[SDL] SDL 1.3 and rendering API state management

[David Olofson]

On Sunday 03 September 2006 11:30, Torsten Giebl wrote:
> Hello !
> 
> 
> > I realized there is another problem as well: Just like glSDL, SDL 
1.3
> > (at least the OpenGL renderer) relies on some parts of the API 
state
> > to remain unchanged between calls. This means an application or 
add-on
> > library cannot safely change anything, nor can it rely on the 
state to be
> > unaffected by SDL rendering calls.
> 
> 
> Is it not possible in OpenGL to save these states,
> then modify them, do all the blittings, restore them ?

Yeah, but it's not something you want to do for every rendered 
primitive...

Indeed, the application can explicitly say "now I'm going to use 
Advanced2D for a while", and then "now I'm going to make some SDL 
rendering calls" - but this is error prone and results in strange and 
hard to find bugs if/when mistakes are made. Even harder to get right 
if you're using for example a rendering lib and a GUI toolkit lib 
together, rather than making the rendering calls directly.

With some kind of mutual notification interface, this could be done 
automatically by SDL and/or the add-on lib - that is, actual work is 
done only when switching between SDL rendering and add-on library 
calls. (Of course, that makes it a bad idea to mix wildly - but 
that's not really what I'm trying to support. I'm just trying to 
minimize the risk of SDL 1.3/2.0 add-on libs mysteriously breaking 
when used together.)


//David Olofson - Programmer, Composer, Open Source Advocate

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