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Ask GR Anything: How do touchscreens work?

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Ask GR Anything is a weekly Q&A column that answers questions submitted by readers (as well as questions we're particularly curious about ourselves). Got a burning question about games or the industry? Ask us in the comments below and you may just get it answered!

At its most basic, a touchscreen is a device that closely monitors the state of a screen. There’s not necessarily one way that it must work; you simply have to have instruments small enough and sensitive enough to detect subtle changes. When you place your finger (or stylus, depending on the type of touch interface) on the screen, something about the screen’s state is altered.

Some touchscreens, like the iPhone, use “capacitive” material that can hold a light electrical charge. The CPU monitors the amount of electric charge in the screen, and when your finger touches it or slides across, a small amount of the electrical charge is changed, which tells the computer where you’ve been touching.

The iPhone’s multi-touch technology is achieved through numerous tiny nodes arranged across the layer of material that holds the electric charge. Each node generates its own signal, allowing the computer to monitor hundreds of spots on the screen instead of monitoring its general state.

Older phones and touchscreens use technology called “resistive” screens that, much more simply, sense pressure. However, the concept is the same. The computer monitors the amount of pressure the screen receives, and displays the changes on-screen. This can seem like ancient tech when compared with the quick, responsive screens on modern phones, but it does have one benefit: Since the CPU monitors the amount of pressure across the entire screen, it can also sense how hard you’re pressing. This is useful for a number of different applications, though obviously (since the tech has been mostly abandoned) not useful enough.

Resistive screens are the kind employed in the Nintendo DS, which is why the handheld doesn’t respond well to multi-touch. Nintendo has stated that, although resistive screens may seem archaic, they’re necessary for the 3DS to be fully backward-compatible with the original DS. Everything comes at a price, it seems.

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19 comments

  • major_major_major_major - November 17, 2011 9:42 a.m.

    What's up wit dat? Okay, real question: How is Nintendo actually doing (fiscally, I mean)? I heard some stuff about their stock going down and would like to know more about their actual situation.
  • ChrisMacDee - November 17, 2011 1:15 a.m.

    Why in the name of Brian Blessed is Final Fantasy XIII-2 coming out before Final Fantasy Versus XIII? I heard that the Versus staff were taken off the project to go to finish off XIII as it was running behind schedule - which is fair enough - but surely now the staff have had a while in which to go back to Versus? :(
  • Longnuts - November 16, 2011 10:18 p.m.

    Hey, I've always wanted to know what Blizzard is really doing every tuesday morning when WoW servers go offline and what it entails.
  • - November 17, 2011 8:26 a.m.

    I like that question! I've wondered that to. I've just sent off a request for more information from Blizzard. If they don't get back to me, I'll try talking to some other MMO developers and see if they can enlighten us a bit. Thanks for the question!
  • NanoElite666 - November 16, 2011 9:40 p.m.

    Here's a question I've wondered for a while... How does GamesRadar decide what is worthy of getting a Super Review as opposed to a boring old normal review. I remember back a while ago you guys reviewed something that I was fully expecting to be getting a Super Review (can't remember what for the life of me unfortunately), and then you went and did a full-blown Super Review for Red Dead Redemption: Undead Nightmare, which I wasn't expecting. So I've been curious since then as to what the deciding factors are.
  • BladedFalcon - November 16, 2011 7:50 p.m.

    There IS one question that has been bugging me for years: What drives publishers/developers, specially those of original IPs, or less popular franchises, to release games in seasons or dates which are crammed with titles that are evidently, and by far, more popular? I mean, sometimes going as far as releasing them in the exact same date or less than a week apart. It just doesn't make sense to me. I mean, I know, that for example, in the case of the months from September trough November, The market rises and more people buy in that season. (At least that's the trend for the last decade or so.) But still, it really doesn't make sense to release some titles such as Rayman: origins, or Saints Row: the third on dates that are packed with triple A titles such as Skyrim, Skyward Sword, Battlefield 3 and Modern Warfare 3. Which are titles that are obviously gonna become a priority in most gamer's mind. It's a lengthy question, I realize. But honestly, I must not be the one wondering this, am I? I mean, if it's this obvious to me, why isn't as obvious to the publishers and just change the release date on a less packed time? And this is something the happens a lot, as evidence in a top & you wrote about games with unfortunate release dates, and even another one about solid games that were doomed to fail because they were released on a date in which something else would obscure them.
  • - November 17, 2011 7:51 a.m.

