Jerome,
2 megs isn't a lot, so I wouldn't be totally surprised if
you're bumping up against a VRAM limit, even though your
front and back buffers alone should fit with almost 800K
to spare.. Ideally, the only
things in VRAM should be your front and back buffers. But
there might be other things there as well, depending on
your app, Windows98, the graphics card, and the graphics
driver. Thee things include other images from your app
(even if you don't create VolatileImage objects, we might
try to create a hardware-cached version of some of your
images), the primary display used by Windows, and resources
used by the GDI and graphics drivers of your card.
In any case, there is a new call in GraphicsDevice
called:
getAvailableAcceleratedMemory()
It should be available in the jdk1.4 Beta2 release. This function
should query the video hardware as to what resources
are actually available. This would give us more information
about why your app might be failing to get the flippable
buffer.
There are various things that could contribute to this problem,
such as hardware/drivers that don't support page flipping,
the time of buffer creation (if you're running in high-res mode
at the time you try to create this stuff, there's not enough room to
create everything given the size that the display takes up
in VRAM). But finding out the answer to the above might help.
Chet.
> Delivered-To: [EMAIL PROTECTED]
> From: "Blouin, Jerome" <[EMAIL PROTECTED]>
> Subject: [JAVA2D] Problem using page flipping
> To: [EMAIL PROTECTED]
>
> All,
>
> I'm developing a 2D demo that scrolls a wide image in a resolution of
640 x
> 480 of 16 bits. To do this I use a rendering loop that uses a
> BufferStrategy (JDK 1.4).
>
> My problem is that I would like to have a page flipping strategy to
have the
> best results, but it seems that the program isn't able to use that
strategy.
> It uses a blitting strategy instead witch causes tearing effects in
the
> demo. To discover that the program doen't do page flipping, I request
the
> BufferCapabilities class. The call to isPageFlipping() always returns
false
> and the call to getFlipContents() always returns null because
> isPageFlipping() returns false, according to the API doc.
>
> I don't understand why page flipping can't be used because my video
card has
> 2 megs of VRAM so this should be big enough to perform page flipping
(2
> pages of 640 x 480 x 16). Also I run the demo in Windows 98.
>
> Any help would be greatly appreciated.
>
> Thanks
>
> Jerome
>
>
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