mods/carts/functions.lua

   1 function carts: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 carts:manage_attachment(player, obj)
  10         if not player then
  11                 return
  12         end
  13         local status = obj ~= nil
  14         local player_name = player:get_player_name()
  15         if player_api.player_attached[player_name] == status then
  16                 return
  17         end
  18         player_api.player_attached[player_name] = status
  19
  20         if status then
  21                 player:set_attach(obj, "", {x=0, y=-4.5, z=0}, {x=0, y=0, z=0})
  22                 player:set_eye_offset({x=0, y=-4, z=0},{x=0, y=-4, z=0})
  23         else
  24                 player:set_detach()
  25                 player:set_eye_offset({x=0, y=0, z=0},{x=0, y=0, z=0})
  26         end
  27 end
  28
  29 function carts:velocity_to_dir(v)
  30         if math.abs(v.x) > math.abs(v.z) then
  31                 return {x=carts:get_sign(v.x), y=carts:get_sign(v.y), z=0}
  32         else
  33                 return {x=0, y=carts:get_sign(v.y), z=carts:get_sign(v.z)}
  34         end
  35 end
  36
  37 function carts:is_rail(pos, railtype)
  38         local node = minetest.get_node(pos).name
  39         if node == "ignore" then
  40                 local vm = minetest.get_voxel_manip()
  41                 local emin, emax = vm:read_from_map(pos, pos)
  42                 local area = VoxelArea:new{
  43                         MinEdge = emin,
  44                         MaxEdge = emax,
  45                 }
  46                 local data = vm:get_data()
  47                 local vi = area:indexp(pos)
  48                 node = minetest.get_name_from_content_id(data[vi])
  49         end
  50         if minetest.get_item_group(node, "rail") == 0 then
  51                 return false
  52         end
  53         if not railtype then
  54                 return true
  55         end
  56         return minetest.get_item_group(node, "connect_to_raillike") == railtype
  57 end
  58
  59 function carts:check_front_up_down(pos, dir_, check_up, railtype)
  60         local dir = vector.new(dir_)
  61         local cur
  62
  63         -- Front
  64         dir.y = 0
  65         cur = vector.add(pos, dir)
  66         if carts:is_rail(cur, railtype) then
  67                 return dir
  68         end
  69         -- Up
  70         if check_up then
  71                 dir.y = 1
  72                 cur = vector.add(pos, dir)
  73                 if carts:is_rail(cur, railtype) then
  74                         return dir
  75                 end
  76         end
  77         -- Down
  78         dir.y = -1
  79         cur = vector.add(pos, dir)
  80         if carts:is_rail(cur, railtype) then
  81                 return dir
  82         end
  83         return nil
  84 end
  85
  86 function carts:get_rail_direction(pos_, dir, ctrl, old_switch, railtype)
  87         local pos = vector.round(pos_)
  88         local cur
  89         local left_check, right_check = true, true
  90
  91         -- Check left and right
  92         local left = {x=0, y=0, z=0}
  93         local right = {x=0, y=0, z=0}
  94         if dir.z ~= 0 and dir.x == 0 then
  95                 left.x = -dir.z
  96                 right.x = dir.z
  97         elseif dir.x ~= 0 and dir.z == 0 then
  98                 left.z = dir.x
  99                 right.z = -dir.x
 100         end
 101
 102         local straight_priority = ctrl and dir.y ~= 0
 103
 104         -- Normal, to disallow rail switching up- & downhill
 105         if straight_priority then
 106                 cur = self:check_front_up_down(pos, dir, true, railtype)
 107                 if cur then
 108                         return cur
 109                 end
 110         end
 111
 112         if ctrl then
 113                 if old_switch == 1 then
 114                         left_check = false
 115                 elseif old_switch == 2 then
 116                         right_check = false
 117                 end
 118                 if ctrl.left and left_check then
 119                         cur = self:check_front_up_down(pos, left, false, railtype)
 120                         if cur then
 121                                 return cur, 1
 122                         end
 123                         left_check = false
 124                 end
 125                 if ctrl.right and right_check then
