As the title says, I am looking for a way to convert a scancode to ASCII. I am writing this for a PS/2 keyboard driver; it would be of great help if someone could explain how I could do this, or provide some example code as a pointer for me to get started. If this isn't possible in C, I can also use C++ or x86 assembly.
Thank you!
You do this via a keyboard mapping table. But this really doesn't belong at the keyboard driver layer, because the mapping is specific to the user's configured layout/language. Instead the driver should output some sort of standardized key codes (could be scancodes, or something more abstract and geometric like X/Xkb uses), an intermediate layer should convert those to key names, and some other (much higher!) layer should convert named key events to changes to text entry contents.
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E.g: On apps like Metamask or Myetherwallet, it often displays the user's public address in a graphic, like some randomised drawing. What is this called and how does one do this?
You're probably talking about blockies. They're a specific variant of the more general idea of "identicons," which use a seed of some sort to generate an icon.
In the case of ssh-keygen (the software used by those wallets to generate keys is probably similar, but as pointed out by the other answer, may serve a different purpose), this is called the randomart and is used as an easy way for humans to validate keys.
I assume you mean the QR Code
This isn't native to Crypto or any one language in particular, it's a matrix-based bar code that can be used to store any type of information - typically URLs or text based information. Functionally, it's not much different than the barcode on your box of Frosted Flakes.
There's multiple sites that generate QR Codes for you, or you can write relatively simple software to make them for you. There's also a few QR Code API's out there that will generate them on the fly.
MetaMask is pretty clever in that actually uses a table with white/black cells instead of an image.
Looking at my MetaMask, I wonder if you actually meant the Identicon which is just a way to interpret a hash as an image.
How do I get the key codes so I can process arrow, pageUp, pageDown, etc, keys using simple C or C++?
I can get the regular keys, I do not know how to get these special keys.
Ncurses should be able to handle that. There is lots of tutorials out there
Linux based systems follow the UNIX tradition, in the sense that those keys are special and their values depend on the terminal settings.
This is so, because in the old days each UNIX system had a complete different type of keyboard. As such it is somehow complex to be able to write generic code to handle those special keys.
The best way is to make use of a terminal handling library, like curses or its successor ncurses.
Here you can get a nice introduction about keyboard usage,
http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/keys.html
There are at least 3 different keyboard layouts who are using the program i make, and i dont care which key they press, the more important thing is where the keys are pressed.
I cant just ask the user to press 100 different keys/combinations, that would take too much time and be very confusing to the user.
Is there some library or something that can do this for me?
This answer says that you can use the keyboard "Scan Code" which should be the same on all keyboards. So it appears that there is in fact a way to determine the key location.
Even without using the scan code, you could implement a mapping table for all the keyboard layouts you support. So if the keyboard layout is US English, the key would map to command A, but on layout German German, it would map to command B, and some other command would map to command A. It may not work for all keyboards, but if it works for all of your users that's what matters. I can see why you were looking for an existing library to do this as it would be a significant amount of work.
This cannot be done. Keyboards do not come with their layout in an electronic form, that could be looked up by the OS. They just send the code for the key pressed, not where the key resides. I'm working on several keyboards daily, which are all classified as having German layout, but with some of the keys being in different places.
The only way to find out at what physical position a specific key is on a specific keyboard is to look at what's printed on the key.
I am trying to build an application for Windows XP 64bit which is able to detect drives of a particular model in the system, and if they are not initialized & formatted perform these processes.
I would also like to be able to query and set the partition information(including the volume label).
I have started putting together code using DeviceIoControl, but I have not been able to figure out how to set/get partition/volume labels or format drives with the method, I have got SMART access working.
Is there any other method that is any easier to use?
Zac
Sounds like you are looking for Disk Management Control Codes.
If I were doing this I would use my own code only to detect things. I would do the partitioning and formatting through diskpart and/or format commands instead. diskpart accepts file argument with a script to execute.
