Curious Alpha Alternative

[Muffin Man 0]

I'm not sure if anyone has figured this out before, and forgive me if you have, but I've discovered a way around using alphas for transparencies in texturing using only normal gif files. It's not fool proof, and it has some small problems, but I'll be damned if it doesn't work.

Let me digress for a moment to explain how I found it first. I started making mods around 1999, while engrossed in Rogue Spear. I wasn't modeling, but I was doing a lot of file editing, re-skinning and interface menu re-texturing. All Rogue Spear transparent tga files had this hot pink background color, and there didn't appear to be any alpha image to speak of. I used to just paste new pics over the old, leaving the background, and they showed up properly in the game every time. I also copied the pink color and created my own images from scratch with that background and they worked. I never used alphas until I got into modeling in OFP.

Anyway, I was working up some textures for a weapon last weekend, and decided to try that background color for kicks. I used it more specifically for my map pic to layout the model, and it was a good while before I realized that the background areas of the pic were appearing as the gray and white checkerboard that transparent alpha tga files show in O2. I went ahead and applied the image to a plane as a texture, to see what would happen, and son of a gun, the background was transparent! This was just a regular old gif file made in PS7 without the alpha plug-in patch.

The only real drawback is that the pink does bleed into the textures around some edges, but if some beginners can't seem to figure out alphas, it's an easy way to get around it and still get transparencies.

Here's the color, give it a shot and see how it works:

[chris330 0]

Nice find. Haven't tried it yet but sounds well wierd. Had to check to make sure it's not April the 1st. I'll give it a go next time I fire up Oxygen.

[Muffin Man 0]

Heh, yeah I know it sounds fishy enough.

It doesn't work with tga, as far as I've been able to see, only gif, and there is that pesky highlight color bleed through thing, like when you use white as your background color, but hell, as difficult as the alpha concept can be for some people, it'll get you around that issue in a pinch, until you can figure alphas out.

[fasad 1]

Magenta was/is the traditional colour used to display transparency before alpha channels were used, simply because it was the least likely colour to use in games. I guess this is a hangover from the early days of OFP's life, before alphas were considered a realistic option???

This is interesting, but it would be much smarter to take 5 minutes to learn how alpha channels work than using a single colour. Using the colour is really no easier and is far less flexible.

[chris330 0]

True enough you can't beat a bit of interesting trivia. It's things like this which can turn up interesting new things occasionally.

[remcen 0]

Magenta was/is the traditional colour used to display transparency before alpha channels were used, simply because it was the least likely colour to use in games.

Yep, i once made a private mod for wolfenstein3d (yes, the DOS game); the same tone was used for transparency in the editor there.

[fasad 1]

me too - we're showing our age... shhhhh

[Victor_S. 0]

Wow, nice find. I never thought to use it even though I have seen it in other games.

[sasyboy 0]

Anyone know of a good tutorial for alpha channels. I've searched for an OFP tutorial using AlTexViewer but I just can't get it to read my tga files. Things driving me nuts and ass for the paa pluging for ps just aint getting them trasparency to show. Left scratching my head Any suggestions? All alpha just looks like a nice white in game and O2.

[Macser_old 0]

Well,I can only describe my method.

I create my image,add an alpha channel,erase the area

of the alpha I want to be visible.Then I save the image

as a 32Bit TGA,making sure I don't exclude the alpha.

Next I open up PaaTool,select my newly created TGA

,select DXT 5:5:5:1 from the menu on the left hand side.

Then save it as fileName.Paa in the correct location.

If you're unsure whether or not your alpha is workin,

open it with Texview.You should see your image with

transparency showing as grey.

Now,I don't know how familiar you are with O2 and Buldozer,

but if the problem is not your alpha channel,then the white

textures ingame means you need to re-check the paths to

your texture files.Buldozer will display white textures if it

can't find the ones assigned to those faces.They will also

show up this way ingame too.

Hope that's of some assistance.

Macser

PaaTool

Texview

[Ian Malcolm 0]

This method is used on all old OFP vegetation. The main advantage of it is that it do not suffer by alphasorting problems. In ArmA is used "sharp" alphachanel instead (just black and white colors only), with same result - i.e. no sorting troubles.