wxMac - continuous rotation of graphics

[Eric Dowty]

Hello:

In upgrading from wxWidgets 2.4 to 2.6, I encountered speed problems with g=
raphics redraw.  If I continously redraw while rotating a moderately comple=
x object, the speed is about half as fast with wx 2.6 (also 2.7) as 2.4.  M=
y code is the same for both 2.4 and 2.6 except as noted below

At the moment, I am compiling wx 2.4 with Metrowerks, and wx 2.6/2.7 with X=
Code, but I doubt if the compiler could make this much difference - there i=
s no evidence of any problem elsewhere.  Rather, I am guessing it is a diff=
erence in the wxWidgets event loops between 2.4 and 2.6/2.7.

Here is an outline of the code - a loop which just rotates and redraws cont=
inuously:
--------------------------------
PushEventHandler(new MyEvtHandler(this)); //handler for buttons, mouse

while( TRUE ) { =


    rotate(); //rotates object

    wxYield(); =


#if !defined(__WXMAC__) or (wxMINOR_VERSION =3D=3D 4) =


    redrawgraph( ); //does OnPaint - skip this for wx 2.6 ONLY

#endif

   if( wxgen.quitnow ) goto stoploop; //quitnow flag set if user hits  butt=
on or mouse

} =


stoploop: =


PopEventHandler(TRUE);

--------------------------------

Note that redrawgraph(), which directly calls ::OnPaint, is needed for 2.4 =
but not 2.6.

The same sort of problem occurs if the user rotates with the mouse.  The sp=
eed comparison is for PPC, but I suppose that Intel code has the same probl=
em (I have not tried to load wxWidgets 2.4 on an Intel machine and compile =
it with XCode).

How could I get V2.6/2.7 to redraw at maximum speed?  Is there some wait cy=
cle which could be disabled?  Does someone have some code for a redraw loop=
, for example rotating an object with the mouse, that really is as fast und=
er 2.6 as 2.4?

Would it make sense to try a completely native event loop, as in the GLCarb=
onAGLWindow sample (for example?)?

Eric Dowty
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