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ai_helper.lua
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ai_helper.lua
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local H = wesnoth.require "lua/helper.lua"
local W = H.set_wml_action_metatable {}
local LS = wesnoth.require "lua/location_set.lua"
-- This is a collection of Lua functions used for custom AI development.
-- Note that this is still work in progress with significant changes occurring
-- frequently. Backward compatibility cannot be guaranteed at this time in
-- development releases, but it is of course easily possible to copy a function
-- from a previous release directly into an add-on if it is needed there.
local ai_helper = {}
----- Debugging helper functions ------
function ai_helper.show_messages()
-- Returns true or false (hard-coded). To be used to
-- show messages if in debug mode.
-- Just edit the following line (easier than trying to set WML variable)
local show_messages_flag = false
if wesnoth.game_config.debug then return show_messages_flag end
return false
end
function ai_helper.print_exec()
-- Returns true or false (hard-coded). To be used to
-- show which CA is being executed if in debug mode.
-- Just edit the following line (easier than trying to set WML variable)
local print_exec_flag = false
if wesnoth.game_config.debug then return print_exec_flag end
return false
end
function ai_helper.print_eval()
-- Returns true or false (hard-coded). To be used to
-- show which CA is being evaluated if in debug mode.
-- Just edit the following line (easier than trying to set WML variable)
local print_eval_flag = false
if wesnoth.game_config.debug then return print_eval_flag end
return false
end
function ai_helper.done_eval_messages(start_time, ca_name)
ca_name = ca_name or 'unknown'
local dt = wesnoth.get_time_stamp() / 1000. - start_time
if ai_helper.print_eval() then
ai_helper.print_ts_delta(start_time, ' - Done evaluating ' .. ca_name .. ':')
end
end
function ai_helper.clear_labels()
-- Clear all labels on a map
local width, height = wesnoth.get_map_size()
for x = 1,width do
for y = 1,height do
W.label { x = x, y = y, text = "" }
end
end
end
function ai_helper.put_labels(map, cfg)
-- Take @map (location set) and put label containing 'value' onto the map.
-- Print 'nan' if element exists but is not a number.
-- @cfg: table with optional parameters:
-- - show_coords: (boolean) use hex coordinates as labels instead of value
-- - factor=1: (number) if value is a number, multiply by this factor
-- - keys: (array) if the value to be displayed is a subelement of the LS data,
-- use these keys to access it. For example, if we want to display data[3]
-- set keys = { 3 }, if it's data.arg[3], set keys = { 'arg', 3 }
cfg = cfg or {}
local factor = cfg.factor or 1
ai_helper.clear_labels()
map:iter(function(x, y, data)
local out
if cfg.show_coords then
out = x .. ',' .. y
else
if cfg.keys then
for _,key in ipairs(cfg.keys) do data = data[key] end
end
if (type(data) == 'string') then
out = data
else
out = tonumber(data) or 'nan'
end
end
if (type(out) == 'number') then out = out * factor end
W.label { x = x, y = y, text = out }
end)
end
function ai_helper.print_ts(...)
-- Print arguments preceded by a time stamp in seconds
-- Also return that time stamp
local ts = wesnoth.get_time_stamp() / 1000.
local arg = { ... }
arg[#arg+1] = string.format('[ t = %.3f ]', ts)
print(table.unpack(arg))
return ts
end
function ai_helper.print_ts_delta(start_time, ...)
-- @start_time: time stamp in seconds as returned by wesnoth.get_time_stamp / 1000.
