Flip's Twisted World Developer Journal

Under A Watchful Eye

by Douglas Gregory - October 2, 2010, 3:19 pm PDT

The camera system in Flip's Twisted World.

An in-game camera is the player's eyes in the game world. It's a moving frame to showcase the game’s art and capture the action; it's a guide to lead players toward objectives and warn them of danger. It's one of the most difficult systems under a 3D platformer game's hood.

Flip's camera has an additional responsibility, in that it's the hidden star of the game’s core mechanic. In very early versions of the game, twisting the world would literally rotate all of the world geometry and objects into a new orientation. Updating all the physics information when we did this quickly became too much. Now, what happens is that the camera does all the work, twisting through an arc to make it appear as though everything has spun around.


Goals of Flip’s Camera:

  • Look well ahead: without intervention, the camera should do a decent job of showing what's around and, especially, ahead of Flip.

  • Be smooth: the camera should move smoothly, without sudden jerks or motion sickness-inducing whirling.

  • Respect player input: we know the automatic system will not always make the best decision. When the player wants the camera elsewhere, the system should not lock-out or fight the player, and should persist the player's stated preference afterward.


Getting the Basics

The approach we used is based on the idea of the camera swinging freely on a weightless boom attached to Flip. This lets the camera sit anywhere in a sphere around flip, with a radius of the boom's length. Each frame, we move Flip, then snap the camera to the nearest point on this sphere. This gets us the basic following behaviour: If Flip runs off to the camera's right, the boom will naturally trail behind slightly, pulling behind Flip to show the level ahead.

While this approach keeps the camera behind Flip and looking forward, it tends on its own to let the camera sink as Flip runs away from it, so you really can't get a good view of what's ahead.

To correct this we track a "target elevation" for the camera. Anytime the player moves the camera up or down, the target elevation is updated. After the boom has swung around to follow Flip, we correct its height by nudging it toward the target elevation. Now no matter how you move Flip around, the camera will respect and maintain the vertical viewing angle you’ve set. All these adjustments are incremental, so the camera movement stays smooth.

We improve the view further by pushing the camera's focal point away from Flip, in the direction opposite the camera. This has the effect of moving Flip lower on the screen, so you can see more of what's ahead of him. We look further ahead when Flip is moving fast, and allow the camera to focus back toward Flip and his immediate surroundings when Flip comes to a rest.


Zoom the Boom

One trick with this approach is that it's very sensitive to the length of the boom used. At first we were using the same value to track the boom length and the camera zoom. This made the camera painfully unresponsive when zoomed-out far, and irritatingly fickle when close-up.

Our solution was to track the two lengths separately. The boom would determine the camera's angle. We'd then extend a line along that angle, and place the camera somewhere on this line according to the current zoom. This allowed us to tune the boom length to have just the right balance of responsiveness and smoothness, which the camera could keep at any zoom.


Watch Out for Tha– !

It doesn't matter how well a camera's following you if it gets stuck behind a wall or tree, so managing obstacles was our next challenge. Given enough time, we may have been able to create a complex system that would detect obstructions ahead and steer the camera around them... but with just seven people and a shoestring budget that wasn't about to happen.

Our obstacle avoidance is quick and dirty: If there's something blocking the view between Flip and the camera, the camera shoots forward until it's on the other side of the obstacle. This can be a little jarring, but it ensures Flip doesn’t escape the camera's (and player's) view for more than a frame or two.

This was one case where we found that a break in smoothness was preferable for playtesters, if the upshot was a better view of the action now. To cut down on unnecessary zooming, we gathered all the things that don’t really block your view (glass, grates, grass, etc.) into their own collision group that the camera simply ignores.


Here's a Hint

The last layer in Flip's camera behaviour is camera hints. These are special, invisible objects we place in the levels, to give the camera more information about what it should be doing in this instance. This lets us keep the camera out of awkward situations, direct it to frame nice vistas or goals/hazards, and help take over camera control when the player’s likely to be too busy elsewhere. Some of our hint objects include:

  • Camera Tunnel: pulls the camera toward one of two directions, for narrow spaces

  • Camera Orbit: directs the camera to orbit around a focal point, keeping it in view

  • Zoom Clamp: puts a limit on the min/max zoom in an area, to show the right amount


How's it Look?

