Archive for the 'Many-Worlds Mario' Category

A follow-up on “Quantum Mario” (also comments are fixed now)

Tuesday, January 18th, 2011

So a random little thing that I ran across and had me sort of floating on air… if you’ve played the amazing indie platformer Super Meat Boy, you’ll have seen an interesting feature they have where once you beat a level, they play back all the (many) attempts it will have taken you to complete it, simultaneously and superimposed. An example, via IGN:

Super Meat Boy

If you’ve been reading my posts here, you’ll have probably figured out by now that I really like punishment platformers. So I’d been playing Super Meat Boy more or less nonstop for several weeks when someone forwarded me this Game Informer interview with Team Meat, wherein it turns out that the replay feature was actually inspired by the “Many-Worlds Mario” video I made and posted here way back in 2008:

How did you come up with the multi-death replay system?

Refenes: Basically, there’s a video that’s been floating around on the Internet for awhile. It’s a modded Super NES emulator that’s rigged to play custom-made Super Mario World levels. They rigged the emulator so it would record every attempt and then overlay them and play them at the same time. So this one video, it’s called Quantum Mario, it’s just one Mario jumping from platform to platform and he’ll fall off on the left, fall off on the right, or get hit with a bullet, or jump off of the bullet. It’s just every one of his attempts. It starts through this incredibly difficult level and just goes all the way through until it’s just one guy remaining. I love that video and I was like “We should do that with Meat Boy and I can do it in real time.” I just kind of coded it in over a weekend or something and perfected it as we were going through the development. It was an on-the-whim kind of thing. And it worked out as a great reward for f—ing up.

So that’s a kind of a weird and encouraging feeling. I spend a month and a half making a bizarre youtube video, and three years later, it turns out the world is slightly different as a result… ^_^

A little housekeeping note: I discovered this weekend that for a really long time– probably six months or more– commenting on this blog has been broken. Apparently one day reCAPTCHA broke and started marking every single comment as spam, then deleting them after two weeks. So I’ve lost literally everything anyone’s posted here for I’m not even certain exactly how long. I am really sorry about this. I’d been thinking, wow, it’s a little odd how comments on the blog seem to have dried up…

I think I can promise a little more traffic on this blog this year. I’ve got a few interesting things in the pipeline: a new game that’s maybe half done, a little iPad music toy that’s mostly done, and a new version of Jumpcore that comes with support for iOS and Android (an alpha of that last thing is here). Also, keep an eye out for a post tomorrow, I think I’ll have something interesting for you…

Super Mario World vs. the Many-Worlds Interpretation of Quantum Physics

Sunday, February 3rd, 2008

Short version: Just watch this video.

Okay, now what was that?

So a few months back some of my friends were passing around these videos of something called “Kaizo Mario World“, which I was told, at first, translated to “Asshole Mario World”. This turned out to have actually been a misunderstanding of something in the youtube posting of the original creator’s videos:

[Asshole Mario] is not the real name for this series of videos, but it is my personal name for it.
The literal translated name for 自作の改造マリオ(スーパーマリオワールド)を友人にプレイさせる is “Making my friend play through my own Mario(Super Mario World) hack”, hence Kaizo(hack) Mario to the USA.

…but, the name is pretty appropriate. Kaizo Mario World is one of a series of rom hacks people create in special level editors that let you take Super Mario World and rearrange all the blocks; the point of Kaizo appears to have been to create the most evil Super Mario World hack ever.

I started watching these videos, but after seeing how the player got past the first gap stopped, went wait, this actually doesn’t look so bad, and started playing it instead. It’s actually not that bad! I was expecting it to be like Super Mario Frustration, Kaizo Mario World’s equivalent in Super Mario Bros. 1 hacks– all ridiculous jumps that require pixel-perfect timing, memorizing the location of a bunch of hidden blocks that exist only to foil a jump and, occasionally, actually exploiting glitches in the game engine.

Kaizo Mario World actually turns out though really to be kind of more like a puzzle game– giving you a series of seemingly impossible situations and then leaving you to figure out how to get past them. It only uses the sadistic-invisible-block trick sparingly (and, hey, even SMB2JP did that a couple times). And it actually turns out to be kind of fun.

It’s still sadistically hard, though, so if you want to play it you have to use what are called “save states”. Most emulators let you do this kind of save-and-rewind thing, where if you screw up you can back up just a few seconds to the last time you were standing in a safe place. So if you’re playing Kaizo Mario world you find yourself playing the same four-second section over and over and over until you get the jump just right, listening to the same two seconds of the soundtrack looping Steve Reich style

Anyway, the idea for the video up top was inspired by an offhanded comment in the “original” Kaizo Mario World youtube post I linked above:

The original videos were in god awful codecs that were a bitch to convert, so unfortunately the Tool Assisted Speedruns came first to most youtube watchers.
This is rather unfortunate, as I feel you lose a lot of the “appeal” by watching those.