-- Same as ai_helper.print_ts(), but also adds time elapsed since
-- the time given in the first argument (in seconds)
-- Returns time stamp as well as time elapsed
local ts = wesnoth.get_time_stamp() / 1000.
local delta = ts - start_time
local arg = { ... }
arg[#arg+1] = string.format('[ t = %.3f, dt = %.3f ]', ts, delta)
print(table.unpack(arg))
return ts, delta
end
----- AI execution helper functions ------
function ai_helper.checked_action_error(action, error_code)
wesnoth.message('Lua AI error', 'If you see this message, something has gone wrong. Please report this on the Wesnoth forums, ideally with a replay and/or savegame.')
error(action .. ' could not be executed. Error code: ' .. error_code)
end
function ai_helper.checked_attack(ai, attacker, defender, weapon)
local check = ai.check_attack(attacker, defender, weapon)
if (not check.ok) then
ai_helper.checked_action_error('ai.attack', check.status)
return
end
ai.attack(attacker, defender, weapon)
end
function ai_helper.checked_move_core(ai, unit, x, y, move_type)
local check = ai.check_move(unit, x, y)
if (not check.ok) then
-- The following errors are not fatal:
-- E_EMPTY_MOVE = 2001
-- E_AMBUSHED = 2005
-- E_NOT_REACHED_DESTINATION = 2007
if (check.status ~= 2001) and (check.status ~= 2005) and (check.status ~= 2007) then
ai_helper.checked_action_error(move_type, check.status)
return
end
end
if (move_type == 'ai.move_full') then
ai.move_full(unit, x, y)
else
ai.move(unit, x, y)
end
end
function ai_helper.checked_move_full(ai, unit, x, y)
ai_helper.checked_move_core(ai, unit, x, y, 'ai.move_full')
end
function ai_helper.checked_move(ai, unit, x, y)
ai_helper.checked_move_core(ai, unit, x, y, 'ai.move')
end
function ai_helper.checked_recruit(ai, unit_type, x, y)
local check = ai.check_recruit(unit_type, x, y)
if (not check.ok) then
ai_helper.checked_action_error('ai.recruit', check.status)
return
end
ai.recruit(unit_type, x, y)
end
function ai_helper.checked_stopunit_all(ai, unit)
local check = ai.check_stopunit(unit)
if (not check.ok) then
ai_helper.checked_action_error('ai.stopunit_all', check.status)
return
end
ai.stopunit_all(unit)
end
function ai_helper.checked_stopunit_attacks(ai, unit)
local check = ai.check_stopunit(unit)
if (not check.ok) then
ai_helper.checked_action_error('ai.stopunit_attacks', check.status)
return
end
ai.stopunit_attacks(unit)
end
function ai_helper.checked_stopunit_moves(ai, unit)
local check = ai.check_stopunit(unit)
if (not check.ok) then
ai_helper.checked_action_error('ai.stopunit_moves', check.status)
return
end
ai.stopunit_moves(unit)
end
----- General functionality and maths helper functions ------
function ai_helper.filter(input, condition)
-- Equivalent of filter() function in Formula AI
local filtered_table = {}
for _,v in ipairs(input) do
if condition(v) then
table.insert(filtered_table, v)
end
end
return filtered_table
end
function ai_helper.choose(input, value)
-- Equivalent of choose() function in Formula AI
-- Returns element of a table with the largest @value (a function)
-- Also returns the max value and the index
local max_value, best_input, best_key = -9e99
for k,v in pairs(input) do
if value(v) > max_value then
max_value, best_input, best_key = value(v), v, k
end
end
return best_input, max_value, best_key
end
function ai_helper.table_copy(t)
-- Make a copy of a table (rather than just another pointer to the same table)
local copy = {}
for k,v in pairs(t) do copy[k] = v end
return copy
end
function ai_helper.array_merge(a1, a2)
-- Merge two arrays without overwriting @a1 or @a2 -> create a new table
-- This only works with arrays, not general tables
local merger = {}
for _,a in pairs(a1) do table.insert(merger, a) end
for _,a in pairs(a2) do table.insert(merger, a) end
return merger
end
function ai_helper.serialize(input)
-- Convert @input to a string in a format corresponding to the type of @input
-- The string is all put into one line
local str = ''
if (type(input) == "number") or (type(input) == "boolean") then
