏中使用的“节点中心”方法，这样角色将始终保持在屏幕上相同的 x 位置：

- (void) centerOnNode: (SKSpriteNode *) node {
CGPoint cameraPositionInScene = [node.scene convertPoint:node.position fromNode:node.parent];
node.parent.position = CGPointMake(self.frame.size.width/5 + node.parent.position.x - cameraPositionInScene.x, node.parent.position.y);
  }

我在 'didSimulatePhysics' 中调用此方法。

When I run this for some time, the programs gets slower and slower. I am guessing that that is due to the fact that I am never removing these nodes and they are always being added. However, to fix this problem, I tried doing something like this:

-(void)update:(CFTimeInterval)currentTime {
[self enumerateChildNodesWithName:@"*" usingBlock:^(SKNode *node, BOOL *stop) {
    if (node.position.x + 50 < player.position.x) {
        [node removeFromParent];
    }
}];  
}

（+50 只是为了确保节点在删除之前不在屏幕上） 但是，当我这样做时，程序并没有删除满足“if”语句的特定节点，而是删除了所有精灵节点。是否有不同的方法或我缺少的东西来解决这个问题？或者有没有其他简单的方法来删除特定节点？

Answer 1

缺少很多细节，例如如何为尖峰设置动画，因此很难说得太具体。不过，从您分享的内容来看，我猜您可能正在寻找类似这样的东西：

    SKAction *moveSpikeAction = [SKAction moveToX:-50 duration:5];
    SKAction *removeSpikeAction = [SKAction removeFromParent];
    SKAction *spikeSequence = [SKAction sequence:@[moveSpikeAction, removeSpikeAction]];
    [yourSpikeSpriteNode runAction:spikeSequence];

这个想法只是当尖峰动画到屏幕外位置时，您可以使用removeFromParent 操作来清除它。