Flip's camera is simple, and that makes it predictable. If we can't make a camera smart enough to always be right, it should at least be easy for the player to anticipate and tweak when necessary. It follows the run and jump gameplay smoothly, and is adaptable to input from hints and from the player. As a result, I think it’s a base we'll be looking to build upon the next time we work on a 3D platformer or action title.

Images

Talkback

I had only heard the name before reading this, but the game actually sounds fascinating. I appreciate the explanation of accelerometers, because there's a lot of misinformation and general ignorance about how the Wii Remote actually works. But as the designer notes that Wii MotionPlus can actually detect twisting, I hope that accessory will be supported as an option. The blue/orange arrow indicators sound like a great idea, especially since the flip won't take place until you release B. (Maybe a little like throwing in Boom Blox?)

MaxiJuly 27, 2010

Is there a chance that Doug will come on to the forums and talk with us?

That detecting the way you play is a great idea. It was done wonderfully in Helix for Wiiware.
Yes In have been keeping track of this games progress and I do like the concept of it.

I played a demo of the game two E3s ago and really liked the concept, but found myself frustrated and confused by the twist mechanic's controls. I'm glad to see Frozen North spent so much time working on the controls, because Doug isn't kidding when he says there was "trouble".

I also played that demo with TYP and I was initially interested in this game, but then I was so turned off by it. However, they've had more than a year to work on it, and as far as I know, they took the E3 critiques to heart and tried to work them out.

DMGregoryDouglas Gregory, Guest ContributorJuly 29, 2010

Quote from: Maxi

Is there a chance that Doug will come on to the forums and talk with us?

Hello, Maxi!  Doug here.  Sorry for the delay, I was just alerted to your comment by a coworker today.  I'd be happy to answer some questions here.  I hope you won't mind if my replies are a little delayed - we're swamped here at Frozen North working on our next title.

Quote from: NWR_Neal

I also played that demo with TYP and I was initially interested in this game, but then I was so turned off by it. However, they've had more than a year to work on it, and as far as I know, they took the E3 critiques to heart and tried to work them out.

We most certainly have taken those critiques to heart.  Post-E3 we overhauled the game's visuals, including an all-new lighting system, and fixed a lot of inconsistencies in the twisting and combat mechanics.  I'm sorry the early version turned you off; we have to admit it really wasn't ready to show at that time.  I hope you'll give the finished product a try, and have a lot more fun!

Thanks to everyone reading for your interest!

Doug, just on the basis of this first entry in the developer diary, I am very inclined to check it out when it hits, and since I'll be formatting all of the subsequent developer diaries, I expect to get even more excited.

MaxiJuly 29, 2010

Oh wow we don't get many developers here.
Hmm questions...
Was the reason for the delay to work on it more or was it to avoid a certain other platformer from taking away the spotlight of this game?

What type of music will be in the title?

Hmm how much will it cost?

DMGregoryDouglas Gregory, Guest ContributorJuly 29, 2010

Hi Maxi,


You hit the nail on the head: our publisher didn't want to release at a time when we'd get eclipsed by Super Mario Galaxy 2.  The hope is that waiting the summer will give Wii gamers' appetite for 3D platformers a chance to grow again.


The music in the game is all done by the legendary Tommy Tallarico, of Electric Playground and Video Games Live fame. He's easily the most prolific game composer, and what he created for Flip's delivers on his long reputation for musical excellence.  We asked him to evoke some of the memorable feeling of classic platformer games like Mario, Sonic, Donkey Kong Country, with a little of Zelda thrown in. He ran with that, adding his own signature spin, so that should give you an idea.


We don't determine the price for the title, but taking a quick look at a few game retailers' websites, it looks like most are planning to sell it for $29.99. That's not an official statement, so don't quote me on that. ;)

MaxiJuly 29, 2010

What do you think of the resergance of platformers this generation on the Wii?

I mean we have games like Wario Land:Shake it,New Super Mario Bros. Wii, Donkey Kong Country Returns, Epic Mickey, Flips Twisted World and Kirby's Epic Yarn.

Do you think it is good to have this many platformers out?

