Camera projection matrix

I posted a gist on GitHub where I was playing with modifying the projection matrix for the camera in Unity.

For background, a matrix is basically a grid of numbers. A vector is a series of numbers. And you can multiply a vector by a matrix you transform that vector in some way, as defined by the matrix. For 3D graphics, you can depict a position in space as a vector and use a projection matrix to decide where that position will appear on the screen.

In normal operation in Unity, you set some parameters like the field of view and near and far clipping planes, and it auto-calculates the projection matrix for the camera.

This shows an example of shifting a tilt-shift lens to photograph a building while keeping parallel vertical lines. You can do the same thing with the projection matrix.

I think that would be suited to some games. See here, you could have a top-down camera that’s viewing the floor completely parallel to the screen, while keeping the vanishing point below the screen.

You might also use it in a platformer. For aesthetics, a lot of landscape photographers and painters prefer to have the horizon a third from the top or bottom, rather than half-way. This would allow you to do that, while keeping the vertical and horizontal lines square.

For these scenarios, I made a OnePointPerspective script. I guess I called it that because it made me think of drawing with a single point of perspective. Unity does have a lensShift property that does a similar thing, but my script also offsets position to compensate and keep the camera aimed at a given subject.

I also made a ZoomInOffset script which is geared towards zooming into a particular portion of the screen. Here you can see the original view, one where I rotate the camera to zoom in on the chef, and one where I use ZoomInOffset. Note it keeps the checkers oriented the same, while rotating the camera doesn’t.


I’ve seen people make the incorrect claim that rotating a camera at a single point will be indistinguishable from panning an image. This example shows how that isn’t quite true.

( It does work when viewing with the human eye, because the human eye doesn’t need to be displayed on a flat surface, so you don’t have single vanishing points like you do in linear perspective. But that’s another discussion. )

You can do a lot of other stuff, many of which will be disorienting. You can, for example, make things get larger in the distance instead of smaller, but I find in practice it makes me feel like everything has reversed normals.

( This is maybe where I get into James J. Gibson’s The Ecological Approach to Visual Perception where you perceive underlying 3 dimensional invariants based on correlated transformations. When multiple things on screen transform simultaneously, you respond to how those transformations correlate to one another. What people will probably be familiar with is parallax. Something near the “camera” moves quickly while something far away moves slowly, and that helps you perceive one as near and the other as far. The projection matrix is very much creating these sorts of correlations, so when the correlation was backward, such that distant things were larger, my brain instead perceived them as closer. )

Anyway, towards the end of experimenting with projection matrices, I made some more free-form scripts. ProjectionMatrixExperiments and ProjectionReplace. Both let you apply Translate, Rotate and Scale transformations, but ProjectionReplace also lets you adjust individual elements in the matrix.

Although I described the Matrix as a grid, Unity displays it like this. You can figure out where each number goes in the grid based on the name. E13 would go in column 1, row 3.

So if you play around with that, you too could make cameras like this:



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History of “leading lines?”

Some recent video game discourse over “leading lines” got me thinking about what is the history of the concept? Obviously it was a thing in photography and/or painting before it was ever used in video games, but for how long?

This reminded me of a quote form Linda Nochlin’s Realism (emphasis mine):

Nobody,’ Perrier insisted, ‘could deny that a stone-breaker is as worthy a subject in art as a prince or any other individual. … But, at least, let your stone-breaker not be an object as insignificant as the stone he is breaking.’ The same point was made by Louis de Geoffroy in discussing the Burial at Ornam: ‘the funeral of a peasant is not less touching to us than the convoy of Phocion. The important thing is to avoid localizing the subject, and in addition, to emphasize the interesting portions of such a scene.’

Not specifically anything about leading lines, but both are about visually emphasizing subjects of the painting. And are prescriptive enough about it to feel Courbet is doing something wrong by not providing such emphasis. The Stonebreakers was painted in 1849 and Burial at Ornans was painted in 1849-1850.

So this train of thought lead to me searching Archive.org for old writing using the phrase “leading lines” in this way. I did find that people were using “leading lines” this way at least as early as the 1800s.

Here I found a book from 1905 that appears meant to teach art appreciation, which makes multiple references to leading lines as an attribute the student should note:

Would it not have been easy to make this a stiff, uninteresting picture? How has the artist avoided such an effect? Does it denote a scientific study of design? Is there an elaborate arrangement of leading lines? Or a brilliant effect from opposing masses of light and dark? Is it conceived in a naturalistic temper?

