Make PaintBrush tool work with WorldEdit region, add "//pbrush" console command.

mods/WorldEdit/worldedit/init.lua

@@ -25,6 +25,7 @@ local function load_module(path)
 end
 
 dofile(path .. "/common.lua")
+dofile(path .. "/math.lua")
 load_module(path .. "/manipulations.lua")
 load_module(path .. "/primitives.lua")
 load_module(path .. "/visualization.lua")

mods/WorldEdit/worldedit/manipulations.lua

@@ -3,7 +3,6 @@
 
 local mh = worldedit.manip_helpers
 
-
 --- Sets a region to `node_names`.
 -- @param pos1
 -- @param pos2
@@ -62,6 +61,33 @@ function worldedit.set_param2(pos1, pos2, param2)
 	return worldedit.volume(pos1, pos2)
 end
 
+--- Changes param2 by a constant value for each node in a region.
+-- @param pos1
+-- @param pos2
+-- @param delta Param2 value to add to each node
+-- @return The number of nodes set.
+function worldedit.add_param2(pos1, pos2, delta)
+	pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+
+	local manip, area = mh.init(pos1, pos2)
+	local param2_data = manip:get_param2_data()
+	local new_p2 = 0
+
+	-- Add delta to every node
+	for i in area:iterp(pos1, pos2) do
+		new_p2 = math.mod(param2_data[i] + delta, 256)
+		if new_p2 < 0 then new_p2 = new_p2 + 256 end
+		param2_data[i] = new_p2
+	end
+
+	-- Update map
+	manip:set_param2_data(param2_data)
+	manip:write_to_map()
+	manip:update_map()
+
+	return worldedit.volume(pos1, pos2)
+end
+
 --- Replaces all instances of `search_node` with `replace_node` in a region.
 -- When `inverse` is `true`, replaces all instances that are NOT `search_node`.
 -- @return The number of nodes replaced.

mods/WorldEdit/worldedit/math.lua

@@ -0,0 +1,13 @@
+math.mod = function(value, m)
+    if value < 0 then
+        while value < -m do
+            value = value + m
+        end
+    elseif value > m then
+        while value > m do
+            value = value - m
+        end
+    end
+    return value
+end
+

mods/WorldEdit/worldedit_commands/init.lua

@@ -589,6 +589,40 @@ worldedit.register_command("param2", {
 	end,
 })
 
+--[[
+    //pbrush: special command for the "Traitor" game.
+
+    Simulates using Traitor's "PaintBrush" tool on a WorldEdit region.
+]]--
+worldedit.register_command("pbrush", {
+    params = "+ / - / [+/-]<steps>",
+    description = minetest.formspec_escape(
+        "Increase/decrease the color tone of all suitable nodes in the current WorldEdit region.\n"
+        .. "Suitable nodes are those that can be colored using the PaintBrush tool "
+        .. "(e.g. the blocks in the 'color' namespace).\n"
+        .. "Using + or - changes the color once; use <steps> for multiple steps.\n"
+        .. "Note that <steps> should be at most 7, higher values are ignored."),
+    privs = {worldeditor=true, creative=true},
+    require_pos = 2,
+    parse = function(param)
+        local found, _, sign, steps = param:find("([+-]?)(%d?)")
+        local delta = 32
+
+        if found == nil then return false end
+        if steps ~= nil and steps ~= "" then
+            local count = math.mod(tonumber(steps), 8)
+            delta = 32 * count
+        end
+        if sign == "-" then delta = -delta end
+        return true, delta
+    end,
+    nodes_needed = check_region,
+    func = function(name, delta)
+        local count = worldedit.add_param2(worldedit.pos1[name], worldedit.pos2[name], delta)
+        worldedit.player_notify(name, count .. " nodes altered")
+    end,
+})
+
 worldedit.register_command("mix", {
 	params = "<node1> [count1] <node2> [count2] ...",
 	description = "Fill the current WorldEdit region with a random mix of <node1>, ...",

mods/WorldEdit/worldedit_commands/mark.lua

@@ -123,6 +123,48 @@ worldedit.marker_update = function(name)
 	worldedit.mark_region(name)
 end
 
