Texture Maps

BigWorld supports the following texture formats

"dds", "bmp", "tga", "jpg", "png", "hdr", "pfm", "dib", "ppm"

These formats are compressed automatically at runtime into .dds files.

TGA (targa) files are converted to the DXT3 format, all other file formats are converted to the DXT1 format.

Because DXT3 uses twice the disk space than DXT1 you should only use tga when you require an alpha channel.

Any file with the suffix _ norms or _normal will be converted to an A8R8G8B8 texture. This is to prevent compressing BigWorld's normal maps.

The texture_detail_levels.xml file found in fantasydemo/res/maps is used to globally define the texture compression of multiple textures either by folder or by file name.

For example, if all the GUI images in your project were being over-compressed, causing undesirable visual artifacts, you could define the following within the texture_detail_levels.xml to prevent them from being compressed.

<detailLevel>
<! -- Defines the directory which compression rules should be applied -->
<prefix>gui/maps</prefix>
<! -- Files including the word "gui" -->
<contains> gui </contains>
<! -- Defines what file type should be compressed. Alternatives include tga -->
<postfix> bmp </postfix>
<! -- Defines what compression the defined file should use. Alternatives include DXT1, DXT3. DXT5 -->
<format> A8R8G8B8 </format>
<lodMode>1</lodMode>
</detailLevel>  

Alternatively, if you find a texture is being over-compressed by the Direct X standards, then you can force it to remain 8-bits per channel (A8R8G8B8) by including a .texformat file with the same name in the same folder. (Such .texformat files can be created in any text editor, such as Notepad, for example.) It is usually a better idea to use the texture_detail_levels.xml file described above, as this can be tied in with graphics settings. However, in some cases it is easier to use a .texformat file.

So, for the following example, let's say that sky_gradient.tga was being over-compressed, resulting in compression artifacts. The file sky_gradient.texformat would then be created and added to the same folder as sky_gradient.tga, thus preventing its compression. The contents of the sky_gradient.texformat file would be the following:

<sky_gradient.texformat>
   <format> A8R8G8B8 </format>
</sky_gradient.texformat>

You can prevent mipmaps from being created entirely if you add the following tag <noResize> true </noResize> to a texformat file. In fact, this will force the engine to simply use the file provided, and not generate a .dds. This should be used sparingly.

To create an animated texture map, follow the steps below:

1 Create a sequence of animation frames in your preferred software. For this example we will use six frames of an electric field.

2 A text file has to be written to play the sequence.

Open a text editor like Notepad and write the following lines (which will later be saved as a .texanim file):

    <root>
       <frames>abcdef</frames>
       <fps> 30 </fps>
       <texture>texturepath/electric1.bmp</texture>
       <texture>texturepath/electric2.bmp</texture>
       <texture>texturepath/electric3.bmp</texture>
       <texture>texturepath/electric4.bmp</texture>
       <texture>texturepath/electric5.bmp</texture>
       <texture>texturepath/electric6.bmp</texture>
    </root>

The syntax of the .texanim file is described below:

The <frames> tag determines the order in which the frames will be played – in this example, six frames (a-f) in sequence.

If you wished to swap frames 2 and 5, the line would read: <frames>aecdbf</frames>.

If you wished to play frame 4 twice to draw out the animation, the line would read: <frames>abcddef</frames>