98 lines
3.7 KiB
Lua
98 lines
3.7 KiB
Lua
local helper = wesnoth.require "helper"
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local utils = wesnoth.require "wml-utils"
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wesnoth.wml_actions.random_placement = function(cfg)
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local parsed = wml.shallow_parsed(cfg)
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-- TODO: In most cases this tag is used to place units, so maybe make include_borders=no the default for [filter_location]?
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local filter = wml.get_child(parsed, "filter_location") or {}
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local command = wml.get_child(parsed, "command") or helper.wml_error("[random_placement] missing required [command] subtag")
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local distance = cfg.min_distance or 0
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local num_items = cfg.num_items or helper.wml_error("[random_placement] missing required 'num_items' attribute")
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local variable = cfg.variable or helper.wml_error("[random_placement] missing required 'variable' attribute")
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local allow_less = cfg.allow_less == true
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local variable_previous = utils.start_var_scope(variable)
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local math_abs = math.abs
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local locs = wesnoth.get_locations(filter)
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if type(num_items) == "string" then
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if num_items:match('^%s%(.*%)%s$') then
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local params = {size = #locs}
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local result = wesnoth.eval_formula(num_items, params)
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num_items = math.floor(tonumber(result))
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elseif num_items:match('^%d+%%$') then
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num_items = tonumber(num_items:sub(1,-2))
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else
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wesnoth.deprecated_message('num_items=lua', 2, '1.17.0', 'Use of Lua for [random_placement]num_items is deprecated. Use WFL instead and enclose the whole thing in parentheses.')
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num_items = math.floor(load("local size = " .. #locs .. "; return " .. num_items)())
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print("num_items=" .. num_items .. ", #locs=" .. #locs)
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end
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end
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local size = #locs
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for i = 1, num_items do
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if size == 0 then
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if allow_less then
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print("placed only " .. i .. " items")
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return
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else
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helper.wml_error("[random_placement] failed to place items. only " .. i .. " items were placed")
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end
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end
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local index = wesnoth.random(size)
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local point = locs[index]
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wml.variables[variable .. ".x"] = point[1]
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wml.variables[variable .. ".y"] = point[2]
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wml.variables[variable .. ".n"] = i
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wml.variables[variable .. ".terrain"] = wesnoth.get_terrain(point[1], point[2])
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if distance < 0 then
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-- optimisation: nothing to do for distance < 0
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elseif distance == 0 then
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-- optimisation: for distance = 0 we just need to remove the element at index
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-- optimisation: swapping elements and storing size in an extra variable is faster than table.remove(locs, j)
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locs[index] = locs[size]
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size = size - 1
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else
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-- the default case and the main reason why this was implemented.
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for j = size, 1, -1 do
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local x1 = locs[j][1]
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local y1 = locs[j][2]
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local x2 = point[1]
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local y2 = point[2]
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-- optimisation: same effect as "if wesnoth.map.distance_between(x1,y1,x2,y2) <= distance then goto continue; end" but faster.
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local d_x = math_abs(x1-x2)
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if d_x > distance then
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goto continue
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end
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if d_x % 2 ~= 0 then
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if x1 % 2 == 0 then
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y2 = y2 - 0.5
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else
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y2 = y2 + 0.5
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end
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end
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local d_y = math_abs(y1-y2)
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if d_x + 2*d_y > 2*distance then
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goto continue
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end
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-- optimisation: swapping elements and storing size in an extra variable is faster than table.remove(locs, j)
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locs[j] = locs[size]
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size = size - 1
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::continue::
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end
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end
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-- TODO: This should really be "do" but is kept as "command" for compatibility
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for do_child in wml.child_range(cfg, "command") do
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local action = utils.handle_event_commands(do_child, "loop")
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if action == "break" then
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utils.set_exiting("none")
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return
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elseif action == "continue" then
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utils.set_exiting("none")
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break
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elseif action ~= "none" then
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utils.end_var_scope(variable, variable_previous)
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return
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end
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end
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end
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utils.end_var_scope(variable, variable_previous)
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end
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