This refers to the way that most emulators, if you are recording a video of yourself playing a game and you do the save-state rewind thing, they’ll rewind the video too, such that the video shows only your final attempt, not any of your messups. People use this to make “speedruns” showing a best-of-all-possible-worlds recording of them playing through some game or other, with all the errors scrubbed out. The guy’s point was that watching Kaizo Mario World this way kind of ruins it, since most of what makes Kaizo great is watching someone fail over and over and over again until they finally get it right.

On the other hand, Kaizo Mario World involves SO much failing that this means all the “real” videos are, like, twenty minutes long just to get through what in a tool-assisted run would have been a two-minute level. So I was thinking, what if you had a special tool that instead of erasing all the screwups, it saved all of them and made a video of all the screwups plus the one successful path superimposed? I kept thinking about this and eventually I just sat down and hacked SNES9X to work exactly like that. The result was the video up top, showing the 134 attempts it took me to successfully get through level 1 of Kaizo Mario World.

I think I’m going to make some more videos in this style of different Kaizo Mario World levels and post them back here, but in the meanwhile, if you want to make your own many-worlds speedrun videos, here’s my custom version of SNES9X 1.43 with the multi-record function:

  1. For the Mac OS X version, click here.

  2. For a Windows version, click here. (Many thanks to Syndalis of 360Arcadians for compiling this for me.)
  3. If you want a Linux version, you’ll have to compile that yourself, but you can do this by finding a copy of the 1.43 source and replacing movie.cpp with this.
  4. And for the full Mac OS X source, click here.


[Update 2/9/08: The Mac version now correctly processes movies recorded in the Windows version.]
[Update 2/10/08: Mac version updated to fix a problem where certain kinds of corrupt recording files could cause the program to loop endlessly; window titlebar now contains status information.]

Note that this is a quickly-tossed-together hack all done to make a single video, and I make NO promises as to the quality, ease-of-use, correctness, or safety of these links. Also, I think the video feature should work with any SNES game, but I’ve only tested it with Kaizo. If anyone attempts to try this yourself, I’d be curious to hear about your results.

To make a video: First, use SNES9X’s “record movie” function to record yourself playing some game; while the game is running, use the save and restore feature at least once. When you’re done, you’ll find that SNES9X has created a yournamehere.smv file and also a series of files with names like yournamehere.smv.1, yournamehere.smv.2, etc. These .number files are all the different “mistake” playthroughs, so keep all these files together in one directory.

To turn this into an actual movie you can watch, you will need to use the OS X version of the emulator. Unfortunately, the Windows and Linux versions can only record multiple-run SMVs– they can’t do the export-to-quicktime thing. The quicktime-export code is based on alterations to the mac-specific parts of 1.43 (although considering that I hear the Quicktime API is mostly identical between Mac and Windows, it might be pretty easy to port that code to Windows at least…).

Anyway, in the OS X version, open up the appropriate ROM and choose “Export to Quicktime Movie” from the Option menu. Before leaving the export dialogue, make sure to click the “Compression…” button. You *MUST* choose either the “None” or “Planar RGB” codecs, and under the “Compressor” pane you *MUST* choose a depth of “Millions of Colors+”. The “+” is important. Once you’ve saved the movie location, go to “Play Movie” in the Option menu and choose the .smv you want to play. The emulator will play through each of the playbacks one by one; when it’s done (you’ll know because the background turns back on) your movie will appear in the location you chose. Note that there’s one more step! You won’t be able to actually play this movie, at least not very well, because the export feature works by creating a different movie track for each playthrough and the file will be huge and bloated. Open your video in Quicktime Player, then choose “export” and export to some video codec with actual compression (like H.264). This will flatten all the different layers of the movie into one. Okay, NOW you’re done.

…So what’s this about quantum physics? Oh, right. Well, I kind of identify the branching-paths effect in the video with the Everett-Wheeler “Many Worlds Interpretation” of quantum physics. Quantum physics does this weird thing where instead of things being in one knowable place or one knowable state, something that is quantum (like, say, an electron) exists in sort of this cloud of potentials, where there’s this mathematical object called a wavefunction that describes the probabilities of the places the electron might be at a given moment. Quantum physics is really all about the way this wavefunction behaves. There’s this thing that happens though where when a quantum thing interacts with something else, the wavefunction “collapses” to a single state vector and the (say) electron suddenly goes from being this potential cloud to being one single thing in a single place, with that one single thing randomly selected from the different probabilities in the wavefunction. Then the wavefunction takes back over and the cloud of potentials starts spreading out again from that randomly selected point.

