Making an Animated Texture

The reader must be familiar with basic material creation in order to understand this tutorial.

We're going to make an animated texture. This special kind of texture contains several images written to the same VTF file, so that the images flash one after the other, much like an animated GIF.

As with normal material creation, we need TGA images whose dimensions are powers of 2. The TGAs we use must be 32-bit this time, though! Each frame of the animated texture you'd like to make must be a separate TGA image. The naming convention should be image000.tga, image001.tga, adding to the number until you reach the final frame.

All of these TGAs must be in some subdirectory of <game>/<mod>/materialsrc, so I will place mine in half-life 2/hl2/materialsrc/rae. Also in this folder must be a text file called image.txt (where image is the name of all of the images, minus the numbers and .TGA extension).

If I have five frames I want to combine into a single texture, this gives me the following files in half-life 2/hl2/materialsrc/rae:

- image000.tga
- image001.tga
- image002.tga
- image003.tga
- image004.tga
- image.txt

The text file, as mentioned in the material creation tutorial, contains special compile parameters for the material. In this case, the text file will tell us that the files marked 000 through 004 should all be compiled into the same VTF file.

Write the following into the text file:

"startframe" "0"
"endframe" "4"

Because of this, you can number the images however you like, as long as they go in order. startframe should be set to the first frame in the animation, and endframe to the last one.

If you have all your 32-bit TGAs and a proper TXT file to reference them, you must now compile the text file. Not all VTEX GUIs may support this, but since image.txt contains information for referencing the other textures, this is necessary. The GUI you use may have a special way of making animated textures; consult its documentation. For VTEX, just drag and drop the TXT file onto the VTEX executable.

If image.txt is compiled correctly, you will simply get a VTF called image.vtf. For instance, I would find that there exists a file half-life 2/hl2/materials/rae/image.vtf.

This VTF can now be referenced by a VMT and used as a normal texture. However, the VMT needs a small change to make it useful. Let's take a standard VMT for this texture:

"LightmappedGeneric"
{
   "$basetexture" "rae/image"
}

Inside the VMT, we can declare a few properties of the animation. Behold:

"LightmappedGeneric"
{
   "$basetexture" "rae/image"
   "Proxies"
   {
      "AnimatedTexture"
      {
         "animatedtexturevar" "$basetexture"
         "animatedtextureframenumvar" "$frame"
         "animatedtextureframerate" 30
      }
   }
}

In this example, we're calling on a proxy, essentially a special way of controlling material behavior, to set a few properties. Animatedtexturevar is the texture (in variable form) that should cycle through all of its frames; animatedtextureframenumvar is a variable in which the current frame will be placed; animatedtextureframerate is the framerate at which the texture will cycle through its frames, in frames per second.

Tada! Animated texture.

[With a special thank-you to Cheeko for getting me to try 32-bit TGAs. My meager 24-bit ones weren't working.]