mods/ENTITIES/mcl_minecarts/functions.lua

   1 function mcl_minecarts:get_sign(z)
   2         if z == 0 then
   3                 return 0
   4         else
   5                 return z / math.abs(z)
   6         end
   7 end
   8
   9 function mcl_minecarts:velocity_to_dir(v)
  10         if math.abs(v.x) > math.abs(v.z) then
  11                 return {x=mcl_minecarts:get_sign(v.x), y=mcl_minecarts:get_sign(v.y), z=0}
  12         else
  13                 return {x=0, y=mcl_minecarts:get_sign(v.y), z=mcl_minecarts:get_sign(v.z)}
  14         end
  15 end
  16
  17 function mcl_minecarts:is_rail(pos, railtype)
  18         local node = minetest.get_node(pos).name
  19         if node == "ignore" then
  20                 local vm = minetest.get_voxel_manip()
  21                 local emin, emax = vm:read_from_map(pos, pos)
  22                 local area = VoxelArea:new{
  23                         MinEdge = emin,
  24                         MaxEdge = emax,
  25                 }
  26                 local data = vm:get_data()
  27                 local vi = area:indexp(pos)
  28                 node = minetest.get_name_from_content_id(data[vi])
  29         end
  30         if minetest.get_item_group(node, "rail") == 0 then
  31                 return false
  32         end
  33         if not railtype then
  34                 return true
  35         end
  36         return minetest.get_item_group(node, "connect_to_raillike") == railtype
  37 end
  38
  39 function mcl_minecarts:check_front_up_down(pos, dir_, check_down, railtype)
  40         local dir = vector.new(dir_)
  41         local cur = nil
  42
  43         -- Front
  44         dir.y = 0
  45         cur = vector.add(pos, dir)
  46         if mcl_minecarts:is_rail(cur, railtype) then
  47                 return dir
  48         end
  49         -- Up
  50         if check_down then
  51                 dir.y = 1
  52                 cur = vector.add(pos, dir)
  53                 if mcl_minecarts:is_rail(cur, railtype) then
  54                         return dir
  55                 end
  56         end
  57         -- Down
  58         dir.y = -1
  59         cur = vector.add(pos, dir)
  60         if mcl_minecarts:is_rail(cur, railtype) then
  61                 return dir
  62         end
  63         return nil
  64 end
  65
  66 function mcl_minecarts:get_rail_direction(pos_, dir, ctrl, old_switch, railtype)
  67         local pos = vector.round(pos_)
  68         local cur = nil
  69         local left_check, right_check = true, true
  70
  71         -- Check left and right
  72         local left = {x=0, y=0, z=0}
  73         local right = {x=0, y=0, z=0}
  74         if dir.z ~= 0 and dir.x == 0 then
  75                 left.x = -dir.z
  76                 right.x = dir.z
  77         elseif dir.x ~= 0 and dir.z == 0 then
  78                 left.z = dir.x
  79                 right.z = -dir.x
  80         end
  81
  82         if ctrl then
  83                 if old_switch == 1 then
  84                         left_check = false
  85                 elseif old_switch == 2 then
  86                         right_check = false
  87                 end
  88                 if ctrl.left and left_check then
  89                         cur = mcl_minecarts:check_front_up_down(pos, left, false, railtype)
  90                         if cur then
  91                                 return cur, 1
  92                         end
  93                         left_check = false
  94                 end
  95                 if ctrl.right and right_check then
  96                         cur = mcl_minecarts:check_front_up_down(pos, right, false, railtype)
  97                         if cur then
  98                                 return cur, 2
  99                         end
 100                         right_check = true
 101                 end
 102         end
 103
 104         -- Normal
 105         cur = mcl_minecarts:check_front_up_down(pos, dir, true, railtype)
 106         if cur then
 107                 return cur
 108         end
 109
 110         -- Left, if not already checked
 111         if left_check then
 112                 cur = mcl_minecarts:check_front_up_down(pos, left, false, railtype)
 113                 if cur then
 114                         return cur
 115                 end
 116         end
 117
 118         -- Right, if not already checked
 119         if right_check then
 120                 cur = mcl_minecarts:check_front_up_down(pos, right, false, railtype)
 121                 if cur then
 122                         return cur
 123                 end
 124         end
 125
 126         -- Backwards
 127         if not old_switch then
 128                 cur = mcl_minecarts:check_front_up_down(pos, {
 129                                 x = -dir.x,
 130                                 y = dir.y,
 131                                 z = -dir.z
 132                         }, true, railtype)
 133                 if cur then
 134                         return cur
 135                 end
 136         end
 137
 138         return {x=0, y=0, z=0}
 139 end
 140