hey!
---
RE: problem: PTS_0005075 (for [EMAIL PROTECTED])
---
ok.. this might be a good one for those interested in
trying to find possible bugs in the PalmOS development
environment (i have looked - and cannot figure this
one out)..
i am trying to perform double buffering, and i have
setup a Graphics.[hc] files for a simple interface
for all of my programs.
i have a main _Graphics_initialize() routine that does
the following:
---
void
_Graphics_initialize()
{
Word error;
scrnBuffer = WinGetDrawWindow();
backBuffer = WinCreateOffscreenWindow(PALM_WIDTH, PALM_HEIGHT,
screenFormat, &error);
ErrFatalDisplayIf(error, "Cannot create offscreen buffer.");
// remove this to make DOUBLE BUFFERING work
backBuffer = NULL;
if (backBuffer != NULL)
WinInitializeWindow(backBuffer);
}
---
whenever i do any drawing routines, i perform the following:
---
if (backBuffer != NULL)
WinSetDrawWindow(backBuffer);
// draw
if (backBuffer != NULL)
WinSetDrawWindow(scrnBuffer);
---
and... when i kill my application - i clean up my memory in
_Graphics_terminate().
---
WinSetDrawWindow(scrnBuffer);
if (backBuffer != NULL)
WinDeleteWindow(backBuffer, false);
backBuffer = NULL;
---
code looks like it should be working to me. but.. when i
execute the application on my palm pilot (and in the
emulator).. it flickers.
if i turn off double buffering (by setting the backBuffer
to NULL) - the same occurs, so the double buffering is
not occuring.
as a bonus.. when i kill the application, i get an error
saying that i am trying to read from an unallocated memory
block.
this tells me that
a) i called _Graphics_terminated, which then frees the
backscreen buffer
b) something is still trying to use the backBuffer?
- this cannot happen, as i check the value of the
backBuffer (if it is not NULL) before i draw?
maybe a method synchronization problem?
the source code and binaries (palm) can be download
here (tar.gz or .zip):
http://www.hig.se/~ardiri/development/palmIII/cube.tar.gz
http://www.hig.se/~ardiri/development/palmIII/cube.zip
i am using Palm III (with patch 3.0.2)
and my development environment is linux (990108 build)
maybe it is just a GCC problem (bug)?
cheers.
az.
--
Aaron Ardiri
Java Lecturer http://www.hig.se/~ardiri/
University-College i G�vle mailto:[EMAIL PROTECTED]
SE 801 76 G�vle SWEDEN
Tel: +46 26 64 87 38 Fax: +46 26 64 87 88
Mob: +46 70 352 8192 A/H: +46 26 10 16 11