 126                         cur = self:check_front_up_down(pos, right, false, railtype)
 127                         if cur then
 128                                 return cur, 2
 129                         end
 130                         right_check = true
 131                 end
 132         end
 133
 134         -- Normal
 135         if not straight_priority then
 136                 cur = self:check_front_up_down(pos, dir, true, railtype)
 137                 if cur then
 138                         return cur
 139                 end
 140         end
 141
 142         -- Left, if not already checked
 143         if left_check then
 144                 cur = carts:check_front_up_down(pos, left, false, railtype)
 145                 if cur then
 146                         return cur
 147                 end
 148         end
 149
 150         -- Right, if not already checked
 151         if right_check then
 152                 cur = carts:check_front_up_down(pos, right, false, railtype)
 153                 if cur then
 154                         return cur
 155                 end
 156         end
 157
 158         -- Backwards
 159         if not old_switch then
 160                 cur = carts:check_front_up_down(pos, {
 161                                 x = -dir.x,
 162                                 y = dir.y,
 163                                 z = -dir.z
 164                         }, true, railtype)
 165                 if cur then
 166                         return cur
 167                 end
 168         end
 169
 170         return {x=0, y=0, z=0}
 171 end
 172
 173 function carts:pathfinder(pos_, old_pos, old_dir, distance, ctrl,
 174                 pf_switch, railtype)
 175
 176         local pos = vector.round(pos_)
 177         if vector.equals(old_pos, pos) then
 178                 return
 179         end
 180
 181         local pf_pos = vector.round(old_pos)
 182         local pf_dir = vector.new(old_dir)
 183         distance = math.min(carts.path_distance_max,
 184                 math.floor(distance + 1))
 185
 186         for i = 1, distance do
 187                 pf_dir, pf_switch = self:get_rail_direction(
 188                         pf_pos, pf_dir, ctrl, pf_switch or 0, railtype)
 189
 190                 if vector.equals(pf_dir, {x=0, y=0, z=0}) then
 191                         -- No way forwards
 192                         return pf_pos, pf_dir
 193                 end
 194
 195                 pf_pos = vector.add(pf_pos, pf_dir)
 196
 197                 if vector.equals(pf_pos, pos) then
 198                         -- Success! Cart moved on correctly
 199                         return
 200                 end
 201         end
 202         -- Not found. Put cart to predicted position
 203         return pf_pos, pf_dir
 204 end
 205
 206 function carts:register_rail(name, def_overwrite, railparams)
 207         local def = {
 208                 drawtype = "raillike",
 209                 paramtype = "light",
 210                 sunlight_propagates = true,
 211                 is_ground_content = false,
 212                 walkable = false,
 213                 selection_box = {
 214                         type = "fixed",
 215                         fixed = {-1/2, -1/2, -1/2, 1/2, -1/2+1/16, 1/2},
 216                 },
 217                 sounds = default.node_sound_metal_defaults()
 218         }
 219         for k, v in pairs(def_overwrite) do
 220                 def[k] = v
 221         end
 222         if not def.inventory_image then
 223                 def.wield_image = def.tiles[1]
 224                 def.inventory_image = def.tiles[1]
 225         end
 226
 227         if railparams then
 228                 carts.railparams[name] = table.copy(railparams)
 229         end
 230
 231         minetest.register_node(name, def)
 232 end
 233
 234 function carts:get_rail_groups(additional_groups)
 235         -- Get the default rail groups and add more when a table is given
 236         local groups = {
 237                 dig_immediate = 2,
 238                 attached_node = 1,
 239                 rail = 1,
 240                 connect_to_raillike = minetest.raillike_group("rail")
 241         }
 242         if type(additional_groups) == "table" then
 243                 for k, v in pairs(additional_groups) do
 244                         groups[k] = v
 245                 end
 246         end
 247         return groups
 248 end