mods/CORE/flowlib/init.lua

   1 flowlib = {}
   2
   3 --sum of direction vectors must match an array index
   4 local function to_unit_vector(dir_vector)
   5         --(sum,root)
   6         -- (0,1), (1,1+0=1), (2,1+1=2), (3,1+2^2=5), (4,2^2+2^2=8)
   7         local inv_roots = {[0] = 1, [1] = 1, [2] = 0.70710678118655, [4] = 0.5
   8                 , [5] = 0.44721359549996, [8] = 0.35355339059327}
   9         local sum = dir_vector.x*dir_vector.x + dir_vector.z*dir_vector.z
  10         return {x=dir_vector.x*inv_roots[sum],y=dir_vector.y
  11                 ,z=dir_vector.z*inv_roots[sum]}
  12 end
  13
  14 local is_touching = function(realpos,nodepos,radius)
  15         local boarder = 0.5 - radius
  16         return (math.abs(realpos - nodepos) > (boarder))
  17 end
  18
  19 flowlib.is_touching = is_touching
  20
  21 local is_water = function(pos)
  22         return (minetest.get_item_group(minetest.get_node(
  23                         {x=pos.x,y=pos.y,z=pos.z}).name
  24                 , "water") ~= 0)
  25 end
  26
  27 flowlib.is_water = is_water
  28
  29 local node_is_water = function(node)
  30         return (minetest.get_item_group(node.name, "water") ~= 0)
  31 end
  32
  33 flowlib.node_is_water = node_is_water
  34
  35 local is_lava = function(pos)
  36         return (minetest.get_item_group(minetest.get_node(
  37                         {x=pos.x,y=pos.y,z=pos.z}).name
  38                 , "lava") ~= 0)
  39 end
  40
  41 flowlib.is_lava = is_lava
  42
  43 local node_is_lava = function(node)
  44         return (minetest.get_item_group(node.name, "lava") ~= 0)
  45 end
  46
  47 flowlib.node_is_lava = node_is_lava
  48
  49
  50 local is_liquid = function(pos)
  51         return (minetest.get_item_group(minetest.get_node(
  52                         {x=pos.x,y=pos.y,z=pos.z}).name
  53                 , "liquid") ~= 0)
  54 end
  55
  56 flowlib.is_liquid = is_liquid
  57
  58 local node_is_liquid = function(node)
  59         return (minetest.get_item_group(node.name, "liquid") ~= 0)
  60 end
  61
  62 flowlib.node_is_liquid = node_is_liquid
  63
  64 --This code is more efficient
  65 local function quick_flow_logic(node,pos_testing,direction)
  66         local name = node.name
  67         if not minetest.registered_nodes[name] then
  68                 return 0
  69         end
  70         if minetest.registered_nodes[name].liquidtype == "source" then
  71                 local node_testing = minetest.get_node(pos_testing)
  72                 local param2_testing = node_testing.param2
  73                 if not minetest.registered_nodes[node_testing.name] then
  74                         return 0
  75                 end
  76                 if minetest.registered_nodes[node_testing.name].liquidtype
  77                 ~= "flowing" then
  78                         return 0
  79                 else
  80                         return direction
  81                 end
  82         elseif minetest.registered_nodes[name].liquidtype == "flowing" then
  83                 local node_testing = minetest.get_node(pos_testing)
  84                 local param2_testing = node_testing.param2
  85                 if not minetest.registered_nodes[node_testing.name] then
  86                         return 0
  87                 end
  88                 if minetest.registered_nodes[node_testing.name].liquidtype
  89                 == "source" then
  90                         return -direction
  91                 elseif minetest.registered_nodes[node_testing.name].liquidtype
  92                 == "flowing" then
  93                         if param2_testing < node.param2 then
  94                                 if (node.param2 - param2_testing) > 6 then
  95                                         return -direction
  96                                 else
  97                                         return direction
  98                                 end
  99                         elseif param2_testing > node.param2 then
 100                                 if (param2_testing - node.param2) > 6 then
 101                                         return direction
 102                                 else
 103                                         return -direction
 104                                 end
 105                         end
 106                 end
 107         end
 108         return 0
 109 end
 110
 111 local quick_flow = function(pos,node)
 112         local x = 0
 113         local z = 0
 114
 115         if not node_is_liquid(node)  then
 116                 return {x=0,y=0,z=0}
 117         end
 118
 119         x = x + quick_flow_logic(node,{x=pos.x-1,y=pos.y,z=pos.z},-1)
 120         x = x + quick_flow_logic(node,{x=pos.x+1,y=pos.y,z=pos.z}, 1)
 121         z = z + quick_flow_logic(node,{x=pos.x,y=pos.y,z=pos.z-1},-1)
 122         z = z + quick_flow_logic(node,{x=pos.x,y=pos.y,z=pos.z+1}, 1)
 123
 124         return to_unit_vector({x=x,y=0,z=z})
 125 end
 126
 127 flowlib.quick_flow = quick_flow
 128
 129
 130         --if not in water but touching, move centre to touching block
 131         --x has higher precedence than z
 132         --if pos changes with x, it affects z
 133 local move_centre = function(pos,realpos,node,radius)
 134         if is_touching(realpos.x,pos.x,radius) then
 135                 if is_liquid({x=pos.x-1,y=pos.y,z=pos.z}) then
 136                         node = minetest.get_node({x=pos.x-1,y=pos.y,z=pos.z})
 137                         pos = {x=pos.x-1,y=pos.y,z=pos.z}
 138                 elseif is_liquid({x=pos.x+1,y=pos.y,z=pos.z}) then
 139                         node = minetest.get_node({x=pos.x+1,y=pos.y,z=pos.z})
 140                         pos = {x=pos.x+1,y=pos.y,z=pos.z}
 141                 end
 142         end
 143         if is_touching(realpos.z,pos.z,radius) then
 144                 if is_liquid({x=pos.x,y=pos.y,z=pos.z-1}) then
 145                         node = minetest.get_node({x=pos.x,y=pos.y,z=pos.z-1})
 146                         pos = {x=pos.x,y=pos.y,z=pos.z-1}
 147                 elseif is_liquid({x=pos.x,y=pos.y,z=pos.z+1}) then
 148                         node = minetest.get_node({x=pos.x,y=pos.y,z=pos.z+1})
 149                         pos = {x=pos.x,y=pos.y,z=pos.z+1}
 150                 end
 151         end
 152         return pos,node
 153 end
 154
 155 flowlib.move_centre = move_centre