Comments on Never Read Passively: Dropping a Dimension: Cocos2D and Box2D on iPhone

I'm making a list of game-ready model shops, if yo...

2010-06-02T19:29:55.216+10:00

I'm making a list of game-ready model shops, if you know another ones please tell me ^^ here's what I've found so far:
(alphabetically sorted)

[b]3dbud.com[/b]
[img]http://img118.imageshack.us/img118/8018/83767809.jpg[/img]
(fantasy characters - animals - monters) -
http://3dbud.com

[b]3drt.com[/b]
[img]http://3drt.com/3dm/characters/real-zombies/characters-real-zombies-3d_01.jpg[/img]
(fantasy - scifi characters - animals - monters)
http://3drt.com

Thanks for your post it really helped me. I'm curr...

2009-05-10T07:58:00.000+10:00

Thanks for your post it really helped me. I'm currently playing with cocos2d and box2d. I found a problem with calling the world step, the box2d step advices to use a fixed timestamp but when using the schedule functionality of cocos2d with a fixed timestamp the simulation is not drawn at the same speed for different fps. So I use the fps as a timestamp, but when the fps is low you will sometimes see object react differently then normal(such as a bounce). So my question is, where do you put your world step call?

(sorry for my bad english btw, I hope you can understand it)

Yeah i saw that - I was referring more to how you ...

2009-04-30T16:28:00.000+10:00

Yeah i saw that - I was referring more to how you did the drawing through Cocos2D. I'll have a look at that HandCircus code now.

@Sam I didn't (as mentioned in the post and in an ...

2009-04-30T16:22:00.000+10:00

@Sam I didn't (as mentioned in the post and in an above comment). I did custom drawing stuff inspired by the debug draw code.

For an example of Box2d debug drawing on the iPhone please see the most excellent post and code (n the box2d SVN) by HandCircus: iPhone port of Box2D Testbed now available

Do you think you could upload the source? I'm comi...

2009-04-30T15:50:00.000+10:00

Do you think you could upload the source? I'm coming from a Flash background (using Box2D too :D) so any help getting in to the rhythm of iPhone development is greatly appreciated. Specifically, I'm curious to see exactly how you did the Box2D debug drawing stuff.

Cheers.

@Bauerpauer yeah I had the same problems and liste...

2009-04-22T08:35:00.000+10:00

@Bauerpauer yeah I had the same problems and listed the solution in my blog post (step 9 and the referenced link).

Make sure you only include box2d.h where you actually use types (implementation or public interface) and make sure anything that does import the header is an objective-C++ file (.mm)

@Jason Thanks for the tips. Now I've got some mo...

2009-04-22T01:09:00.000+10:00

@Jason

Thanks for the tips. Now I've got some more problems... I basically just started over, using the Box2D iPhone Testbed as a starting point. I ripped out all of the demo code, dropped in the cocos2d project, and started to build a blank-slate app. Everything cocos2d-related compiles properly, but as soon as I add

#import "Box2D.h"

to GameLayer.h (GameLayer is going to be a Cocos2d Layer that manages the b2World instance, etc...), I get build errors on all of the float32 const's in b2Settings.h:

error: initializer element is not a constant

Any ideas?

@Bauerpauer I didn't use Box2d's debug drawing fac...

2009-04-21T09:09:00.000+10:00

@Bauerpauer I didn't use Box2d's debug drawing facility directly. I wrote custom cocosnodes that rendered themselves based on the logic from debug drawing.

For example, I have a block class that extends cocosnode and that manages a box2d body and shape. The draw method for the block class uses similar logic (copy-paste) as is used to render body-shapes in the box2d debug draw logic (specifically enumeration from b2world and opengl from the iphone port of box2d). If you do this, you will needed to ensure you setup the gl drawing state yourself in each draw function.

Regarding scale - I started out using the 1:1 scale for the iphone screen. This worked fine, but is not so good for the default box2d configuration that prefers bodies between 0.1 and 10 unit lengths. Scaling is built into cocosnodes, simply determine an appropriate scale factor and use that to translate between the box2d and cocos2d worlds (touching, drawing, etc).

Jason, Did you have to do anything special to g...

2009-04-21T01:47:00.000+10:00

Jason,

Did you have to do anything special to get Box2D's debug shape drawing to work? I'm close, but it looks like cocos2d is tweaking the OpenGL ES settings enough to really skew the scale of the entire world. For example, I'm trying to get Box2D's "Chain" demo running alongside cocos2d, and the chain renders about 50-pixels tall starting at the left side of the screen. If the answer is obvious, go easy please, I'm a complete no0b at the game programming stuff ;)

@Dougal Thanks mate. For anyone else out there de...

2009-04-20T21:17:00.000+10:00

@Dougal Thanks mate.

For anyone else out there developing iPhone apps on PPC hadware, I solved my codesign problem with a handly little script by "Tiku" (search the page) on iPhone SDK CodeSign Error.

Jason, most of this goes over my head technically ...

2009-04-19T23:06:00.000+10:00

Jason, most of this goes over my head technically but what's really interesting is the thought processes behind your development process plus the fact you go to such trouble putting I down on paper. It would take ages (especially after oftentimes disenheartening coding). It's very generous of you and I'm sure you've made many a would-be app developer's day. Keep it up. 2D or bust. Dougal