[SDL] DirectX 7?

David Olofson david.olofson at reologica.se
Mon Sep 30 07:09:01 PDT 2002

On Friday 27 September 2002 02:05, Neil Griffiths wrote:
> Yes, there would be no point otherwise. However, don't get stuck
> thinking that it's a 3D API. It isn't, you'd still be treating it as
> 2D. It's just that SDL itself would be using the features of your 3D
> card to draw the graphics. Hell, something nice would be fake
> anti-aliasing which would be to render at 800x600 and to scale down to
> and display at 640x480 - and this could be done in hardware. :)

That's where it gets complicated... As long as the "wrapper" knows which 
tiles belong together, it's just a matter of copying border pixels around 
to keep the filtering from "leaking" around the edges of quads.

However, as soon as you explicitly render surfaces side by side (as in a 
tiled map), you end up in a situation where the API can't easilly figure 
out what to do. Disabling texture filtering seems to be the only way to 
deal with that, even with FSAA, as whatever texture filtering you use, 
edges will look different... :-/

Now, if the API supports "tiled layers" as a form of virtual surfaces, 
this could be solved relatively easilly. (Well, at least it doesn't take 
a full scene analyze before rendering each frame. :-)

> And in reply to Patrick from before... :)
> PM> Hmm, yeah, I kinda wish sdl 2.0 had everything in software so in
> the long run PM> all of this wouldnt matter. Exploit what you can with
> hardware APIs, if you PM> cant, fall back to an internal software
> routine.
> Right, that's what I've been saying all along. There wouldn't be
> anything extra that would be done because of the OpenGL or DX8
> targets. There would always be a software fall-back for people who
> don't have those - and GDI needs to be there. DirectX7 would also be
> nice, I'll admit, but there's going to be a lot of work done there...
> It's just that we can take advantage of modern hardware and I believe
> we should do that!


Considering the poll results, it's rather strange that the insterest in 
the 2D-on-3D approach isn't even bigger than it is. I've received info on 
29 machines now, and only *one* lacks accelerated 3D.

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

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