>     I'm writing a simple 2D rendering engine for a game. The framework is
> done but there's something wrong, that I can't figure out. The engine is
> actually a derivative of a CWnd and handles paint, timer and mouse events.
> In the game you can open some windows so there can be some instances of
the
> engine. The problem is that when first started it runs perfectly - during
an
> animation with 200 objects the CPU usage is 5%-10%. But when the window
> which is the owner of the engine is closed and opened several times, after
> the 3rd or 4th try the CPU usage during the same animation goes up to
100%.
> The code in both cases is the same and I can't understand how that is
> possible. I think some resources probably get exhausted, but what kind of
> resources can cause that effect? The count of the GDI handles and the
memory
> used by the engine stay the same during all tries. Another thing is that
> when the CPU goes to 100%, the kernel CPU time is up to 100% too, which I
> guess means that it slows down during API calls, but I must say again,
that
> this is the absolutely SAME code each try. And the most suspicios thing is
> that when I drag another window over the window with the engine a little
> bit, just to hide 10% of it, the CPU goes to 5%-10% again.
>     I'll appreciate any opinions that could lead to the reason for this.
> Thanks in advance.

> Hi Alexander,

> Just a thought, but have you tried to break in the de{*filter*} while your app
> is thrashing? Just hit F12 in the IDE, open up a call stack window and
cycle
> through each of your threads (using the menu's Debug>Threads to give each
> thread a chance to get focus in the de{*filter*}). Then you can step through
> each thread for a few calls and hopefully see some sort of endless loop or
> something. It almost sounds as if you have a WM_PAINT handler that is not
> calling BeginPaint / EndPaint properly (or not properly using its
CPaintDC,
> which calls those for you). In cases like that, Windows will just keep
> sending WM_PAINT over and over again.

> Regards,
> Mike

>     The good news is that either my computer is not working properly, or
my
> windows, or the de{*filter*} - I don't know which of them, because when I
tested
> the same thing under different computer, which runs under XP everything
> works just fine. (I'm running under Win 2k)

> Hi Michael,
>     I already have tried to break while having high CPU, but the
application
> has at about 9 threads and most of them are stopped in their message loops
> during the break. Another thing is that it usually stops in assembly code
> and I don't know it so well so I can't understand exactly what's going on.
>     I checked the CPaintDC object that I use and it's used properly (I
mean
> it's created only if the update region is not empty). But I find it
strange
> to have a problem like this, because it would happen always or at least
more
> often over the same situation and the same source.
>     I don't use any static or global objects in the engine, except for one
> pooler, but it's singleton -  so there's nothing that gets reused
improperly
> during creation of multiple instances one after another.
>     The good news is that either my computer is not working properly, or
my
> windows, or the de{*filter*} - I don't know which of them, because when I
tested
> the same thing under different computer, which runs under XP everything
> works just fine. (I'm running under Win 2k)
>     Thank you anyway. I really appreciate it.

> > Hi Alexander,

> > Just a thought, but have you tried to break in the de{*filter*} while your
app
> > is thrashing? Just hit F12 in the IDE, open up a call stack window and
> cycle
> > through each of your threads (using the menu's Debug>Threads to give
each
> > thread a chance to get focus in the de{*filter*}). Then you can step through
> > each thread for a few calls and hopefully see some sort of endless loop
or
> > something. It almost sounds as if you have a WM_PAINT handler that is
not
> > calling BeginPaint / EndPaint properly (or not properly using its
> CPaintDC,
> > which calls those for you). In cases like that, Windows will just keep
> > sending WM_PAINT over and over again.

> > Regards,
> > Mike

> Hi Michael,
>     I already have tried to break while having high CPU, but the
application
> has at about 9 threads and most of them are stopped in their message loops
> during the break. Another thing is that it usually stops in assembly code
> and I don't know it so well so I can't understand exactly what's going on.
>     I checked the CPaintDC object that I use and it's used properly (I
mean
> it's created only if the update region is not empty). But I find it
strange
> to have a problem like this, because it would happen always or at least
more
> often over the same situation and the same source.
>     I don't use any static or global objects in the engine, except for one
> pooler, but it's singleton -  so there's nothing that gets reused
improperly
> during creation of multiple instances one after another.
>     The good news is that either my computer is not working properly, or
my
> windows, or the de{*filter*} - I don't know which of them, because when I
tested
> the same thing under different computer, which runs under XP everything
> works just fine. (I'm running under Win 2k)
>     Thank you anyway. I really appreciate it.