Outlines for the Study of Art

The Art Journal proved a good source. Here’s one from 1882(?)

‘Merry as the Day is long,’ by Mr. Fred. Morgan. The best picture which we have ever seen from Mr. Morgan’s easel. Three children playing in a farmyard, and climbing about a pair of huge timber wheels, are contrasted with the tired form of an old labourer to whom they are gleefully shouting. The shadows are rather blue, and there is a want of force in the composition of light and shade, but the colour is harmonious and warm, and the leading lines are thoroughly expressive and agreeable.

The Art Journal

Here’s an earlier case where a painting is complemented on its use of leading lines:

In the blue drawing-room are a picture of ‘The Marriage of St. Catherine,’ by Andrea Schiavone, pleasing in the leading lines, glowing in the colouring …

From The Penny Magazine 1840

From 1825 I found an example using it in reference to architecture rather than painting.

The horrible deformities called Steeples, … are unfortunately ever introduced in such situations as to ruin the effect of the porticoes over which they stand, by an arrangement which in most cases interferes with the leading lines of the main feature.

A footnote in Illustrations of the Public Buildings of London (1825)

Though these references don’t necessarily say the leading lines are used to guide the eye. Much of the “leading lines in video games” discourse is about using those lines to draw attention to something in particular, but these old quotes seem to evaluate them aesthetically pleasing in themselves and make no note of what is being emphasized. I start to wonder if they originally meant “leading” as “foremost” and someone retroactively took it to be about leading the eye about the image? A folk etymology that in-turn changes the use of the phrase.

So I search for “leading the eye” and find this from The Art Union Monthly:

A coast-view is somewhat of a trial for a landscape painter; for consisting generally of so little, the want of objects must be atoned for by the finest feeling in leading the eye over the generally flat surfaces of which these scenes are composed.

Art Union Monthly (1842)

So that supports the idea that paintings were considered in that way and there was an expectation that painters are playing a part in leading the viewer’s eye.

Maybe I need to read something like this book? The Education of the Eye by Peter de Bolla.

It claims that at the moment when works of visual art were first displayed and contemplated as aesthetic objects two competing descriptions of the viewer or spectator promoted two very different accounts of culture.

It would make sense to me if the idea of “leading lines” developed in parallel with the idea of the art connoisseur. The connoisseur wants a framework to discuss the painting in more detail than “this is good.”

I’m also interested in how different movements in painting thought about it. From Linda Nochlin’s Realism, as well as some other contemporary criticism of the realists, I get the sense they would paint things that many saw as unpleasing composition, because it reflects what they would naturally see in real life. While the Romantics, for example, I get the sense they were willing to paint what might be “unrealistic” to support the desired composition of the painting.

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Joystick accuracy test

I got a few people to run a program I made to test their accuracy with the thumbstick on a gamepad.

What kicked off this train of thought, was I was considering radial UI as an interface. How many options could you reasonably include in a radial menu? That would depend on how accurate you could count on people being.

The test showed the user an arrow indicating a direction they needed to match. They then needed to point their thumbstick in the same direction as the arrow and press a button.

An example of what the user saw during testing

I put each used through three phases. The first and last phase showed no visual feedback about the direction their thumbstick is facing. The second phase did show the direction they are pressing as another arrow and they needed to match the two arrows. Repeating with no visual feedback in the final phase was to test whether accuracy would improve after the second phase.

To ensure everyone was tested on a full range of directions, I generated 30 directions for each phase, each within a different 12 degree range, and then shuffled them. So every 12 degree segment is tested once per phase.

You can see here, phase 2 was much more accurate when they got visual feedback.

The mean average for degrees inaccuracy in phase 1 was 10.9 and in phase 2 was 10.4. Median went from 9.2 to 8.8. So it doesn’t feel like the training phase lead to a huge improvement.

I got curious about whether there were certain directions more prone to clockwise or counter-clockwise error, but my first shot at visualizing that was difficult to understand.
This was cleaner. Instead of connecting the target and goal angles, I created lines at the target angle, and extended it outward for clockwise error, and inward for counter-clockwise error.

Maybe there’s a small cluster of rightward at the top and bottom right. There may or may not be a slight rightward skew, but it’s a small enough sample it might be a coincidence.

This is the average input direction for each user, compared to the average target direction. If this isn’t a coincidence, I wonder if the slight right offset is from using the left thumbstick, and tests with the right thumbstick would show the opposite?
Here we have each subject (named A to H) and a box plot of their inaccuracy for first and third phase.

