Zelda II: The Adventure of Link/Luck Manipulation - Revision history

Neil: /* Practical Consequences */

2015-05-08T18:10:22Z

Practical Consequences

← Older revision		Revision as of 18:10, 8 May 2015
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	[http://www.twitch.tv/error72/c/6027800 Error72 has a strategy that is fast and effective], however the "low beam" techniques used in the strategy make it difficult to execute.		[http://www.twitch.tv/error72/c/6027800 Error72 has a strategy that is fast and effective], however the "low beam" techniques used in the strategy make it difficult to execute.

	[http://www.twitch.tv/simpoldood/c/~~6540578~~ Simpoldood has a variant of that visible at the start of this PB run] that is easier to do, but has some hitches and timing that make it less reliable.		[http://www.twitch.tv/simpoldood/c/6127759 Simpoldood has a variant of that visible at the start of this PB run] that is easier to do, but has some hitches and timing that make it less reliable.

	[https://www.youtube.com/watch?v=rWTt6pSBP5U My strategy exists] and I've had a lot of success with it. It's slower by about 2 seconds than Error's, and it has a timed hit, but I've personally had the best success with it because I hate low beams. It also sometimes gives a bad encounter pattern on the way to Rauru, requiring a slight hesitation on the way out of the cave, to avoid that.		[https://www.youtube.com/watch?v=rWTt6pSBP5U My strategy exists] and I've had a lot of success with it. It's slower by about 2 seconds than Error's, and it has a timed hit, but I've personally had the best success with it because I hate low beams. It also sometimes gives a bad encounter pattern on the way to Rauru, requiring a slight hesitation on the way out of the cave, to avoid that.

Neil: /* Opening 50 PBag */

2015-05-08T18:02:14Z

Opening 50 PBag

← Older revision		Revision as of 18:02, 8 May 2015
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	For the P Bag drop, the two key windows are the ones at about 1600 frames, and at about 1920 frames. Hit either of those windows reliably, and P Bag drops go from the usual 1/8 chance, to much higher.		For the P Bag drop, the two key windows are the ones at about 1600 frames, and at about 1920 frames. Hit either of those windows reliably, and P Bag drops go from the usual 1/8 chance, to much higher.

			= Practical Consequences =

			There are a few known ways of getting a PBag that are much better than random at getting the drop.

			[http://www.twitch.tv/error72/c/6027800 Error72 has a strategy that is fast and effective], however the "low beam" techniques used in the strategy make it difficult to execute.

			[http://www.twitch.tv/simpoldood/c/6540578 Simpoldood has a variant of that visible at the start of this PB run] that is easier to do, but has some hitches and timing that make it less reliable.

			[https://www.youtube.com/watch?v=rWTt6pSBP5U My strategy exists] and I've had a lot of success with it. It's slower by about 2 seconds than Error's, and it has a timed hit, but I've personally had the best success with it because I hate low beams. It also sometimes gives a bad encounter pattern on the way to Rauru, requiring a slight hesitation on the way out of the cave, to avoid that.

	= Technical details =		= Technical details =

Neil: /* Technical details */

2015-03-12T13:57:06Z

Technical details

← Older revision		Revision as of 13:57, 12 March 2015
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	I made a spreadsheet using the RNG table that powerofthepowerofthe posted (Editor's note: Here are [[Zelda II: The Adventure of Link/RNG Tables\|RNG output tables]] created by powerofthepowerofthe). It seemed to work pretty well: I'd check for updates to $0492, and on the frame I saw the update, I could use the RNG value to check which drop I'd get.		I made a spreadsheet using the RNG table that powerofthepowerofthe posted (Editor's note: Here are [[Zelda II: The Adventure of Link/RNG Tables\|RNG output tables]] created by powerofthepowerofthe). It seemed to work pretty well: I'd check for updates to $0492, and on the frame I saw the update, I could use the RNG value to check which drop I'd get.

	Then I started fighting a bunch of bots in a weak encounter over and over and noticed that the drops weren't going into $0492 anymore. It seems the RNG is bigger than two bytes, and the ~~"mystery value"~~ decides both which address should receive the drop and which address should be read to decide the drop. When I kept killing enemies, the ~~mystery value~~ would change. I don't know anything about the Zelda 1 RNG, so maybe that's normal, but it might be necessary to look into the RNG algorithm a bit more to account for this behavior. If it is normal, then we just need to determine how the mystery value is set. If there's a Zelda 1 mystery value with known behavior, then fantastic.		Then I started fighting a bunch of bots in a weak encounter over and over and noticed that the drops weren't going into $0492 anymore. It seems the RNG is bigger than two bytes, and the enemy table index decides both which address should receive the drop and which address should be read to decide the drop. When I kept killing enemies, the enemy table index would change.

