Tag: physics

PannenKoek’s Epic 3 3/4-Hour Explanation Of Mysterious Mario 64 Invisible Walls

You may remember PannenKoek as that person who has been trying to figure out how to complete Super Mario 64 in as few A button presses as possible, an odd, but no less noble, quest. They’ve been at it for quite a long time now, 13 years, but they’re still going. They have two loaded Youtube channels containing the pixelated fruits of their labors, PannenKoek2012 and UncommentatedPannen. Whenever you see a random Youtube video that uses the File Select music from Super Mario 64 as background music, they’re paying homage to PannenKoek, god of the game explainers.

While explaining aspects of Mario 64, that foundational, primordial 3D platformer, sometimes they ably explain complex and niche topics in computer science along the way. We’ve covered their videos before, more than once probably, and marveled at how by explaining some unexpected behavior in Nintendo’s N64 launch title, they have managed to make something important about how computers do things comprehensible. In three videos, they explained how Mario 64 handles terrain well enough that one feels (somewhat misguidedly) that they could implement their own 3D platformer. They made a bizarrely interesting video about how characters blink their eyes that shows various ways that games implement timers and randomness. They have a whole video on pseudorandom number generation, and another on floats, that computer number representation system that has deeply weird implications.

Their most recent video is a three hour, 45 minute epic that explains why sometimes, when Mario jumps, he seems to strike something invisible in his way. It’s a consequence of several unusual decisions Nintendo made in constructing the physics of Mario’s world, which includes the fact that level edge walls in Mario 64 aren’t implemented as geometry, but as a consequence of the lack of geometry: if there is no floor over a space, then the game rules it as Out Of Bounds. It won’t let Mario enter this completely invisible unspace under normal conditions, and will instantly kill him if he somehow enters into it. It is like antimatter. And that’s not even getting into how ceilings operate.

Here, then, it is. It is a lot, and I wouldn’t blame you if you can’t get through it all, but for a certain intersection of game obsession and brain chemistry, it is engrossing, and that’s before they even get to the periodic table of invisible walls:

Game Finds: Cosmic Collapse

We love it when we find weird and unique indie games to tell you all about! Our alien friends to the left herald these occasions.

A fair amount has been said about Suika Game, an inexpensive and addictive Switch game that has players dropping fruit into a physics-enabled bin. Two fruit of the same type that touch immediately merge into a larger fruit, and the goal is to join them together like this until you create a mighty Watermelon. You can keep going at that point, although with one of those majestic spheres in the bin it won’t be much longer before one or more fruits extends up out of the bin, which brings the game to an end.

The history of this unexpected Flappy Bird-like phenomenon is laid out in an article in the Japan Times. Until recently the game was exclusive to the Japanese eShop, although that needn’t actually a barrier. People from any territory can create eShop accounts for any other, and play all their purchases on the same Switch, but now I notice that Suika Game is even on the U.S. shop. And of course, as often happens when a simple and elegant game blows up out of nowhere, a horde of imitators has arisen, which a quick Googling will reveal. I count six free web versions just on a quick perusal of the search results.

But what might actually be better than Suika Game is the Pico-8 recreation of it, Cosmic Collapse.

Cosmic Collapse is more expensive than Suika Game, but that just means it’s $5 instead of $3. Instead of happy fruit, you merge together planets. They go up in size from Pluto (an honorary planet), through Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, Jupiter and then Sol herself. If you’re wondering, all planets are presented without rings. If joining two suns causes anything to happen I don’t know. (In the comments on the itch.io project, the developer says that there are objects beyond the Sun.)

Cosmic Collapse could be played just like the original, but it adds some extra features. Scoring is modified by a simple combo system: successive planets merged due to one drop have their points multiplied, encouraging the planning of sequences. And, at certain score awards, you’re granted a missile that can be used to destroy any one object in the bin. Used judiciously, it can allow your game lengths, and scores, to greatly increase. My highest so far is nearly 15,000.

The biggest advantages it has over Suika Game is in the polish and the physics. The many web clones tend to play like they were hacked together in an afternoon, but even the original is clearly a low-effort production, right down to its generic, non-looping music. The celestial orbs in Cosmic Collapse bounce around in a lively manner after merging in ways that take some practice to master, and even the smaller planets have their uses. The tiniest of space rocks, dropped at the right spot, can be just what you need to knock two other planets apart from each other, or separate one from the wall of the bin. You see? Pluto’s good for something after all!

Both Suika Game and Cosmic Collapse suffer from a certain unfairness. You don’t get to control the order in which fruit or planets get dropped into the bin. It’s been observed that even a lot of skill and practice can only get you so far if the orb-selection dice don’t roll favorably for you. The best advice I can offer, in the early game, is to try to sort the circles in size from one side of the bin to the other, which at least will make it easier to find a good place to drop things. Also in Cosmic Collapse, keeping the surface of the bin as low as you can helps a lot, since the propulsive force of the spheres, especially the smallest ones, is increased the further it falls, and that can be a marvelous prod to shaking up a static bin.

Cosmic Collapse (itch.io and Steam, $5)

Sonic Retro’s Physics Guide

tl;dr: The description of the physics and implementation details of the 16-bit Sonic the Hedgehog games hosted at Sonic Retro is complete and amazing.

This is one going out to all you developers out there, either current or aspiring.

