Using GCJ with LWJGL?

OpenGL Development
#1

I tried compiling one of my games using GCJ and it said


BestGameEver.java:7: error: Class or interface `org.lwjgl.opengl.glu.GLU' not found in import.
   import org.lwjgl.opengl.glu.GLU;

My game uses LWJGL, obviously. So is it possible to use GCJ at all?

#2

I don’t konw GJC, but this looks like a classpath problem - ie: the compiler can’t find the lwgjl jar.

#3

Yeah, which is odd because I have the .jar in my Java extensions folder, so everything should be able to read it. So I thought.

#4

never install lwjgl in the extension folder, it’s asking for trouble!
always install it in its own folder and point to it using classpath and java.library.path

#5

Yeah, people have told me not to do this, but never told me why. What’s the problem exactly? And don’t I have to put the .dll files there anyway?

And as another question: if I’m compiling through the unix box how do I set the classpath correctly? I only know how to do it with a compiler.

#6

Because you’ll end up with multple versions of the files in the classpath. Other LWJGL applications will crash because it uses your files in the ext directory wich is a of a different version. Nigthmare, so just don’t do it.

#7

Yea I couldnt run your game because of it.

#8

This might be a bit off-topic but are there any windows binaries of GCJ? Does MingW provide it?

thinks the layout of the gcc site is confusing… links to links to links…

Nm… http://www.thisiscool.com/gcc_mingw.htm

#9

Okay, so if I have it in the classpath and create a jar, can I bundle the LWJGL jars inside my jar and have it work? I’ve never bothered doing this the correct way because I keep getting issues with it.

Also, if I have the .dll files in the classpath will that work correctly as well? I thought that I flat out needed these in the ext folder.

Thanks guys.

#10

You have to have the .dll-files in your java.library.path.

There are three ways to do this:

  • either have your .ddls in the working directory
    (eg. placing it beside your excutable jar and state in your readme, that one has to start the game from this directory)

  • place the files in the PATH-environment
    (eg. use a start-script, that adds the appropriate directory to the PATH-environment variable)

  • or start the jar with -Djava.library.path=
    (eg. use a start-script, that calls java with this system property set to the appropriate directory)

I am not sure, if it is possible to use GCJ to compile a LWJGL game. It seems unlikely to me and even if it works, it might not give a runtime performance gain (if this is what you are after…).

#11

Thanks very much for the help.

I thought I might as well try GCJ with LWJGL, because one of the reasons keeping me from using it in the first place is Swing. As I’m not using it now, I thought I’d give it a shot and see what happens.