	The RNG does update on every frame, so I don't think this will help you manipulate anything unless there's some clump of good drops that you can target by playing at a specific speed. It does teach us that the P-bag probabilities are 1/8 and 1/2, though, unless the sequence for some of the RNG bytes is really wack. Maybe knowing that is enough.		The RNG does update on every frame, so I don't think this will help you manipulate anything unless there's some clump of good drops that you can target by playing at a specific speed. It does teach us that the P-bag probabilities are 1/8 and 1/2, though, unless the sequence for some of the RNG bytes is really wack. Maybe knowing that is enough.

Neil: /* Technical details */

2015-03-12T13:54:51Z

Technical details

← Older revision		Revision as of 13:54, 12 March 2015
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	003612: A:06 X:01 Y:01 S:EF P:nvUBdIZC $E8A3:A9 00 LDA #$00 ; It is! Zero the counter for next time		003612: A:06 X:01 Y:01 S:EF P:nvUBdIZC $E8A3:A9 00 LDA #$00 ; It is! Zero the counter for next time
	003612: A:00 X:01 Y:01 S:EF P:nvUBdIZC $E8A5:9D DE 05 STA $05DE,X @ $05DF = #$06		003612: A:00 X:01 Y:01 S:EF P:nvUBdIZC $E8A5:9D DE 05 STA $05DE,X @ $05DF = #$06
	003612: A:00 X:01 Y:01 S:EF P:nvUBdIZC $E8A8:A6 10 LDX $0010 = #$04 ; Load ~~Mystery Value~~ into X. It's 4 here		003612: A:00 X:01 Y:01 S:EF P:nvUBdIZC $E8A8:A6 10 LDX $0010 = #$04 ; Load Memory Table Index into X. It's 4 here
	003612: A:00 X:04 Y:01 S:EF P:nvUBdIzC $E8AA:7E 14 04 ROR $0414,X @ $0418 = #$01 ; ???		003612: A:00 X:04 Y:01 S:EF P:nvUBdIzC $E8AA:7E 14 04 ROR $0414,X @ $0418 = #$01 ; ???
	003612: A:00 X:04 Y:01 S:EF P:NvUBdIzC $E8AD:BD 1B 05 LDA $051B,X @ $051F = #$82 ; Read RNG byte 4		003612: A:00 X:04 Y:01 S:EF P:NvUBdIzC $E8AD:BD 1B 05 LDA $051B,X @ $051F = #$82 ; Read RNG byte 4
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	029149: A:06 X:02 Y:02 S:F1 P:nvUBdIZC $E8A3:A9 00 LDA #$00 ; So we zero it		029149: A:06 X:02 Y:02 S:F1 P:nvUBdIZC $E8A3:A9 00 LDA #$00 ; So we zero it
	029149: A:00 X:02 Y:02 S:F1 P:nvUBdIZC $E8A5:9D DE 05 STA $05DE,X @ $05E0 = #$06		029149: A:00 X:02 Y:02 S:F1 P:nvUBdIZC $E8A5:9D DE 05 STA $05DE,X @ $05E0 = #$06
	029149: A:00 X:02 Y:02 S:F1 P:nvUBdIZC $E8A8:A6 10 LDX $0010 = #$04 ; ~~Mystery~~ value is 4 again		029149: A:00 X:02 Y:02 S:F1 P:nvUBdIZC $E8A8:A6 10 LDX $0010 = #$04 ; Enemy Table Index value is 4 again
	029149: A:00 X:04 Y:02 S:F1 P:nvUBdIzC $E8AA:7E 14 04 ROR $0414,X @ $0418 = #$07		029149: A:00 X:04 Y:02 S:F1 P:nvUBdIzC $E8AA:7E 14 04 ROR $0414,X @ $0418 = #$07
	029149: A:00 X:04 Y:02 S:F1 P:NvUBdIzC $E8AD:BD 1B 05 LDA $051B,X @ $051F = #$D0 ; The low 3 RNG bits are 0		029149: A:00 X:04 Y:02 S:F1 P:NvUBdIzC $E8AD:BD 1B 05 LDA $051B,X @ $051F = #$D0 ; The low 3 RNG bits are 0

Neil: /* Technical details */

2015-03-11T16:59:01Z

Technical details

← Older revision		Revision as of 16:59, 11 March 2015
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	The following comes courtesy of __sdfg on the SDA forums, with permission.		The following comes courtesy of __sdfg on the SDA forums, with permission.

