Other input functions?

[Viza74]

inkey() seems to be only fireing once in the frame the key was pressed, which limits its use in games quite a lot. Is there a way to get the current up/down state of a key (and of the joy if we are at it)?

[oliverhermanni]

Check the snake example from line 67.

Joystick works like usual with PEEKing at 56320 for Port #2 and at 56321 for Port #1.

[Viza74]

Hmm, in which version?... There is no code for joystick neither in master nor develop branch. I copied the input routine from there to begin with :) I can probably implement it trough peek/poke-ing, but IMHO it would be worthwhile to support the mentioned functions "natively" from the language itself.

[oliverhermanni]

Sorry, the first line was meant for INKEY input. ;)

For joystick: It works through POKE and PEEK like in BASIC. In my game I do it like this:

game_loop:
    j = peek(56320)

    if j = 126 then call moveup : goto loop_repeat
    if j = 125 then call movedown : goto loop_repeat
    if j = 123 then call moveleft : goto loop_repeat
    if j = 119 then call moveright : goto loop_repeat

loop_repeat:        
    goto game_loop

moveup, movedown, etc. are PROCs which move the player sprite. Basically it looks like this:

proc movedown
    \yy = \yy + 1 
    poke 53249, \yy 
    for t = 0 to \move_speed : next t 
endproc

yy is a global variable which contains the current position of the sprite. move_speed is a CONST, which is set to 512 in my game. It slows down the movement. ;)

You're right, they could be implemented directly, but would enlarge the library code and therefore shrinks the available memory.

[Viza74]

Thanks for the code!

Well, it is short enough to not need any support in the form of language commands, but not very friendly looking :) Maybe compile time constants can help without using memory?... Something like:

joy2 = peek(_JOY2STATE_)
if joy2 = _JOY2UP_ then blahblah

Although this still could be unfriendly because of the high number of required constants. :-/

[oliverhermanni]

It's like I would do it with BASIC, but less GOSUBs. :)

In another issue I asked for the possibility to include source files. This would help me a lot to clean up my code and I could store constants or procs in extra libraries. Casba also mentioned predefined constants there.

[neilsf]

INKEY is nothing but a wrapper around the KERNAL GETIN function which consumes the input and will return 0 the next time it is called.

The documentation ("The INKEY() function returns the keyboard code of the currently pressed key") is very misleading - I'll fix that.

Joystick support would be a cool feature. Also, another function that checks if a key is currently pressed, would be nice in the future. I think I'll get back to this after v2 is done. :-)

@Viza74 I was also thinking about predefined constants, like _JOY1_. It would be very cool if someone could write a complete list of constants, like _BACKGROUND_, _BLACK_, _YELLOW_, _SPRITE0POSX_ or whatever, I think there could be hundreds of them. Could be useful to have a look at the cc65 compiler, they've done a similar job already if I remember well.

@oliverhermanni instead of slowing down the code with an empty FOR loop, I'd suggest you to wait for a new frame in each loop. This way you'll get a smooth 50 fps animation! Check the code here in the Bouncing Ball example:

https://github.com/neilsf/XC-BASIC/blob/775aca5e3ce49cf208b055c1e01733e56f5c1a26/tests/bounce.bas#L30

[oliverhermanni]

I'll start with the constants. I already have some of them. Any format you prefer?

[neilsf]

Cool, thanks! Any format will do, e.g. a text file or a spreadsheet... Numbers can be decimal or hexa as well.

[neilsf]

These features will be implemented later in userland extensions.