    This is definitely a good question. I'd like to tackle this issue soon. Keep your eyes peeled.
  • BladedFalcon - November 17, 2011 5:17 p.m.

    Hey! awesome! Thanks Andy! I'll be looking forward to see some kind of official answer to this from you ^^
  • CH3BURASHKA - November 17, 2011 10:26 a.m.

    I assume the publisher's illusions of symbiotic sales is what drives this one. It's simply a confirmation bias: games sell well during holiday season, publishers put out more games, they sell well, and on and on. Obviously some games are lost by the wayside (I'm assuming Rayman Origins will be one of those games), but their hopes are if people start buying, they start buying BIG. In that way, it's basically a gamble for them - go big or go home. In the past few years, devs like Bethesda and Capcom have shown that you can release games early on and still make money, it's simply that others haven't caught on to that, or are too seduced by the promise of the holiday season. Besides, if everyone rushes off to spread evenly throughout the year, there will be low and high points, so those who claimed the slow-selling times will start moving back to holiday time releases, and we're back where we started. To sum up, it's mostly strategic, but sometimes it's simply a mistake (Rayman, Shadows of the Dead, Beyond Good and Evil, etc).
  • BladedFalcon - November 17, 2011 6:14 p.m.

    Yeah, i can see where you're coming from. And like I mentioned above, i get the holiday season is very attractive for most publishers. But again, every year, as a consumer or a journalist,y you can see from a mile away when a game is gonna be boned over due to it's release date. And that's in the end what bothers me the most, publishers and execs can't really be that blind or stupid, can they? Perhaps Andrew can find a more informed answer by asking those in charge of asking such decisions. That's what I'd like to hear, if there's a reason we're not seeing here, and I'm pretty sure there must be.
  • CaptCOMMANDO - November 16, 2011 5:23 p.m.

    That was quite informative. I have a question, Was "Castelvania:Lords of Shadow" created by MecurySteam, the same people who made Jericho(the Horror FPS), and it was originally called just "Lords of Shadow" but no one would publish the game after the failure of Jericho so Konami slapped the Castlevania license on it to make sales? Just a rumor I heard on the interwebs.
  • BladedFalcon - November 16, 2011 7:38 p.m.

    Lords of Shadow was indeed developed by Mercury Steam. But the second part is likely a lie, or an incomplete truth. Maybe the project was originally called Lords of Shadow. But despite what many may complain bout, a lot of the plot, characters, and even some of the game play touches are based on Castlevania games, so they didn't just "Slap" the license into it.
  • - November 17, 2011 7:32 a.m.

    Hey CaptCommando, That's a great question. We've heard some of the same rumors. Though what we heard isn't that they slapped a Castlevania license to increase sales, but rather that MercurySteam pitched the title they were working on to Konami who decided it could be the next Castlevania. There's a pretty obvious switch in the middle of the game where the content starts skewing towards a Castlevania edge: the art and tone of the game changes, old plot threads are abandoned etc. Which says to us that something very drastic happened at the midway point in development. Whether this rumor is completely true though, is unknown. We probably wont be able to dedicate an entire column to this. Though it would be great if we can. We adored Lords of Shadow, and would love to solve that mystery. Andrew
  • Kingsman - November 16, 2011 5:04 p.m.

    What kind of mistakes?
  • bitchassafriBLAMamericANTISTA - November 16, 2011 4:49 p.m.

    how do developers program enemy A.I.? specifically how do they develop the enemy A.I. to make mistakes?
  • CH3BURASHKA - November 16, 2011 5:08 p.m.

    They don't program mistakes; that's called bad AI.
  • Manguy17 - November 16, 2011 5:12 p.m.

    Im going to assume your joking...but if not, Im sure he means designed mistakes like drivers messing up in forza 4
  • IceBlueKirby - November 16, 2011 9:16 p.m.

    AI is usually programmed to give the appearance of being human-controlled, so, as a human makes mistakes, so should the AI. In theory at least.
  • - November 17, 2011 7:48 a.m.

    I've wondered about that myself. We may need to do a column on that subject. Thanks for your question!

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