http://java.sun.com/products/java-media/2D/perf_graphics.html


Hi all,

  having read thru the above document I'm currently writing a test of JDK 1.4's
Java2D performance for a project. I know it's in beta still but...

In the section "Tips for Attaining Better Performance" it talks about
acceleration of images with 1-bit transparency (which I assume is
Transparency.BITMASK). To quote:

"Acceleration support for 1-bit transparency enables you
to accelerate sprites with transparent pixels so..."

However when I gc.createCompatibleImage( width, height, Transparency.BITMASK )
the resulting drawImage()'s are really slow. My test (filling the screen with
10x10 of these images) for different transparencies passed into
createCompatibleImage() results in:

OPAQUE          25 fps
BITMASK         1 fps
TRANSLUCENT     12 fps

fps = frames/second -> higher = better

Strange, I would have thought BITMASK would have been close to OPAQUE because it
would be accelerated by DirectDraw, and TRANSLUCENT would be the slowest. Can
someone explain why BITMASK isn't accelerated as the document says it should be.

Also, how do I create a VolatileImage with 1-bit transparency? I can't seem to
find anyway to do it? There is no createVolatileImage( width, hieght,
transparency ). And incidentally, using a VolatileImage in the above test
results in 50 fps.

My system:
Windows 2K, DirectDraw 8, Riva TNT 2, JDK 1.4 beta 2.

thanks in advance,
Damon.

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