|
|
|
This thread is locked; no one can reply to it.
|
| kbhit() vs. allegro equivalents |
|
Dave Kovich
Member #3,437
April 2003
|
I'm sure about the details of kbhit() but im almost certain it isnt picking up every key press. The npcs in my game have the same walking speed as the character however they appear to move faster...i assume this is because every time through the loop, the npc moves or doesnt move based on whats its supposed to do while the character may not be moving during some loops because the kbhit function isnt picking up every key hit ( the player is holding the key down ). So my question is, should i use an allegro equivalent of kbhit() or wont it make a diffrence, and, is there a function i should use to test for the key being held down instead? Any help is appreciated. |
|
Johan Peitz
Member #9
April 2000
 |
For moving things like the player sprite, where the player will hold down keys, you shouldn't use kbhit() or allegro keypressed/readkey at all. I suggest you read up on the keyboard functions in the allegro manual. There's an array key[..] that you can check for keypresses. Look it up, it is your friend. -- |
|
Murray Bozinsky
Member #696
October 2000
 |
Hey, this is rather another question than a reply, but as it concerns hitting keys, i'll post it here instead of starting a new thread. Here it is: Is there a way to "slow down" the keyboard? Well assume I have a menu and hitting ESC opens/closes this menu. If I use a simple if (key[KEY_ESC] && !menu_is_active) open_menu(); and if (key[KEY_ESC] && menu_is_active) close_menu(); hitting ESC once will open and close the menu a hundred times. Or assume I'm coding a text-input box. If I hit a character on the keyboard, this character will be added to the input-line 100x instead of once. I know I could either use a loop like if (key[KEY_ESC]) while (key[KEY_ESC]) or I could implent a timer that locks the keyboard for a certain time after each keypress. Using a loop will pause the game-logic and using a timer for this is a pain in the *ss. Isn't there a more simple and comfortable way? Thanks in advance, /Murray Bozinsky |
|
gnolam
Member #2,030
March 2002
 |
char keylog[KEY_MAX]; memcpy((void*)keylog,(void*)key,sizeof(keylog)); poll_keyboard(); if ((key[KEY_ESC]) && (!keylog[KEY_ESC])) { /* this will only be executed once per keypress */ if (!menu_is_active) open_menu(); else close_menu(); }
-- |
|
BAF
Member #2,981
December 2002
 |
if ( ( readkey() >> 8 ) == KEY_ESC && !menu_is_active ) open_menu(); //...// Try that! [edit]mine showed up first i edited and gnolam came on before me. !:'( |
|
Murray Bozinsky
Member #696
October 2000
|
Hey gnolam, I think I understand. All I have to do is polling the keyboard and copying the keyboard-buffer to a temp-buffer say twice a second, right? that sounds easy, thank you! /Murray Bozinsky |
|
CGamesPlay
Member #2,559
July 2002
 |
Nobody said anything about twice a second, btw. -- Ryan Patterson - <http://cgamesplay.com/> |
|
Dave Kovich
Member #3,437
April 2003
|
Annnyyywayyy.......in reply to johan peitz, after i read your reply i looked through the keyboard section of the allegro manual and cant find what i think im supposed to be looking for ( which is a function that you use when a key is being held down, right? ). So whats the function, and how should i use it? Thanks. |
|
Matthew Leverton
Supreme Loser
January 1999
 |
Johan Peitz said: I suggest you read up on the keyboard functions in the allegro manual. There's an array key[..] that you can check for keypresses. Look it up, it is your friend.
|
|
Zaphos
Member #1,468
August 2001
|
readkey() reads at the OS-determined key_repeat_rate -- so if you hold down the key it will see the new key presses at about the same rate that a letter would appear if you held down that letter's key while in, say, notepad. What you want is simply to read key[] buffer to see if a key is currently held or released: If you really still think you want to use readkey, you can try to use allegro's set_keyboard_rate() function to a low, non-zero value -- don't set it to 0, though! I believe allegro interprets a value of 0 as infinity (no repeat) instead of infinite repeat (infinite repeat is sorta not possible, I think, so this actually makes sense). Edit: Matthew beat me!