str = tostring(input)
elseif type(input) == "string" then
str = string.format("%q", input)
elseif type(input) == "table" then
str = str .. "{ "
for k,v in pairs(input) do
str = str .. "[" .. ai_helper.serialize(k) .. "] = "
str = str .. ai_helper.serialize(v)
str = str .. ", "
end
str = str .. "}"
else
error("cannot serialize a " .. type(input))
end
return str
end
function ai_helper.split(str, sep)
-- Split string @str into a table using the delimiter @sep (default: ',')
local sep, fields = sep or ",", {}
local pattern = string.format("([^%s]+)", sep)
string.gsub(str, pattern, function(c) fields[#fields+1] = c end)
return fields
end
--------- Location set related helper functions ----------
function ai_helper.get_LS_xy(index)
-- Get the x,y coordinates for the index of a location set
-- For some reason, there doesn't seem to be a LS function for this
local tmp_set = LS.create()
tmp_set.values[index] = 1
local xy = tmp_set:to_pairs()[1]
return xy[1], xy[2]
end
function ai_helper.LS_of_triples(table)
-- Create a location set from a table of 3-element tables
-- Elements 1 and 2 are x,y coordinates, #3 is value to be inserted
local set = LS.create()
for k,v in pairs(table) do
set:insert(v[1], v[2], v[3])
end
return set
end
function ai_helper.to_triples(set)
local res = {}
set:iter(function(x, y, v) table.insert(res, { x, y, v }) end)
return res
end
function ai_helper.LS_random_hex(map)
-- Select a random hex from the hexes in location set @map
-- This seems "inelegant", but I can't come up with another way without creating an extra array
-- Return -1, -1 if @map is empty
local r = math.random(map:size())
local i, xr, yr = 1, -1, -1
map:iter( function(x, y, v)
if (i == r) then xr, yr = x, y end
i = i + 1
end)
return xr, yr
end
--------- Location, position or hex related helper functions ----------
function ai_helper.cartesian_coords(x, y)
-- Converts coordinates from hex geometry to cartesian coordinates,
-- meaning that y coordinates are offset by 0.5 every other hex
-- Example: (1,1) stays (1,1) and (3,1) remains (3,1), but (2,1) -> (2,1.5) etc.
return x, y + ((x + 1) % 2) / 2.
end
function ai_helper.get_angle(from_hex, to_hex)
-- Returns the angle of the direction from @from_hex to @to_hex
-- Angle is in radians and goes from -pi to pi. 0 is toward east.
-- Input hex tables can be of form { x, y } or { x = x, y = y }, which
-- means that it is also possible to pass a unit table
local x1, y1 = from_hex.x or from_hex[1], from_hex.y or from_hex[2]
local x2, y2 = to_hex.x or to_hex[1], to_hex.y or to_hex[2]
local _, y1cart = ai_helper.cartesian_coords(x1, y1)
local _, y2cart = ai_helper.cartesian_coords(x2, y2)
return math.atan2(y2cart - y1cart, x2 - x1)
end
function ai_helper.get_direction_index(from_hex, to_hex, n, center_on_east)
-- Returns an integer index for the direction from @from_hex to @to_hex
-- with the full circle divided into @n slices
-- 1 is always to the east, with indices increasing clockwise
-- Input hex tables can be of form { x, y } or { x = x, y = y }, which
-- means that it is also possible to pass a unit table
--
-- Optional input:
-- @center_on_east (false): boolean. By default, the eastern direction is the
-- northern border of the first slice. If this parameter is set, east will
-- instead be the center direction of the first slice
local d_east = 0
if center_on_east then d_east = 0.5 end
local angle = ai_helper.get_angle(from_hex, to_hex)
local index = math.floor((angle / math.pi * n/2 + d_east) % n ) + 1
return index
end
function ai_helper.get_cardinal_directions(from_hex, to_hex)
local dirs = { "E", "S", "W", "N" }
return dirs[ai_helper.get_direction_index(from_hex, to_hex, 4, true)]
end
function ai_helper.get_intercardinal_directions(from_hex, to_hex)
local dirs = { "E", "SE", "S", "SW", "W", "NW", "N", "NE" }
return dirs[ai_helper.get_direction_index(from_hex, to_hex, 8, true)]
end
function ai_helper.get_hex_facing(from_hex, to_hex)
local dirs = { "se", "s", "sw", "nw", "n", "ne" }
