GL render Alpha issue

Hi all:
this issue has been existed from blender 2.5 alpha till now,
and i just wondering if there were any others notice that or just me

the issue is when i apply a texture with alpha channel to a object, and the final result of GL Render will shows a weird alpha channel in final output image.

alright, here’s some pics show how the issue is,
the very first one is in blender view port with glsl shader active:
http://lh5.ggpht.com/_AkiLsP9cB3o/TNEYUfbC8HI/AAAAAAAAAUY/R0RLEu9sYXI/s800/Alpha%20issue_01.jpg
the window has applied to a texture with alpha channel, it looks just okay for now.
and the next one is the result of GLSL Render in blender:

http://lh3.ggpht.com/_AkiLsP9cB3o/TNEYUmyHFfI/AAAAAAAAAUc/tbbzNlKN0-s/s800/Alpha%20issue_02.jpg
still looks okay, but when i switch to alpha mode to check my alpha channel like the following pic:

http://lh5.ggpht.com/_AkiLsP9cB3o/TNEYUmpNzRI/AAAAAAAAAUg/n73tYTmJVBU/s800/Alpha%20issue_03.jpg
it shows a weird alpha, looks like there’s nothing behind the window.
the alpha channel suppose to be looks like the following image that has already fixed in gimp by myself:

http://lh3.ggpht.com/_AkiLsP9cB3o/TNEYUkH3k1I/AAAAAAAAAUk/pBjU9-ZX2p0/s800/Alpha%20issue_04.jpg
is there anyone knows why?
if it indeed an error of blender itself, then could it be fixed before blender 2.6?
thx if someone answered

aYen

No one currently bothered by this like me?
i’ve post it to blender bug tracker though, hope it could help dev to find and fix it

aYen

but the GLSL preview has no issue? I think you mixed up the two alpha images because the faulty one is last, not the one you fixed in gimp.

anyways always good to bug track.

http://www.opengl.org/wiki/GLSL_:_common_mistakes

Actually i don’t know what is the issue with this… but i can’t help wondering if you activated the windshield wipers lever… just kiddin’ :smiley:

hi aermartin:

glsl result looks just fine, but when look into alpha channel it just something wrong with that.
sorry i can just do some simple codec but not a coder, so i don’t know what the exact problem is. but i still don’t think the problem is the texture itself, coz i tried so many times, and do all i can to make the alpha channel simple for different texture still with same problem happened.

and the original report thread of this issue is here:
https://projects.blender.org/tracker/index.php?func=detail&aid=24550&group_id=9&atid=498
just in case you are care about it too.

aYen

ha i do some constrain on it to have it moving, but the model itself is not made by me.

aYen

Are you using a texture map for transparency? does it have a proper alpha channel or are you using black paint?.
It looks like the blacks on the texture map are not pure black except where the map has been retouched i.e. on the windscreen.
Try making a copy of the original texture map and repaint the blacks (those you are using for transparency) with 100% black

hi aermartin:

glsl result looks just fine, but when look into alpha channel it just something wrong with that.
sorry i can just do some simple codec but not a coder, so i don’t know what the exact problem is. but i still don’t think the problem is the texture itself, coz i tried so many times, and do all i can to make the alpha channel simple for different texture still with same problem happened.

and the original report thread of this issue is here:
https://projects.blender.org/tracker/index.php?func=detail&aid=24550&group_id=9&atid=498
just in case you are care about it too.

aYen

sorry for double post, but i don’t know how to delete it, so i just shorten it.

I dont know if it is connected, but for the past week or two I have also been experincing strange things occuring with the GLSL display. The light levels would change for instance on changing a material setting, or after saving the file etc. I thaught I would check to see if I had outdated graphic drivers on the NVidia web site, and was supprised when after running the new widget, it pointed me to some drivers a year older than the ones I had installed.
Since installing these, sofar I havent noticed any glitches.

258.96_desktop_winxp_32bit_international_whql - these were the ones installed when I had problems.

15.45_nforce_winxp32_international_whql - these seem to work better.

Worth checking, if you havent allready.

Hi rebogey:

basically, i test it and get this result under several system and hardware, i can’t really tell how much i’ve tested, but at least there’re two different computer that i use for test mostly.
one at my company and one at home, and the one at home is running in multi-OS between ubuntu 10.04 and win7, both have same problem with blender last few releases,
and i have to update my graphic card driver frequency for test, so no matter what version of driver i use, it leads to the same problem.

but still thanks a lot!
it just notice me should check out some system settings besides the blender itself too.

but can anyone help me to do the same test to see if there’s still the same problem in blender that under different environment?
if so, then that would be great~

aYen