Quote from: DMGregory

You hit the nail on the head: our publisher didn't want to release at a time when we'd get eclipsed by Super Mario Galaxy 2.

That's a smart move. All too often publishers want to simply push the product out the door. Hopefully that also meant the development team got a few more months to tweak and polish.

Quote:

The music in the game is all done by the legendary Tommy Tallarico, of Electric Playground and Video Games Live fame. He's easily the most prolific game composer, and what he created for Flip's delivers on his long reputation for musical excellence.  We asked him to evoke some of the memorable feeling of classic platformer games like Mario, Sonic, Donkey Kong Country, with a little of Zelda thrown in. He ran with that, adding his own signature spin, so that should give you an idea.

Jonny held a fantastic interview with Tommy shortly before E3 2010 to get the word out about Video Games Live. He shares a lot about the process behind running a show like VGL, also talks about his work on Metroid Prime. Anyone who missed it should really check it out.

DMGregoryDouglas Gregory, Guest ContributorAugust 01, 2010

Quote from: Maxi

What do you think of the resergance of platformers this generation on the Wii?

Platformers are one of my favourite genres, personally, so I think this can only be a good thing. Having more platformer options on the market:
- gives players more choice and more gaming opportunities
- encourages more experimentation and exploration among devs, to distinguish their offering
- (if they sell) demonstrates to publishers the business case for funding more platformer titles


When it works, this feedback loop creates more fun (or profit) for everyone involved. There is the risk of a flood of mediocre titles riding the coat tails of more successful ones, but so far I haven't seen that in the latest platformer surge. In any case, there are enough sources of solid review information available now (like this site) to keep most gamers from being stung by shovelware. So, bring on the platformers, I say. There's still tons of room to explore and innovate in this genre.

Quote from: TheYoungerPlumber

That's a smart move. All too often publishers want to simply push the product out the door. Hopefully that also meant the development team got a few more months to tweak and polish.

Unfortunately, a delay in shipping doesn't necessarily come with more funding to extend development. To keep our studio in the black, we've had to move on from Flip's to new paying work in the meantime. While it would be nice to refine FTW even further, I think you'll like what we've been creating since then.

Hey everyone! There's a new entry in the diary about the character design of Flip.

MaxiAugust 05, 2010

Hmm while most of the designs look nice there wasn't really a hook with them.There was something missing in them.I'm not sure what though.

Is there a video I can watch? It sounds like you've come up with a robust system with which to realise the original concept, but I'm struggling to visualise how it all plays out. Camera viewpoint, for example. I assume you'd need quite a lot of control over the camera to examine the level layout ahead of you. But how does the camera track Flip as the gravity changes while making sure you still know where you are and where you will be? That's what I'm trying to wrap my head around.

The third entry, about the game's story and voice acting, is up.

MoronSonOfBoronGarnet Red, Contributing WriterAugust 10, 2010

NEEDS SPOILER TAGS, ARRRGH

ToruresuAugust 13, 2010

I wonder if the name acronym FTW was intentional.

MaxiAugust 13, 2010

I didn't even notice that. Maybe it was.

MGladneyMitch Gladney, Guest ContributorAugust 16, 2010

Hey guys,

The synopsis doesn't give the WHOLE story away, just touched on a few key events.  ;)

As far as Flip's Twisted World matching up with FTW, that was purely coincidental. The name of the game we pitched was actually called up & dn. (Up and Down) The logo worked both right side up and upside down.

Thanks,

Mitch

These guys are good writers. I'm totally fascinated by this game's development.

I just read the latest entry pertaining to the http://www.nintendoworldreport.com/devjournal/23954 boss design and really, it is a fascinating prospect, the idea of fighting a boss with the twist mechanic. I can't even conjure any imaginary scenarios, but there's absolutely a lot of potential there.


It has made me more enthusiastic to try out And Yet It Moves on WiiWare, which is probably the closest thing to Flip's Twisted World at this moment. Sure, I respect that a direct comparison might show them to be very different, but it is nevertheless also a platformer that lets the player alter gravity. In fact, it sounds like it has complete freedom in rotation as opposed to 90 degree increments; apparently, the answer to making complete freedom of rotation viable is to ensure none of the terrain or platforms are flat.