It’s amazing to me how fussed, nay, obsessed-over the 16-bit Sonic the Hedgehog games are even to this day. There are a lot of good things about them, and arguably the best is their platforming engines, which are among the best in the field. They take advantage of the processing power of the Genesis/Mega Drive, fueled by a Motorola 68000 processor, the same processor as the classic Apple Macintosh, clocked only slightly slower. This was basis of Sega’s infamous “blast processing” slogan at the time, touting how much faster the Genesis was than the Super Nintendo Entertainment System. This was somewhat unfair, as SNES carts often came with supplemental chips in them that acted like co-processors, and was of a completely different architecture as well with different characteristics, but it did make the Sonic engine possible. A lot of the credit also goes to Sonic programmer Yuji Naka, who is legendary in game coding circles for a very good reason.

If this is the kind of discussion that makes your heart race, we’re glad to have you reading Set Side B! If it’s not, that’s okay. I’m a bit stymied myself, even though I love dives like this.
(All images in this post from Sonic Retro.)

The result of the Genesis’s power and Naka’s expertise was a game engine with, yes, raw speed, but also a lot of nuance. If you jump and land on an enemy or monitor, you can control the height of your rebound, no matter how fast you were going when you hit it. If you jump while on a slope, you don’t jump straight up but away from it, which takes some getting used to at first but can be taken advantage of. There’s lots of fun little cases like these, and figuring them out, and their implications, is the source of a lot of the joy of playing Sonic the Hedgehog for the first time.

Those two places where the slope only intrudes slightly into Sonic’s ground tile are what get me.

I’d even argue, without the solid engine, and great level design taking advantage of it, all of Sega of America’s marketing efforts, which formed the foundation of the media juggernaut that Sonic has become today, with several cartoon series and comic books, and two successful movies and a third one in the works, would have been for naught.

Judging by the later 2D adventures, the nuances of Sonic the Hedgehog’s engine are difficult to grasp without a good amount of effort. It is likely that Sega themselves don’t have the institutional memory to understand how they worked, which is why they went to Christian “The Taxman” Whitehead, and others from the fan game community, to make Sonic Mania, which has a faithful recreation of the original games’ physics.

Why has no one made a Sonic half-pipe trick skateboarding game?

Bringing it back around, the obsession of the Sonic fan community has produced a number of disassembles of the game’s code, which have served as the basis for a wide array of romhacks of rather shocking levels of quality. I wrote about many of those in the Someone Set Up Us The Rom ebooks (ahem).

They also served as the basis for the subject of this post, the physics descriptions at Sonic Retro. Here is basically all you need to make a Sonic-style platformer. Synthesizing this and putting it into practice is a formidable task on its own, but it’s a doable one, and you don’t have to read source code (other than your own) to do it. To those who attempt this task, we salute you! And let us know how it goes!

Sonic Retro: Physics Guide

Baba Is You XTREME

By now many of you are no doubt familiar with Alvi Tekari’s Baba Is You (itch.io, Steam, Switch, Android, iOS). The premise is simple. In a Sokoban-style world composed of discrete blocks aligned with a grid, you try to get a figure (usually the sheep Baba) to a goal (usually a flag). But nearly everything about this game world is malleable, according to special word blocks in each level. If a set of three blocks is arranged in a horizontal (reading left to right) or vertical (reading top to bottom) line, then that statement becomes true throughout the level. In fact, every level comes with certain statements already in effect: it is only because somewhere it says BABA IS YOU that you can control Baba, and if something else IS YOU, then you can move it too. And you can make new rules by moving the words to make new sentences.

Baba Is You became an indie darling from its game jam release in 2017, and in 2019 it absolutely exploded, being featured on several game stores including Nintendo’s eShop picks page. Its rules are simple, yet their implications becoming diabolically complex later on. Not to give away some absolutely amazing secrets, but there are very few games that get as hilariously weird as Baba Is You-or as difficult. Baba Is You is a challenge that will keep you going for weeks, but eventually pays it all off with one of the best end game sequences anywhere. If you haven’t played it yet, you really should. I did a Q&A with Alvi Tekari for Game Developer about the creation of Baba Is You, and I think it’s one of the best interviews we’ve done.

This is all to make sure we’re on the same page when I mention the sublimely ridiculous Baba Is You XTREME, a free parody of Baba Is You made by Baba Is You‘s own creator!

Baba Is You XTREME seems just like the original at first, right until you press the first key and discover: the game now has a completely spurious physics engine! Baba no longer snaps a step at a time centered in the cells of a Sokoban grid, but now moves around freely, with acceleration and friction. The same is true with all the other objects on the screen that are IS PUSH. Objects that ARE STOP are locked in place, though.

Rules like SKULL IS DEFEAT might seem insurmountable, until you turn to the power of ROCK

The addition of physics makes the execution of any move into a challenge to itself. The rule system is still in place, some old words have much weirder implications, and there are even some new words to explore. There’s only 11 levels (it is a free game, after all), but around level seven you’ll be scratching your head. But one implication of the physics is that words that are in a corner aren’t completely impossible to shift like they were in a grid setting, so with some dedicated pushing it’s possible to break some troublesome sentences here that would be impossible in Baba Is You‘s Cartesian cosmos.

This physics make this a much trickier puzzle than it would be in Baba Is You

It’s completely free, so if you’re a fan of BIY it’s worth checking out. And if you haven’t tried Baba Is You yet, it is worth a look too!

Baba Is You XTREME (itch.io, Windows)