精灵上的无限滚动（视差）答案

【问题标题】：Infinite scrolling on a sprite(Parallax)精灵上的无限滚动（视差）
【发布时间】：2013-08-28 09:38:53
【问题描述】：

我是 cocos2d 世界的新手，我正在开发我的第一个教程并面临一个问题我的问题是我有一个图像（1024 X 320）并且我的方向是横向我需要从右到左连续移动该图像为此我使用了 Ray 的太空射击教程（感谢他）但图像没有似乎一次又一次地出现。我的代码是..

-(id) init
{
    if( (self=[super init])) {
        CGSize screenSize = [CCDirector sharedDirector].winSize;

        // 1) Create the CCParallaxNode
        backgroundNode = [CCParallaxNode node];
        [self addChild:backgroundNode z:-1];

        // 2) Create the sprites we'll add to the CCParallaxNode
        Back = [CCSprite spriteWithFile:@"bg_front_spacedust.png"];
        //Back.position=ccp(screenSize.width/2, screenSize.height/2);
        Back.rotation = -90;
        Back1 = [CCSprite spriteWithFile:@"bg_front_spacedust.png"];
        Back1.rotation = -90;

        // 3) Determine relative movement speeds for space dust and background
        CGPoint dustSpeed = ccp(0.1, 0.1);

        // 4) Add children to CCParallaxNode
        [backgroundNode addChild:Back z:0 parallaxRatio:dustSpeed positionOffset:ccp(screenSize.width/2, screenSize.height/2)];
        NSLog(@"back.content width is...%f",Back.contentSize.width);
        [backgroundNode addChild:Back1 z:1 parallaxRatio:dustSpeed positionOffset:ccp(screenSize.width/2, screenSize.height*2)];

        // 5) Enable updates
        [self scheduleUpdate]; 
}
    return self;
}


- (void)update:(ccTime)dt {

    // 1) Update background position
    CGPoint backgroundScrollVel = ccp(0,-1000);
    backgroundNode.position = ccpAdd(backgroundNode.position, ccpMult(backgroundScrollVel, dt));

    // 2) Check for background elements moving offscreen
    NSArray *spaceDusts = [NSArray arrayWithObjects:Back, Back1, nil];
    for (CCSprite *spaceDust in spaceDusts) {
        if ([backgroundNode convertToWorldSpace:spaceDust.position].x < -spaceDust.contentSize.width) {
            [backgroundNode incrementOffset:ccp(2*spaceDust.contentSize.width,0) forChild:spaceDust];
        }
    }
}

请帮我解决这个问题
提前致谢。

【问题讨论】：

标签： iphone ios cocos2d-iphone parallax

【解决方案1】：

试试这个

if (backgroundNode.position.y <-screenSize.height*2)
            backgroundNode.position = ccp(0,0);

因为 init 方法仅在您正在执行的方法中调用一次，因此您需要在更新方法中再次将 backgroundNode 的 Position 设置为 0 时才会执行一次。这里的倍数可能会有所不同

【讨论】：

【解决方案2】：

试试这个代码，它正在创建一个从下到上移动的视差，在 paraNode addChild 行中将 CGPointMake(0, 1.0) 更改为这个 CGPointMake(1.0,0)。

-(id) init
 {
// always call "super" init
// Apple recommends to re-assign "self" with the "super's" return value
if( (self=[super init]) )
{
    float yPos =0.0;
    NSMutableString *fileNameString = [[NSMutableString alloc]initWithCapacity:0];
    if (IS_IPHONE_5)
    {
        [fileNameString appendString:@"Background-568h.png"];
        yPos= 560.0;
    }
    else
    {
        [fileNameString appendString:@"Background.png"];
        yPos= 470.0;
    }
    background1 = [CCSprite spriteWithFile:fileNameString];
    background1.tag = 1;
    background1.anchorPoint = CGPointMake(0,0);

    background2 = [CCSprite spriteWithFile:fileNameString];
    background2.tag = 2;
    background2.anchorPoint = CGPointMake(0,0);

    background3 = [CCSprite spriteWithFile:fileNameString];
    background3.tag = 3;
    background3.anchorPoint = CGPointMake(0,0);

    background4 = [CCSprite spriteWithFile:fileNameString];
    background4.tag = 4;
    background4.anchorPoint = CGPointMake(0,0);


    paraNode = [CCParallaxNode node];
    [paraNode addChild:background1 z:1 parallaxRatio:CGPointMake(0, 1.0) positionOffset:CGPointMake(0, 0)];
    [paraNode addChild:background2 z:2 parallaxRatio:CGPointMake(0, 1.0) positionOffset:CGPointMake(0, -yPos)];
    [paraNode addChild:background3 z:3 parallaxRatio:CGPointMake(0, 1.0) positionOffset:CGPointMake(0, -yPos*2)];
    [paraNode addChild:background4 z:4 parallaxRatio:CGPointMake(0, 1.0) positionOffset:CGPointMake(0, -yPos*3)];



    [self addChild:paraNode z:-1 tag:123];
    [self updateFrameRate:0.7 andYposition:yPos];

    [fileNameString release];
    fileNameString = nil;
}
return self;
 }

 -(void)updateFrameRate:(float)speedValue andYposition:(float)yposToSet
 {

   move1 = [CCMoveBy actionWithDuration:speedValue position:CGPointMake(0, yposToSet)];
   move2 = [CCMoveBy actionWithDuration:0.0 position:CGPointMake(0, -yposToSet)];
   move3 = [CCMoveBy actionWithDuration:0.0 position:CGPointMake(0, 0)];
   CCSequence* sequence = [CCSequence actions:move1,move2,move3, nil];
   CCRepeatForever* repeat = [CCRepeatForever actionWithAction:sequence];
   [paraNode runAction:repeat];

}

【讨论】：