1. I'm using Physics2D.Net, not Box2D, and as far as I know, Physics2D.Net doesn't have a ground object. However, I might be able to create a dummy object with infinite mass that ignores collisions and anchor the joint to that.
2. The problem is, I kind of had to choose between SGDK2 physics and 3rd-party physics. I don't think mixing them works well. I guess I didn't try, but if I leave the platforms out of the physics engine's model, then I have to figure out how to tell sprites that are
in the model to position and move themselves like they are still using SGDK2 physics. I need to develop new logic to decide what happens, for example, when a sprite hits another sprite that is riding the platform. I have to merge the SGDK2 physics that was telling the sprite's inertia to follow that of the platform with the 3rd party physics that is telling the sprite to move away (and probably even rotate!) as a result of being hit. It's too hard to use 2 physics engines, I think, so I just throw everything into the physics engine and it all takes care of itself for the most part. I just need to figure out how to manipulate things via the physics engine instead of directly. I have toyed with the thought, though, of limiting which sprites are represented in the physics engine. I think I just talked myself out of it
, but it's still in the back of my mind -- having participation in realistic physics be implemented more like an additional rule instead of intrinsic to the project's "engine".