+--[[
+    Determines if the thing currently being pointed at is one of the following:
+    - one of the Worldedit position boxes to delimit a Worldedit region
+    - one of the special cubes that Worldedit puts at certain nodes to
+      visualize the bounds of a selection region
+
+    The function uses knowledge about the internal structure of the Worldedit
+    regions.  Also, it uses the API function "ObjectRef:get_entity_name" to
+    determine the registered names of the object pointed at.  However, the
+    documentation states that this function will be removed in the future[1].
+    --------------------------------------------------------------------------
+    [1] https://minetest.gitlab.io/minetest/class-reference/#objectref
+--]]
+worldedit.is_marker_region = function(pointed_thing)
+    if pointed_thing ~= nil and pointed_thing.type ~= nil then
+        if pointed_thing.type == 'object' and pointed_thing.ref ~= nil then
+            local ref = pointed_thing.ref
+
+            if ref.get_entity_name ~= nil then
+                local objname = ref:get_entity_name()
+
+                if objname == 'worldedit:region_cube' or
+                    objname == 'worldedit:pos1' or
+                    objname == 'worldedit:pos2' then
+                    return true
+                end
+            end
+        end
+    end
+    return false
+end
+
+--[[
+    Returns true if `user` is the owner of the Worldedit marker region
+    currently being pointed at.
+--]]
+worldedit.is_region_owner = function(pointed_thing, user)
+    local region_ref = pointed_thing.ref
+    local region_entity = region_ref:get_luaentity()
+    return (user == region_entity.player_name)
+end
+
 minetest.register_entity(":worldedit:pos1", {
 	initial_properties = {
 		visual = "cube",

mods/color/init.lua

@@ -9,6 +9,15 @@ local function register_color(name)
    })
 end
 
+local function region_add_delta(pos1, pos2, player, delta)
+    if minetest.is_protected(pos1, player) or minetest.is_protected(pos2, player) then
+        minetest.debug('*** you are trying to paint in a protected region, '
+            .. player .. '!')
+    else
+        worldedit.add_param2(pos1, pos2, delta)
+    end
+end
+
 register_color('black')
 register_color('white')
 
@@ -27,8 +36,18 @@ minetest.register_tool('color:brush', {
       end
    end,
    on_use = function(itemstack, user, pointed_thing)
-      if pointed_thing.type ~= 'node' then return end
       local player = user:get_player_name()
+      if worldedit.is_marker_region(pointed_thing) then
+         if worldedit.is_region_owner(pointed_thing, player) then
+             if worldedit.pos1[player] ~= nil and worldedit.pos2[player] ~= nil then
+                local pos1 = worldedit.pos1[player]
+                local pos2 = worldedit.pos2[player]
+                region_add_delta(pos1, pos2, player, 32)
+             end
+         end
+         return nil
+      end
+      if pointed_thing.type ~= 'node' then return end
       local pos = minetest.get_pointed_thing_position(pointed_thing)
       local node = minetest.get_node(pos)
       if minetest.get_item_group(node.name, 'stainable') > 0 then
@@ -37,6 +56,19 @@ minetest.register_tool('color:brush', {
          end
       end
    end,
+   on_secondary_use = function(itemstack, user, pointed_thing)
+      local player = user:get_player_name()
+      if worldedit.is_marker_region(pointed_thing) then
+         if worldedit.is_region_owner(pointed_thing, player) then
+             if worldedit.pos1[player] ~= nil and worldedit.pos2[player] ~= nil then
+                local pos1 = worldedit.pos1[player]
+                local pos2 = worldedit.pos2[player]
+                region_add_delta(pos1, pos2, player, -32)
+             end
+         end
+      end
+      return nil
+   end,
 })
 
 color.make_darker = function(pos, node, puncher, pointed_thing)