pyopengl-users

[PyOpenGL-Users] Keyboard Input

[Snails <sn...@so...>]

Hello all.
I'm writing a simple pong game in python, using pyOpenGL of course. I've =
got most of it down, but when I used glutKeyboardFunc to capture input =
from the keyboard, I encountered a problem: when a key is pressed and =
not released, instead of being called continuously (good), my callback =
function is called once, then there's a small delay, and only then is it =
called continuously (bad). I'm not especially knowledgeable about how =
the keyboard works, but this is obviously the same behavior as in a text =
box, when you press any key, it delays a bit after the initial press =
before generating more keypresses.

I've looked in the OpenGL and GLU reference, but none of them seem to =
have any functions that deal with keyboard input. GLUT doesn't seem to =
have any alternate way of checking keypresses, as in SDL, where you can =
check if a key is being pressed NOW, or stack up all key presses so that =
you can deal with them one at a time.

Is there any way to solve this from within OpenGL? Assuming that the =
answer to that is NO, I'm not exactly sure how to approach this problem: =
I've tried doing it through the various modules that come with python, =
no success there (not even a good lead). I've also tried finding other =
libraries or modules to do this with. It occurred to me that I could use =
SDL only for this part of my game, but I don't especially like the idea =
of importing all of it for only this small part that I can't seem to get =
around.

Portability is rather important, but if there's no single module I can =
use to read (what do you call this type of keyboard input anyway?) the =
keyboard in the desired way, a platform-specific solution would be =
helpful also, and the best would be one from within PyOpenGL itself.=20

Oh, and I've searched google for it for lengthy periods of time, and =
even found a thread about a guy who was making.. a pong game! Sadly, no =
one seems to have encountered this problem - or maybe they were not =
bothered by it - or maybe the solution is really obvious - or maybe this =
is all one giant hallucination (God is teasing me again). Either way, =
help would by appreciated.

    Amos

Re: [PyOpenGL-Users] Keyboard Input

[Mike C. F. <mcf...@ro...>]

Don't have time to do much testing, but here are some ideas:

    * glutIgnoreKeyRepeat -- use this, then use a timer/polling solution
      so that what you get are the down event, then while the key is
      down you issue the equivalent of a repeat every X milliseconds
      (glutTimerFunc), and you stop when you get the up event.  To do
      this, you need to track the currently-down keys yourself and
      remove them from your tracking table when the up-event comes in.
    * Use PyGame as your GUI library and it's (game-oriented) mechanisms
      for polling current keyboard state (e.g. pygame.key.get_pressed()
      with the same basic event+timer mechanism as for GLUT.  The
      advantage here being that PyGame does all the tracking of
      currently-down keys for you.

HTH,
Mike

Snails wrote:

> Hello all.
> I'm writing a simple pong game in python, using pyOpenGL of course. 
> I've got most of it down, but when I used glutKeyboardFunc 
> <http://pyopengl.sourceforge.net/documentation/manual/glutKeyboardFunc.3GLUT.html> to 
> capture input from the keyboard, I encountered a problem: when a key 
> is pressed and not released, instead of being called continuously 
> (good), my callback function is called once, then there's a small 
> delay, and only then is it called continuously (bad). I'm not 
> especially knowledgeable about how the keyboard works, but this is 
> obviously the same behavior as in a text box, when you press any key, 
> it delays a bit after the initial press before generating more 
> keypresses. 

...

> Portability is rather important, but if there's no single module I can 
> use to read (what do you call this type of keyboard input anyway?) the 
> keyboard in the desired way, a platform-specific solution would be 
> helpful also, and the best would be one from within PyOpenGL itself.

...
 
_______________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://members.rogers.com/mcfletch/