S/Z rotation

[GoldPlatedDish]

I'm not fully aware of what SRS can't do; here's an example:

[fumen]105@deB3jbA3ibC3hbB3sbkIWVADCpTAyi1TAS4gNE0i2r?DFbs2B3AAAA7eAnMPWADCpTAyi1TAS4gNE0i2rDFbs2BDTB?AA[/fumen]

Pieces are in their initial spawn orientation.

Can someone tell me why the S/Z won't spin in their respective direction?
Thanks a lot  

(CW: clockwise
CCW: counter-clockwise)

[caffeine]

Apparently there's no wall kick for those.

[Blink]

yeah i get messed up sometimes with that too in 20G, i think it's going to kick up but instead it just locks there.

[Kitaru]

Yeah, that's one of SRS's failings. It will kick in all sorts of zany situations, but not that one simple one? I always found that sort of weak, haha.

[jujube]

yeah i don't think it makes any sense. i mean, you can rotate the Z CCW but not CW, and it ends up 1 column above a basic CW rotation, so you're really rotating left to go right.

[hurtchow]

After reading this thread, I got curious about what you guys were talking about so I kept rotating an S piece with the same button over and over again. It's like it alternates clockwise/counterclockwise. It dances from left to right... Kinda weird.

[GoldPlatedDish]

Here's another quirk, involving the same Tetriminos:

[fumen]105@xdA3obD3ibA3kbE3kbB3nbB3nbB3nbA3pbksVVADCp?TAyi1TAS4gNE0i2rDFbs2B3AAAA7eAH8OWADCpTAyi1TAS4?gNE0i2rDFbs2BDTBAA[/fumen]

Again, pieces are in their initial spawn orientation.
Thoughts?

[hurtchow]

I totally don't understand what those flash thingies are proving.

[Fantaisie]

Sadly, Mr. jagorochi (KIL) website is unavailable for a long time. Mr. jagorochi is a SRS expert player, and he had a website explaining very well how SRS rotation rule works. Forgive me, but I cannot remember many details, but every time a tetramino is rotated, the game attempts to place it in 5 alternate positions sequentially. If a attempted position is unavailable, it tries the next one, until it gives up after all 5 have been attempted. GoldPlatedDish, in the positions you have shown, all the 5 alternate positions are unavailable, and so the game has given up attempting to rotate the tetramino.

SRS is a very difficult rotation rule to learn, as each of the 6 tetramino (not including O) can have 5 alternate positions, for each of the 8 ways of rotation (including clockwise and counter-clockwise). This means 240 alternate positions will need to be memorized in order to understand when a tetramino will rotate, although it is impossible to imagine how to do so. In practise players will often try rotating many ways if the first rotation is unsuccessfull.

[caffeine]

More like 80 since Z/S/J/L/T all share the same tables, but really with some practice in 20G you get the hang of what works and what doesn't.

I'm not saying it could've been done better. SRS's kick tables are a strange thing indeed.

[tepples]

Mr. jagorochi is a SRS expert player, and he had a website explaining very well how SRS rotation rule works. Forgive me, but I cannot remember many details, but every time a tetramino is rotated, the game attempts to place it in 5 alternate positions sequentially. If a attempted position is unavailable, it tries the next one, until it gives up after all 5 have been attempted. GoldPlatedDish, in the positions you have shown, all the 5 alternate positions are unavailable, and so the game has given up attempting to rotate the tetramino.

Caffeine put the SRS table into a document about Tetris DS on GameFAQs. The source code of Lockjaw has an SRS table in wktables.c.

[!--quoteo--][div class=\\\'quotetop\\\']QUOTE[/div][div class=\\\'quotemain\\\'][!--quotec--]each of the 6 tetramino (not including O) can have 5 alternate positions, for each of the 8 ways of rotation (including clockwise and counter-clockwise). This means 240 alternate positions will need to be memorized in order to understand when a tetramino will rotate[/quote]
It's not 240, for three reasons:

• L, S, T, and Z all use the J table. So we have to consider only I and J tables: 80 positions.
• The table for four counterclockwise rotations from spawn orientation is a mirror image of the table for four clockwise rotations, apart from some very minor order differences rotation of an I tetromino about its end block. In fact, versions of Lockjaw prior to 0.11 relied on this fact to the point that they didn't even store the mirror image table. So we have to consider only clockwise tables: 40 positions.
• There is a suggestion (that I haven't analyzed fully) that if you press one rotation button then the other, the table for the second rotation is the exact inverse (-x, -y) of the first. That might reduce it to 20 positions.

