just_test_tribute/boost_cart/functions (copy 1).lua

function boost_cart:get_sign(z)

	if z == 0 then
		return 0
	else
		return z / math.abs(z)
	end
end

function boost_cart:manage_attachment(player, status, obj)

	if not player then
		return
	end

	local player_name = player:get_player_name()

	if default.player_attached[player_name] == status then
		return
	end

	default.player_attached[player_name] = status

	if status then
		player:set_attach(obj, "", {x=0, y=6, z=0}, {x=0, y=0, z=0})
		player:set_eye_offset({x=0, y=-2, z=0},{x=0, y=-2, z=0})
	else
		player:set_detach()
		player:set_eye_offset({x=0, y=0, z=0},{x=0, y=0, z=0})
	end
end

function boost_cart:velocity_to_dir(v)

	if math.abs(v.x) > math.abs(v.z) then
		return {x=boost_cart:get_sign(v.x), y=boost_cart:get_sign(v.y), z=0}
	else
		return {x=0, y=boost_cart:get_sign(v.y), z=boost_cart:get_sign(v.z)}
	end
end

function boost_cart:is_rail(pos, railtype)

	local node = minetest.get_node(pos).name

	if node == "ignore" then

		local vm = minetest.get_voxel_manip()
		local emin, emax = vm:read_from_map(pos, pos)
		local area = VoxelArea:new{
			MinEdge = emin,
			MaxEdge = emax,
		}
		local data = vm:get_data()
		local vi = area:indexp(pos)
		node = minetest.get_name_from_content_id(data[vi])
	end

	if minetest.get_item_group(node, "rail") == 0 then
		return false
	end

	if not railtype then
		return true
	end

	return minetest.get_item_group(node, "connect_to_raillike") == railtype
end

function boost_cart:check_front_up_down(pos, dir_, check_down, railtype)

	local dir = vector.new(dir_)
	local cur = nil

	-- Front
	dir.y = 0
	cur = vector.add(pos, dir)

	if boost_cart:is_rail(cur, railtype) then
		return dir
	end

	-- Up
	if check_down then

		dir.y = 1
		cur = vector.add(pos, dir)

		if boost_cart:is_rail(cur, railtype) then
			return dir
		end
	end

	-- Down
	dir.y = -1
	cur = vector.add(pos, dir)

	if boost_cart:is_rail(cur, railtype) then
		return dir
	end

	return nil
end

function boost_cart:get_rail_direction(pos_, dir, ctrl, old_switch, railtype)

	local pos = vector.round(pos_)
	local cur = nil
	local left_check, right_check = true, true
	
	-- Check left and right
	local left = {x=0, y=0, z=0}
	local right = {x=0, y=0, z=0}

	if dir.z ~= 0 and dir.x == 0 then
		left.x = -dir.z
		right.x = dir.z
	elseif dir.x ~= 0 and dir.z == 0 then
		left.z = dir.x
		right.z = -dir.x
	end
	
	if ctrl then

		if old_switch == 1 then
			left_check = false
		elseif old_switch == 2 then
			right_check = false
		end

		if ctrl.left and left_check then

			cur = boost_cart:check_front_up_down(pos, left, false, railtype)

			if cur then
				return cur, 1
			end

			left_check = false
		end

		if ctrl.right and right_check then

			cur = boost_cart:check_front_up_down(pos, right, false, railtype)

			if cur then
				return cur, 2
			end

			right_check = true
		end
	end
	
	-- Normal
	cur = boost_cart:check_front_up_down(pos, dir, true, railtype)

	if cur then
		return cur
	end
	
	-- Left, if not already checked
	if left_check then

		cur = boost_cart:check_front_up_down(pos, left, false, railtype)

		if cur then
			return cur
		end
	end
	
	-- Right, if not already checked
	if right_check then

		cur = boost_cart:check_front_up_down(pos, right, false, railtype)

		if cur then
			return cur
		end
	end
	
	-- Backwards
	if not old_switch then

		cur = boost_cart:check_front_up_down(pos, {
			x = -dir.x,
			y = dir.y,
			z = -dir.z
		}, true, railtype)

		if cur then
			return cur
		end
	end
	
	return {x=0, y=0, z=0}
end

function boost_cart:boost_rail(pos, amount)

	minetest.get_meta(pos):set_string("cart_acceleration", tostring(amount))

	for _,obj_ in pairs(minetest.get_objects_inside_radius(pos, 0.5)) do

		if not obj_:is_player()
		and obj_:get_luaentity()
		and obj_:get_luaentity().name == "carts:cart" then
			obj_:get_luaentity():on_punch()
		end
	end
end