cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   aibo99
   Member

   Hi,

   I want to know how to use GL_REPEAT, and my scenario is as below.

   - The PNG image is 1024 pixels (width) x 128 pixels (height).
   - A visible frame / window is 128 x 128 pixels.
   - The PNG image needs to scroll horizontally and loop repeatedly under the visible frame / window.

   Can someone teach me how to use GL_REPEAT to achieve the animation effect ??

   Thanks a lot.

   Posted 1 year ago #
2. 

   lordbritishix
   Member

   First, create a big sprite that will contain your repeatable background. And then set the texture parameters (either linear, nearest, etc) and set it to repeat. Lastly, set the texture property of your sprite to use the parameter that you have just created.

   background = [CCSprite spriteWithFile:file rect:CGRectMake(0, 0, 480*1000, 320)];
   ccTexParams params = {GL_LINEAR,GL_LINEAR,GL_REPEAT,GL_REPEAT};
   [background.texture setTexParameters:&params];

   Cheers,
   Jim

   Posted 1 year ago #
3. 

   icanzilb
   Member

   Hi Jim,

   I've seen the exact same code also in couple of other web sites, and it is obviously correct, but my sprite still does not want to repeat... so I'm wondering where the problem could be if it does not repeat? Any known bugs maybe?

   best, Marin

   Posted 1 year ago #
4. 

   cephei
   Member

   Hi, i'm also having some problems with this code (i'm still a new cocos user).
   To test my code, i've modified the init-method of 'Parallax2' in ParallaxTest.m (included in the cocos2d tests) to the following:
   

   -(id) init
   {
   	if( (self=[super init] )) {
   
   		self.isTouchEnabled = YES;
   
   		// background layer: another image
   		CCSprite *background = [CCSprite spriteWithFile:@"background.png"];
   		// scale the image (optional)
   		background.scale = 1.5f;
   		// change the transform anchor point (optional)
   		background.anchorPoint = ccp(0,0);
   		ccTexParams params = { GL_LINEAR, GL_LINEAR, GL_REPEAT, GL_REPEAT };
   		[[background texture] setTexParameters:&params];
   
   		[background runAction:[CCRepeatForever actionWithAction:[CCMoveBy actionWithDuration:5.f position:ccp(-720.f,0.f)]]];
   		[self addChild:background z:0 tag:kTagNode];
   
   	}

   Can anyone tell me what i'm doing wrong here?

   Posted 1 year ago #
5. 

   cephei
   Member

   already found the answer to my problem: just had to adapt the rect size.
   @icanzilb: make sure you also move the sprite, setting the parameters alone is not enough

   Posted 1 year ago #
6. 

   andersonf78
   Member

   The golden tip is: the sprite file **MUST** be a power of 2 to properly repeat (16x16, 32x32, 64x64, 128x128 and so on).

   If you mistakenly use a non-power of 2 sprite, the application will not crash, but you'll get annoying gaps in the patterns.

   Posted 1 year ago #

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