A lot of scientists really don’t like this “collapse” thing, because they’re uncomfortable with the idea of nature doing something “at random”. Physics was used to dealing with randomness before quantum physics came along– the physics of gases are all about the statistics of randomly moving gas particles, for example– but those kinds of randomness aren’t assumed to be actually random, just “effectively random” because the interactions of air molecules are so chaotic and complicated that they’re too unpredictable for humans to track. Think about what happens when you roll a die: the number that comes up when the die lands isn’t strictly speaking “random”, it’s absolutely determined by the physics of motion and the velocity at which you let go of the die and so forth. The “randomness” of a die roll isn’t about actual indeterminacy, but rather just a way of talking about your ignorance of how the deterministic processes that control the die operate. Quantum physics, on the other hand, has things that as far as anyone can tell are really, objectively random, with no mechanism producing that randomness and nowhere apparent to stick one.

Since this makes some physicists uncomfortable, they came up with a sort of a philosophical trick: they interpret quantum physics in such a way that they say when there’s more than one possible random outcome of some quantum process, then the different possibilities all happen, in alternate universes. They can’t prove or disprove that this idea is true– from the perspective of someone inside one of these universes, everything behaves exactly the same as if the “wavefunction collapse” really was just picking a random option. But it’s one way of looking at the equations of quantum mechanics, and as far as the mathematics cares it’s as valid as any other. Looking at things this way, if there’s a 3/4 chance of a quantum process doing one thing and a 1/4 chance of it doing the other, then we get three universes where the one thing happens and one universe where the other one does. This does mean that there’s some universe where two seconds ago all of the atoms in your heart spontaneously decided to quantum-tunnel two feet to the left, but in almost every universe this doesn’t happen so we don’t worry about that.

Science fiction authors love this. There’s a bunch of stories out there exploring this idea of a multiverse of infinite possibilities all occurring side by side (the best of these I’ve ever read being Robert Anton Wilson’s Schrödinger’s Cat). Most of these stories get things totally wrong. Science fiction authors like to look at many-worlds like, this morning you could either take the bus to work or walk, so the universe splits in two and there’s one universe where you decided to walk and one universe where you decided to take the bus. This is great for purposes of telling a story, but it doesn’t really work like that. The many-worlds interpretation is all about the behavior of quantum things– like, when does this atom decay, or what angle is this photon emitted at. Whereas human brains are big wet sloppy macroscopic things whose behavior is mostly governed by lots of non-quantum processes like neurotransmitters releasing chemicals.

This said, tiny quantum events can create ripples that have big effects on non-quantum systems. One good example of this is the Quantum Suicide “experiment” that some proponents of the Many-Worlds Interpretation claim (I think jokingly) could actually be used to test the MWI. The way it works is, you basically run the Schrödinger’s Cat thought experiment on yourself– you set up an apparatus whereby an atom has a 50% chance of decaying each second, and there’s a detector which waits for the atom to decay. When the detector goes off, it triggers a gun, which shoots you in the head and kills you. So all you have to do is set up this experiment, and sit in front of it for awhile. If after sixty seconds you find you are still alive, then the many-worlds interpretation is true, because there is only about a one in 1018 chance of surviving in front of the Quantum Suicide machine for a full minute, so the only plausible explanation for your survival is that the MWI is true and you just happen to be the one universe where the atom’s 50% chance of decay turned up “no” sixty times in a row. Now, given, in order to do this, you had to create about 1018 universes where the Quantum Suicide machine did kill you, or copies of you, and your one surviving consciousness doesn’t have any way of telling the people in the other 1018 universes that you survived and MWI is true. This is, of course, roughly as silly as the thing about there being a universe where all the atoms in your heart randomly decided to tunnel out of your body.

But, we can kind of think of the multi-playthrough Kaizo Mario World video as a silly, sci-fi style demonstration of the Quantum Suicide experiment. At each moment of the playthrough there’s a lot of different things Mario could have done, and almost all of them lead to horrible death. The anthropic principle, in the form of the emulator’s save/restore feature, postselects for the possibilities where Mario actually survives and ensures that although a lot of possible paths have to get discarded, the camera remains fixed on the one path where after one minute and fifty-six seconds some observer still exists.

Note: Please do not use the comments section of this post to discuss ROMs or where to get them. IPSes are okay. Thanks.