Build Errors with DrawPrimitives « cocos2d for iPhone

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Build Errors with DrawPrimitives

(15 posts) (5 voices)

Started 2 years ago by ghostradio
Latest reply from riq

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ghostradio
Member

I'm trying to draw a line in my scene, but when I call drawLine(), I get a build error. Here's my draw() method:

- (void) draw { glColor4f(1.0, 0.0, 0.0, 1.0); glLineWidth(1.0f); drawLine(CGPointMake(0, 0), CGPointMake(100, 100)); }

And here's the error I'm getting:

cd /Users/jbuhler/Sites/SonyMusic/Icarus
setenv IPHONEOS_DEPLOYMENT_TARGET 3.0
setenv MACOSX_DEPLOYMENT_TARGET 10.5
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/g++-4.2 -arch armv6 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.0.sdk -L/*****/build/Debug-iphoneos -F*****/build/Debug-iphoneos -filelist /*****/build/Icarus.build/Debug-iphoneos/SingWithMe.build/Objects-normal/armv6/*****.LinkFileList -mmacosx-version-min=10.5 -Wl,-dead_strip -miphoneos-version-min=3.0 -framework Foundation -framework UIKit -framework CoreGraphics -framework MediaPlayer -framework AudioToolbox -framework OpenGLES -framework QuartzCore -framework SystemConfiguration -framework CoreLocation -o /*****/build/Debug-iphoneos/*****.app/*****
Undefined symbols:
"drawLine(CGPoint, CGPoint)", referenced from:
-[GamePlayScene draw] in GamePlayScene.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

(***** is where I've stripped out the client's name and/or project name.)

I'm using Cocos2d 0.8.0 RC2.

Any ideas what I'm doing wrong here?

Posted 2 years ago #
pabloruiz55
Member

Hi! I had the same problem, i am using 0.8

It happens when you want to use any of the draw primitive functions.
The weird thing is that if you copy the code from the functions and paste it in the draw function it works.

Any ideas?

Posted 2 years ago #
ghostradio
Member

As a weird little sidenote… If I use the draw() method I posted above in a descendant of Scene, I get the errors. However, if I use the code in something that directly extends CocosNode, it seems to work. Problem is, I want to draw these lines in a Scene, and not a new node.

Posted 2 years ago #
riq
Key Master

make sure that you have these files added to your project / cocos2d static library:
- cocos2d/DrawingPrimitives.m
- cocos2d/DrawingPrimitives.h

the old:
- cocos2d/primitives.m
- cocos2d/primitives.h
were renamed.

Posted 2 years ago #
LongJohnnyE
Member

I did so, and eventually manually included #include 'DrawingPrimitives.h' at the top, but I was still getting that same error.

Again, copying the function right into my file fixed the problem :/.

Posted 2 years ago #
ghostradio
Member

@riq -

I've got both of those files included, and they are included in the "Compile Sources" build phase of my target.

Another theory I'm working on is that the classes in which calls to the drawing stuff works have their File Type property set to "sourcecode.c.objc", where the classes that fail have the type set to "sourcecode.cpp.objcpp". I'm still pretty new to this Obj-C stuff, so if there's an obvious reason that doesn't work, and is causing the problem, what would it be?

Posted 2 years ago #
riq
Key Master

the drawing prmitives are free functions (plain C functions).
are you calling them from c++ code ? it should work also from c++... but this is just a guess.

Posted 2 years ago #
ghostradio
Member

I'm calling it from Obj-C code, but the filetype is flagged as "sourcecode.cpp.objcpp". This was done to avoid some build errors with some c++ audio code another team member wrote, that this class needs to interact with.

Posted 2 years ago #
riq
Key Master

what kind of errors did you get when it is called from c++ ?

Posted 2 years ago #
Steve Oldmeadow
Administrator
If you call it from .mm files then the header needs to be wrapped with an extern "C".
```
#ifdef __cplusplus
extern "C" {
#endif

... define functions here ...

#ifdef __cplusplus
}
#endif
```
Posted 2 years ago #
ghostradio
Member

@riq - I got the linking error pasted into my original post in the forums. (honestly - not trying to be a jerk there, it's just easier to link than repost the error.)

@Steve -

Since I'm a n00b at this stuff, what exactly do you mean by wrapping the header with an extern "C"? Where do I put the wrapper - in my .mm file, or just around where I call the functions?

Thanks a lot for the help guys - I really appreciate it.

Posted 2 years ago #
Steve Oldmeadow
Administrator

Primitives.h needs the extern "C" wrapped around its function definitions if you want to use them from .mm files.

Look at chipmunk.h for guidance but basically you would put the #ifdef after the imports in Primitives.h.

Posted 2 years ago #
ghostradio
Member

I think that did it! It at least builds now, but unfortunately I can't test it to see if it works, since I left my iPod cable at the office, and this game doesn't like running in the simulator very well.

Thanks again for the help, and if I have any other questions, you guys will be hearing from me again. ;) As a side note, it now builds, but why? Can you explain what the extern does in a nutshell, or do you know of a good link I could read up some more about this on?

Posted 2 years ago #
Steve Oldmeadow
Administrator

http://www.parashift.com/c++-faq-lite/mixing-c-and-cpp.html

Posted 2 years ago #
riq
Key Master

thanks steve.
fixed in r1215

Posted 2 years ago #

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