In terms of improving after the test phase, I found as many subjects were worse during the third phase, just as many as improved. For accuracy, if we had a 5-section radial menu, it would require accuracy within 36 degrees, which would fit most of this. 6-section radial would require 30 degree accuracy, which would start excluding a few people here. In practice, I’m sure I’d add visual feedback for accuracy, but it’s an interesting experiment.

Maybe also I’ll try a future test where, instead of arbitrary direction on the circle, visually divide it into segments like a radial menu. Then see how people fare with 5 segments, then 6, then 7 and so on.

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Paintings

A collection of paintings I’ve been doing on a general theme. I figured I’d put them up here.

I hadn’t done much physical painting really. I drew a lot but just with ink or pencil, so no colour. I made some colour images on computer, but the way you choose colours is very different on computer. So the process of mixing colours to match what I’m seeing has been a useful exercise, I think.


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Garbage Truck games

I saw this article on why kids loves garbage trucks. And it got me looking at games about garbage trucks.

Obviously there must be a garbage truck simulator in the vein of Euro Truck Simulator or Train Simulator.

I found Recycle: Garbage Truck Simulator but since this was kicked off by kids who love garbage trucks, I saw how much focus the trailer puts on managing the whole system over just driving the truck.

From one of the negative reviews on that: “You can’t control the garbage man only the driver which sucks.” Which is a neat perspective of what that person wanted out of a garbage truck game.

Some android games seem more aimed at kid level, but then are also kind of cheap. This one doesn’t show any animation for the actual pick up, just fading out and then the garbage is gone? This feels like, for a garbage truck game, a critical lack of juice, if the act of picking up garbage is completely glossed over like that.

There’s this one where apparently the garbage man is a transformer? But just does a “knocking one foot” animation next to the garbage cans instead of a more fitting animation.

This one shows a suitable animation for picking up the dumpsters, but dropping off the garbage at the dump it sort of, tips a dumpster back out of the truck? I don’t think that’s how it works.

I guess one tricky thing is if you do want to target an audience young enough to delight in garbage trucks, you also have to make it much simpler than actually driving a garbage truck. If you want to make a highly accurate garbage truck simulator, then you’ll lose a lot of that younger audience.

Is there some way to push an element of garbage collection further? To make it sort of the Crazy Taxi of garbage collection? Not to mean just like Crazy Taxi but you drive a garbage truck, because the underlying nature is different. So exactly what way you want to push the craziness is different.

One thing I’d considered before was Crazy Taxi but you’re delivering pizzas, but the down side is you then go back to the pizza place for pick-up. The starting point of your delivery is always the same, where a taxi game lets both your start and end point keep changing. Garbage collector would have the problem that you’re typically following the same route over and over. So can you just have a list of routes and you just try to get the fastest time on each route?

Or should it be more like Paper Boy? You’re not just racing for time, but you can somehow do a better or worse job picking up the garbage. Maybe you can throw garbage?

Maybe there’s some fun to be had from the need to switch between driving mode and pick up mode? It does have a kind of frantic “juggling” aesthetic I like in some games?

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Game Design Requires Aesthetic Choices

One thing I see sometimes on the game design subreddit, is questions of the form “Is ____ considered good / bad game design?”

So I guess I have two pet peeves with that. One, it does a passive voice attempt to ignore exactly who is doing the considering. Two, it isolates one element from the game as a whole.

Analogy with colours

For analogy, I’m going to imagine painters, asking if something is a good colour. “I’m making a painting. Should I use blue?” It doesn’t make sense to answer that without seeing the rest of the painting.

You can’t very well choose the colours for a painting by going through each colour and getting and up / down vote in isolation. You have to consider the context you’re using the colour.

Subjectivity

But also you can’t really say there’s a single objective evaluation whether a design is good or bad. At least not if you want to consider game design as an art form rather than an optimization problem. To be an art form there needs to be room for interpretation and different aesthetic choices.

This is where I’m bothered by the passive voice, “is it considered …” Considered by whom?

Colour theory

To return to the colour analogy, consider colour theory. For all the attempts to systematically understand colours, there isn’t really in colour theory that says, these colours are good, these colours are bad, or even these colours in combination are good or bad. It might say you have a complementary colour scheme, or analogous, or triadic. But when it comes down to it, you’re going to make an aesthetic choice for whether that’s something you want to use.

Bisexual lighting vs. teal and orange

Back in the day, when people noticed all the movie posters were teal and orange, some people would slide into the comments to let us all know that actually, teal and orange is good because they’re complementary colours.