	~~Anyway, here~~'s a bucket of FCEUX for a small drop:		Here's a bucket of FCEUX for a small drop:

	<pre>		<pre>

Neil: /* Technical details */

2015-03-11T16:53:50Z

Technical details

← Older revision		Revision as of 16:53, 11 March 2015
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	</pre>		</pre>

	I made a spreadsheet using the RNG table that powerofthepowerofthe posted (Editor's note: Here are [[Zelda II: The Adventure of Link/RNG Tables\|RNG output tables]]		I made a spreadsheet using the RNG table that powerofthepowerofthe posted (Editor's note: Here are [[Zelda II: The Adventure of Link/RNG Tables\|RNG output tables]] created by powerofthepowerofthe). It seemed to work pretty well: I'd check for updates to $0492, and on the frame I saw the update, I could use the RNG value to check which drop I'd get.
	created by powerofthepowerofthe). It seemed to work pretty well: I'd check for updates to $0492, and on the frame I saw the update, I could use the RNG value to check which drop I'd get.

	Then I started fighting a bunch of bots in a weak encounter over and over and noticed that the drops weren't going into $0492 anymore. It seems the RNG is bigger than two bytes, and the "mystery value" decides both which address should receive the drop and which address should be read to decide the drop. When I kept killing enemies, the mystery value would change. I don't know anything about the Zelda 1 RNG, so maybe that's normal, but it might be necessary to look into the RNG algorithm a bit more to account for this behavior. If it is normal, then we just need to determine how the mystery value is set. If there's a Zelda 1 mystery value with known behavior, then fantastic.		Then I started fighting a bunch of bots in a weak encounter over and over and noticed that the drops weren't going into $0492 anymore. It seems the RNG is bigger than two bytes, and the "mystery value" decides both which address should receive the drop and which address should be read to decide the drop. When I kept killing enemies, the mystery value would change. I don't know anything about the Zelda 1 RNG, so maybe that's normal, but it might be necessary to look into the RNG algorithm a bit more to account for this behavior. If it is normal, then we just need to determine how the mystery value is set. If there's a Zelda 1 mystery value with known behavior, then fantastic.

	The RNG does update on every frame, so I don't think this will help you manipulate anything unless there's some clump of good drops that you can target by playing at a specific speed. It does teach us that the P-bag probabilities are 1/8 and 1/2, though, unless the sequence for some of the RNG bytes is really wack. Maybe knowing that is enough.		The RNG does update on every frame, so I don't think this will help you manipulate anything unless there's some clump of good drops that you can target by playing at a specific speed. It does teach us that the P-bag probabilities are 1/8 and 1/2, though, unless the sequence for some of the RNG bytes is really wack. Maybe knowing that is enough.

Neil at 16:53, 11 March 2015

2015-03-11T16:53:01Z

@@ Line 1: / Line 1: @@
 The Zelda II RNG changes with every frame. In the NES version, the counter starts when SDA timing starts. Generally that doesn't matter, since things will never happen at the same time, but the one key exception is that in any category where the North Palace Magic Container is done first, a 50 point bag can be manipulated.
 Here is a chart of the Zelda II RNG at the start of the game, with a 10 frame moving average. Each bar represents the numbered frame, and the 9 frames preceding.
@@ Line 6: / Line 10: @@
 For the P Bag drop, the two key windows are the ones at about 1600 frames, and at about 1920 frames. Hit either of those windows reliably, and P Bag drops go from the usual 1/8 chance, to much higher.

Neil: Created page with "The Zelda II RNG changes with every frame. In the NES version, the counter starts when SDA timing starts. Generally that doesn't matter, since things will never happen at the ..."

2013-07-18T15:06:24Z

Created page with "The Zelda II RNG changes with every frame. In the NES version, the counter starts when SDA timing starts. Generally that doesn't matter, since things will never happen at the ..."

New page

The Zelda II RNG changes with every frame. In the NES version, the counter starts when SDA timing starts. Generally that doesn't matter, since things will never happen at the same time, but the one key exception is that in any category where the North Palace Magic Container is done first, a 50 point bag can be manipulated.

Here is a chart of the Zelda II RNG at the start of the game, with a 10 frame moving average. Each bar represents the numbered frame, and the 9 frames preceding.

http://redcandle.us/wp-content/uploads/2013/03/zelda2-droprate-movingaverage.png

For the P Bag drop, the two key windows are the ones at about 1600 frames, and at about 1920 frames. Hit either of those windows reliably, and P Bag drops go from the usual 1/8 chance, to much higher.