Re: [chuck-users] KBHit and arrow keys

The behavior of KBHit is kind of standard for ketting data from some asynchronous source. Since the chuck program (or any user prog) runs at some unknown speed it is possible for several keys to be pressed before you get control. In that case the boolean (KBHit) returns true. Your input routine would then process all the characters in the input buffer. That's why kb.getchar returns (and removes) the first char in the input buffer. When kb.getchar returns zero, you know that you have processed all of the input. This allows KBHit to get re-enabled so that it will indicate when new stuff is available. This isn't unique to the keyboard, but is pretty much the way all interrupt driven I/O works. So, be happy: what you thought were warts in your program were really elegant solutions to a universal problem. Or something like that. Jim Hinds jahbini@jahbini.org http://www.celarien.com/ http://www.jahbini.info/ On Apr 27, 2006, at 6:00 AM, chuck-users- request@lists.cs.princeton.edu wrote:

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1. KBHit and arrow keys. (Kassen)

From: Kassen Date: April 26, 2006 10:22:12 AM HST To: "ChucK Users Mailing List" Subject: [chuck-users] KBHit and arrow keys. Reply-To: ChucK Users Mailing List

Hello all,

The new keyboard input is great but getting the arrow and F1-F10 and so on keys to work is kinda tricky, I found. I cooked up a sorta kinda maybe solution to this that I thought might be useful to others as well. See below.

use the up and down keys to increase or decrease "bla", then print bla's current value. This won't win any beauty contests but it does work. I'm not at all sure why it needs two temporary variables but I can't get it to work without them. If I don't use temporary variables it seems that I can only use one test on kb.getchar() before it disappears(??) and one test isn't enough for anything beyond the most simple of triggers. The same method could be used to get function keys to work.

I hope this is of use to some. This works on my IBM- compatible laptop running XP, no refunds if it turns out Mac's use some entirely different way of reading the keyboard; I have no idea how those work. If it's found useful I could add it to the Wiki?

Yours, Kas.

---------------------------------------------------------------------- -------- // the keyboard input KBHit kb;

//some setting that's of great importance somewhere int bla;

// time-loop while( true ) { // wait on kbhit event kb => now;

// potentially more than 1 key at a time while( kb.more() ) { //store number to avoid it getting lost after one check kb.getchar() => int K;

//arrow keys are encoded in two numbers with the first being 224 if (K == 224 )

{ //wait for the second number kb => now;

//the same "anti number disapear" trick kb.getchar() => int L;

//do intuitively sensible stuff to "up"... if(L == 72) 1 +=> bla;

//........and "down"...... if(L == 80) 1 -=> bla;

//...and make the result go somewhere. <<<"bla is", bla>>>; } else { //do something else to normal keys <<<K>>>; } } } -------------------------------------------------

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