cocos2d for iPhone

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

1. 

   dell
   Member

   Hi everyone... Maybe this has been answered before but in the posts I have seen they suggest setting the scaling of the graphics to 2X which would be hell on older iPhones. Apple suggests the @2x as a way for the system to automatically detect which image to use.

   I know Riq is working on this as there is a bug. So thank you Riq for addressing this issue and for wonderful cocos2D! But I see this question asked in so many posts so I want to try and clarify it once and for all.

   1. Will cocos2d support @2x in the future?
   2. What about spritesheets? Will the same naming convention work with them?
   3. Is there a current graphics method to make a game running iPhone 4 and iPhone 2G/3G/GS by recognizing which phone/device is running that will call up the right graphic size?
   4. For now is there a way to programmatically determine device?
   5. What about using device modifier within Cocos2d? See below... This is the standard convention method in xCode in iOS 4...

   Standard: <ImageName><device_modifier>.<filename_extension>
   High resolution: <ImageName>@2x<device_modifier>.<filename_extension>

   For example... To create a full screen background you would have the following images based on your device in iOS 4:

   iPhone 2G/3G/GS 480x320 background.png
   iPhone 4 960x480 background@2x~iphone.png
   iPad 1024x768 background~ipad.png

   I think the answer to these questions will help out all devs using cocos2D and cut down on the numbers of posts asking the same question in a different way! Thanks for the answers in advance. I have read all retina and iPhone 4 graphics posts on here and well it seems no one has the definitive answer so far. So please for the sake of the community can someone provide the answers here?

   Posted 1 year ago #
2. 

   quano
   Member

   There seems to be a lot of confusion about this subject, me included. Your questions are all valid.

   The thing I'm thinking about the most right now is how you're suppose to support all the different screens properly. I don't want the logic to be different.

   Also, adding a low-res image on a high rez device should still make the image as big as the high res one (like UIKit). I don't think this is the case with cocos2d now.

   I asked my brother on this matter, who is an OpenGL pro or something, and he said I should look into viewport normalization or something. Apparently, the default OpenGL viewport is 0 to 1, and not 0 to 320 or what have you. I think having the same logic coordinate for all is key to solving this.

   Posted 1 year ago #
3. 

   taber
   Member

   +1 for @dell. i was in the middle of working on a game when iPad was about to come out, so in preparation i re-coded all my sprite loading code with an ugly device macro sprinkled throughout... something like: ccp(0,0, (IS_IPAD ? 768 : 320), (IS_IPAD ? 1024 : 480)) that was just for the ipad/iphone part... i've been putting off throwing the retina stuff into the mix for the same reason as dell's post - i want to be sure i'm doing it the "right" way.

   i also recently added retina display support to another iphone app (using uikit only, .xib's etc., no cocos2d) and it was super super easy to do. i basically just created the @2x images. no need to remove the file extensions from the image loading code or mess around with image position/coordinates etc. so i'm very curious if something similar is (or will be) available in cocos2d.

   knowing almost nothing about opengl (haha) it sounds like quano's way of scaling the viewport to match the device's scale factor may be pretty promising! :)

   Posted 1 year ago #
4. 

   dell
   Member

   Yes I agree using @2x images is easy on a pure uiKIT and xib based project. I think with the growing number of iPhone 4's out there doing a multiple image size universal project in CoCos2D will become mission critical for the dev community here. I know it can be done currently and I am hoping that some of the more experienced members will post their solution.

   On a side note I have the code running to play video in my game on a 3.1.3 device within CoCos2D however iOS4 has a different mediaplayer framework and now I am struggling to get it to work with CoCos2D. However I hope to get it going as my game will run on iPhone 4 as well as iPhone 3/3GS and iPad. So it's becoming interesting to support multiple devices even though the iPhone OS is very friendly to having code work across multiple devices.

   Posted 1 year ago #
5. 

   quano
   Member

   I don't know what'll happen if you mess this up, but it seems cocos2d sets its projection up in:

   CCDirector -> -(void) setProjection:(ccDirectorProjection)projection

   	glViewport(0, 0, size.width, size.height);
   	glMatrixMode(GL_PROJECTION);
   	glLoadIdentity();
   	gluPerspective(60, (GLfloat)size.width/size.height, 0.5f, 1500.0f);
   
   	glMatrixMode(GL_MODELVIEW);
   	glLoadIdentity();
   	gluLookAt( size.width/2, size.height/2, [self getZEye], size.width/2, size.height/2, 0, 0.0f, 1.0f, 0.0f);	

   Maybe editing these values or looking into these gl calls will be a step closer to a solution.

   Posted 1 year ago #
6. 

   quano
   Member

   I've managed to get cocos2d working with both low-res screens and high-res ones, still using the same coordinates. See this example (try on iPhone 4):
   http://dl.dropbox.com/u/608462/cocos2d%20test%20res.zip

   Basically, what I do is setting the default scale in CCdirector to the scale of the contentScaleFactor, and then for the high-res images, you need to halve the scale. Preferably, you should implement an extension of CCSprite, which sets its scale depending on if the image is high-res or low res (check if its filename includes @2x or not).

   edit:
   ahh, seems like people have been coming up with solutions to this while I was gone anyways:
   http://www.cocos2d-iphone.org/forum/topic/8511

   I suppose my solution is pretty much identical to the one Matt showed, but instead of halving the size of high-rez images, he's doubling it for low-res (after he changed some lines in CCSprite). Hopefully, we'll see better support for having the same/similar coordinates on screens with different resolution in the coming versions of cocos2d.

   Posted 1 year ago #

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