But, like I said, deciding you want to use complementary colours is an aesthetic choice. A more recent trend has been the bisexual lighting with pink, purple and blue, which are analogous rather than complementary.

Colour theory can tell us a lot about how colours work together, but you still have to make an aesthetic decision about whether that’s the way you want them to work together.

Game feel is an aesthetic

I see people when discussing game feel, often try to short-cut directly to, “this is good game feel, this is bad game feel.”

Game feel has the word “feel” in it. I guess some people want to interpret that as “feels good” or “feels bad” but I interpret it more like: “this feels rough while this feels smooth.” This feels heavy, this feels light. This feels hard, this feels soft.

Those are choices where the right answer depends on context, and it also depends on your aesthetic preferences.

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Modal controls in video games

In UX, modes are when the same input results in a different action depending upon the state of the program.

I’ve played games where there’s a “town” mode and a “action” mode, where your “fight” actions are replaced with “talk to” actions, so you can’t run around the town attacking people.

Two games I’ve played lately have got me thinking about contextual controls.

First is Alan Wake.

Second is Flinthook.

Flinthook has a grappling hook, which will grab onto loops in the level, and launch you forward once it grabs one. The grappling hook can also be used to pop bubbles, for some enemies that are protected by a bubble shield.

The game doesn’t expect you to aim precisely at a loop, and if it did, that would be frustrating. In the heat of the moment, you can’t be expected to aim within a 10 degree range with a thumbstick. So there’s a pretty forgiving auto-aim.

But I can see how that gets complicated by the alternate use for the hook, to pop bubble shields. If you mean to pop a bubble shield, and it grabs a loop instead, it will launch you directly towards a shielded enemy. If you really did want to grab a loop, maybe you’ll accidentally fall to your doom.

Alan Wake usually changes modes more scene-to-scene than moment to moment. It’s more like the town mode versus

Alan Wake frequently sets you up for a particular scene, and lets you play out that scene with whatever subset of abilities you will have. Maybe you have a gun, so you can shoot the ghosts. Maybe you only have a flashlight that temporarily slows them down. And there are town-mode scenes where you don’t have either. But not just your items change, but you might lose the ability to run and jump, because you’re not in danger right now. You move at a normal walking pace instead of run. There’s one scene, where Alan’s wife screams from the next room, and suddenly you can run again. Because the character is suddenly in a state where they are willing to run.

A lot of games have contextual actions, where the same button will do different things based on where you are located. An “action” button that opens a door if you’re in front of a door, turn on a light if you’re in front of a light, talk to a person if you’re in front of a person. Does the player’s mental model accept “action” as a single ability? I think this is safe. We have lots of mouse-controlled games where precisely what action you take depends on what you click on, so controlling it with the position of the main character makes sense, too.

In UX, you’re supposed to be very cautious when relying on modes. Are you making something the user could be confused about which mode they are in?

I guess two things to consider about modes here are, visibility and granularity.

The Alan Wake example has a larger granularity than Flinthook. It changes from scene to scene, after you reach a new area and/or have a cut scene. Where in Flinthook, it can change because you were two inches to the left and now a different thing is in range. The Town Mode is large granularity while the Action button is smaller granularity. 

Visibility is important if you want the players to not be confused by the change in behaviour. A lot of games with an Action button will have an on-screen prompt that comes up when you’re in range of an item you can interact with. With the mouse-cursor example, hover-state to show clickable areas serves the same purpose. Alan Wake will include in the cut-scenes when you’re given a gun or a flashlight, etc. It may be less explicit when you are in town mode or not.

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Video game architecture and the dimensions of doors in Gone Home

This is a door model from Gone Home. Anything strike you as odd?

Computer model of a door from Gone Home. Dimensions are 206 by 123 by 13 centimetres

Dimensions of Gone Home doors.

It’s pretty thick isn’t it?

For comparison, I measured a door in my own home and referenced a Home Depot link on standard door sizes.

Sizes of doors available, width ranges from 30 to 36 inches, and height from 80 to 96

My doors are 80 inches by 36 inches, which is the most squat door you can buy from Home Depot. And 1 5/8 inches thick. Based on my shot here with a cassette tape for reference, the Gone Home door is about 4 inches thick.

A four inch casette tape laid lengthwise is the same as the thickness of the door.

And only 64 inches tall. That’s like a five-foot-four tall door? Pretty short. So maybe that’s the wrong point of reference. But if we assume the doors are 80 inches tall, as is standard, then they’re five inches thick and 48 inches across.

