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--- cw4:4rpl_tools [2025/06/28 18:29] – kalli
+++ cw4:4rpl_tools [2025/08/29 21:04] (current) – [Pseudo RNG based on Linear congruential generator (LCG)] kalli
@@ Line 3857: / Line 3857: @@
-===== Next UseFul Function goes here =====
+===== Pseudo Random Number Generator, based on sinus =====
 <hidden click here for source code>
-<code 4rpl file name.4rpl>
+Several basic functions based on Grabz' rng lite function of "<-seed sinus 10000 mul dup floor sub".
+Copy the functions directly into your script or run the below script in your cpack and have other scripts send messages to request a randfloat or randint.
+Difference between the functions:
+  * "seeded": provide a seed to the generator. The generated number will always be the same for the same seed.
+  * "index": these seeds are sequenced. In the same map for the same index, the generated number 1,2,3,... will be the same after map restart.
+  * "spiked": the generator is seeded with the elapsedtime of the gaming session, making the outcome uncontrollable.
+  * No prefix: these are sequenced seeds and they use index 0.
+Example code with messages:
+<code example.4rpl>
+->int
+->index
+->first
+->last # The last integer itself will be excluded.
+"sinRandInt" <-first <-last 2 listN sendmsg
+<-*sinRandInt trace
+"sinRand01" 0 sendmsg
+<-*sinRand01 trace
+"indexSinRandInt" <-index <-first <-last 3 listN sendmsg
+<-*sinRandInt trace
+"indexSinRand01" <-index sendmsg
+<-*sinRand01 trace
+"spikedSinRandInt" <-first <-last 2 listN sendmsg
+<-*sinRandInt trace
+"spikedSinRand01" 0 sendmsg
+<-*sinRand01 trace
+"seededSinRandInt" <-seed <-first <-last 3 listN sendmsg
+<-*sinRandInt trace
+"seededSinRand01" <-seed sendmsg
+<-*sinRand01 trace
+</code>
+----
+<code SinusRNG.4rpl>
+:once
+	# Creating lists and a starting mapconstant for the seed sequences.
+	createlist ->prevSeedList
+	createlist ->seedCountList
+	getmapsize 2 div swap 2 div swap dup2 getterrain 1 add dup 99999 floodfillterrain getlistcount ->mapConstant
+	# Setting up the messages so that other scripts can request a random seed.
+	"sinRandInt" "sinRandInt_CALL" registerformsg
+	"sinRand01" "sinRand01_CALL" registerformsg
+	"indexSinRandInt" "indexSinRandInt_CALL" registerformsg
+	"indexSinRand01" "indexSinRand01_CALL" registerformsg
+	"spikedSinRandInt" "spikedSinRandInt_CALL" registerformsg
+	"spikedSinRand01" "spikedSinRand01_CALL" registerformsg
+	"seededSinRandInt" "seededSinRandInt_CALL" registerformsg
+	"seededSinRand01" "seededSinRand01_CALL" registerformsg
+:sinRandInt_CALL
+	<-_DATA listtostack @sinRandInt ->*sinRandInt
+:sinRand01_CALL
+	@sinRand01 ->*sinRand01
+:indexSinRandInt_CALL
+	<-_DATA listtostack @indexSinRandInt ->*sinRandInt
+:indexSinRand01_CALL
+	<-_DATA @indexSinRand01 ->*sinRand01
+:spikedSinRandInt_CALL
+	<-_DATA listtostack @spikedSinRandInt ->*sinRandInt
+:spikedSinRand01_CALL
+	@spikedSinRand01 ->*sinRand01
+:seededSinRandInt_CALL
+	<-_DATA listtostack @seededSinRandInt ->*sinRandInt
+:seededSinRand01_CALL
+	<-_DATA @seededSinRand01 ->*sinRand01
+:sinRandInt # INPUT: integer first randInt + integer last randInt. OUTPUT: an integer in between the first and last randInt, excluding the last randInt.
+->last
+->first
+@indexSinRand01 <-last <-first sub mul <-first add asint
+:sinRand01 # INPUT: none.
+@indexSinRand01
+:indexSinRandInt # INPUT: the index of the seed sequence + integer first randInt + integer last randInt. OUTPUT: an integer in between the first and last randInt, excluding the last randInt.
+->last
+->first
+	@indexSinRand01 <-last <-first sub mul <-first add asint
+:indexSinRand01 # INPUT: the "index" of the seed sequence. OUTPUT: the next seed from that sequence.
+# The random numbers will be generated with the previous seed that is stored under that index.
