nuclide/Documentation/Materials/commands/tcmod.md

Materials: Commands

tcmod

Syntax

tcMod <…>

Overview

Specifies how texture coordinates are modified after they are generated.

The valid functions for tcMod are rotate, scale, scroll, stretch and transform.

Transform is a function generally reserved for use by programmers who suggest that designers leave it alone.

When using multiple tcMod functions during a stage, place the scroll command last in order, because it performs a mod operation to save precision, and that can disturb other operations.

Texture coordinates are modified in the order in which tcMods are specified. In otherwords, if you see:

 tcMod scale 0.5 0.5  tcMod scroll 1 1

Then the texture coordinates will be scaled thenscrolled'''.

Functions

rotate

This keyword causes the texture coordinates to rotate. The value is expressed in degrees rotated each second. A positive value means clockwise rotation. A negative value means counterclockwise rotation. For example "tcMod rotate 5" would rotate texture coordinates 5 degrees each second in a clockwise direction. The texture rotates around the center point of the texture map, so you are rotating a texture with a single repetition, be careful to center it on the brush (unless off-center rotation is desired).

scale

Resizes (enlarges or shrinks) the texture coordinates by multiplying them against the given factors of and <tScale). The values "s" and "t" conform to the "x" and "y" values (respectively) as they are found in the original texture. The values for sScale and tScale are NOT normalized. This means that a value greater than 1.0 will increase the size of the texture. A positive value less than one will reduce the texture to a fraction of its size and cause it to repeat within the same area as the original texture (Note: see clampmap for ways to control this).

Example: tcMod scale 0.5 2 would cause the texture to repeat twice along its width, but expand to twice its height (in which case half of the texture would be seen in the same area as the original)

scroll

Scrolls the texture coordinates with the given speeds. The values "s" and "t" conform to the "x" and "y" values (respectively) as they are found in the original texture. The scroll speed is measured in "textures" per second. A "texture" is the dimension of the texture being modified and includes any previous material modifications to the original texture). A negative s value would scroll the texture to the left. A negative t value would scroll the texture down.

Example: tcMod scroll 0.5 -0.5 moves the texture down and right (relative to the texture's original coordinates) at the rate of a half texture each second of travel.

This should be the LAST tcMod in a stage. Otherwise there maybe popping or snapping visual effects in some materials.

stretch

Stretches the texture coordinates with the given function. Stretching is defined as stretching the texture coordinate away from the center of the polygon and then compressing it towards the center of the polygon.

: A base value of one is the original dimension of the texture when it reaches the stretch stage. Inserting other '''values positive or negative in this variable will produce unknown effects.

: This is the measurement of distance the texture will stretch from the base size. It is measured, like scroll, in textures. A value of 1 here will double the size of the texture at its peak.

: See the explanation for phase under the deform vertexes keyword.

: this is wave peaks per second.

:

• Sin: the texture expands smoothly to its peak dimension and then shrinks smoothly to its valley dimension in a flowing manner.
• Triangle: The textures stretch at a constant rate and spend no appreciable time at the peak or valley points.
• Square: The texture is shown at its peak for the duration of the frequency and then at its valley for the duration of the frequency.
• Sawtooth: the texture stretches like a triangle wave until it reaches a peak, then instantly drops to the valley, as in a square wave.
• Inversesawtooth: this is the reverse of the sawtooth wave.

transform

Transforms each texture coordinate as follows:

S' = s * m00 + t * m10 + t0 T' = s * m01 + t * m11 + t1

This is for use by programmers.

turb

Applies turbulence to the texture coordinate. Turbulence is a back and forth churning and swirling effect on the texture.

The parameters for this are defined as follows:

• : Currently undefined.
• : This is essentially the intensity of the disturbance or twisting and squiggling of the texture.
• : See the explanation for phase under the deformvertexes keyword.
• : Frequency. This value is expressed as repetitions or cycles of the wave per second. A value of one would cycle once per second. A value of 10 would cycle 10 times per second. A value of 0.1 would cycle once every 10 seconds.