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OpenGL Pure OpenGL?

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Hi everybody, since I want to move from DiretX to OpenGL now, because I want my games to become cross platformed, I started reading some tutorials and papers on OpenGL. I had not really a lot of time now, because I've got an exam this thursday, but however, I've got a question. When reading about setting up OpenGL I saw a lot of solutions with SDL, GLUT, etc. So what I want to know is, can I create an cross platformed solution with OpenGL with fullscreen in windows without using another 1000 libraries and stuff I don't want to bother with? And one more which was bothering me, while skimming over NeHe's tuts, what the hell is GLAUX? So if someone could give me an short summary to these questions and maybe add some points he consideres to be worth knowing I'd be very thankfull. cheers, marcel

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Yes you can make an app with "pure" openGL. You absolutely will need to use at least win32 for the windows interfaces to get the app actually started. But that makes sense, hard to get something running in windows without a windows library...

Outside of that, however, you don't need anything else. Personally, I don't like GLUT, but whatever. SDL is just a convenient mechanism by which you can get the windows part of things initialized. win32 can get icky and confusing.

-me

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OpenGL is a strictly graphics library. It does not deal at all with Windowing or anything. You can set up OpenGL the same way you set up Direct3D using the Win32 API. Because OpenGL is cross-platform however, it makes sense to make your setup cross-platform as well.

To this end, there have been many libraries created to wrap up the setup code on various platforms so that you don not have to. These libraries are always very simple to use and you should be able to get them up in a few minutes (I prefer SDL).

Glaux is the OpenGL auxilary library and has some utilities to load bitmap images. It is very out of date and buggy, so you should not use it. You can use one of several image loading libraries to replace it (SDL_Image is my favorite).

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You cannot use "pure" OpenGL for a cross-platform app, because OpenGL does not specify the means by which you could create a window / set the rendering context, etc. It also ONLY deals with rendering onto a buffer, so when it comes to loading image files from the disk, receiving mouse input, playing sound, etc then you have to deal with those seperately.

The lowest level library for dealing with OpenGL windowing control is custom per platform (xgl, wgl, are the xwindows and windows versions of the API for managing windows) ... but many people have wrapped this functionality into cross-platform libraries before.

GLU is basically part of OpenGL as well and should not be avoided in an attempt to stay "pure"

GLUT is a great choice for initially messing with the OpenGL specfic graphics commands, but pretty useless for real work. I do however recommend it for pasting OpenGL code while learning the API since you will concentrate solely on putting in the graphics commands and not building the application.

SDL is an attempt at a cross-platform replacement for DirectX, including Windowing, Graphics, Sound, Input, CDROM control, etc. The good thing about it is, you don't have to initialize and use the parts you don't want. So what I personally have done is simply use SDL only for its ability to create windows in a cross-platform way that I can use OpenGL with.

There are many others, but really if you ONLY want to plug in cross-platform graphics, SDL is probably your best bet.

Good Luck.

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thx for the answers m8s

ok I knew that I'd need some windows stuff for windows but I considered that to be trivial

fine that's what I wanted to know, personaly I prefer doing stuff by my self instead of using wrapper libraries, actually I want to write a cross platformed lib for creating 2d games on my own and thats why I want to take care of alle the stuff on my own, later on I maybe will use sdl, as it seem to be a very good lib, but for now while learning and creating my low level stuff I want to do it my self

well however thx a bunch

cheers,
marcel

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if u want cross platform stuff i recommend sdl ( i use it), if u use it u can be pretty sure your app will run on windows/macos/linux/amiga etc

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Hi MMarcel,

I highly recommend going the SDL route. It will at least let you prototype results quickly, without getting caught up in the details of OS-specific coding (e.g. Win32 system calls and message-handling).

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Quote:
Original post by MMarcel
thx for the answers m8s

ok I knew that I'd need some windows stuff for windows but I considered that to be trivial

fine that's what I wanted to know, personaly I prefer doing stuff by my self instead of using wrapper libraries, actually I want to write a cross platformed lib for creating 2d games on my own and thats why I want to take care of alle the stuff on my own, later on I maybe will use sdl, as it seem to be a very good lib, but for now while learning and creating my low level stuff I want to do it my self

well however thx a bunch

cheers,
marcel


If you want it to be cross platform, you will need to be familiar with creating a window in linux (in all its flavors), windows, and Mac. If you can do that easily and efficiently, then go for it. SDL (as other libraries) wrap this functionality into and extremely easy to use library.

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