Texturing: DDS format in BF2 explained

[AfterDune]

(if you find any errors, feel free to let me know, I'm just trying to help people on their way)


This tutorial will try to answer the following question: When to use what DDS format?


Okay, we have the following topics:

• Image dimensions
• Formats and differences
• Mipmaps
• Alpha / Transparency
• Atlas
• When to use what format
• How to save DDS files using Photoshop

Image dimensions
DDS image dimensions must be a power of 2.


Formats and differences
There are different formats. We'll highlight only a few in this tutorial:

• DXT1 files are basically 4 times smaller than equivalent DXT5 ones, due to compresion algorythms and no or 1bit alpha mask
• DXT1 only supports opaque or 1 bit alpha mask, meaning a pixel is 100% opaque or 100% transparent and no trade off
• DXT5 supports 8bit transparency (256 shades of transparency) or 1bit alpha
• 8.8.8.8 ARGB, no idea about this one . You only use it in one occasion as far as I'm aware. Keep on reading

Mipmaps
Mipmaps are pre-calculated, optimized collections of images that accompany a main texture, intended to increase rendering speed and reduce aliasing artifacts. Yes, that's a mouthful. Just take a look at this image, it'll explain 1000 words:



If you're close to the object using this texture, it will use the biggest mipmap. The further you get away from the object, the smaller the mipmap is that will be displayed, which ultimately is better for performance.


Alpha
With or without alpha.
Alpha layers are used to set transparency for example.
Ask yourself, is any part of my image transparent?




Atlas
An atlas is nothing more than a collection of image files, combined into a single image. If the atlas image is 'full', you'll end up with multiple atlas files. That's no problem, performance wise it's still better to let the system open, read and close 1 or 2 (atlas) images, rather than hundreds of small images.

If you're not using an atlas, you may have to take an extra step when saving your images. This counts only for menu files though (images stored in the menu zipfiles).

Example of an atlas:


(click to enlarge)


When to use what format

Minimap
Location: levels/your_mapname/hud/
Format: DXT1, no alpha, no mipmaps

Map overview
Location: levels/your_mapname/info/
Format: DXT1, no alpha, no mipmaps, rename to PNG

Map loading screen
Location: levels/your_mapname/info/
Format: DXT1, no alpha, no mipmaps, rename to PNG

Weapon icon
Location: menu/hud/texture/ingame/weapons/icons/hud/selection/
Format with atlas: 32-bit TGA
Format without atlas: 32-bit TGA, flip image vertically, rename to DDS

Weapon selection icon
Location: menu/hud/texture/ingame/weapons/icons/hud/selection/
Format with atlas: 32-bit TGA
Format without atlas: 32-bit TGA, flip image vertically, rename to DDS

Vehicle icon
Location: menu/hud/texture/ingame/vehicles/icons/hud/vehicleicons/
Format with atlas: 32-bit TGA
Format without atlas: 8.8.8.8 ARGB, no mipmaps

Minimap icon
Location: menu/hud/texture/ingame/vehicles/icons/minimap
Format: DXT1, 1-bit alpha, no mipmaps

Object textures
Information: statics, vehicles, weapons, etc.
Location: objects/...
Format: DXT5 (in most cases), interpolated alpha (in most cases), generate mipmaps

Sky texture
Location: common/textures/sky/
Format: DXT1, no alpha, no mipmaps

Flags (minimap and scoreboard)
Location: menu/hud/texture/ingame/flags/icons/hud/score/your_teamname/
Location: menu/hud/texture/ingame/flags/icons/minimap/your_teamname/
Format: DXT1, 1-bit alpha, no mipmaps


How to save DDS files using Photoshop

First you need to have the Nvidia DDS plugin. You can download it here. Select 32- or 64-bit, depending on what version of Photoshop you're running.

If you save your texture as DDS file, the following window will pop up:



With the knowledge you now have, you should be able to save your texture in the right format .