ODE w/ Cocoa

[hangt5]

I downloaded, compiled, and installed ODE (successfully) and did a few fun little carbon tests. I now, really really want to incorporate it into my (cocoa based) game. I saw that someone made a 'Cocoa port' a while back, but apparently its not up to date. Is there a way to get the normal up to date version of ODE working in a cocoa application?... Short of porting it that is.

[Josh]

Why wouldn't it work in a Cocoa app? Isn't it C?

[hangt5]

I get Zerolink: unknown symbol errors in my cocoa app, and it runs perfectly in my carbon app. If i make the cocoa file obj-c++ i get a bunch of errors: "Template with C Linkage", "Undefined Type ID, please import objc/objc.h", "/usr/include/ode/odemath.h:122: error: declaration of C function `double dDISTANCE(const double*, const double*)' conflicts with
"...etc

EDIT: apparently im getting all the same errors as this Thread (http://www.idevgames.com/forum/showthread.php?t=8745). The fix at the end of the thread didnt work...

EDIT2: its c++

[TomorrowPlusX]

Hey, I made the "Cocoa port" -- all it was was ODE built to a framework, and an implementation of drawstuff which was GLUT happy. The thing is, after I submitted some patches to get clean building on OS X, maintaining a build was unecessary. So just build it from the command line and you're gold.

Now, regarding calling ODE from ObjC -- DON'T. ODE's headers have *many* function parameters and variables named "id", which is a reserved keyword in ObjC.

If you want to use Cocoa for your frontend ( I do, for example ) you'll need to be careful regarding what you expose. You can, basically, get away with having your interface include <ode/common.h> which is ObjC friendly, and your implementation include <ode/ode.h>

This works, so long as you're not using dGeomTrimesh. That requires includes which aren't ObjC friendly. You'll have to make an abstraction layer if you want to do that.

[hangt5]

Cool. Thanks a lot for the information, and the bug reports.

[hangt5]

I get the same errors/linker errors. :mad:

In Obj-C i get at runtime "ZeroLink: unknown symbol '___cxa_pure_virtual'."

And in Obj-C++ i get these compiling errors.