Almost every game use keyboard as input. I have been searching for 2 days on this topic and found quite much about it. Keyboards have many disadvantages, but main problems I found are different layouts and second that if you are pressing 3 keys at time, it can lead to corruption (row-column error). If you don't know what I'm talking about, keyboard is made as grid and it checks which row and column has connected. But if you press E,D (row 1,2 column 3)
and R (row 1, column 4), keyboard can show even F because it find it pressed(row 2, column 4 both pressed).
So I think we can't do anything about that second, but if anyone got idea how to solve it better then use keys that don't form L, I'd be glad :)
But my main problem are different keyboard layouts which is real pain. I'm slovak so Slovak layout of numbers look like this:
+ľščťžýáíé and with shift 1234567890, we also got QWERTZ but you can use QWERTY.
You all know how the English look like but just for sure:
1234567890 and shift !##$%^&*()
Most of time I'm using english one because I got used to it when programming. Anyway there are different people using different layouts. When you are making game that depend on which key is pressed, for example good old WASD pattern, you can't use that on french one which is AZERTY layout. It would be strange. Same as using numbers for choosing gun in action game. As you can see slovak would have to press shift to get it work.
I'm also using OpeGL. There is problem when you are mapping which keys are pressed. For example widely used solution to make map of 256 bools for each charakter, is suffering from SHIFT. You press a, SHIFT and release a you got: a down, A up. So I thought about binding some keys together, as A and a, 1 and !, but then I realized I'll just change layout and everything is wrong.
So what is solution for that? I think there is someone out there that is in game industry or made some game and had to solve this. Only solution that comes on my mind is to force english layout for UI (and choosen layout for chat).
After next searching I found what I need but I need cross-platform one:
virtual key codes
And next search revealed SDL key
Result: Don't ever start with GLUT if you go making games, use SFML or SDL
Thanks to everyone for helping me, there were more problems in this so idea of key binding/mapping, SDL and so on, each helped me alot.
If you're getting a "character" every time user presses something, then your keyboard routines aren't suitable for game input - only for text entry.
You need to use input routines that completely ignore keyboard layout switching and operate on some kind of raw keycodes (so when user presses shift+a, you'll know that shift is pressed and that "a" key is pressed, but you won't get "A" character). Also, routines should allow you to query if a key is pressed or not.
For windows that is DirectInput or XInput. For cross-platform this is libsdl and SDL_GetKeyState. And you'll need to provide keymapping options for the user. Glut probably isn't suitable for your task.
The common approach seems to be to ignore the problem. Worse-is-better in its early stage.
Unfortunately I'm using svorak keyboard layout so it really doesn't just work for me.
I've been approaching this same problem by binding into multiple keys on the keyboard. So that player jumps from both x and j -keys. It doesn't do so well in something that isn't shoot-jump -kind of game.
Nice stuff would be if you could just find row/col or some driver-near interface to your keyboard.
Some auto-keyboard configuration software would be neat though I've not yet seen anything like that. Maybe we should write one?
First up, separate keypresses from text entry. You shouldn't care what letter or number comes up when you press a key with shift as well - the operating system should handle that and generate an event you can use in the rare times you need the text. Usually, you should just look for the key press and any shift presses and act on those.
Second, load the bindings from keys to commands from a data file, rather than hardcoding it. Distribute default bindings for QWERTY and whatever default layout you have. If the data format is quite straightforward then people won't mind customising it to fit their keyboard and preferences. You can also add an in-game keybinding editor later.
This isn't really about OpenGL since by default that doesn't care about keypresses. Perhaps you are using an addon library or extension that handles keys for you - ensure that whatever you're using can give you individual key values and the state of shift/alt/ctrl independently, and that it also provides text input via an independent system.
Allow your users to define the keys to use for each action ...
or use the arrow keys .. that should be pretty universal :)
Turn the keyboard input into metadata, so you could allow users to configure at their will but also provide different keyboard shortcuts depending on the keyboard layout used in a config file .