Camouflage shader
Introduction
The "camo" shader creates a pseudo-random tri-color camouflage pattern on the object using a fractal noise pattern. This is a procedural shader based upon a fractal noise function known as fractional brownian motion or fBm.
The fractal noise function produces a pseudo-random number in the
range [-1.0 … 1.0] from the 3-space coordinates of a point in the
bounding volume of the region. This noise value is used to determine
the color of the object at the given location.
| Noise Value | Object Color |
|---|---|
nv < thresh1 |
color 1 |
nv < thresh1 and nv < thresh2 |
color 2 |
nv > thresh2 |
color 3 |
The fractal pattern has infinite resolution. As a result, the borders of the color splashes never become pixelated, no mater how close the eyepoint is to the surface.
| parameter | Abbreviation | Default Value |
|---|---|---|
Noise Parameters |
||
lacunarity |
l |
2.1753974 |
H |
H |
1.0 |
octaves |
o |
4.0 |
size |
s |
1.0 |
vscale |
v |
1.0/1.0/1.0 |
delta |
d |
1000/1000/1000 |
Shader Specific Parameters |
||
thresh1 |
t1 |
-0.25 |
thresh2 |
t2 |
0.25 |
color1 |
c1 |
97/74/41 |
color2 |
c2 |
26/77/10 |
color3 |
c3 |
38/38/38 |
- Lacunarity
-
The grid on which the noise function is built is scaled by this value for each successive octave of noise which will be combined to produce the final result.
- Octaves
-
The number of times the noise grid will be scaled and recombined to produce the final noise function
- Size, Vscale
-
If size is set it is used as a scalar which defines the size of the noise grid on the object. So if t2=0.5 and size=5mm then splotches of color3 would tend to be no larger than 5-10mm. If non-uniform scaling is required, Vscale can specify the grid size in X, Y and Z.
- Delta
-
This specifies a translation in noise space for the origin of region space. Since the origin of noise space is reflected 8 ways, it is undesirable to have that portion of noise space overlap with region space.