populate_collision_data = function()
	for _,def in pairs(Definitions) do
		assert(def.w)
		assert(def.h)
		if def.pos == nil then def.pos = {} end
		if def.hs == nil then def.hs = {} end
		def.hs.x = def.w/2
		def.hs.y = def.h/2 + 30
		def.pos.x = def.x + def.hs.x
		def.pos.y = def.y + def.hs.y
	end
end