+->i
+	<-prevSeedList[<-i] eq0 if
+		<-i <-mapConstant add 2357 mul @seededSinRand01 dup 10000000 mul 1 add asint ->prevSeedList[<-i]
+->seedCountList[<-i]
+	else
+		<-prevSeedList[<-i] @seededSinRand01 dup 10000000 mul <-seedCountList[<-i] 1 add dup ->seedCountList[<-i] add asint ->prevSeedList[<-i]
+	endif
+:spikedSinRandInt # INPUT: integer first randInt + integer last randInt. OUTPUT: an integer in between the first and last randInt, excluding the last randInt.
+->last
+->first
+	elapsedtime asint @seededSinRand01 <-last <-first sub mul <-first add asint
+:spikedSinRand01
+	elapsedtime asint @seededSinRand01
+:seededSinRandInt # INPUT: integer seed + integer first randInt + integer last randInt. OUTPUT: an integer in between the first and last randInt, excluding the last randInt.
+->last
+->first
+	@seededSinRand01 <-last <-first sub mul <-first add asint
+:seededSinRand01
+	# abs <-power pow <-add add sin <-sinMul mul dup floor sub
+.05 pow 99419 sub sin 619 mul dup floor sub
+</code>
+</hidden>
+----
+===== Pseudo RNG based on Linear congruential generator (LCG) =====
+The downside of the above sinus based functions, is that they have few resulting digits. They are more than adequate to pick a random cell on a map (max 512 possibilities), but unsuited for generating random numbers larger than a few thousand.
+The below LCG functions should work for up to 6 digits = 10^6, but I've only done a test up to 10^5. Rolling 1 million random integers between 0 and 10^5 with @lcgRandInt, missed only 8 possible results. The same test with @sinRandInt missed 42458 possible results.
+<hidden click here for source code>
+<code LinearCongruentialGenerator.4rpl>
+# Quick Example.
+10000 @lcgRandInt
+:lcgRandInt # INPUT: integer first randInt + integer last randInt. OUTPUT: an integer in between the first and last randInt, excluding the last randInt.
+->last
+->first
+@indexLcgRand01 <-last <-first sub mul <-first add asint
+:lcgRand01 # INPUT: none.
+@indexLcgRand01
+:indexLcgRandInt # INPUT: the index of the seed sequence + integer first randInt + integer last randInt. OUTPUT: an integer in between the first and last randInt, excluding the last randInt.
+->last
+->first
+	@indexLcgRand01 <-last <-first sub mul <-first add asint
+:indexLcgRand01 # INPUT: the "index" of the seed sequence. OUTPUT: the next seed from that sequence.
+# The random numbers will be generated with the previous seed that is stored under that index.
+->i
+	<-prevSeedList[<-i] eq0 if
+		<-i <-mapConstant add 13 mul @seededLcgRand01 dup 10000000 mul 1 add asint ->prevSeedList[<-i]
+->seedCountList[<-i]
+	else
+		<-prevSeedList[<-i] @seededLcgRand01 dup 10000000 mul <-seedCountList[<-i] 1 add dup ->seedCountList[<-i] add asint ->prevSeedList[<-i]
+	endif
+:clearIndexSinLcgRand
+	<-seedCountList clearlist
+	<-prevSeedList clearlist
+:spikedLcgRandInt # INPUT: integer first randInt + integer last randInt. OUTPUT: an integer in between the first and last randInt, excluding the last randInt.
+->last
+->first
+	elapsedtime dup 10 log ceil 7 sub neg 10 swap pow mul asint <-spikedLcgAdd 1 add dup ->spikedLcgAdd mul @seededLcgRand01 <-last <-first sub mul <-first add asint
+:spikedLcgRand01
+	elapsedtime dup 10 log ceil 7 sub neg 10 swap pow mul asint <-spikedLcgAdd 1 add dup ->spikedLcgAdd mul @seededLcgRand01
+:seededLcgRandInt # INPUT: integer seed + integer first randInt + integer last randInt. OUTPUT: an integer in between the first and last randInt, excluding the last randInt.
+->last
+->first
+	@seededLcgRand01 <-last <-first sub mul <-first add asint
+:seededLcgRand01
+	asint 1103515245 mul 12345 add abs asfloat 2147483647 div 10 mul dup floor sub
+:once
+# Creating lists and a starting mapconstant for the seed sequences.
+	createlist ->prevSeedList
+	createlist ->seedCountList
+	getmapsize 2 div swap 2 div swap dup2 getterrain 1 add dup 99999 floodfillterrain getlistcount ->mapConstant
+	# <-SEED ->mapconstant # Alternative for map constant.
 </code>

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