return dirs[ai_helper.get_direction_index(from_hex, to_hex, 6)]
end
function ai_helper.find_opposite_hex_adjacent(hex, center_hex)
-- Find the hex that is opposite of @hex with respect to @center_hex
-- Both input hexes are of format { x, y }
-- Output: {opp_x, opp_y} -- or nil if @hex and @center_hex are not adjacent
-- (or no opposite hex is found, e.g. for hexes on border)
-- If the two input hexes are not adjacent, return nil
if (H.distance_between(hex[1], hex[2], center_hex[1], center_hex[2]) ~= 1) then return nil end
-- Finding the opposite x position is easy
local opp_x = center_hex[1] + (center_hex[1] - hex[1])
-- y is slightly more tricky, because of the hexagonal shape, but there's a trick
-- that saves us from having to build in a lot of if statements
-- Among the adjacent hexes, it is the one with the correct x, and y _different_ from hex[2]
for xa,ya in H.adjacent_tiles(center_hex[1], center_hex[2]) do
if (xa == opp_x) and (ya ~= hex[2]) then return { xa, ya } end
end
return nil
end
function ai_helper.find_opposite_hex(hex, center_hex)
-- Find the hex that is opposite of @hex with respect to @center_hex
-- Using "square coordinate" method by JaMiT
-- Note: this also works for non-adjacent hexes, but might return hexes that are not on the map!
-- Both input hexes are of format { x, y }
-- Output: { opp_x, opp_y }
-- Finding the opposite x position is easy
local opp_x = center_hex[1] + (center_hex[1] - hex[1])
-- Going to "square geometry" for y coordinate
local y_sq = hex[2] * 2 - (hex[1] % 2)
local yc_sq = center_hex[2] * 2 - (center_hex[1] % 2)
-- Now the same equation as for x can be used for y
local opp_y = yc_sq + (yc_sq - y_sq)
opp_y = math.floor((opp_y + 1) / 2)
return {opp_x, opp_y}
end
function ai_helper.is_opposite_adjacent(hex1, hex2, center_hex)
-- Returns true if @hex1 and @hex2 are opposite from each other with respect to @center_hex
local opp_hex = ai_helper.find_opposite_hex_adjacent(hex1, center_hex)
if opp_hex and (opp_hex[1] == hex2[1]) and (opp_hex[2] == hex2[2]) then return true end
return false
end
function ai_helper.get_closest_location(hex, location_filter, unit)
-- Get the location closest to @hex (in format { x, y })
-- that matches @location_filter (in WML table format)
-- @unit can be passed as an optional third parameter, in which case the
-- terrain needs to be passable for that unit
-- Returns nil if no terrain matching the filter was found
-- Find the maximum distance from 'hex' that's possible on the map
local max_distance = 0
local width, height = wesnoth.get_map_size()
local to_top_left = H.distance_between(hex[1], hex[2], 0, 0)
if (to_top_left > max_distance) then max_distance = to_top_left end
local to_top_right = H.distance_between(hex[1], hex[2], width+1, 0)
if (to_top_right > max_distance) then max_distance = to_top_right end
local to_bottom_left = H.distance_between(hex[1], hex[2], 0, height+1)
if (to_bottom_left > max_distance) then max_distance = to_bottom_left end
local to_bottom_right = H.distance_between(hex[1], hex[2], width+1, height+1)
if (to_bottom_right > max_distance) then max_distance = to_bottom_right end
local radius = 0
while (radius <= max_distance) do
local loc_filter = {}
if (radius == 0) then
loc_filter = {
{ "and", { x = hex[1], y = hex[2], radius = radius } },
{ "and", location_filter }
}
else
loc_filter = {
{ "and", { x = hex[1], y = hex[2], radius = radius } },
{ "not", { x = hex[1], y = hex[2], radius = radius - 1 } },
{ "and", location_filter }
}
end
local locs = wesnoth.get_locations(loc_filter)
if unit then
for _,loc in ipairs(locs) do
local movecost = wesnoth.unit_movement_cost(unit, wesnoth.get_terrain(loc[1], loc[2]))
if (movecost <= unit.max_moves) then return loc end
end
else
if locs[1] then return locs[1] end
end
radius = radius + 1
end
return nil
end
function ai_helper.get_passable_locations(location_filter, unit)
-- Finds all locations matching @location_filter that are passable for
-- @unit. This also excludes hexes on the map border.
