73 lines
2.1 KiB
Lua
73 lines
2.1 KiB
Lua
-- A randomizer based on Tetra Legends' "Tetra-X" game mode
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-- There are two main rules:
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-- * if piece hasn't been generated for 13+ pieces, force it
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-- * if piece has been generated in the last two pieces, don't give it out
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--
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-- The official implementation also has self-balancing functionality (bias
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-- towards pieces that have appeared less often).
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local Randomizer = require 'tetris.randomizers.randomizer'
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local TetraXRandomizer = Randomizer:extend()
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function TetraXRandomizer:initialize()
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local pieces = {"I", "J", "L", "O", "S", "T", "Z"}
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self.count = {}
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self.lastseen = {}
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self.totalcount = 0
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self.pieceselection = pieces
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for _, piece in ipairs(pieces) do
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self.count[piece] = 0
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self.lastseen[piece] = -1 -- use -1 as magic value for "not seen"
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end
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end
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function TetraXRandomizer:generatePiece()
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local generated = nil
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while true do
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generated = self.pieceselection[math.random(#self.pieceselection)]
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if not (self.lastseen[generated] == 0 or self.lastseen[generated] == 1) then
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break
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end
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end
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-- piece has not been generated in the last 13+
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for piece, val in pairs(self.lastseen) do
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if val >= 13 then
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generated = piece
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break
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end
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end
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for piece, val in pairs(self.lastseen) do
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if piece == generated then
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self.lastseen[piece] = 0
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else
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if val ~= -1 then
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self.lastseen[piece] = val + 1
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end
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end
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end
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self.count[generated] = self.count[generated] + 1
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self.totalcount = self.totalcount + 1
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-- shuffle the piece selection for the next time
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self.pieceselection = {}
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for piece, count in pairs(self.count) do
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-- in this case 6 = #piece types - 1, so all probabilities sum to 1
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local probability = (self.totalcount - count) / (self.totalcount * 6)
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local chances = math.floor(probability * 1000 + 0.5) -- simulated "round"
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for _ = 1, chances do
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table.insert(self.pieceselection, piece)
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end
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end
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return generated
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end
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return TetraXRandomizer
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