Mop it upSeptember 07, 2010

I must've missed this somehow, but I've just read this article. This game is starting to sound like a winner. I like what I saw on the quick list of game mechanics, especially the one about being able to try things without punishment. It leaves more room to experiment and have fun figuring out puzzles. Interesting visualization of the Wii Remote... it sounds like it's a bit complicated to work with. I guess I now know why some companies have such trouble getting it to work right. Their way around the different positions people hold it is rather ingenious. I hope it works like they say.

Quote:

Platformers are one of my favourite genres, personally, so I think this can only be a good thing. Having more platformer options on the market:
- gives players more choice and more gaming opportunities
- encourages more experimentation and exploration among devs, to distinguish their offering
- (if they sell) demonstrates to publishers the business case for funding more platformer titles


When it works, this feedback loop creates more fun (or profit) for everyone involved. There is the risk of a flood of mediocre titles riding the coat tails of more successful ones, but so far I haven't seen that in the latest platformer surge. In any case, there are enough sources of solid review information available now (like this site) to keep most gamers from being stung by shovelware. So, bring on the platformers, I say. There's still tons of room to explore and innovate in this genre.

I've got nothing to add to this, I just wanted to say I pretty much agree with all of it.

New entry is up! Like A Boss Part Two

MaxiSeptember 08, 2010

I'm really liking the design of the bosses. These days most bosses are realistic looking. It is nice to see this type of design.

Formatting and posting these every week has been an absolute pleasure. I will be sad when I don't have an e-mail from Majesco PR in my inbox every Monday or Tuesday.

FlipsterSeptember 08, 2010

"Originally, Butch was in the Glacier World's seas cleaning up a chemical spill from a potion sucked in from Master Fulcrum's lab, but when we decided to go in the direction of collecting Chapter Stones, he became a surly porpoise resolute on drilling the ice, searching for an elusive Chapter Stone."

Could this maybe have had anything to do with being controversial towards oil spills, or no? I guess since your idea of Chapter Stones has been around before the recent oil spill that is unlikely, but it still seems like an interesting coincidence, or maybe it's just me over-thinking it  :P:

I also enjoyed your guys' throwaway story, mostly for two reasons:

1. For me it's always been about the events and characters in a video game, not necessarily the main plot, but how the player progresses through that main plot and what memorable characters and events are experienced along the way.

2. Since Flip is actually in a far-off land inside of a magical book, if a sequel ever arises not only could you show a more consistent or in-depth universe if desired (much like what Banjo-Tooie was to Banjo-Kazooie), but it would also be less constraining for the plot to create a whole other universe with new characters and worlds without it seeming like an inorganic or unnatural progression.

Personally I always tend to love the first of a platforming series the most for having all of the basic themes (Super Mario 64, Jak and Daxter: The Precursor Legacy, Banjo-Kazooie, etc.), but more and more am I starting to appreciate a series' progression into a universe that is more of it's own, although that doesn't mean it NEEDS to be dark like Jak 2 or Banjo-Tooie.  :)

Mop it upSeptember 08, 2010

Part Two? Where is Part One?

EDIT: Silly me! I totally missed the sidebar with all the other entries posted. Looks like I have some more reading to do...

UltimatePartyBearSeptember 15, 2010

This developer diary has been a real treat, and it worked to not only put this game on my radar, but make me very interested in it.  I especially liked the bit about Flip's hit box getting wedged in the level geometry and doing weird things.  I've seen some really hilarious, but also some really frustrating bugs that come from that kind of thing.

I really appreciate the latest entry.  The TEV is a mysterious black box to most, so it's nice to not only see it getting use, but mathematical explanations of how it can be used creatively.  Heck, I haven't even seen NintendoWare mentioned anywhere since 2007.  I hope you guys have a chance to play with the lower-level TEV stuff and give Nintendo and High Voltage Software a run for their money!

ejamerSeptember 27, 2010

Wow, what a great (ongoing) read.  Thanks very much to the Frozen North Production guys for sharing, and for NintendoWorldReport for hosting.


Best of luck with the game.  If it turns out half as good as it looks then it'll be worth owning.  :D

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