How to move background images infinitely in iOS coco2d - ios

Question

I have to move background images in iOS Coco2d but I am having a few difficulties. I have tried some solutions provided on some websites but have not been successful in getting them to work properly. Below is the code I am currently working on:-
The background moves smoothly the first time but it is not working properly after that:-
Code in init function :-
bg1 = [CCSprite spriteWithFile: #"bg1.png"];
bg1.anchorPoint = CGPointZero;
[self addChild:bg1 z:-2];
bg2 = [CCSprite spriteWithFile: #"bg1.png"];
[self addChild:bg2 z:-3];
bg2.anchorPoint = CGPointMake(480, 0);
// schedule a repeating callback on every frame
[self schedule:#selector(nextFrame:) interval:.4f];
- (void) nextFrame:(ccTime)dt {
id actionMove = [CCMoveTo actionWithDuration:.4 position:ccp(bg1.position.x - 100 * dt, bg1.position.y)]; //winSize.height/2)];
id actionMove1 = [CCMoveTo actionWithDuration:.4 position:ccp(bg2.position.x - 100 * dt, bg2.position.y)]; //winSize.height/2)];
id actionMoveDone = [CCCallFuncN actionWithTarget:self selector:#selector(spriteMoveFinished:)];
[bg1 runAction:[CCSequence actions:actionMove,actionMoveDone, nil]];
[bg2 runAction:[CCSequence actions:actionMove1,actionMoveDone, nil]];
}
-(void)spriteMoveFinished:(id)sender {
CCSprite *sprite = (CCSprite *)sender;
if(sprite == bg1) {
if (bg1.position.x < -480) {
[self removeChild:bg1 cleanup:NO];
bg1.position = ccp( 480 , bg1.position.y );
[self addChild:bg1 z:-2];
}
}
else if(sprite == bg2)
if (bg2.position.x < -480) {
[self removeChild:bg2 cleanup:NO];
bg2.position = ccp( bg1.position.x+ 480 , bg1.position.y );
[self addChild:bg2 z:-3];
}
}
}

Answer 1

Try this, make sure you flip background 2.
#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
#define MM_BG_SPEED_DUR       ( IS_IPAD ? (6.0f) : (2.0f) )
-(void)onEnter
{
[super onEnter];
[self initBackground];
[self schedule: #selector(tick:)];
}
-(void)initBackground
{
NSString *tex = #"BG/Background.png";//[self getThemeBG];
mBG1 = [CCSprite spriteWithFile:tex];
mBG1.position = ccp(s.width*0.5f,s.height*0.5f);
[self addChild:mBG1 z:LAYER_BACKGROUND];
mBG2 = [CCSprite spriteWithFile:tex];
mBG2.position = ccp(s.width+s.width*0.5f,s.height*0.5f);
mBG2.flipX = true;
[self addChild:mBG2 z:LAYER_BACKGROUND];
}
-(void)scrollBackground:(ccTime)dt
{
CGSize s = [[CCDirector sharedDirector] winSize];
CGPoint pos1 = mBG1.position;
CGPoint pos2 = mBG2.position;
pos1.x -= MM_BG_SPEED_DUR;
pos2.x -= MM_BG_SPEED_DUR;
if(pos1.x <=-(s.width*0.5f) )
{
pos1.x = pos2.x + s.width;
}
if(pos2.x <=-(s.width*0.5f) )
{
pos2.x = pos1.x + s.width;
}
mBG1.position = pos1;
mBG2.position = pos2;
}
-(void)tick:(ccTime)dt
{
[self scrollBackground:dt];
}

Answer 2

I think this way is a little simpler. You initialize the backgrounds in initand move them in update.
In the init method:
// position backgrounds
CCSprite *bg1 = [CCSprite spriteWithSpriteFrame:spriteFrame];
CCSprite *bg2 = [CCSprite spriteWithSpriteFrame:spriteFrame];
CCSprite *bg3 = [CCSprite spriteWithSpriteFrame:spriteFrame];
bg1.anchorPoint = ccp(0, 0);
bg1.position = ccp(0, 0);
bg2.anchorPoint = ccp(0, 0);
bg2.position = ccp(bg1.contentSize.width-1, 0);
bg3.anchorPoint = ccp(0, 0);
bg3.position = ccp(2*bg1.contentSize.width-1, 0);
_backgrounds = #[bg1, bg2, bg3];
[self addChild:bg1 z:INT_MIN];
[self addChild:bg2 z:INT_MIN];
[self addChild:bg3 z:INT_MIN];
In the update method:
// endless scrolling for backgrounds
for (CCSprite *bg in _backgrounds) {
bg.position = ccp(bg.position.x - 50 * delta, bg.position.y);
if (bg.position.x < -1 * (bg.contentSize.width)) {
bg.position = ccp(bg.position.x + (bg.contentSize.width*2)-2, 0);
}
}
Note: the code is for Cocos2d 3.0