Hi, Chris.
I am sure, that those changes should be reverted back or at least we
should rethink.
Note, that when I paint something from the buffered image to the
surface, I'll get correct image. Because OGLBlitSwToSurface, that is
used in this case, will block alpha for opaque surface. But when I
enable managedimage for the same code, I'll get incorrect image, because
of incorrect alpha in OGLBlitSwToTexture. Probably OGLBlitSwToTexture
assumes that both of sw and texture should be opaque or non opaque. Not
sure that this is correct.
09.07.2012 21:40, Chris Campbell wrote:
Hi Sergey,
Do you happen to know the intent behind this original change from macosx-port?
http://hg.openjdk.java.net/macosx-port/macosx-port/jdk/rev/50b8fef5df7d
The commit message for that changeset didn't have much information; it just
said:
"Fixing AWT components painted over in white"
Perhaps it was trying to work around a Mac-specific driver issue?
It seems unfortunate to create all textures (on all platforms) as RGBA even if
the image is opaque. At the very least, it invalidates the documentation for
OGLSD_InitTextureObject():
* If the isOpaque parameter is JNI_FALSE, then the texture will have a
* full alpha channel; otherwise, the texture will be opaque (this can
* help save VRAM when translucency is not needed).
Also, I remember a time when GL_ALPHA_SCALE and GL_ALPHA_BIAS weren't optimized
by some drivers. Maybe it is no longer an issue for modern drivers; not sure.
Maybe these changes (such as 7125723) should be #ifdef MACOSX to make it clear
that it's working around Mac-specific bugs (assuming that was the case).
Just want to make sure we're not creating layers of workarounds here. Or, if
the workarounds are needed, it would be nice if they were explicitly documented
and/or made conditional for specific platforms.
Thanks,
Chris
P.S. Good to see some activity on the OGL pipeline. I don't get paid to worry
about these things anymore though, so perhaps I should just crawl back in my
hole now :)
On Jul 9, 2012, at 4:35 AM, Sergey Bylokhov wrote:
Hi Everyone,
Please review the fix for 7181438.
This bug was introduced in 7u4b11, when macosx-port was integrated to jdku7 by
this changeset:
http://hg.openjdk.java.net/jdk7u/jdk7u-dev/jdk/rev/9dfe50f456be
Note that now we always set format to GL_RGBA. So opaque surface has an alpha
channel.
We handle this situation in: OGLBlitSurfaceToSurface, OGLBlitSwToSurface,
OGLBlitToSurfaceViaTexture,
but there is no check in OGLBlitSwToTexture().
I assume that code for alpha verification should be the same.
Bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7181438
Webrev can be found at: http://cr.openjdk.java.net/~serb/7181438/webrev.00
Also note that CR 7177173 and 7124244 depends from this one.
--
Best regards, Sergey.
--
Best regards, Sergey.
