objective-c - iOS 上的连续滚动 Sprite GLKit Sprite 之间的间隙

Question

我一直在尝试为我在 iOS 上的 OpenGL ES 2.0 + GLKit 游戏创建一个类。当我提高滚动速度时， Sprite 之间的差距会变大。我在 Google 上进行了大量搜索，但没有找到适合我的答案。

我的 Scrolling sprite 类继承自具有位置、比例、子项等的“节点”(有点像 Cocos2D)。该类有一个 sprite(节点)数组，它们在 x 轴上以设定的速度移动，当到达屏幕末端时移动到最后一个 sprite 的正确位置。

这是我的代码的主要部分:

    -(id)initWithTexture:(GLKTextureInfo *)texture effect:(GLKBaseEffect *)effect xScrollRange:(float)range yPosition:(float)y xScrollVelocity:(float)velocity{
if (self = [super init]) {
        //set globals
    self.velocity = velocity;
    xRange = range;

        //create a first sprite, set position, add to children
    JGSprite *firstSprite = [[JGSprite alloc] initWithTexture:texture effect:effect];
    firstSprite.position = GLKVector2Make(range, y);
    [self.children addObject:firstSprite];

        //calc how many sprites are needed to cover range+1
    float spritesNum = range/firstSprite.contentSize.width;
    int spritesNumRound = roundf(spritesNum)+1;

        //add enough sprites to cover the screen
    for (int i = 1; i < spritesNumRound; i++) {
            //create, set position, add to children
        JGSprite *sprite = [[JGSprite alloc] initWithTexture:texture effect:effect];
        sprite.position = GLKVector2Make(range - (i*sprite.contentSize.width), y);
        [self.children addObject:sprite];

    }

        //if moving left, set last sprite as right most
    if (velocity < 0)
        lastReorderedSprite = 0;
    else    //set left most
        lastReorderedSprite = self.children.count-1;



   }

    return self;
}

-(void)update:(float)dt
{
        //loop through sprites
    for (JGNode *node in self.children)
    {
            //update sprites position
        node.position = GLKVector2Make(node.position.x + self.velocity*dt, node.position.y);

        //if moving left
    if (self.velocity < 0)
    {
            //if reached gone off screen
        if (node.position.x <= -node.contentSize.width/2) 
        {
                //get last node
            JGNode *lastSprite = [self.children objectAtIndex:lastReorderedSprite];

                //set the position to the right of the last node
            node.position = GLKVector2Make(lastSprite.position.x+lastSprite.contentSize.width, node.position.y);

                //set re-positioned node as lastreordered
            lastReorderedSprite = [self.children indexOfObject:node];
        }            
    }
    else //moving right
    {
            //gone off screen   
        if (node.position.x >= xRange+node.contentSize.width/2) 
        {
                //get last node
            JGNode *lastSprite = [self.children objectAtIndex:lastReorderedSprite];

                //set the position to the left of the last node
            node.position = GLKVector2Make(lastSprite.position.x-node.contentSize.width, node.position.y);

                //set re-positioned node as lastreordered
            lastReorderedSprite = [self.children indexOfObject:node];

        }

    }
    }
}

如果有人能告诉我如何阻止间隙形成，我将不胜感激 :) 提前致谢!

Answer 1

问题很可能出在这一行:

node.position = GLKVector2Make(node.position.x + self.velocity*dt, node.position.y);

当您提高速度时，添加到 x 的量也会增加。我的猜测是您的一个对象的速度更新晚于其他对象。要修复它，只需让每个对象检查它与其他对象之间的距离是否符合您的要求，如果不是，则将其移到那里。