# OpenGL Cross-platform?

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Hello, I'm developing a physics simulation with OpenGL and Glut on WindowsXP using MSVC++ 2005 Express. (Although, I'm open to using other compilers.) My main concern is that I want people running linux and Mac OS X to be able to run my code as well without having to compile it themselves. What is the best way going about this. I'm guessing I'd have to use some sort of makefile. However, I've never done this. The people that I'm going to be distributing my program to aren't technically savvy when it comes to programming. At the most, I can expect them to type ./make install. But really, I'd rather have a precomiled version already there for them. Being that I only have access to Win32, what would be the best way to either compile a cross-platform binary, or to offer a make file that's cross platform. (I'm not sure I even know what I'm talking about :)) Thank you.

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And just a side note: I REALLY don't want to go with Java here. I'd like to stick with c++.

Thanks again.

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One very common library is GLUT which would allow you to write portable code and have simple keyboard and mouse input. There are other libraries out there but I've only used GLUT. An alternative is to separate out your OS (non-portable) code from your OpenGL (portable) code and manually convert the OS code between systems. I suggest this only because you gain more flexibility if you need it.

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You could have separate makefiles;

Makefile.OSX
Makefile.LINUX
Makefile.Win32

You could use something like ClanLib or SDL for cross platform APIs.

You can get the GNU compiler/linker for all three platforms.

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Right on the front page there's a kjam article.

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there are three ways you can achieve your goal:

either you distribute to the users so they have to compile it themselves. while this is not the most comfortable way for the users, it is quite simple to do for you as the distributor.
to make compilation as easy as possible on unixoid platforms, for example linux and osx, the "make" tool is the most common way to go. writing the required makefiles yourself can be hell, so there are tools that make things easier.
they are called the "autotools", because their names, like "autoconf", "autoscan", "automake" and so on start with "auto". well, these are actually unix programs themselves, so you need to set up some kind of emulation to run them under windows. there is a combination of packages i would recommend:
MinGW, which contains the GCC compilers for windows
MSYS, which contains more unix tools, like "make", which is crucial for the makefile approach, and finally
MSYS DTK, the MSYS Developer Toolkit, which contains the autotools and some more programs.

there are some tutorials on the net about the gnu autotools. here is a link to gnu's webpage for autoconf with some links to the other tools involved in the build process. you could try to google for some beginner tutorials.

nevertheless, i still do not like using the make system since it so compilcated that it would be of no use for me to learn, at least at the moment. (i'd be happy to hear some recommendations on alternatives to make and the autotools)

the other approach is to compile your code to binaries for the target platforms. this is called "cross compiling". i haven't used this technique myself, so i cannot give you advice on this. nevertheless, asking google might help. if i remember correctly you can use gcc to cross compile to linux, but i'm not sure if the gcc binary included in MinGW is able to do it. maybe you need to compile gcc yourself, which may get hard since you will have some trouble with the required libraries and headers, since gcc is natively built for linux and unix.

option number three, which is only applyable to a linux target, would be to download and burn a so-called linux "live cd". this enables you to boot linux directly from cd without the danger of your harddrive or it's data being damaged. so, now you could compile the source under linux natively. nevertheless you need either some kind of network share to copy the resulting binary to or you have to write on your harddisk, which could be a problem if it is formatted with NTFS instead of FAT since the writing drivers for NTFS sometimes crash, which could lead to data loss. Knoppix is such a live cd distribution, although i do not know for sure if there is a compiler included, but i guess so. just have a look at the page, maybe it's mentioned there.

good luck, whatever you decide to do :)

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Check out SDL -- http://www.libsdl.org

Very popular with commercial developers targetting linux, osx and windows. Has ports to many other platforms.

Very easy to work with, and handles crossplatform input and GL init for you.

It of course does a bunch of 2D and sound options too, but you don't have to use those if you don't want to.

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Thanks guys.

I'm a student employee in the IT department at the university I attend. We mainly have PC's, but we have a few labs with Macs (No intel processors though :()

Also, I can go the live CD route for linux as mentioned, or I'll just install it on an older computer of mine.

I had always put off SDL because I had thought the support for 3D graphics was very limited. But I seem to be wrong. I like it's feature set and the api seems straight forward, so I'll give it a try.

So, I'll be using SDL + g++ on windows. Then, I'll talk my boss into letting me develop on one of the school macs. And getting linux setup on one of my computers isn't a problem. I just hope my code is truly portable.

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