rangi42 / polishedcrystal

An upgrade to Pokémon Crystal. Brings features and content up to date, and adds some original content.

Pokémon Polished Crystal

This is a custom Pokémon game based on the Pokémon Crystal disassembly.

My goal is to create what the title says: an improved, polished version of Pokémon Crystal. It fixes bugs, takes into account the official game changes since 2001, and adds some new ideas of my own. Many features restore what was removed from R/B/Y, or original to HG/SS.

I've had vague plans to make a Pokémon game for years. I'm very impressed by the effort that's gone into disassembling Pokémon Crystal and making the code so well-organized. Thanks to making it open-source (and to the ROM hackers that inspired me), I'm finally making this game a reality.

There are many ways to create games but the way we work at Game Freak may be a little different from other companies. That is, we constantly change and tweak what we have come up with. To make a fun game even more fun and polish it up, we take what we have made and start thinking about it from scratch. And to make the game the most fun to play we make endless changes and tweaks no matter how long it takes. It may not be the best way, but I think these tweaks are important to make our games fun and better.

— Junichi Masuda, "HIDDEN POWER of masuda No. 7"

Download and Play

The current beta version is 3.0.0. It has some incomplete original content and known bugs, but it's playable from start to finish. Download the nightly release to get the very latest ROM, up-to-date with the master code branch.

The most recent official version is 2.2.0 as of September 20, 2016. The changelog lists all changes since then. I recommend playing the 3.0.0 beta instead.

If you want to do a Nuzlocke Challenge, check out Nuzlocke mode in the Option menu!

If you have any questions about these steps, read the FAQ!

Features

A full list of features is in FEATURES.md. Features new to the beta are in CHANGELOG.md. Some highlights:

• 253 Pokémon, including some new evolutions.
• 48 new moves.
• 65 TMs and 21 move tutors.
• Many new mechanics, including the Fairy type, Physical/Special split, Natures, unlimited TMs, Running Shoes, and continuous Repel.
• New maps: some restored from R/B/Y, some devamped from HG/SS, and some original.
• New characters, including Lorelei and Agatha from R/B/Y, Lyra and the Team Rocket Executives from HG/SS, and others.
• More post-game content, like Gym Leader rematches and an event after the battle with Red.
• An improved level curve with steadily increasing challenges throughout the game.
• Music and graphics devamped from other versions.
• Nuzlocke mode in the Option menu, enabling the basic rules of the Nuzlocke Challenge.

Discussion

You can post questions or comments on any of these sites. But please read the FAQ first if you have a question.

• Discord
• Skeetendo
• PokéCommunity
• Romhack.me
• /r/PokemonROMHacks
• Nuzlocke Forums
• Pokémon Hackers Online

Screenshots

polishedcrystal's Issues

Power Herb should use the regular item consumption routine

This allows it to be handled properly with Unburden and opponent Pickup

Receiving HM02 Gives TM00 (Item Overflow)

Upon receiving HM02 Fly I also received TM00 Tackle.

It appears to be an item overflow bug within the TM/HM pocket as having 16 TM/HMs causes the issue.

Also Strength becomes the cancel button and Cancel is now an HM for aqua tail.

git rev-parse HEAD reports : d36bc3d

I know this isn't the latest version but trying to use an old save with a new revision doesn't load.

I can provide a sav file upon request.

DynamicPunch animation gets stuck on inverted colors

Probably others too.

Anger Point halts multi-hit moves

If Anger Point activates due to a critical hit, further multi-hits are cancelled. Most easily seen with Skill Link.

Fix overflow in UpdateNoRTC for NO_RTC build

What I need to do here is mask off the top bits and check if the current hi-days is %11111 (i.e. just before it would overflow). When that happens there's a few possibilities here:

• Reset the whole RTC to zero
• Go back a week (so the last week repeats itself indefinitely)
• Repeat the last day indefinitely

NOTE: 13 bits for days allows for 8'192 in-game days -- over 22 in-game years -- which, given that a day in-game takes 4 real hours, would require the player to play for 3.75 continuous real years to overflow.

Dig goes on forever

Acrozz: "When my Geodude used Dig, he kept digging a hole for the rest of the battle and I had to reset."

Large sprite animations have corrupt tiles in stats screen

Sprite animations that use tile IDs $80 and above will not have those tiles flipped horizontally in the stats screen, so they'll appear corrupt.

Affected sprites:

• Weavile
• Leafeon
• Gliscor
• Rhyperior
• Togekiss
• Magmortar

AI use of CheckTypeMatchup is completely broken

@FredrIQ:

The code assumes something that is incorrect, completely breaking its usage of this function in every case it is used (which is pretty much everywhere in its switch-out routines, and various move scoring checks). I assumed this was introduced by my changes to said routine, but the bug is actually present in vanilla Crystal. Found it while trying to implement Anticipation.
Fixing this will be rather annoying.