[Fantaisie]

tepples, the TDS guide (http://www.gamefaqs.com/portable/ds/file/930648/42155) and the wktables.c of Lockjaw, neither are correct. There are errors and they are not consistent with the actual TDS cartridge.

One might think that it is possible to reduce the number of positions required for memorization from 240 to 80, or even less, but this is not correct. In practise, it is impossible to imagine how to memorize so many "meaningless wallkick numbers", instead players memorize wallkicks in the context of "common situations that happen in games". Even when that which is required is exactly the same wallkick "number" with same tetramino, if the situation (that is to say the shape of the stack) is different, they are memorized as different wallkicks. This is more clearly notable with the S and Z tetramino. In practise, one may need to memorize more or less than 240 positions, depending on which situations occur with most frequency in games. Most expert players use ~40 positions which are most important, in the rest of the uncommon positions, they will be unfamiliar with how to rotate the tetramino optimally, and will often require to rotate the tetramino many ways and may even make a mistake. Even expert players will make mistakes, not because of unco-ordinated hands, but because they haven't memorized the required number of positions for complete comprehension of the rotation rule.

[jujube]

One might think that it is possible to reduce the number of positions required for memorization from 240 to 80, or even less, but this is not correct. In practise, it is impossible to imagine how to memorize so many "meaningless wallkick numbers", instead players memorize wallkicks in the context of "common situations that happen in games". Even when that which is required is exactly the same wallkick "number" with same tetramino, if the situation (that is to say the shape of the stack) is different, they are memorized as different wallkicks.

i agree that it's easier to learn situations with SRS and how to approach them, instead of trying to remember all the wallkick tests and their order.

but i think you're overestimating the complexity of SRS kicks, and underestimating the ability of the player to learn them if he or she chooses. many casual players would not attempt to learn even the simplest kicks in any rotation system. there are only a few things you have to remember about SRS Z kicks if you're coming from ARS:

1. http://kitsune-zeta.com/Tools/TetrisField/?v105@7eBE0jsAd
rotate CCW to this position.

2. http://kitsune-zeta.com/Tools/TetrisField/...qeA3vbE5j7eAMBd
rotate CCW (not CW) to this position (same as ARS, but inconsistent with SRS on a flat field).

3. http://kitsune-zeta.com/Tools/TetrisField/...hbD3pbM5j7eAEBd
rotate either direction first, then rotate that same direction again.

now for some twists that are only possible with SRS. if you don't think you'll need these, you simply don't need to learn them:
4. http://kitsune-zeta.com/Tools/TetrisField/...gbE3pbE0j7eAMBd
rotate CW (basic SRS rotation, doesn't need a kick).

5. http://kitsune-zeta.com/Tools/TetrisField/...hbD3pbM0j7eAEBd
rotate CCW twice.

6. http://kitsune-zeta.com/Tools/TetrisField/...hbD3pbszj7eAEBd
rotate CW twice.

7. http://kitsune-zeta.com/Tools/TetrisField/...gbF3pbkpj7eAsAd
rotate CW.

8. http://kitsune-zeta.com/Tools/TetrisField/...gbF3pbkpj7eAsAd
rotate CCW.

mirror everything in situations 1-8 for the S piece, so it doesn't take any extra memorization.

to make all of these things possible you need kicks that do more than ARS. you have to learn to rotate the correct direction too, because for example in situations 5 and 6 the piece has a different point of entry and needs to kick to a different relative position.

i understand that situations 2 and 3 are a little unintuitive, but it's just not very much to learn, and it's easy to recall when playing at high speeds. the more complicated situations are things that happen less often and it's an exercise to the player to learn them. but just because something more complicated is possible with SRS it doesn't make the system more complicated if you don't attempt to fill weird holes.

[meow]

very nice S/Z twists jujube!

srs is crazy

[zaphod77]

very nice S/Z twists jujube!

srs is crazy

Ther is a unifying principle in SRS rotation.. but it's very difficult to see it.

There are only three kick tables.

1) th eo piece, which is designed to neither rotate, nor kick.
2) THe I piece. This is where ACE screws up, and gets it wrong.
3) everything else.

Most notable for the T piece, some parts of the kick table can never be reached, because in any situation that that position is available, an earlier spot in the table is guaranteed to also be available.  SO the T is the simplest piece to learn, other than O.

The hardest are, of course, the S and Z.

ALso notable is that the guideline appears to process clockwise and counterclockwise rotation seperately.  It is possible to perform both a clockwise and a counterclockwise rotation in the same frame on tetris DS. Because of wallkicks, this can in certain very limited circumstances be useful.

When you rotate one way, then rotate back the other way, the kicks are indeed reversed.this does not guarantee the piece will return to it's original spot, because an earlier kick in the table may take priority from the new position.