In file included from /usr/include/ode/ode.h:34,
from /Users/bobsmith/ODETest3/ODETest3View.mm:2:
/usr/include/ode/odemath.h: In function `double dDISTANCE(const double*, const double*)':
/usr/include/ode/odemath.h:122: error: declaration of C function `double dDISTANCE(const double*, const double*)' conflicts with
/usr/include/ode/odemath.h:120: error: previous declaration `float dDISTANCE(const float*, const float*)' here
/usr/include/ode/odemath.h: At global scope:
/usr/include/ode/odemath.h:180: error: template with C linkage
/usr/include/ode/odemath.h:181: error: template with C linkage
/usr/include/ode/odemath.h:182: error: template with C linkage
/usr/include/ode/odemath.h:183: error: template with C linkage
/usr/include/ode/odemath.h:184: error: template with C linkage
/usr/include/ode/odemath.h:185: error: template with C linkage
/usr/include/ode/odemath.h:187: error: template with C linkage
/usr/include/ode/odemath.h:188: error: template with C linkage
/usr/include/ode/odemath.h:189: error: template with C linkage
/usr/include/ode/odemath.h:190: error: template with C linkage
/usr/include/ode/odemath.h:191: error: template with C linkage
/usr/include/ode/odemath.h:192: error: template with C linkage
In file included from /usr/include/ode/ode.h:44,
from /Users/bobsmith/ODETest3/ODETest3View.mm:2:
/usr/include/ode/odecpp_collision.h: In member function `void dSpace::setCleanup(int)':
/usr/include/ode/odecpp_collision.h:133: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h: In member function `int dSpace::getCleanup()':
/usr/include/ode/odecpp_collision.h:135: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h: In member function `void dSpace::add(dxGeom*)':
/usr/include/ode/odecpp_collision.h:138: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h: In member function `void dSpace::remove(dxGeom*)':
/usr/include/ode/odecpp_collision.h:140: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h: In member function `int dSpace::query(dxGeom*)':
/usr/include/ode/odecpp_collision.h:142: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h: In member function `int dSpace::getNumGeoms()':
/usr/include/ode/odecpp_collision.h:145: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h: In member function `dxGeom* dSpace::getGeom(int)':
/usr/include/ode/odecpp_collision.h:147: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h: In member function `void dSpace::collide(void*, void (*)(void*, dxGeom*, dxGeom*))':
/usr/include/ode/odecpp_collision.h:150: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h: In member function `void dHashSpace::setLevels(int, int)':
/usr/include/ode/odecpp_collision.h:174: error: undefined type `id', please import <objc/objc.h>
/Users/bobsmith/ODETest3/ODETest3View.mm: In function `objc_object* -[ODETest3View initWithFrame:](ODETest3View*, objc_selector*, _NSRect)':
/Users/bobsmith/ODETest3/ODETest3View.mm:12: error: cannot convert `double' to `NSOpenGLPixelFormatAttribute' in initialization
/Users/bobsmith/ODETest3/ODETest3View.mm: In function `void -[ODETest3View awakeFromNib](ODETest3View*, objc_selector*)':
/Users/bobsmith/ODETest3/ODETest3View.mm:65: error: assignment of function `time_t time(time_t*)'
/Users/bobsmith/ODETest3/ODETest3View.mm:65: error: cannot convert `objc_object*' to `time_t ()(time_t*)' in assignment
/Users/bobsmith/ODETest3/ODETest3View.mm:66: error: cannot convert `time_t (*)(time_t*)' to `NSTimer*' in argument passing
/Users/bobsmith/ODETest3/ODETest3View.mm:67: error: cannot convert `time_t (*)(time_t*)' to `NSTimer*' in argument passing
/Users/bobsmith/ODETest3/ODETest3View.mm: In function `void -[ODETest3View reshape](ODETest3View*, objc_selector*)':
/Users/bobsmith/ODETest3/ODETest3View.mm:79: warning: passing `float' for argument passing 3 of `void glViewport(long int, long int, long int, long int)'
/Users/bobsmith/ODETest3/ODETest3View.mm:79: warning: argument to `long int' from `float'
/Users/bobsmith/ODETest3/ODETest3View.mm:79: warning: passing `float' for argument passing 4 of `void glViewport(long int, long int, long int, long int)'
/Users/bobsmith/ODETest3/ODETest3View.mm:79: warning: argument to `long int' from `float'
from /Users/bobsmith/ODETest3/ODETest3View.mm:2:
In file included from /usr/include/ode/ode.h:34,
/usr/include/ode/odemath.h:122: error: declaration of C function `double dDISTANCE(const double*, const double*)' conflicts with
/usr/include/ode/odemath.h:120: error: previous declaration `float dDISTANCE(const float*, const float*)' here
/usr/include/ode/odemath.h:180: error: template with C linkage
/usr/include/ode/odemath.h:181: error: template with C linkage
/usr/include/ode/odemath.h:182: error: template with C linkage
/usr/include/ode/odemath.h:183: error: template with C linkage
/usr/include/ode/odemath.h:184: error: template with C linkage
/usr/include/ode/odemath.h:185: error: template with C linkage
/usr/include/ode/odemath.h:187: error: template with C linkage
/usr/include/ode/odemath.h:188: error: template with C linkage
/usr/include/ode/odemath.h:189: error: template with C linkage
/usr/include/ode/odemath.h:190: error: template with C linkage
/usr/include/ode/odemath.h:191: error: template with C linkage
/usr/include/ode/odemath.h:192: error: template with C linkage
from /Users/bobsmith/ODETest3/ODETest3View.mm:2:
In file included from /usr/include/ode/ode.h:44,
/usr/include/ode/odecpp_collision.h:133: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h:135: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h:138: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h:140: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h:142: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h:145: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h:147: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h:150: error: undefined type `id', please import <objc/objc.h>
/usr/include/ode/odecpp_collision.h:174: error: undefined type `id', please import <objc/objc.h>
/Users/bobsmith/ODETest3/ODETest3View.mm:12: error: cannot convert `double' to `NSOpenGLPixelFormatAttribute' in initialization
/Users/bobsmith/ODETest3/ODETest3View.mm:65: error: assignment of function `time_t time(time_t*)'
/Users/bobsmith/ODETest3/ODETest3View.mm:65: error: cannot convert `objc_object*' to `time_t ()(time_t*)' in assignment
/Users/bobsmith/ODETest3/ODETest3View.mm:66: error: cannot convert `time_t (*)(time_t*)' to `NSTimer*' in argument passing
/Users/bobsmith/ODETest3/ODETest3View.mm:67: error: cannot convert `time_t (*)(time_t*)' to `NSTimer*' in argument passing
/Users/bobsmith/ODETest3/ODETest3View.mm:79: warning: passing `float' for argument passing 3 of `void glViewport(long int, long int, long int, long int)'
/Users/bobsmith/ODETest3/ODETest3View.mm:79: warning: argument to `long int' from `float'
/Users/bobsmith/ODETest3/ODETest3View.mm:79: warning: passing `float' for argument passing 4 of `void glViewport(long int, long int, long int, long int)'
/Users/bobsmith/ODETest3/ODETest3View.mm:79: warning: argument to `long int' from `float'



In my .h i included <ode/common.> and in my .m(m) i included <ode/ode.h>

[hangt5]

I fixed this by including libstdc++.a in my project.

[TomorrowPlusX]

Excellent! I've seen a couple posts with similar ODE problems here lately, and now there's an answer that can be given to those who see it.

For what it's worth, ODE is actually C++ on the inside. But it's wrapped in C. ODE's C interface is robust and reliable across releases, but the internal C++ changes a lot.

It's a little hoary, but it does the job. Makes me feel funny, though, writing an ODE C++ wrapper around C which wraps C++ :P

[Duane]

how is a C wrapper around C++ possible?

[Josh]

how is a C wrapper around C++ possible?
Sure, it's possible. I don't really see a point to it, and it causes confusion when you have to do things like link to libstdc++.a... but it's possible.

[Duane]

I thought that C didn't really recognize that C++ existed?

[wadesworld]

Nayr,

Trying to use a native C++ interface for a library opens up a host of C++ compatibility issues, and that's why 99% of libraries will expose a C interface only, even though the implementation may be in C++.

Wade