-- @unit is optional: if omitted, all hexes matching the filter, but
-- excluding border hexes are returned
-- All hexes that are not on the map border
local width, height = wesnoth.get_map_size()
local all_locs = wesnoth.get_locations{
x = '1-' .. width,
y = '1-' .. height,
{ "and", location_filter }
}
-- If @unit is provided, exclude terrain that's impassable for the unit
if unit then
local locs = {}
for _,loc in ipairs(all_locs) do
local movecost = wesnoth.unit_movement_cost(unit, wesnoth.get_terrain(loc[1], loc[2]))
if (movecost <= unit.max_moves) then table.insert(locs, loc) end
end
return locs
end
return all_locs
end
function ai_helper.distance_map(units, map)
-- Get the distance map DM for all units in @units (as a location set)
-- DM = sum ( distance_from_unit )
-- This is done for all elements of @map (a locations set), or for the entire map if @map is not given
local DM = LS.create()
if map then
map:iter(function(x, y, data)
local dist = 0
for _,unit in ipairs(units) do
dist = dist + H.distance_between(unit.x, unit.y, x, y)
end
DM:insert(x, y, dist)
end)
else
local width, height = wesnoth.get_map_size()
for x = 1,width do
for y = 1,height do
local dist = 0
for _,unit in ipairs(units) do
dist = dist + H.distance_between(unit.x, unit.y, x, y)
end
DM:insert(x, y, dist)
end
end
end
return DM
end
function ai_helper.inverse_distance_map(units, map)
-- Get the inverse distance map IDM for all units in @units (as a location set)
-- IDM = sum ( 1 / (distance_from_unit+1) )
-- This is done for all elements of @map (a locations set), or for the entire map if @map is not given
local IDM = LS.create()
if map then
map:iter(function(x, y, data)
local dist = 0
for _,unit in ipairs(units) do
dist = dist + 1. / (H.distance_between(unit.x, unit.y, x, y) + 1)
end
IDM:insert(x, y, dist)
end)
else
local width, height = wesnoth.get_map_size()
for x = 1,width do
for y = 1,height do
local dist = 0
for _,unit in ipairs(units) do
dist = dist + 1. / (H.distance_between(unit.x, unit.y, x, y) + 1)
end
IDM:insert(x, y, dist)
end
end
end
return IDM
end
function ai_helper.generalized_distance(x1, y1, x2, y2)
-- Determines distance of (@x1,@y1) from (@x2,@y2) even if
-- @x2 and @y2 are not necessarily both given (or not numbers)
-- Return 0 if neither is given
if (not x2) and (not y2) then return 0 end
-- If only one of the parameters is set
if (not x2) then return math.abs(y1 - y2) end
if (not y2) then return math.abs(x1 - x2) end
-- Otherwise, return standard distance
return H.distance_between(x1, y1, x2, y2)
end
function ai_helper.xyoff(x, y, ori, hex)
-- Finds hexes at a certain offset from @x,@y
-- @ori: direction/orientation: north (0), ne (1), se (2), s (3), sw (4), nw (5)
-- @hex: string for the hex to be queried. Possible values:
-- 's': self, 'u': up, 'lu': left up, 'ld': left down, 'ru': right up, 'rd': right down
-- This is all relative "looking" in the direction of 'ori'
-- returns x,y for the queried hex
-- Unlike Lua default, we count 'ori' from 0 (north) to 5 (nw), so that modulo operator can be used
ori = ori % 6
if (hex == 's') then return x, y end
-- This is all done with ifs, to keep it as fast as possible
if (ori == 0) then -- "north"
if (hex == 'u') then return x, y-1 end
if (hex == 'd') then return x, y+1 end
local dy = 0
if (x % 2) == 1 then dy=1 end
if (hex == 'lu') then return x-1, y-dy end
if (hex == 'ld') then return x-1, y+1-dy end
if (hex == 'ru') then return x+1, y-dy end
if (hex == 'rd') then return x+1, y+1-dy end
end
if (ori == 1) then -- "north-east"
local dy = 0
if (x % 2) == 1 then dy=1 end
if (hex == 'u') then return x+1, y-dy end
if (hex == 'd') then return x-1, y+1-dy end
if (hex == 'lu') then return x, y-1 end