|
|
aybabtu
Member #2,891
November 2002
|
Can't you just clear_keybuf() |
|
gillius
Member #119
April 2000
|
No you can't do that. key is defined to be read-only I think. I don't think clear_keybuf clears the key array anymore with the latest Allegro versions -- I remember people complaining that it broke their code. Gillius |
|
Sirocco
Member #88
April 2000
 |
Quote: No you can't do that. key is defined to be read-only I think.
Yep, the key[...] array is a state collection container, meaning that the values in it get updated at regular intervals. Which is basically a fancy way of saying writing to it will have no effect Side note: The interesting thing about PLC programming (industrial motion controllers and such) is that they are mostly based on state collection containers, so you don't work with variables per se on a regular basis. It's really easy work, but it can be difficult to remember that you can't take input from a device (encoder, limit switch, pressure monitor, etc) and modify that input -- that just won't work for the same reason Blah, I prefer PC programming, but there's more money in PLC work, so... --> |
|
gnolam
Member #2,030
March 2002
|
Murray Bozinsky: Or whatever time interval you want - myself, I copy it before every poll. Wasteful? we don't need no steeenkin' memory bandwidth! Sirocco: Heh, I actually got to do a bit of PLC programming for a group project last semester. I got away with doing the "difficult"* work with the PLC while my teammates did most of the "easy" paperwork * this project basically only required setting parameters for a PID regulator, adding a manual/automatic switch and an automatic cutoff when the input reached a certain value - all in all, about 7 variables and say, 2 or 3 conditionals to keep track of -- |
|
StevenVI
Member #562
July 2000
 |
You people are silly if(key[KEY_*]) // do thing that must be executed every frame while(keypressed()) { int k = readkey() >> 8; switch(k) { case KEY_*: /* do thing that needs more time in between hits, such as performing the keychecking on a menu */ break; } } That way, you can set the keyboard repeat rate, and that's the minimum amount of time that will exist between those keypresses where more than one frame is needed in between. -Steve __________________________________________________ |
|
Evert
Member #794
November 2000
 |
Quote: No you can't do that. key is defined to be read-only I think. Technically, it's not, because you can't define variables as read-only from user code and writable from library code, but if you could, then it should be read-only. |
|
Murray Bozinsky
Member #696
October 2000
|
@Harry Carey: Quote: You people are silly . This is how I always control the time between keypresses: As I already said, a while loop pauses the game-logic. While the key is pressed, the loop is working, hence nothing else is updated. /Murray Bozinsky |
|
CGamesPlay
Member #2,559
July 2002
|
BUT, we realize this, and it's not like we're going to go loading any data during that loop. By the same logic, every instruction pauses game logic, and while any instruction is being executed, no others can. -- Ryan Patterson - <http://cgamesplay.com/> |
|
Dave Kovich
Member #3,437
April 2003
|
So can someone maybe give me a quick example of what a simple loop looks like...(is this right?): while( loop > 0 ) } |
|
StevenVI
Member #562
July 2000
|
Dave: Murray: The key buffer works differently from the key[] array. Items are only added to it at the rate set by set_keyboard_rate -- meaning that if you set the delay and rate for key buffer repeats to say 250ms, then after you have pressed KEY_ESC the first time, it won't show up in the key buffer until 1/4 of a second later -- but the game loop still runs normally, totally unaware that there's another process counting the ticks between the last time KEY_ESC was enqueued in the buffer. Does that explain things a bit better? -Steve __________________________________________________ |
|
Dave Kovich
Member #3,437
April 2003
|
Isnt that basically what you're doing if you were to forget while loops all together, and call |
|
gnolam
Member #2,030
March 2002
|
vsync() timing == <u>EVIL</u> -- |
|
|
. This is how I always control the time between keypresses:
