Post Reply 

Alpha broken??

Sep 5, 2014, 08:15
Post: #1
Question Alpha broken??
Good day everyone. I am trying to create a tga with a dilated transparent image on a darker backround for padding for textures in a game.

I am unable to have an alpha mask in my tga over my green backround, I used to easily do this in photoshop.

Due to my hard drive having crashed recently I cannot use photoshop for many reasons, mainly due to not being able to recover my serial.

I have tried for hours, I have asked for help, people attempt to mock or simply ignore instead of helping. Is this simply because it is impossible with gimp?
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 08:47
Post: #2
RE: Alpha broken??
Any time I used PS, always had problems with the way it uses the alpha channel, so not surprised that the reverse is true.

I am not into games, I do know many use the alpha channel in a non-standard way.

A quick search (gimp +tga +alpha) brought up several hits, one was untick RLE compression when exporting.

A single layer with alpha looks ok here

This is viewed in XnViewMP so it should be independent of Gimp

[Image: 4HNpI1N.jpg]

test.taga has alpha + 100 opacity
test2.tga has 50 % layer opacity and I pasted in the alpha mask, which looks ok to me.

Maybe if you attach an image made in PS someone with games knowledge can comment.

** https://www.gimp-forum.net/ now answering questions**
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 09:10
Post: #3
RE: Alpha broken??
Again I am guessing.

I wonder if the Gimp layer mask is your PS alpha mask

http://i.imgur.com/xSfNyw7.jpg
http://i.imgur.com/hfiGLcV.jpg

** https://www.gimp-forum.net/ now answering questions**
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 09:23
Post: #4
RE: Alpha broken??
Hrmph, I think I am closing in on a solution. After thorough reading and testing a bit, I took a tga I made in ps to gimp. I exported as tga, it was good. I added a simple full transparent layer, and exported again, it failed. I will test more, and post files with how to.
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 10:23
Post: #5
RE: Alpha broken??
Well, it is odd to me. Never really had this issue, thought it would be simple with gimp. Not sure what the issue is, but when merging layers, it seems that the "alpha ruins other channels".

I've gotten it right to, create image, transparent, draw some lightish green lines representing "grass", make layer backround with darker green, then duplicated the lightish green, merged it down to darker, dilated. Then with the lightish, use alpha to selection, merge down, create layer mask with selection, exported and here is what I got. http://s000.tinyupload.com/?file_id=4968...5382657221 You will notice that if you remove alpha it goes green basically, I was struggling to have that green backround with alpha in my tga files before. Thanks to some of the things Ofnuts has said before, I have managed to achieve this. The purpose of this is to have some padding for your transparent assets.
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 13:56 (This post was last modified: Sep 5, 2014 13:58 by Zrahurgh.)
Post: #6
RE: Alpha broken??
Whenever I have any layer, even fully transparent, and merge with a layer which has full other channel or whatever isn't specifically alpha, for example that .tga, then the green channel or whatever around the grass/non-alpha, will turn black.

This makes me unable to adjust the alpha cut off correctly. Can't have my pink flowers having a black outline. But this isn't suuper huge, as I can simply do "alpha to selection, merge down, create layer mask with selection", but to me this seems somewhat broken.
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 14:03
Post: #7
RE: Alpha broken??
Please let me know if you aren't quite understanding. Will upload files and such.
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 16:12
Post: #8
RE: Alpha broken??
I am currently using 2.9 x64 experimental. What you said did not work for me though. Levels, then alpha select, output to 1, adding layer, pointer, sample merged checked, merge down, fail.

Attempted multiple times, multiple ways too, tried adjusting both together and alone to output 1.

Pointer and channels report green as black.
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 17:10
Post: #9
RE: Alpha broken??
8 bit initially, just tried 16 and 16 float. Nothing, will install 2.8.14 now and test.
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 17:21
Post: #10
RE: Alpha broken??
In gimp 2.8.14, the same tga file cannot be viewed in the same way as with the experimental. Which was by simply switching alpha channel off in channels tab. Also attempted what you said and checked with pointer, no success.

Are you sure your method was right and that you looked through the image properly to see if it was alpha?

Select alpha in grass from tga, levels, min output to 1, create new transparent layer, merge down? Is this right?
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 20:56
Post: #11
RE: Alpha broken??
Well that's just weird man. It works to merge it down on your file, the alpha is 1 on "grass" layer...

Sat and tried to select alpha and, went level, set alpha minimum output to 1, and it didn't work at all?! http://s000.tinyupload.com/?file_id=0756...8839082695
Find all posts by this user
Quote this message in a reply
Sep 5, 2014, 20:59
Post: #12
RE: Alpha broken??
I would really like to figure this out! I've seen quite a few people saying they struggle harshly with this.
Find all posts by this user
Quote this message in a reply
Sep 6, 2014, 06:25
Post: #13
RE: Alpha broken??
I was trying and trying and trying, have now succeeded with setting minimum alpha output to 2.

Output to 1 simply doesn't have any effect on either versions of gimp for me.

How did you go about setting alpha to 0 again? With adjust minimum input? Just want to make sure that there is no better way. Seems alright though.

So I selected entire layer, adjusted alpha min out to 2, then merged layer, set min in to 2, and it seems fine!
Find all posts by this user
Quote this message in a reply
Sep 6, 2014, 09:38
Post: #14
RE: Alpha broken??
Nope, was using pixel display the whole time man.
Find all posts by this user
Quote this message in a reply
Post Reply 


Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  Color alpha function and its current errors Fuse809 0 168 Oct 11, 2014 03:53
Last Post: Fuse809
  Several hyperlinks broken adrian5683 3 195 Sep 7, 2014 09:28
Last Post: caz
  Colour balance is broken in 2.8? snowjoke 1 162 Sep 4, 2014 00:11
Last Post: snowjoke
  Gimp 2.8 freezing on Color to alpha Garverick 8 398 Aug 16, 2014 18:18
Last Post: Garverick
  Layer alpha issue Alternicity 1 247 Aug 4, 2014 19:53
Last Post: Alternicity

Forum Jump:


GIMP ForumPortalArchiveContactTermsRSS