Increase the distance between the same map on maps shuffling (#869)

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savilli 2021-04-29 15:49:58 +02:00 committed by GitHub
parent 2cfbd9b4c4
commit 47cc8928f7
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@ -214,28 +214,44 @@ local shuffled_idx
math.randomseed(os.time()) math.randomseed(os.time())
-- Fisher-Yates shuffling algorithm, used for shuffling map selection order -- Fisher-Yates-Savilli shuffling algorithm, used for shuffling map selection order
-- Adapted from snippet provided in https://stackoverflow.com/a/35574006 -- Adapted from snippet provided in https://stackoverflow.com/a/35574006
local function shuffle_maps(idx_to_avoid) -- Improved to ensure that the first maps from current shuffled order differ
-- from the last maps from previous shuffled order
-- You can set the minimum distance between the same map using map_recurrence_threshold param
local function shuffle_maps(previous_order, map_recurrence_threshold)
local maps_count = #ctf_map.available_maps
map_recurrence_threshold = math.min(map_recurrence_threshold or 0, maps_count - 1)
if previous_order == nil then
map_recurrence_threshold = 0
previous_order = {}
for i = 1, maps_count do
previous_order[i] = i
end
end
-- Reset shuffled_idx -- Reset shuffled_idx
shuffled_idx = 1 shuffled_idx = 1
-- Create table of ordered indices -- Create table of ordered indices
shuffled_order = {} shuffled_order = {}
for i = 1, #ctf_map.available_maps, 1 do
shuffled_order[i] = i -- At first select maps that don't intersect with the last maps from previous order
for i = 1, map_recurrence_threshold do
local j = math.random(1, maps_count - map_recurrence_threshold)
local k = maps_count - map_recurrence_threshold + i
shuffled_order[i] = previous_order[j]
previous_order[j] = previous_order[k]
end end
-- Shuffle table -- Select remaining maps
for i = #ctf_map.available_maps, 1, -1 do for i = map_recurrence_threshold + 1, maps_count do
local j = math.random(i) local j = math.random(1, maps_count - i + 1)
shuffled_order[i], shuffled_order[j] = shuffled_order[j], shuffled_order[i] local k = maps_count - i + 1
end shuffled_order[i] = previous_order[j]
previous_order[j] = previous_order[k]
-- Prevent the last map of the previous cycle from becoming the first in the next cycle
if shuffled_order[1] == idx_to_avoid then
local k = math.random(#ctf_map.available_maps - 1)
shuffled_order[1], shuffled_order[k + 1] = shuffled_order[k + 1], shuffled_order[1]
end end
end end
@ -257,7 +273,7 @@ local function select_map()
-- If shuffled_idx overflows, re-shuffle map selection order -- If shuffled_idx overflows, re-shuffle map selection order
if shuffled_idx > #ctf_map.available_maps then if shuffled_idx > #ctf_map.available_maps then
shuffle_maps(shuffled_order[#ctf_map.available_maps]) shuffle_maps(shuffled_order, tonumber(minetest.settings:get("ctf_map.map_recurrence_threshold")) or 3)
end end
else else
-- Choose next map index, but don't select the same one again -- Choose next map index, but don't select the same one again