if (hex == 'ld') then return x-1, y-dy end
if (hex == 'ru') then return x+1, y+1-dy end
if (hex == 'rd') then return x, y+1 end
end
if (ori == 2) then -- "south-east"
local dy = 0
if (x % 2) == 1 then dy=1 end
if (hex == 'u') then return x+1, y+1-dy end
if (hex == 'd') then return x-1, y-dy end
if (hex == 'lu') then return x+1, y-dy end
if (hex == 'ld') then return x, y-1 end
if (hex == 'ru') then return x, y+1 end
if (hex == 'rd') then return x-1, y+1-dy end
end
if (ori == 3) then -- "south"
if (hex == 'u') then return x, y+1 end
if (hex == 'd') then return x, y-1 end
local dy = 0
if (x % 2) == 1 then dy=1 end
if (hex == 'lu') then return x+1, y+1-dy end
if (hex == 'ld') then return x+1, y-dy end
if (hex == 'ru') then return x-1, y+1-dy end
if (hex == 'rd') then return x-1, y-dy end
end
if (ori == 4) then -- "south-west"
local dy = 0
if (x % 2) == 1 then dy=1 end
if (hex == 'u') then return x-1, y+1-dy end
if (hex == 'd') then return x+1, y-dy end
if (hex == 'lu') then return x, y+1 end
if (hex == 'ld') then return x+1, y+1-dy end
if (hex == 'ru') then return x-1, y-dy end
if (hex == 'rd') then return x, y-1 end
end
if (ori == 5) then -- "north-west"
local dy = 0
if (x % 2) == 1 then dy=1 end
if (hex == 'u') then return x-1, y-dy end
if (hex == 'd') then return x+1, y+1-dy end
if (hex == 'lu') then return x-1, y+1-dy end
if (hex == 'ld') then return x, y+1 end
if (hex == 'ru') then return x, y-1 end
if (hex == 'rd') then return x+1, y-dy end
end
return
end
function ai_helper.split_location_list_to_strings(list)
-- Convert a list of locations @list as returned by wesnoth.get_locations into a pair of strings
-- suitable for passing in as x,y coordinate lists to wesnoth.get_locations.
-- Could alternatively convert to a WML table and use the find_in argument, but this is simpler.
local locsx, locsy = {}, {}
for i,loc in ipairs(list) do
locsx[i] = loc[1]
locsy[i] = loc[2]
end
locsx = table.concat(locsx, ",")
locsy = table.concat(locsy, ",")
return locsx, locsy
end
--------- Unit related helper functions ----------
function ai_helper.get_live_units(filter)
-- Same as wesnoth.get_units(), except that it only returns non-petrified units
local all_units = wesnoth.get_units(filter)
local units = {}
for _,unit in ipairs(all_units) do
if (not unit.status.petrified) then table.insert(units, unit) end
end
return units
end
function ai_helper.get_units_with_moves(filter)
-- Using formula = '$this_unit.moves > 0' is slow, this method is much faster
local all_units = wesnoth.get_units(filter)
local units = {}
for _,unit in ipairs(all_units) do
if (unit.moves > 0) then table.insert(units, unit) end
end
return units
end
function ai_helper.get_units_with_attacks(filter)
-- Using formula = '$this_unit.attacks_left > 0' is slow, this method is much faster
-- Also need to check that units actually have attacks (as attacks_left > 0 with no attacks is possible)
-- The latter has to go through unit.__cfg which is slow, but there is no way around that, as far as I know
local all_units = wesnoth.get_units(filter)
local units = {}
for _,unit in ipairs(all_units) do
if (unit.attacks_left > 0) and (H.get_child(unit.__cfg, 'attack')) then
table.insert(units, unit)
end
end
return units
end
function ai_helper.get_closest_enemy(loc)
-- Get the closest enemy to @loc, or to the current side's leader if @loc not specified
local x, y
local enemies = ai_helper.get_live_units {
{ "filter_side", { { "enemy_of", { side = wesnoth.current.side } } } }
}
if not loc then
local leader = wesnoth.get_units { side = wesnoth.current.side, canrecruit = 'yes' }[1]
x, y = leader.x, leader.y
else
x, y = loc[1], loc[2]
end
local closest_distance, location = 9e99
