Re: [Super-tux-devel] SuperTux

[Matze B. <ma...@br...>]

On Mon, 28 Mar 2005, Luke-Jr wrote:

> Just noticed that plans are to be OpenGL-only in the future... Is there really
> a good reason for this? I have seen a few systems in which OpenGL mode is too
> slow to be playable, but software rendering is very good and smooth...
These slow systems have messed up their drivers and are using software 
emulated opengl. But it should be possible in nearly all cases to fix 
that.

As for game developers opengl has lots of advantages:
- Hardware acceleration for lots of things, so that you are several 
magnitudes faster compared to software mode
- There are lots of nice effects possible that would just be too slow in 
software mode. (advanced lighting, blending, rotating or even pixelshaders 
which allow to run pixel based "filters" in realtime)
     For supertux I can think of several nice effects:
  	- Add a bit of lighting to touch up the repetitive
            background/tiles
  	- Having a sun with sunrays blending into the game
  	- Letting the screen "float" when swimming in water
  	- Fade out foreground layer when tux is hidden by these tiles
  	  (when you find secrets...)

And despite of this opengl has not only technical advantages but also 
makes life alot easier for coders:
- It has a nice clean and easy to use API
- The API does more things for you (storing a transformation stack, 
automatic rotation, scaling)

In anyway what I don't like as a coder is maintaining our current wrapper 
that supports opengl and software mode... I'd rather spend my time in 
other parts of the game.

(However from a deployment point of view we can be sure to lock out some 
of our userbase by going opengl only. Esp. on more exotic systems that 
have no proper opengl support yet, or for people with really old hardware 
- though for these people the game is unplayably slow anyway I guess...)
So we probably need some "market research" here to determine how many 
people would really need software mode :) Is anyone here on the list who 
would really need software mode and could explain why?
I know of ~20 people personally who play supertux and they all have 
hardware that is able to handle opengl easily. (18 people on win32, 2 on 
linux - worst of these systems is a 900Mhz Athlon with geforce 2 mx card).

Greetings,
  	Matze