compile box2d trunk on iphone... « cocos2d for iPhone

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compile box2d trunk on iphone...

(5 posts) (4 voices)

Started 1 year ago by jordo
Latest reply from njohn

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I'm tearing my hair out trying to figure out why I can't compile the latest box2d trunk into my project...

In file included from libs/Box2D/Collision/b2BroadPhase.h:22,
                 from /joyridinpowerups/libs/Box2D/Collision/b2BroadPhase.cpp:19:
libs/Box2D/Common/b2Settings.h: In function 'float32 b2MixFriction(float32, float32)':
libs/Box2D/Common/b2Settings.h:142: error: 'sqrtf' is not a member of 'std'

This is the error I get... some weird namespace issue. Anyone has any ideas??? (yes this file #includes <cmath>...

Posted 1 year ago #

nvh
Member

I ran in to the same problem just now. I don't really get what's causing this problem, but I've found a fix.
I walked trough the commit history of box2d and found that at some point the cmath functions were prefixed with std:: (so std::sqrtf() instead of just sqrtf() ). Apparently Xcode doesn't understand this, but by removing std:: before the functions that are giving errors, I was able to compile the code without errors.
Still, I'm curious to know what's causing this problem, and why it doesn't work in Xcode, so if anyone has any suggestions I'm interested!

Posted 1 year ago #
riq
Key Master
If you add:
```
using namespace std;
```
does it work ?
Posted 1 year ago #
jordo
Member
using
```
using namespace std;
```
doesn't not work... since the code in box2d has namespace prefixed... std::sqrtf()... Not sure why this doesn't work in Xcode, I'm by no means a expert at build process, but this should compile...
Posted 1 year ago #
njohn
Member

AFAIK sqrtf() is not a member of the std:: namespace. I was having the same issue, I replaced all of the std::sqrtf() with ::sqrtf() i.e. use global name space. This worked.

Then I ran in to another issue that I can't recall exactly ;-(

@riq
BTW, the current version of box2D on 0.99.4 is broken. It has problems with certain size circle shape definitions being able to penetrate objects. Is there a plan to move to a known working later version?

Sorry if this has already been discussed, I did take look, but could not find anything..

Posted 1 year ago #

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