for _,enemy in ipairs(enemies) do
enemy_distance = H.distance_between(x, y, enemy.x, enemy.y)
if (enemy_distance < closest_distance) then
closest_distance = enemy_distance
location = { x = enemy.x, y = enemy.y}
end
end
return closest_distance, location
end
function ai_helper.has_ability(unit, ability)
-- Returns true/false depending on whether unit has the given ability
local has_ability = false
local abilities = H.get_child(unit.__cfg, "abilities")
if abilities then
if H.get_child(abilities, ability) then has_ability = true end
end
return has_ability
end
function ai_helper.has_weapon_special(unit, special)
-- Returns true/false depending on whether @unit has a weapon with special @special
-- Also returns the number of the first weapon with this special
local weapon_number = 0
for att in H.child_range(unit.__cfg, 'attack') do
weapon_number = weapon_number + 1
for sp in H.child_range(att, 'specials') do
if H.get_child(sp, special) then
return true, weapon_number
end
end
end
return false
end
function ai_helper.get_cheapest_recruit_cost()
local cheapest_unit_cost = 9e99
for _,recruit_id in ipairs(wesnoth.sides[wesnoth.current.side].recruit) do
if wesnoth.unit_types[recruit_id].cost < cheapest_unit_cost then
cheapest_unit_cost = wesnoth.unit_types[recruit_id].cost
end
end
return cheapest_unit_cost
end
--------- Move related helper functions ----------
ai_helper.no_path = 42424242 -- Value returned by C++ engine for distance when no path is found
function ai_helper.get_dst_src_units(units, cfg)
-- Get the dst_src location set for @units
-- @cfg: configuration table
-- - moves: if set to 'max' use max_moves of units, rather than current moves
local max_moves = false
if cfg then
if (cfg['moves'] == 'max') then max_moves = true end
end
local dstsrc = LS.create()
for _,unit in ipairs(units) do
local tmp = unit.moves
if max_moves then
unit.moves = unit.max_moves
end
local reach = wesnoth.find_reach(unit)
if max_moves then
unit.moves = tmp
end
for _,loc in ipairs(reach) do
local tmp = dstsrc:get(loc[1], loc[2]) or {}
table.insert(tmp, { x = unit.x, y = unit.y })
dstsrc:insert(loc[1], loc[2], tmp)
end
end
return dstsrc
end
function ai_helper.get_dst_src(units)
-- If @units table is given use it, otherwise use all units on the current side
if (not units) then
units = wesnoth.get_units { side = wesnoth.current.side }
end
return ai_helper.get_dst_src_units(units)
end
function ai_helper.get_enemy_dst_src(enemies)
-- If @enemies table is given use it, otherwise use all enemy units
if (not enemies) then
enemies = wesnoth.get_units {
{ "filter_side", { { "enemy_of", { side = wesnoth.current.side} } } }
}
end
return ai_helper.get_dst_src_units(enemies, { moves = 'max' })
end
function ai_helper.my_moves()
-- Produces an array with each field of form:
-- [1] = { dst = { x = 7, y = 16 },
-- src = { x = 6, y = 16 } }
local dstsrc = ai.get_dstsrc()
local my_moves = {}
for key,value in pairs(dstsrc) do
table.insert( my_moves,
{ src = { x = value[1].x , y = value[1].y },
dst = { x = key.x , y = key.y }
}
)
end
return my_moves
end
function ai_helper.enemy_moves()
-- Produces an array with each field of form:
-- [1] = { dst = { x = 7, y = 16 },
-- src = { x = 6, y = 16 } }
local dstsrc = ai.get_enemy_dstsrc()
local enemy_moves = {}
for key,value in pairs(dstsrc) do
table.insert( enemy_moves,
{ src = { x = value[1].x , y = value[1].y },
dst = { x = key.x , y = key.y }
}
)
end
return enemy_moves
end
function ai_helper.next_hop(unit, x, y, cfg)
-- Finds the next "hop" of @unit on its way to (@x,@y)
-- Returns coordinates of the endpoint of the hop (or nil if no path to
-- (x,y) is found for the unit), and movement cost to get there.
