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OpenArena Contributions => Graphics => Topic started by: Gig on March 19, 2013, 08:29:18 am



Title: Problem creating new textures (SOLVED: it was a little problem with my image)
Post by: Gig on March 19, 2013, 08:29:18 am
Hi guys!

I'm trying to add a few textures from my own on a map of mine, using Q3Radiant.
Trying to create a specular texture, I've given a look to this page:
(DO NOT LINK) h t t p s : / / openarena . wikia . com/wiki/How_to_create_specular_textures
But it's too complicated for my brain (I have not even understood if it does mean the same thing I mean for "specular", it seems to talk about a completely different thing!)... and so I tried a different approach, much simpler but that for some cases may be enough.
So I went to Photoshop, took a 256x256 photo of mine, and copy-pasted it four times into a new 512x512 image. Then I used flip horizontally, flip vertically, flip vertically and horizontally on three of the four parts of the image.

When placed in the map, the result looks acceptable... but there is a strange thing: along the borders of the texture, I can see a thin line, that shouldn't be there.
I tried to use both JPG and TGA, but nothing changed. I can't figure out why that thin border is displayed.
Any ideas? What do I did wrong?


Title: Re: Problem creating new textures
Post by: fromhell on March 19, 2013, 08:50:24 am
That line is caused by antialiasing in your selection tool. I can see the line on the top of your result texture image.


The "specular" bits are a special shader script which requires an alpha channel for it to work. JPEG doesn't offer alpha channels (though technically, it is possible to hack the texture uploader to load additional greyscale JPEGs as alpha channels, and this is something i've tried once).


Title: Re: Problem creating new textures
Post by: Gig on March 19, 2013, 09:05:42 am
That line is caused by antialiasing in your selection tool. I can see the line on the top of your result texture image.
Uhm... extremely zooming the web page, maybe also I can see there is something like a very, very thin line of a different shade at the border of that image. Thank you for the hint. So, it's something added by Photoshop. Does someone know how to disable that effect?
Otherwise, I will try to do the same thing using a different program.

UPDATE: probably it's also in the "starting" image. I did that image some years ago... maybe at that time I used some layer blending options that added that. Probably it's not something added by Photoshop by default, it's something I added years ago and now I forgot!

Quote
The "specular" bits are a special shader script which requires an alpha channel for it to work. JPEG doesn't offer alpha channels (though technically, it is possible to hack the texture uploader to load additional greyscale JPEGs as alpha channels, and this is something i've tried once).
Okay, so it's a completely different kind of "specular" from what I intended with that word. This explains why I did understand nothing from that page. Maybe someone may edit that wiki" page to clarify what is intended with "specular", there?

Howerver, I think that also page with some tips about how to make textures with the "specular" I mean, could be good. Is there a better term than "specular" for them?


Title: Re: Problem creating new textures (SOLVED: it was a little problem with my image)
Post by: Gig on March 20, 2013, 01:59:43 am
Okay, I confirm that was the issue. Once removed the first line of pixels around the starting image, everything worked ok. That was a try of emboss that I used when I created that image years ago, and I forgot about it.

Howerver, I still think that the wiki should explain what that "specular" in that page actually means... and maybe we could create a separate page about how to make "corresponding" textures...