Some useful links:

First, some basics:

Half-Life Color Decals are a trick discovered by the user community. Valve originally wrote their decal code supporting a maximum-sized image of 64 x 64. Not only that, but the image itself could be only greyscale, with a generic list of a dozen colors or so for you to choose from once inside the game. Players made their own greyscale decals, and everyone was happy.

And then the world changed. Someone discovered that the decal image itself was actually stored in a WAD file once you chose it; supposedly done so that the engine had a common format to deal with. This WAD file is named pldecal.wad, and a separate one exists for every mod you play. The actual decal is named LOGO inside that WAD. By creating your own WAD file, and putting your own image in there, you bypass the default mechanism for creating the WAD file and can spray full-colored images.

For those of you who aren't overly familiar with Half-Life textures, a WAD file is a collection of game images. It's like a ZIP file that contains nothing but images of varying types for the game to use.

Great, so how do I do this?

• Download the latest version of Wally (1.53 and up)
  • Run the downloaded self-extracting EXE, and extract the program to your hard drive
• Start Wally
• Go to Wizard|HL Color Decal Wizard:

• Select your Half-Life folder (use the little [..] button to bring up a GUI)
• Choose the mod you want to put the decal in (IE cstrike for Counter-Strike)
• Choose where you're going to provide the image for the decal
  • Clipboard: you must already have an image on the clipboard
  • File: IE a BMP, PCX, or JPG file sitting on your hard drive
  • Let me edit: you can make the decal yourself using Wally's editing tools
• Click on OK when you're ready to have Wally create your decal

That's it!

What you'll end up with is a brand spanking new WAD file, named pldecal.wad, and your image of choice will be named appropriately inside that WAD... ie {LOGO.

Please Note: Once Wally builds the WAD file, it won't automatically save the file to your hard drive. We're giving you a chance to back out of the decal in case something went terribly wrong... like you picked a picture of your sister instead of Latetia Casta. So... in order to finalize the deal, you're going to have to save the new decal. You'll be told of this as soon as you try and close the WAD, or close Wally. Just click on Yes when it asks you to save and Wally will put the decal in the appropriate directory. Or, just shortcut the whole deal and hit Ctrl-S. Of course, if something did go wrong, click on No and start over.

Animated Decals (advanced)

It is possible to create animated decals. You have the same restrictions and rules as you do for normal decals, except that the total size of all images in your animation must be less than the 16k limit you have with normal decals. This means you can't have a dozen images at 64x64. The best size I've been able to use with a decent animation sequence is 7 frames at 32x32. The second "problem" with animated decals is that they only animate one time, immediately after you spray it.

Use this nifty calculator to determine whether or not you can create an animation sequence with the specified parameters:

So how do I make an animated decal? You can't use the Decal Wizard, as the tutorial above shows. The reason being the Wizard is designed for single animations and can't be used for more than one frame. You can use it to get started with the WAD file, but overall there is no advantage going that route. This is an advanced topic, and you really should have firm understanding of the WAD editor in Wally and how to add images to a WAD.

First, create a new WAD by going to File|New, and choosing "Half-Life Package (WAD3)" as the type. Then, import in all of your images, either by using the clipboard, or loading up each image from disk. If you're using the clipboard, name them {frame1, {frame2, {frame3, etc. This way, Wally will reserve index #255 for pure blue so you don't have to mess with that. If you load them from disk, you might want to manually rename your files like I've listed above so that they also have index #255 reserved properly.

Once you have all of your images loaded into the WAD, you have to rename them to match the sequence expected for an animation loop. Your first image should be named +0{LOGO, your second image should be named +1{LOGO, and so on. Once you've got them all renamed, save the WAD to your mod's directory and go try it out.

Click here for an example animated decal.

FAQ

Q. ARGH! Every time I go to check to see if my decal is there, it's changed to something else! WTF!?
A. This is a very common problem that people e-mail or post about. The problem lies in using the Multiplayer|Customize menu choice once inside the game. You absolutely cannot go to Multiplayer|Customize when using custom decals. If you do that, Half-Life will attempt to read your custom WAD file and check to see if the file is okay. Because it doesn't match what it thinks you're supposed to have (we are tricking the system here, remember) it deletes your WAD file and creates a new one. Yes, you heard right. What this essentially means is if you want to use custom decals, you're going to have to learn to not go into that customize screen.

With that said, there is a way around this. For those savvy players out there that understand what's really going on here, you can make your pldecal.wad file read-only. I'm not even going to suggest how to do this or tell people explicitly how they can do it, because as soon as I do someone is going to write and ask how to stop making it read-only even though they have the instructions right in front of them.

Q. ARGH! This thing isn't working, I can't live without my color decals, I'm dying here, PLZ HELP ME OH GOD!

A. Okay, first off, you need to relax. Take a long, deep breath. Not having color decals is not the end of the world, and people really need to understand that this is a game. Now I'll get off my soapbox, and try to help you out. Keep reading!

Q. When I join a server and spray my decal, it shows up but it's entirely monochrome!
A. This is another common problem we've seen. This issue has to deal with the color palette. If you decided to venture out and create your WAD file manually, IE without using Wally's decal wizard, then this problem might have ensnared you. Each image in Half-Life is 8-bit. This means 256 colors in the palette. The decal system reserves exactly one entry out of these 256 palette entries for its own use. That palette entry is index 255.

In order for your color decal to work, index #255 in your image's palette must be pure blue. When you use the wizard, Wally takes care of this for you. When you don't use the wizard, you must make sure to handle it yourself. Open up your image inside Wally. Go to Colors|Edit Palette. Double-click on the very bottom-right square in the palette dialog that appears. This will let you change the color for that index. Enter the number zero (0) for both Red and Green fields. Enter 255 in the Blue field. Click OK, click OK again, and then save your image back into the WAD, and save your WAD. Go try it again, and it should be working.

Q. My decal works on some servers, but not on others!
A. Some server admins have chosen to disallow custom decals, because of their size. This means you can't upload your fancy decal to their server for other people to see. As a result, when you spray your decal it appears as the default Half-Life logo.

Q. Every time I try to use an image I've got, Wally tells me it's not divisible by 16 or something like that. WTF is this?!
A. Half-Life textures are limited in the sizes that you can have. Decals are restricted even further. All textures must be in dimensions that are multiples of 16. This means 16 x 16, 32 x 16, 64 x 32, 128 x 64, etc. If you take your image's width and height and divide them each by 16, and the results are not whole integral numbers, then your image is not going to work. You must trim it down or enlarge it just enough so that it fits those constraints. Decals have one further constraint: the total size (meaning width * height) must be less than or equal to 10752. So if you multiply the width times the height and come up with a figure larger than 10752, you'll have to trim it down.

You can use Wally's selection tool to trim off the edges of your image and copy only the section that will fit the requirements. Down at the bottom of the Wally screen is a status bar that shows you the current size of the selection as you're dragging it across your image. Keep adjusting the selection until it matches the criteria, then go to Edit|Copy to copy that to the clipboard. Try the decal wizard again.

Q. I give up! I don't understand this stuff and nothing is helping me figure this out.
A. Don't give up, just keep on trying. Find another tutorial out there. Ask some of your online friends who have gotten it working. Check out some of the sites where people have collections of pre-made WAD files for you to simply drop in. Re-read all of the steps, and the FAQ items. Maybe there's a step you overlooked, or some piece of information you assumed was correct but actually isn't.

If all else fails, and you still can't seem to get anything working right, try posting on the Wally forum, or even the Counter-Strike forums. It really can be done, obviously, and there isn't any magic going on :-)