-- Only unoccupied hexes are considered
-- @cfg: standard extra options for wesnoth.find_path()
-- plus:
-- ignore_own_units: if set to true, then own units that can move out of the way are ignored
local path, cost = wesnoth.find_path(unit, x, y, cfg)
if cost >= ai_helper.no_path then return nil, cost end
-- If none of the hexes are unoccupied, use current position as default
local next_hop, nh_cost = { unit.x, unit.y }, 0
-- Go through loop to find reachable, unoccupied hex along the path
-- Start at second index, as first is just the unit position itself
for i = 2,#path do
local sub_path, sub_cost = wesnoth.find_path( unit, path[i][1], path[i][2], cfg)
if sub_cost <= unit.moves then
local unit_in_way = wesnoth.get_unit(path[i][1], path[i][2])
-- If ignore_own_units is set, ignore own side units that can move out of the way
if cfg and cfg.ignore_own_units then
if unit_in_way and (unit_in_way.side == unit.side) then
local reach = ai_helper.get_reachable_unocc(unit_in_way)
if (reach:size() > 1) then unit_in_way = nil end
end
end
if not unit_in_way then
next_hop, nh_cost = path[i], sub_cost
end
else
break
end
end
return next_hop, nh_cost
end
function ai_helper.can_reach(unit, x, y, cfg)
-- Returns true if @unit can reach (@x,@y), else false
-- This only returns true if the hex is unoccupied, or at most occupied by unit on same side as @unit
-- that can move away (can be modified with options below)
-- @cfg:
-- moves = 'max' use max_moves instead of current moves
-- ignore_units: if true, ignore both own and enemy units
-- exclude_occupied: if true, exclude hex if there's a unit there, irrespective of value of 'ignore_units'
cfg = cfg or {}
-- Is there a unit at the goal hex?
local unit_in_way = wesnoth.get_unit(x, y)
if (cfg.exclude_occupied) and unit_in_way then return false end
-- Otherwise, if 'ignore_units' is not set, return false if there's a unit of other side,
-- or a unit of own side that cannot move away (this might be slow, don't know)
if (not cfg.ignore_units) then
-- If there's a unit at the goal that's not on own side (even ally), return false
if unit_in_way and (unit_in_way.side ~= unit.side) then return false end
-- If the unit in the way is on 'unit's' side and cannot move away, also return false
if unit_in_way and (unit_in_way.side == unit.side) then
-- need to pass the cfg here so that it works for enemy units (generally with no moves left) also
local move_away = ai_helper.get_reachable_unocc(unit_in_way, cfg)
if (move_away:size() <= 1) then return false end
end
end
-- After all that, test whether our unit can actually get there
local old_moves = unit.moves
if (cfg.moves == 'max') then unit.moves = unit.max_moves end
local can_reach = false
local path, cost = wesnoth.find_path(unit, x, y, cfg)
if (cost <= unit.moves) then can_reach = true end
unit.moves = old_moves
return can_reach
end
function ai_helper.get_reachable_unocc(unit, cfg)
-- Get all reachable hexes for @unit that are unoccupied (incl. by allied units)
-- Returned array is a location set, with value = 1 for each reachable hex
-- @cfg: parameters to wesnoth.find_reach, such as { additional_turns = 1 }
-- Additionally, { moves = 'max' } can be set inside cfg, which sets unit MP to max_moves before calculation
local old_moves = unit.moves
if cfg then