In Neverwinter Nights EE, MTR files take precedence over TXI files. This information is only included for reference.
The theory behind the TXI system is to attach properties to a certain texture. When a texture is loaded in game, the engine looks for an accompanying TXI file - recognized by having the exact same name as the texture but with the TXI extension. If the game engine does not find a TXI file, it simply loads the texture by itself. Inside the TXI file can be one or more attributes assigned to the texture, such as texture warping (for water and lava), environment mapping effects, animation, etc.
These fields go in the TXI file for the base texture. That is, do not specify these fields in the bumpmap or environment map TXI files - they will be ignored.
Specify if the environment map to use with a “shinywater” texture. Default is no bumpyshinytexture.
bumpyshinytexture myenvmapname
This parameter is always used in conjunction with the bumpmaptexture parameter “shinywater” (see below).
Specify a bumpmaptexture. Default is no bumpmaptexture. Options are “shinywater”.
bumpmaptexture shinywater
Specify an environment map for static geometry. Dynamic geometry uses the environment map provided on the model. Default is no environment map.
envmaptexture myenvmapname
Specify a blending mode for a material. This blending mode will override the standard mode. Options are "additive", "punchthrough", "default". Default is default.
blending default
Specify a transparency setting for a material. This determines how much to “fade out” the alpha channel of the texture.
alphamean 0.563
For performance reasons, it is best practice to specify the alphamean parameter for ANY texture with transparency (i.e. an alpha channel). The TXI files used with the vanilla tilesets are a good point of reference to use in determining alphamean values.
These fields are applied to the texture being read in. Some are specific to different types of textures (like bump maps) and will be ignored if the TXI belongs to a texture which is not of the same type. I will try to document these cases.
Specify the default width and height of a texture in the absence of an image. These are usually set when you are using a procedural texture. Default for both values is 16
defaultwidth 16
defaultheight 16
Specify the procedural type. Only use this if a texture needs to be generated procedurally. Options are "water", "life", "perlin", "arturo" or "wave". Default is no procedural type.
proceduretype arturo
Specify how the texture can be downsampled. Default is a min of 0, max of 15.
downsamplemax 2
downsamplemin 0
Specify whether to mipmap the texture. Valid values are 0 (off) or 1 (on) Default mipmap is on.
mipmap 0
Specify whether to filter the texture using linear filtering or not. If set to 0, filtering is nearest, otherwise it is linear. Default filtering is linear.
filter 1
Specify the gamma correction for this filter. Default gamma correction is 1.0.
gamma 0.5
Specify whether this texture is a bumpmap. If this flag is set, the texture module will expect to read in a texture which is grayscale. Default is 0.
bumpmap 1
Specify what kind of bumpmapping this bump map will do: specular, diffuse, or both. These values are ignored if this texture is not a bump map. Default: isdiffusebumpmap 0, isspecularbumpmap 1
isdiffusebumpmap 1
isspecularbumpmap 1
Specify a scaling factor for the bumpmap height. If you want higher peaks and lower valleys in the bump map, set the value to be greater than 1. If you want a smoother bump map, set this value to less than 1. Default is set to 1.
bumpmapscaling 1.5
Specify a color for specular bumpmap highlights (RGB). This value is modulated with the bump mapping light's color to produce the final highlight color. Default is (1,1,1).
specularcolor 0.5 0.5 0.8
These fields only apply to those textures which are procedural. If these values are specified on a nonprocedural texture, they will be ignored.
These two fields specify how a procedure should be applied to create a final texture. The scaling factor indicates how much the channels of the final procedural image should be affected by the # procedural result. The translation factor indicates how much to add to the scaled results for each channel.
Default: Channelscale is all 1's, channeltranslate is all 0's. This creates a grayscale semitransparent image based on the procedure.
channelscale 4
0
0.5
0.5
0
channeltranslate 4
0.5
0.5
0.5
0.5
The following field indicates whether to distort an image using the procedure. If this field is set to 1, it requires that an image be provided for this texture. Also, if this value is set to 1, all channelscale and channeltranslate values will be ignored. Default is set to 0.
distort 1
If this value is set to 1, the texture distortion occurs in an angular fashion. If 0, distortion occurs in a linear fashion. Both are valid but can produce different distortion effects. Default is set to 0.
distortangle 0
This value indicates how much the texture should be distorted (in texels). If the value is small, the original image will not be distorted significantly. If it is too large, the distortion will generate a very noisy and chaotic result. Default is set to 5.0.
distortionamplitude 3.5
This value indicates the speed of the procedure. Most procedures can be sped up or slowed down based on this value. Default is 1.0.
speed 2.0
The following two parameters are used for Arturo procedural textures. The actual arturo function is calculated using the size specified in these parameters and is then upsampled to the size of the texture. You may be able to get better results by tinkering with these, although the default values work very reasonably. Default is 15 for both.
arturowidth 17
arturoheight 17