This point was re-kindled because Gone Home was listed in a list of architecture games. The doors in the game had struck me as a kind of uncanny valley of architecture. Like, I expect in a more fantastic-themed game that wasn’t otherwise filled with familiar objects, I never would have noticed how oddly proportioned the doors were.

Another example from the architecture games was Mirror’s Edge, which is about free-running. The ways in which you experience a virtual space can be transformed by the abilities granted to the player in how they can navigate that space. I once read something (which I can’t track down right now) that made an analogy between skateboarding and cruising for sex, in that both transformed architecture by how the participants use it. Or your experience of a freeway is very different if you are walking versus if you are driving. Video games also dramatically change how you navigate a space based on what movement the game enables.

I myself made a recent point about movement restrictions being part of what makes a Pac-Man-like a Pac-Man-like. It’s not just about the shape of the maze, but that the character occupies the entire width of the path.

In this post from SciFi Interfaces, and in the linked video, the author notes that interfaces in movies really serve the audience rather than the characters.

So if the doors in Gone Home are not like normal doors, I think that’s because they weren’t designed for people living in a house. They were really designed for someone playing Gone Home. Not for someone navigating with their feet, but navigating with WASD and a mouse. And so, just as freeways are built at car scales rather than human scales, the Gone Home house is built at first-person controller scale.

Note also the doors are double-hinged. So every time you open a door, it opens away from you. That is definitely done for the player’s sake. If you’ve ever played a first-person game where the door ends up pushing you backwards when you open it, that can be awkward to get through. This could also explain why they’re wider than usual; a wide doorway is easier to drive through than a narrow one.

In my last post about Virginia and montage I had a brief tangent how video games almost take navigation of space as a given. Gone Home is a narrative-driven game, but it still has to have these considerations for how to navigate a physical space. Because that’s how you find the different pieces of the story, by navigating to the physical objects representing each piece of the story.

If you compare to narrative in books and movies, the physical locations of things don’t usually get as much attention as they do in games. People care about the relationship between two characters, more than exactly how to travel from one house to the other. But video games, the strengths of it, the types of interfaces we have, that makes physical space the most common interaction type. Even character conversations are typically controlled by walking to the location of the character you want to talk to. And in Gone Home you access the pieces of backstory by finding the location of noteworthy objects in the house.

For comparison, consider Her Story or Analogue: A Hate Story. Where they are similar to Gone Home is that the main story is really backstory. The player’s actions aren’t the story, they learn about the story. Where they differ from Gone Home is that you navigate those stories non-spatially. In both you access the stories from a diagetic computer, so the architectural space you navigate and the means by which you navigate it are both defined by that computer’s interface. Rather than any physical space. (In both, the computer is not quite working as intended, to add a challenge to using it.)

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Virginia, video games and montage

I played Virginia lately, which is unusual among games, I think, because of its use of montage. What I’m talking about isn’t exclusively what people call “a montage” in film, (eg: training montage) though there are some scenes like that in Virginia. But also the broader use of editing to connect one shot to another. Montage is a huge deal in film. It’s pervasive. Soviet montage theory posits that it’s the one element that is unique to film, that can’t be imported from another medium, like painting or theatre.

Even in movies that aren’t super-experimental, you’ll see edits that imply a connection between the end of one scene and the beginning of the next. Near the beginning of The Terminator, Kyle Reese searches through a phone book until he finds the name “Sarah Connor” and tears the page out. The next shot is the first appearance of Sarah Connor. It implies this is who he’s looking for without saying it outright. But this sort of thing is rarely used in games.

One classic example (which I think I picked up from a film studies book) is someone traveling by car from one place to another. In some early films, they would have shown a character get into a car and drive away, then cut to their new location where the car enters and they get out. Later, they learned how much of this could be eliminated. Maybe they could get into a car and cut directly to knocking on the door of the location they drove to. Maybe they could declare their intention to go somewhere and cut to them driving. And the audience would figure out the implication.

In Grand Theft Auto, (The last GTA I’ve played was Vice City, so let me know if this doesn’t apply to the newer GTAs) you have a button for getting in and out of cars. Unless it’s a cutscene, it’s always in your control to get in or out of a car. If you have the task of going from A to B and going inside a building, the game will show you every step of that process, however you do it. When you get into the car, it will not presume your intentions about where you’re going and cut directly to your destination the way a movie would. And maybe that makes sense, because what if the game’s presumption was wrong?

