While some may have played indie games in their sleeping sacks, those who played Lucky Frame's caterpillar sim ROFLPILLAR, exhibited at alt.ctrl.GDC, have partaken in the rare, if not unique, experience of playing a game with a sack controller, which becomes part of your caterpillar body.

Lucky Frame, makers of IGF Finalists Bad Hotel and Pugs Luv Beats, have created something metamorphic with ROFLPILLAR, which requires players to eat as much fruit as possible on the screen that hangs above their heads tucked underneath a custom built house.

The caterpillars are controlled by a string that is held to players' waists, whose legs remain tucked in colorful sacks. Players can use a speed-up boost, too, which comes in handy once they realize more "points" can be earned from eating their opponent's growing body.

As part of the alt.ctrl.discuss series that looks at the first exhibit EIC John Polson organized, Yann Seznec of Lucky Frame discusses the creation and iteration of this ROFL-funny experience.

How does the game work, especially with the button for power ups and string attached to the catepillar-body-bag?

When each player gets into a caterpillar sack and sticks their head in the house, this pulls the gametrak string out a bit. when they press the button to start the game this calibrates their current position to be the center point...then, when the players move their hips back and forth their respective caterpillars will move in response to their movements. Move left, the caterpillar goes left, etc. It's remarkably effective - people pick it up almost instantly and don't even realize quite how much they are moving!

The game itself is very simple, the aim is to get to the end as the biggest caterpillar - eating an apple adds a segment to your caterpillar, and running into your opponent will remove some of their segments. Each time you eat an apple you are given some form of powerup (speed, invincibility, etc) which is activated by pressing the button.

How did the idea of ROFLPILLAR come about?

The idea really comes from Jonathan Brodsky, who started thinking about games that would require pushing against physical restraints of some sort. From Jonathan, "The caterpillar idea came from Ricky Haggett of Honeyslug who suggested it as a theme when I told him I wanted to make a game where people wriggled around on the floor."

We had a number of ideas playing with this concept, including having games where people would be tied to chairs, or wrapped in sleeping bags, and so on. He hit on the idea of being a caterpillar, which instantly felt like the perfect interaction. One of the earliest ideas we had was to set the game in a cocoon, with the player struggling to get out of the chrysalis and become a butterfly!

Parallel to that line of thinking we were also really curious about making local multiplayer immersive games. The new trend towards VR, most obviously in terms of the Oculus Rift, is often by definition a very solitary experience - one person dons a headset and everyone else watches. That type of play can be very powerful, but we are particularly interested in social interaction, so of course we gravitated towards something that more than one person could play together, and ideally put on a bit of a show for anyone not playing!

From Jonathan, "The reason that I wanted to make a game about being restrained was from my experience of playing with VR, and finding the lack of a body a really interesting thing. So I thought how fun it would be to roll around on the floor with a VR headset on."

The third key part of our thinking was to try and make it as low cost as possible. So everything was hacked together using old game controllers, cheap wood, and a TV monitor. Thus, Roflpillar (rolling on the floor laughing caterpillar) was born.

How did you build and iterate on it?

The game is comprised of a small wooden structure that holds a TV screen about 50cm from the floor, facing downwards. We went through a few iterations of this, starting with scrap wood that was lying around the office, followed by rebuilding it with decent wood from a local lumberyard, and finally for alt.ctrl.GDC our super amazing friend Charlie Bucket built a proper structure using nice thick wood and metal brackets.

Sitting on top of the television is a custom built electronics box that connects to the motion sensors.

Sean McIlroy, our artist, then worked with artist extraordinaire Morgan Cahn to make a gorgeous covering for the whole structure, to hide the TV and make it look all magical. We've gone through a few iterations of this, starting with just some fabric draped over the top, moving onto a super beautiful but fragile painted cardboard structure, followed by a much stronger frame and fabric solution. Morgan also sewed up the caterpillar sacks for people to get in - our first version didn't have the sacks, which resulted in some unfortunate situations regarding people wearing dresses, so they are both cool looking and practical!

The motion sensors are attached to those sacks. For these we hacked apart a few Gametraks, which are a generally-forgotten proto-motion controller from the early 2000s that were only sold in Europe, I believe. They are effectively rotary string encoders - a long string of fishing wire attached to a potentiometer and pulled through a joystick. Each gametrak has two (one for each hand), and you can find them for around £5 in charity shops around Britain. They really are a steal, because you can hack them apart really easily and use them to make all sorts of fun things (like a musical pig sty for example).

In any case, the gametraks are attached to the sacks and hooked up to the electronics box, which houses a Teensy microcontroller which feeds the data from the strings to a laptop via USB. The laptop runs the game (built in Unity), sending the video output to the TV. That's the whole setup!

Early concept art for the software:
ROFL concept art.png

The very first prototype, using chairs and a TV screen from Sean's grandmother:
ROFL prototype.jpg

Version 1 at Game City:
game city rofl.jpg

alt.ctrl.GDC version:
alt.ctrl ROFL.jpg(photo from Eurogamer)

Who built what, and when and where was has it been exhibited?

It was very much a team effort by the Lucky Frame team (Jonathan, Sean, and myself), together with enormous help from Morgan Cahn and Charlie Bucket. So far it has been shown at Game City Nottingham, Tacos Bluegrass & Videogames, Drop in and Play, alt.ctrl.GDC, Wild Rumpus in London, Wild Rumpus at GDC, and A MAZE (assuming we can track down a TV there!).

How would you release a commercial version of this, if at all?

It seems impossible but we've actually given it some thought! Realistically the most complex part is the electronics. So we've thought about making a package for sale where we would make the electronics box and modified gametraks, and provide the plans to build everything else yourself (together with the software of course). Perhaps we could also make the costumes and house covering! This is interesting to us also because people could potentially use the sensors and electronics to make their own games. It would almost be like selling a new gaming platform, which is kind of hilarious.

What sort of design aspects haven't you discussed about ROFLPILLAR before?

One extra thing I haven't mentioned is the sound, which was quite fun to make. It's built using a combination of field recordings from the Edinburgh Botanic Gardens and some recordings I made of an orchestra who shall remain nameless. Each time you eat an apple it actually generates a random orchestral note from a scale, so it's secretly an ambient musical generation machine, too!

[If you are making an alternative controller or device, be sure to reach out to EIC John Polson. For other alt.ctrl stories, read here. *Top video by Ind13, filmed at GDC 2014.]