[Feature request] Anti-aliasing support for SDL_Renderer

[LloydJHowarth]

Currently we can set MSAA with OpenGL for example:

SDL.GL_SetAttribute(SDL_GLattr.SDL_GL_MULTISAMPLEBUFFERS, 1);
SDL.GL_SetAttribute(SDL_GLattr.SDL_GL_MULTISAMPLESAMPLES, 4);

This gives us very nice anti-aliasing support for jagged edges on geometry rendered with SDL_RenderGeometry as an example. However it would be nice if we could have a flag or hint to enable some form of AA with all SDL_Renderer backends and not have to force OpenGL specifically

For example:

SDL.SetHint("SDL_RENDERER_MSAA", "4"); // 2, 4, 8, etc

This would be a great feature.

[slouken]

Feel free to submit a PR for this, and include support for other backends (such as D3D, Vulkan, Metal, etc)

[LloydJHowarth]

Unfortunately I don't have the knowledge to attempt this hence the request here.

Hopefully someone with the required knowledge could implement this in the future,

Thanks