I'm trying to use XSPSetPixelDoubling http://wiki.maemo.org/Game_developme...ing_inside_SDL but it seems not to work.
Is XSPSetPixelDoubling supported on N900?

Nope, since the hardware that did that is gone on the N900.

Alternatives are
- Just scale in software (plain 2x)
- Use the SGX (via opengl es, libhildon (animation actors) or sdl_haa).
- Use the omap dispc (no samples yet)

Thanks for the info.

BTW: Where did you find out about HAA? Google is not much help here. (Finds DrNokSNES sources )

SDL_haa (libsdl-haa1.2-dev) is my own work and currently only in use by DrNokSnes, but it is a plain SDL wrapper around the Hildon Animation Actor atoms, and animation actors are documented: http://maemo.org/api_refs/5.0/5.0-fi...tionActor.html

If you're going the SGX route, then I suggest using actors to scale (since they will still work as fast when the compositor is enabled, for example in windowed mode). But for simpler scalings, software _is_ the better choice for now.

Thanks for the link. The API documentation is nice, but what about more general questions: What is an Animator Actor? what can I use it for? how? usage example?

I'm looking through DrNokSnes source, but it is a lot of guesswork.

I found http://wiki.maemo.org/Documentation/...d_Size_Windows which is enlightening.

The Fremantle compositor (aka hildon-desktop) reads the window contents every time those change; converts them to a GLES texture, uploading it to the SGX; and then uses Clutter (GLESv2) to render them to the screen.
An animation actor is just a special type of window that is rendered in a special way. You can configure the compositor (via xatoms) to render any of those windows rotated, scaled, etc. at your pleasure.

If you were to do this with GLES API by yourself (and assuming a composited/non fullscreen mode), the compositor would get your large GLES scaled image and REupload it to the SGX to again convert it a to a texture, thus slowing down the process.

Another example (for SDL_haa) is: http://git.maemo.org/git/sdlhildon/?...a/test/basic.c

basis.c is enough to get a grip what to do. I just added SDL_haa scaling to psx4all. Thanks again.

I have a problem though.
If I create SDL_FULLSCREEN window, the actor works ok on it. But if I change windows, the SDL fullscreen window is closed and I loose the actor. When I switch back to the SDL app window, the fullscreen window is recreated, but without the actor.

Ouch. I see that's broken since PR1.1... ah well, I was making dangerous assumptions there either way. For the next revision I won't try to keep in sync with the SDL screen automatically.

The first workaround that comes to mind is deleting the actor, calling HAA_Quit, then HAA_Init and recreating the actor.