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Making a GUI for OpenGL Games?
stuck in a bind asks: "I am currently coding a civilization-type game (in C) but on a galactic scale. OpenGL is used to draw everything so far. However I have been unable to find a decent, nice GUI, practically all of them are coded in C++.
The only other options I can think of is coding my own toolkit (too much work, and I would hate to reinvent the wheel here), using SDL to draw 2D bitmaps on top of my OpenGL window. The last option would be to switch to GTK and use the GTK GL widget. What would the educated gamer/programmers of Slashdot recommend?"
using SDL to draw 2D bitmaps on top of my OpenGL window.
don't use SDL's method for blitting SDL_Surface's over OpenGL.. it's too slow.
do your 2D with OpenGL (textured polys).
-metric
OO is pretty much ideal for GUI programming. So why not code up your GUI in C++ and leave the rest of your game in C?
Is there some reason you're opposed to C++?
What would the educated gamer/programmers of Slashdot recommend?
Choose one:
(1) Switch to C++. Problem solved. Nobody in their right mind (outside of tiny platforms such as the Gameboy and certain icky parts of the Playstation 2) is still writing games in straight C. C++ does a much better job of encapsulation and maintaining a clear codebase - particularly if you expect the codebase to be worked on by more than one person.
Besides, UI programming is a pain in the ass without object-orientated encapsulation.
(2) If you're amazingly stubborn and still don't want to modernize your codebase, you can still use C++ without C++ features (you can ignore language features like classes, for example). This will let you use the C++ toolkits that you want.
(3) Write your own. If you really have the incentive and dedication to write a game, you should be able to write a UI toolkit for it.
I know that what you want is a C-based UI toolkit that can render widgets in OpenGL. I recently had to research this, and my impression is that you're stuck. As others have suggested, you might consider switching to a C++ compiler and just linking in your C code. You'll be hard pressed to find an advanced UI toolkit that isn't based in C++. Object orientation just matches user interface coding too well.
i tepapers.html
Here's the results of my search. This was for an application which had a very large number of Windows-like UI elements, but had to be able to render a 3D world using OpenGL.
FLTK -- Unsuitable. LGPL. Can open GL windows. Uses direct calls to OS line-drawing routines, so could be adapted to render directly to GL. Reasonable number of widgets, but ugly. No skin support. Development slow (two check-ins in last month).
wxWidgets(aka wxWindows) -- Good. LGPL. Can open GL windows.Used by Mitch Kapor's Chandler PIM project. Would require separate UI thread not to block. Requires awkward preprocessor macros in UI classes. Third-party graphical widget layout tools.
GLOW -- Unsuitable. Renders to GL. Not actively maintained. Uses advanced C++ (STL, RTTI). Clean code. No access to OS features, based on GLUT. Very simple, ugly widgets. Small library of widgets
Qt -- Very good. Commercial license. Can open GL windows. Included graphical UI layout tools. XML-based UI files, but compiled into code rather than loaded at runtime.
GLUI -- Unsuitable. LGPL. Renders to GL. Not actively maintained. Simplistic C++ code. No access to OS features, based on GLUT. Very simple, ugly widgets. Small library of widgets.
XPToolkit(aka Mozilla/XUL) -- Unsuitable. Tri-license MPL/LGPL/GPL. No GL support. Would need to ship Mozilla or Firefox as part of app. Excellent ideas for XML-based UI layout, though.
Full-custom with XML library -- Good. Renders to GL. Easiest for migration. Could do in-game UI editing, both for default skin, user skins, and script UI controls. Probably more work for you.
Also, if you're new to UI library development, I strongly suggest you read the Qt whitepapers. Their concept of signals and slots seems quite powerful (though I have not used it myself).
Qt 3.3 whitepaper:
http://www.trolltech.com/products/wh
James
Why is it someone wants to design a game, its "Been done".. Maybe he has new ideas. Let the guy try. What would of happened if Linus said "Well, Minix is good enough for me"....
Exactly...