View Full Version : Alpha Channels

Krimsyn Kane
09-03-2006, 06:18 PM
I know there is a tutorial thread on alpha channels but I'm having a really hard time with it so I'm wondering if anyone knows how I can tackle a certain problem. I want to try using an alpha channel to make part of a texture, a characters face texture to be specific, completely transparent. Invisible. Is this possible, am I suggesting the right method?

09-03-2006, 07:17 PM
Yes it is possible and yes thats the right method. :) What program are you using? For GIMP you just have to right click on the background layer and click add alph channel. After that you can use the eraser tool to make an area semitransparent, or use the select tools to select an area and then push control+K to clear it. The proccess should be similar in photoshop, but I haven't used it for a long time and couldn't tell you how.

09-03-2006, 08:04 PM
i know i am having trouble with the tutorial as well but i am not wanted to make the items transparent, but to make the items shiny.

09-03-2006, 08:49 PM
I'll try add pictures to this post later, but I'm going to run through a fairly detailed explanation for Photoshop as it seems quite a few people are having problems with this.

Okay, first thing you need to do is open whatever texture you want with photoshop on the bottom right of your screen you should see a window with three tabs, Layers, Channels and Paths. Click the Channels tab.

Now on the bottom of this inset menu should be an button that lets you create a new channel, if you are having trouble finding it, just drag your mouse of the buttons and wait until a balloon pops up and says Create New Channel. Anyway, click that button and create a new channel, along with the RGB, Red, Green, Blue channels you should also see a new channel labeled "Alpha 1"

Double Click on Alpha 1 and a new window should show up. Make sure that Masked Area is checked and that the Color is black, and that the opacity is 100%. Basically you've just set up your Alpha Channel at least thats the way I do it.

Now anything that is colored black in the alpha channel will appear invisible in the game (if no .txi property is applied to it). Anything that is colored white will appear normally and shades of grey is pretty much like applying opacity to your texture. Meaning 25%grey would be 25% opacity. So you probably want to paint your alpha channel pure white except for the black part that you want to be invisible.

If you are going to use a shader, e.g. CM_baremetal, CM_gunmetal etc. than the alpha channel can pretty much be interpreted as the opacity of the shader. Meaning that a 100% black in the alpha channel with appear as 100% shader and 0% original texture in the game, so usually pure black is an overkill.

Hope this helps some,

Krimsyn Kane
09-04-2006, 11:46 AM
That helps a lot, thanks Mav!

Darth Dragoon
09-04-2006, 12:11 PM
is there any tutorials on creating alpha channels with corel paint shop pro X r Photo It?

Krimsyn Kane
09-04-2006, 12:21 PM
Dont know but maybe theres help files within the program itself?

09-04-2006, 12:41 PM
is there any tutorials on creating alpha channels with corel paint shop pro X r Photo It?

Paint Shop Pro:

A truckload of other PSP tutorials (will require some 'snooping' effort on your part ;) )