In Virginia, you never get in or out of a car. But because it’s a video game, that means you never choose to get in or out of a car. It’s a thing that just happens when you complete the current scene. I think this gets at why montage isn’t used more often in games. So much of its power is in the things you don’t need to show, but every time you do that, that’s something that’s not in the player’s control.

If you chop down a tree in Legend of Zelda: Breath of the Wild, the tree turns into a big log, with no branches. A lot of survival games that include the option to turn trees into wood will do just that. Trees change directly into wood at the moment you chop them down. Is this closer to the native version of the edit in games? The intention to turn the tree into a log was a safe presumption, so they abbreviated the action.

Though maybe that’s really about granularity of controls. When you tell a character where to go in an RTS, they do that. In a platformer, you have to tell them which direction to run, how fast, when to jump, down to the millisecond. Maybe choosing what is and isn’t under the player’s control is equivalent to choosing what is and isn’t shown to the viewer.

In some cases in Virginia, that lack of control makes things feel out of your control, like fate is pushing you down a certain path. I think this is in keeping with the intended tone. It’s actually in the slower parts where I found it more of a drawback that I didn’t know for certain what would trigger the end of a scene. I sometimes got into a “pixel hunting” mode where I had to guess which thing the creators wanted me to do.

One game that used montage more sparingly is Night in the Woods. One major difference is that it’s used near the end of the game in locations you’ve become familiar with. So when it skips over parts of what you’ve seen before, you can remain grounded and understand where you are. Where in Virginia, they use montage even in locations you’ve seen for the first time, which can feel disorienting.

I notice I’ve been focused a lot on locations and traveling. Maybe this says something about what things you do in games. GTA bills itself as an “open world” game, and that often means it treats its world as one big continuous location. My example of cutting down trees in Breath of the Wild is an abbreviation of actions other than travel. Travel seems to be the one action in games that is most likely to remain unabbreviated. People complain that “walking simulators” have no interaction but right in the name it says you can walk. Walking is taken as a given.

Which brings to mind the other use of abbreviated travel in Night in the Woods, which I might have overlooked. Much of the game takes place in the central Possum Springs platforming map, but often there are other locations that are accessed through dialogue options. Someone will ask you to come along to such-and-such and if you say yes, poof, there you are. I did almost overlook it, but I guess this abbreviation in games draws attention to itself only when it does take control away from the player. Since this one is explicitly activated through the dialogue choices, you don’t feel the missing time as much.

So maybe a lot of it is a distinction between continuous and discrete controls. 80 Days is a game all about travel, but the travel is controlled entirely through multiple choice, not by pushing a joystick. Your position will move to the next stop on your journey, rather than have the player move through the entire path. Where Virginia has you control your movement in first-person through continuous motion, so when that motion is abbreviated, you feel the missing time and the missing control.

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Games as systems of information

So lately I’ve been reading Rules of Play and I have a small discussion about something they get into in the chapter Games as Systems of Information.

In it, they summarize a typology of information in games as described by Celia Pearce in The Interactive Book. (Which maybe next I should read that)

  • info known to all players
  • info known to only one player
  • info known to the game only
  • randomly generated information

Rules of Play however disagrees with two things. One is that Pearce includes the rules of the game itself as information. Two is the distinction between info known “to the game only” is hard to distinguish from randomly generated information.

I think both of these points of contention are places that computer games allow approaches that would not be possible in board games. And Rules of Play interprets it through the latter without considering what is possible with the former.

In board games, at least one player needs to know the rules of the game in order to play by those rules, but with computer games, the rules can be automatically enforced by the computer. Video game tutorial levels are designed based on the idea that the player does not yet know the rules of the game. In which case, it does make sense to consider the rules of the game as information.

Consider Damian Sommer’s Chesh where the movement capabilities of the pieces are randomly assigned. When starting a game, the player does not yet know how the pieces move. When telling someone the “rules” of chess, you would likely include how each piece moves, right? So it would follow that Chesh is a game where neither player knows the rules, but the game does.

And the use of computers also helps strengthen the difference between info known to the game and info that has not yet been generated. In the electronic board game Stop Thief, the Electronic Crime Scanner doles out clues as to the location of the thief, which the players are attempting to deduce. The clues can’t be completely random, they have to be determined by the thief’s true location, which none of the players will know at first. If we imagine the computer as a “dungeon master” we could re-frame this as information known to only one player. But that has its own problems. They aren’t making strategic decisions to attempt to win the game, they’re only facilitating the game for the other players. So would it make more sense to classify the Electronic Crime Scanner as part of the game, rather than a computer player.

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