Odd multiple input problem

[TempodiBasic]

Hi guys
I think that this is a good solution... only if someone let me see where I must put _KEYCLEAR to void the buffer's tail :-((

Code: QB64: [Select]

1. CONST left = 1, right = 2, up = 3, down = 4, fire = 5, true = -1
2. DIM arrow(1 TO 10) AS INTEGER, comm AS LONG, comms(1 TO 10) AS STRING
3. arrow(left) = 19200
4. arrow(right) = 19712
5. arrow(up) = 18432
6. arrow(down) = 20480
7. COLOR 11, 2
8.  
9. PRINT (arrow(left)), (arrow(right)), (arrow(up)), (arrow(down))
10. SLEEP 2
11. DO
12.     CLS
13.     comm = _KEYHIT ' memorize hardware input
14.  
15.     ' inizialize engine flag
16.     IF comm > 0 THEN
17.         ' key is pressed
18.         IF (comm) = ((arrow(left))) THEN
19.             comms(left) = STR$(true)
20.         ELSEIF (comm) = ((arrow(right))) THEN
21.             comms(right) = STR$(true)
22.         ELSEIF (comm) = ((arrow(up))) THEN
23.             comms(up) = STR$(true)
24.         ELSEIF (comm) = ((arrow(down))) THEN
25.             comms(down) = STR$(true)
26.         END IF
27.     ELSEIF comm < 0 THEN
28.         ' key is released
29.         IF (comm) = -((arrow(left))) THEN
30.             comms(left) = ""
31.         ELSEIF (comm) = -((arrow(right))) THEN
32.             comms(right) = ""
33.         ELSEIF (comm) = -((arrow(up))) THEN
34.             comms(up) = ""
35.         ELSEIF (comm) = -((arrow(down))) THEN
36.             comms(down) = ""
37.         END IF
38.     END IF
39.  
40.  
41.     ' engine
42.     throw.x = 0
43.     LOCATE 3, 1: PRINT "Xmove=";
44.     IF VAL(comms(left)) = true THEN throw.x = -1: PRINT " Left   "
45.     IF VAL(comms(right)) = true THEN throw.x = 1: PRINT " Right "
46.  
47.     throw.y = 0
48.     LOCATE 5, 1: PRINT "Ymove=";
49.     IF VAL(comms(up)) = true THEN throw.y = -1: PRINT " UP    "
50.     IF VAL(comms(down)) = true THEN throw.y = 1: PRINT " Down "
51.     IF throw.x = 0 AND throw.y = 0 THEN throw.x = 1
52.  
53.     IF comm = (32) AND spacepress = false THEN
54.         spacepress = true
55.         LOCATE 1, 1: PRINT "Spacepress="; spacepress; "  "
56.         '     CALL spawn_shot(0, throw.x, throw.y)
57.     ELSE
58.         spacepress = false
59.     END IF
60.     IF comm = (27) THEN END
61.     ' _KEYCLEAR
62.     LOCATE 1, 1: PRINT "Spacepress="; spacepress; "   "
63.     _LIMIT 10
64.  
65. LOOP
66.  

[Pete]

Yes, the buffer is a huge problem when running the code. You can retrieve a single key entry by using _KEYCLEAR immediately after:    comm = _KEYHIT ' memorize hardware input

I'm surprised this worked for you, because on my system, it will not detect more than 2 keys when I use left arrow + up arrow + spacebar. Now some other combos work, but the one mentioned left arrow + up arrow + spacebar needs to work to have a breakthrough. I wish I could remember a way to get PEEK to recognize a spacebar press. In my attempt, I had to substitute Shift for the spacebar, so I really can't say if a way to PEEK a spacebar press would work or not. It just isn't apples to apples... more like Apples to Windows. Anyway, only certain PEEK/POKE are still preserved, as this was all 16-bit stuff, back in the day. I did find that PEEK(197) worked to find a key press on a Commador64, but that lower rage is apparently ignored on non-16 bit systems. Oh well, that's "progress" for you!

Pete

[TempodiBasic]

Hi Pete
about _KEYCLEAR
it doesn't solve the problem of the buffer

if I put it just after _KEYHIT I got a strange effect ON OFF for the key pressed without any detection if the key has hold or no.
If I put _KEYCLEAR in the area of waiting for new cycle after _LIMIT 10 and/or before _KEYHIT the program doesn't catch input from keyboard.
.....

about my workaround I have tested it using an USB keyboard and it can catch only 2 arrow keys and no more plus!
Also _KEYHIT seems to soffer of Hardware limitations.
In this case I think that also using PEEK  or INP there is no matter to do. Where the hardware fails there is not possible to use so combo! So for using  professional games with combo using plus 2 keys , the user must use a gamer keyboard with no limit (like PS/2 as said in the article linked by Steve).

Well at my home, if I want develop a game with such kind of combo (more than 2 keys) I must use one of the 2 notebook TOSHIBA that with their inner keyboard let me catch all the keys I like to catch. But if I use an USB keyboard (I have tested 2 keyboards USB and wireless made by different manufacter [Sigma, Trust]) I fall in the hardware issue.
While the 2 HP notebook  show the hardware issue also with their inner keyboard. 

Thank for reply Pete

In sum: the solution is  use a power hardware for gaming  or write a game with no such kind of combos.