Started by yojc on 20 May 2021 • 12,633 views
@dizzy9
No worries, I was just asking out of pure curiousity. Thanks for spending your time!
Another thing I've noticed while playing around with the straw, is that when you light it up, leave the screen and immediately come back, the straw will continue to burn, but it will not disappear afterwards like it's supposed to. (if you don't come back, it will burn up as normal). A minor oversight, but still weird.
I cannot reproduce the error you described, can you make a gif of it or something?
Btw, another fun, small oversight with the straws flame: It doesnt care for map the straw is on(look under the spider).
https://i.ibb.co/ZT0P8xd/straw.gif
[quote data-userid="178" data-postid="89899"]
I cannot reproduce the error you described, can you make a gif of it or something?
[/quote]
Here you go:
https://www.youtube.com/watch?v=D426BKDjld4
Played on Aladdin revision. Two matches were hacked into inventory for presentation purposes. (having tested it on the Blue revision, it seems to work a bit intermittently there...? clearly there's more to this glitch than meets the eye)
I see. It doesnt work on all maps. Looking at the code, this happens because the code does NOT look for the straw item but instead relies on a pointer in the item ram table that points to the straw object. By changing screen, you shuffle items in the RAM upon map re-entry. This can be used to remove other items from the map, if new order in RAM happens to point at other item(although lot of time, it will point to empty entry).
https://i.ibb.co/3kFD0D8/straw-erease.gif
Has there been any investigation into items you can't use at the very top of the screen? I recall that you can't catch Pogie on the highest step you can stand on in the lower screen, and in the blue version, when you drop the match on the straw at the very top of a screen, the straw won't ignite, but neither will Dizzy pick up the straw. That makes me wonder how much of the object interaction code gets run there and what makes it skip the rest. Could it be a limitation of the game engine or of how the Nintendo Entertainment System itself handles sprites in the early scanlines?
@bag-of-magic-food
Its not NES related limitation but due to how the code was written.
If the hitbox top goes over the screen edge, does wrap around the screen. Because of how 8bit values work, the numbers to represent that position also wraps around, making the hitbox appear as if it was on the bottom of the screen rather the top.
There is no dedicated check if the interaction takes place at the top of the screen.
I've noticed something peculiar about the infamous invincibility glitch.
In the Blue version, you can't activate this glitch while getting damaged by mice on Keldor City streets, and the ant near the waterfall. In the Red version, you can. Why could that be? (in both versions, you're immune to damage from them while the glitch is active)
Regarding the reappearing stars glitch... seems like in Blue version, when you collect last star and don't leave the area until the star counter animation finishes, all stars in said area will reappear. I could replicate this bug in the cave under the cemetery (as shown above), and also in the lower clouds; however, I failed to replicate it on the Zaks' Castle middle floor for whatever reason. I've not checked any other areas.
This has never happened to me in the Red version, and I somehow doubt the bug is still there, unless it's not as easy to trigger as it looks.
I've attached a FCEUX savestate right before entering the cave (with two stars to collect), as well as complete FCEUX movie (from game start; I happened to be recording at the time), in case that helps.
https://www.sendspace.com/file/h430df
@yojc
Oh, I've made an investigation about this one day....didnt I post about it somewhere? I could swear I did, but I cant find it now.
In essence, its location driven. When you collect last star, the gameplay is abruptly cut off by a dialog. This changes a ram value that had an index in the bit array with stars. The value returned once the "you got all stars" dialog is closed is location dependent. Its possible to for the ram value to point at location in memory other than star bit array. Interestingly, it can point at table of food eaten. Red and PAL version take steps to fix that, meaning Twins knew there was something wrong with it.
I hope to make a NES Secrets about it at some point.
Thanks for the explanation! Another mystery solved. Since the dialog is the main culprit for this glitch, could this be recreated with another dialogs? (for example, interacting with a character? like Dora in her frog form?) You know, being able to duplicate stars at will would be immensely handy...
Speaking of stars... Could it be that the Blue version can't show more than one star on screen at once? I was wondering why the star on the left keeps disappearing:
@yojc
While I didn't test for it, Im very doubtful it would work with other dialogs. Thats because the dialog interrupts the initialization of the big number that happens when you collect a star.
Even grabbing an item at the same frame wouldn't work(probably) because it doesn't happen in that exact function that handles the appearance of the big number.
Also, while looking for answer to your latest question, I've found a new glitchy spot.
Im not sure if its of any use in speedrun since I dont really follow the BLUE version but maybe?
If you jump from this spot and hold left, you can clip though.
https://gfycat.com/warmpleaseddassie
So... I've somehow managed to glitch a star into a state where it's blinking and can be collected indefinitely. Not sure what is that about?
https://gfycat.com/bouncypracticalcoelacanth
https://www.sendspace.com/file/ai8wmr
Ah, yes. I was aware of this and planned to show it off in a video explaining the whole star glitch(if I ever have time, that is).
You see, within glitches RAM range, there is a counter that just keeps incrementing every frame. What you did with the star glitch was to point the pointer to that specific RAM address. That counter always increases, refreshing its bits and thus, reenabling the star.
Surprisingly, I've found yet another extra lifes cheat in PAL version.
To activate it, pause the game, press and hold Up+A buttons and unpause the game (while still holding up+a!)
This will only work, however, if flying cheat has been enabled (probably why this was not found for so long).
I was watching a speedrun of the Blue version, and when opening Start menu while being damaged in the cemetery, the music became slightly corrupted. I'm not sure if I came across this before, what could be the cause?
https://www.youtube.com/watch?v=Z04j9kQPpsA&t=3340s
I looked into music driver very long time ago. I only remember that the SFX implementation is quite poor.
The same effect can be sometimes heard in yolkfolk village when you stop elevator, although it goes away very fast.
If I were to guess, the graveyard\mines music doesnt reset some audio variables that sfx changes.
Pausing the game invokes an sfx on top of another sfx(when player got hit), so maybe something connected to that?
So, I've been playing the NES Blue version again, and I came across a peculiar bug right at the end of the game. In the Zaks' tower, something went wrong and Zaks never shoot out from the projectiles from his wand, meaning I couldn't actually defeat him. He also didn't jump at all, however he did blink. The "evil faces" spawned normally. I've never seen this before - what's that all about?
@yojc
I've never heard of something like this! Do you happen to have a recording of it?
On another note, I finally got some bit of time and was able to compile unused CHR tiles in main part of the game(no title screen, menu, minigames, scroll etc)
The below applies to RED version. Blue and PAL may(and most likely does) be different.
For each location, theres an image with unused tiles in grayscale(zoomed by x2) as well as list of each tile with some notes.
I hope someone can put this data on Room cutting floor.
Huts:
https://i.imgur.com/PeutveN.png
0x4F
Not used at all.
0x50
Not used at all.
0x61
Not used at all.
0x73
Not used at all.
0x78
Not used at all.
0xAB
Not used at all.
0xB9
Not used at all.
0xCB
Looks very similar to tile 0x30, which is actually used.
Not used at all.
Beach:
https://i.imgur.com/qZS187C.png
0x69
Not used at all.
0xC7
Not used at all.
Cemetery:
https://i.imgur.com/8pJXQkw.png
0x22
Not used at all.
0x24
Used in unused Metatile.
0x28
Not used at all.
0x2F
Used in unused Metatile.
0x36
Used in unused Metatile.
0x55
Not used at all.
0x75
Used in unused Metatile.
0xB2
Not used at all.
0xC4
Not used at all.
Forest:
https://i.imgur.com/fdsXxKB.png
0x22
Exact same tile also goes unused in Cementary.
Not used at all.
City of Keldor:
https://i.imgur.com/ETYvbLC.png
0x6C
Not used at all.
0x7F
Not used at all.
0x83
Not used at all.
Blackbeard pirate ship:
https://i.imgur.com/VxPhFza.png
0x45
Not used at all.
0x4C
Not used at all.
0x55
This and 0x45 and be placed in vertical fashion to form a right side of a cloud.
Not used at all.
0x69
Used in unused Metatile.
0x6A
Used in unused Metatile.
City tunnels:
https://i.imgur.com/dxSokj1.png
0x0C,0x0F,0x30,0x33,0x36
Not used at all.
0x38,0x3A
Seem like wall tiles.
0x40
Not used at all.
0x67
Not used at all.
0x8B to 0x96
Name of each street.
These ARE used, technically.
For each tunnel, these are uploaded into different place in memory.
Thats how same Metatile can display different street name.
Still, These are on the list because the base tiles for the tunnels upload
256 tiles, even though there arent this many tiles.
Since these street names are stored right after the base tunnel tiles, they do get uploaded as well.
Underground:
https://i.imgur.com/gx3ScuZ.png
0x10
A leftover from BLUE version.
Used in unused Metatile.
0x12
A leftover from BLUE version.
Used in unused Metatile.
0x14
A leftover from BLUE version.
Used in unused Metatile.
0x16
A leftover from BLUE version.
Used in unused Metatile.
0x93
A piece of support beam(?).
Not used at all.
0xAA
A piece of bridge railing.
Not used at all.
0xCE
Not used at all.
0xCF
Not used at all.
Zakeria:
https://i.imgur.com/38PXHfQ.png
0x68
Not used at all.
0xBB
Unused waterfall tile(?).
Not used at all.
0xBC
Used in unused Metatile.
0xCD
Used in unused Metatile.
Castle:
https://i.imgur.com/CrpTTeP.png
0x1B
An unused piece of a brick.
Not used at all.