PACKAGE: SDL2 Add set scale mode for DirectFB video backend

[tiopex]

Allow to use hint SDL_HINT_RENDER_SCALE_QUALITY to set scale quality for DirectFB video backend

[Apaczer]

ok so via: https://raw.githubusercontent.com/libsdl-org/SDL/refs/tags/release-2.0.20/include/SDL_hints.h

we can set env var export SDL_RENDER_SCALE_QUALITY= and change scaling method with:

• "0" or "nearest" - Nearest pixel sampling
• "1" or "linear" - Linear filtering
• "2" or "best" - Linear with anti-aliasing?

[tiopex]

Anti-aliasing is only defined, but not used anywhere currently in DirectFB2 https://github.com/directfb2/DirectFB2/blob/4d6b7ddd8477b4b52aa78ec82a3add28ade0c965/include/directfb.h#L3559

You can change scale quality directly from code, via env variable or via directfbrc file

[Apaczer]

just wondering why this code is commented out for renderer->SetTextureScaleMode and non-existent for data->render_options in SDL2 code, what's the difference between? Any idea?

[tiopex]

It was commented there was #if 0. This method is used to control scale quality during rendering