Basically, whenever it uses CheckTypeMatchup (not BattleCheckTypeMatchup), it assumes that it can make the function do the right thing by setting hl to the defending types (hl+1 for type 2), which is correct, and a to the attacking type which isn't correct, because CheckTypeMatchup will proceed to get the type from the current move struct by "ld a, BATTLE_VARS_MOVE_TYPE; call GetBattleVar". I assumed this was a change I did myself, but looking at pret shows that it is there in vanilla as well. It is, however, more annoying to fix in Polished Crystal, since not only does one have to properly handle offensive/defensive types, but also abilities (just ignoring them is a bad idea unless one wants to make the AI not understand abilities).
Earlier tonight I was going to fix this by making CheckTypeMatchup all read from hl/a/b/c/d instead of reading the battle state on the fly such as:
hl is defending type (hl+1 the secondary one)
a is the offensive move
b is the offensive ability
c is the defending ability
d is 0 or 1 depending on identification (and set to 1 by CheckTypeMatchup regardless, if b is SCRAPPY.
However the result became quite awkward since I pretty much run out of usable registers and I was afraid to introduce bugs. Not sure what to do about this. Possibly do another attempt relying on RAM buffers (stuff like Buffer1-6, etc) so I don't have to do a ton of push/popping to do what I want.

Nope, hence the comment is still there. This isn't related to type matchups being broken in general (which was recently fixed), but a vanilla AI bug that completely broke switch logic.
Fixing this is a trivial change in vanilla Crystal, but due to the fact that type matchup logic has to factor in abilities, is a much harder change to apply properly to Polished Crystal (unless you decide to simply just ignore abilities, which I don't want to). The reason is that the cases where the AI use of this is broken is the case where the AI is checking non-active Pokémon. This means that not only is the type not matching (something the AI handles, it just misunderstands what the function does in a trivial way but completely broken way), but also defending and attacking Pokémon's abilities.
There are 2 methods for how to go about fixing it.
1: Whenever the AI wants to check this, temporarily change both attacking and defending Pokémon's ability. This needs to change back (properly! Keep Trace in mind, never mind Transform/Imposter) afterwards
2: Set ability to check in some parameter for the CheckTypeMatchup function. This is problematic because it kills any ability to reuse general ability logic (stuff like Mold Breaker, etc) and also needs free RAM (because there isn't enough registers) -- allthough I think Buffer* would do here.
There is also an edge case issue involving powder moves and Grass types, but I think this doesn't come up in practice because they're all status moves.
At this point I've concluded that messing with this isn't worthwhile considering that I want to rewrite the AI either way at some point later.

Telelport occasionally fails

abradolf: "Abra's Teleport occasionally fails."

Teleport should only fail if a trapping move or Ability prevents fleeing, and is not countered by a held item or another Ability.

Port Prism's xorshift PRNG

The current PRNG is not sufficient for generating several random numbers in short succession, as is needed with generation of new Pokémon (three DVs, nature, ability, shininess, and gender).

Redundant code in LoadEnemyMon and InitEnemyMon

battle/core.asm's LoadEnemyMon jumps early to InitEnemyMon if it's a link or Battle Tower battle, but continues with its own code for regular trainer battles. InitEnemyMon simply reads everything from the OTPartyMon data structure. LoadEnemyMon apparently has a more complicated way of doing the same thing, with lots of individual checks for "if it's a trainer battle, get this particular data item from OTPartyMon, otherwise generate a new one for a wild Pokémon". The only thing that isn't redundant is that LoadEnemyMon registers Pokémon as seen in the Pokédex.

HP gets corrupted after Disable wears off

After Disable wears off, damaging a Pokémon gives it extra HP.

battle/effect_commands.asm:BattleCommand_CheckTurn ld [EnemyDisabledMove], a is responsible.

After the low HP sound plays in battle, some of the instruments are missing

Mareep learns Fire Blast rather than Spark

Reported by abradolf.

Nuzlocke mode sometimes turns on by itself (maybe)

This was reportedly in 2.2.0. I was not able to reproduce it, and it may be gone in 3.0.

Per-turn status animations might not always work

Double-check Psn, Prz, Brn, Slp, and Frz. They should all have short animations that play along with the per-turn message.

Pidgey's faint cry is higher-pitched

According to one report. It should be lower-pitched.

Boulder puzzles are broken

Boulders do not fall into holes.

In-battle item use messages show the wrong Pokémon name

I used Full Restore on Pikachu, but it printed Mewtwo's name.

And on Lugia, it printed Mew's name.

Pokémon with Sheer Force can still cause flinching with Bite

Presumably Totodile.

Speed Boost does not activate at the end of each turn

Sometimes Speed Boost does not activate at the end of a turn. It also does activate sometimes incorrectly, e.g. as a result of a faint+switch.

Burns do not halve Attack

BRN halves damage by physical moves (i.e. halves Attack). This was removed in 6bb6abf.

Foe's Substitute makes your moves become something else

After rematch Koga's Tentacruel used Substitute, my Mewtwo's moves all turn into Ember. Switching out does not fix this.

