boost_cart/functions.lua
2014-08-09 17:37:02 +02:00

101 lines
2.0 KiB
Lua

function boost_cart:get_sign(z)
if z == 0 then
return 0
else
return z / math.abs(z)
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)
local node = minetest.get_node(pos).name
return minetest.get_item_group(node, "rail") ~= 0
end
function boost_cart:get_rail_direction(pos_, dir_, ctrl, old_switch)
local pos = vector.round(pos_)
local dir = vector.new(dir_)
local cur = nil
local left_check, right_check = true, true
old_switch = old_switch or 0
-- 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 = vector.add(pos, left)
if boost_cart:is_rail(cur) then
return left, 1
end
left_check = false
end
if ctrl.right and right_check then
cur = vector.add(pos, right)
if boost_cart:is_rail(cur) then
return right, 2
end
right_check = true
end
end
-- Front
dir.y = 0
cur = vector.add(pos, dir)
if boost_cart:is_rail(cur) then
return dir
end
-- Down
dir.y = -1
cur = vector.add(pos, dir)
if boost_cart:is_rail(cur) then
return dir
end
-- Up
dir.y = 1
cur = vector.add(pos, dir)
if boost_cart:is_rail(cur) then
return dir
end
-- Left, if not already checked
if left_check then
cur = vector.add(pos, left)
if boost_cart:is_rail(cur) then
return left
end
end
-- Right, if not already checked
if right_check then
cur = vector.add(pos, right)
if boost_cart:is_rail(cur) then
return right
end
end
return {x=0, y=0, z=0}
end