Against a wild level 2 Pidgey hacked to know Substitute, my moves now become Double Slap. Against a level 3, Aerial Ace.

Dig sometimes prints that both Pokémon dug a hole

This was observed at least once in 2.2.0.

Status condition failure messages are inaccurate

"Gastly Paralyzed my Pokemon with Lick. When it uses Hypnosis it says “Chikorita is already asleep” even though it's paralyzed."

Some NPC trainers use wrong items

Lance uses X Spcl. Atk, Karen uses Potion, etc. (This was in 2.2.0.)

Running away sometimes fails

Level 100 Mewtwo failed to run away from a level 26 Magikarp.

Edit: This is still happening.

Calling Bill to change boxes corrupts the PC

This was reported back in 2.2.0. I cannot reproduce it.

Caught Pokémon have wrong held items

I've caught a Teddiursa holding an Ultra Ball and a Caterpie (IIRC) holding a Great Ball. On the other hand, a Bellsprout I caught had the correct Gold Leaf.

Shlotz has caught an Ekans holding a Safari Ball, and another holding a Master Ball.

Edit: Adrevilicious on Discord confirmed that this is still an issue, with Spinarak holding a Safari Ball.

TMs refresh PP

This was in 2.2.0 and in some of the official games. Overwriting a move with N PP should not have more than that, even if the new max PP is greater.

Wild Pokémon with Forewarn crash the game

Vulpix and Drowzee, specifically.

Held Berries don't always disappear when used

"After giving a Pokemon the last Oran Berry in my bag, the Pokemon will still have the Berry after using it in battle, although it is only used once in that battle." (via)

If you lose to a wild mon after winning a CANLOSE battle, the game crashes

LostBattle is the culprit

Pokémon have full PP when caught

They should lack PP for the moves they used in battle.

Rage does not always build when hit

Gender ratios are wrong

Both wild and gift Pokémon have too many females. The base ratios are not being correctly applied.

Gender is determined last after at least six previous PRNG calls (for the IVs, nature, ability, and shininess), so maybe the fault is with biased randomness?

Some wild Pokémon sent to PC appear level 0 before being withdrawn

"Captured a shiny, level 24 Tauros; it got sent to the PC where it became a level 0 mon; trying to see the stats freezes the game (possibly due to the game being unable to calculate the stats of a level 0 mon). This happens regardless of what type of ball I use to capture it. Getting it out of the box restores it to its normal level and all screens are visible."

Guts, Hustle, and Solar Power do the wrong thing

It boosts move power regardless of whether it's physical or not (Guts and Hustle should only boost Physical moves while Solar Power should only boost special ones). Posting it here to avoid forgetting it. The reason this was not addressed right away is because effect_commands is full once again, and because the way damage calculation-affecting abilities are checked could really use a rework to simplify it.

Pursuit on switch is followed by Struggle

abradolf: "Also, mons automatically use Struggle right after Pursuit's effect activates (read: a switch is in order --> foe's Pursuit hits before the mon is switched out --> another mon is switched in --> foe uses Struggle and hits --> battle resumes as usual)."

Trapping moves don't take effect

Articunwho: "Trapping moves don't seem to take effect. I get the "was trapped by Wrap!" status message, but there's no recurring damage after each turn, and every time Wrap is used again, the "trapped by Wrap" message pops up once more."

Slight Compilation error

Make Debug doesn't seem to do anything while Make Crystal does this error

error: Section name "Audio" is already in use

Air Balloon message doesn't print for the opponent's first Pokémon

Cooltrainer♂ Finch has a Geodude and Mareep holding Air Balloons. The message only prints for Mareep.

The Air Balloon message piggybacks on Spikes logic, which probably does not run for the first Pokémon.

Slot machines are broken

Introduced by commit e004e41

Some unique IV combinations make Pokémon start with wrong HP

For example, Youngster Joey's Rattata, which has perfect IVs:

Unnerve is broken

"Unnerve allows enemy mons to consume their berries while printing out a really weird message."

Dark types are not immune to moves whose priority was increased by Prankster

This should be resolved once Magic Bounce is implemented (they will share a check).

Headbutt overworld animation looks weird

It should have grass underneath the shaking tree.

Caught Pokémon sent to the PC appear as level 255

When withdrawn, their level corrects itself.

Weather and some ability animations trigger the last used move animation

"Weather like Sunny Day and Rain Dance, as well as abilities that take place every turn like Speed Boost (as seen on Bugsy's Yanma) occasionally trigger the damage animation on the opponent's Pokemon. No damage is dealt obviously, but the animation and sound effect are present." (via)

Edit: "It looks like it recycles the last used animation. In this case it was the animation for taking damage, since Sentret was the last to attack."

Edit: 889182d may have fixed this.

The TM Pocket flashes an uncolored TM icon when loading

This is a consequence of optimizing the pocket by loading the icon once at the very start, so scrolling is fast because it just updates the palette.