| 834 |
|
<p> |
| 835 |
|
|
| 836 |
|
<dt> |
| 837 |
+ |
<a NAME="WGMDfunc"> |
| 838 |
+ |
<b>WGMDfunc</b> |
| 839 |
+ |
</a> |
| 840 |
+ |
|
| 841 |
+ |
<dd> |
| 842 |
+ |
WGMDfunc is a more programmable version of <a HREF="#Trans2">trans2</a>, |
| 843 |
+ |
with separate modifier paths and variables to control each component. |
| 844 |
+ |
(WGMD stands for Ward-Geisler-Moroder-Duer, which is the basis for |
| 845 |
+ |
this empirical model, similar to previous ones beside Ashik2.) |
| 846 |
+ |
The specification of this material is given below. |
| 847 |
+ |
<pre> |
| 848 |
+ |
mod WGMDfunc id |
| 849 |
+ |
13+ rs_mod rs rs_urough rs_vrough |
| 850 |
+ |
ts_mod ts ts_urough ts_vrough |
| 851 |
+ |
td_mod |
| 852 |
+ |
ux uy uz funcfile transform |
| 853 |
+ |
0 |
| 854 |
+ |
9+ rfdif gfdif bfdif |
| 855 |
+ |
rbdif gbdif bbdif |
| 856 |
+ |
rtdif gtdif btdif |
| 857 |
+ |
A10 .. |
| 858 |
+ |
</pre> |
| 859 |
+ |
|
| 860 |
+ |
The sum of specular reflectance (<I>rs</I>), specular transmittance (<I>ts</I>), |
| 861 |
+ |
diffuse reflectance (<I>rfdif gfdif bfdif</I> for front and <I>rbdif gbdif bbdif</I> for back) |
| 862 |
+ |
and diffuse transmittance (<I>rtdif gtdif btdif</I>) should be less than 1 for each |
| 863 |
+ |
channel. |
| 864 |
+ |
|
| 865 |
+ |
<p> |
| 866 |
+ |
|
| 867 |
+ |
Unique to this material, separate modifier channels are |
| 868 |
+ |
provided for each component. |
| 869 |
+ |
The main modifier is used on the diffuse reflectance, both |
| 870 |
+ |
front and back. |
| 871 |
+ |
The <I>rs_mod</I> modifier is used for specular reflectance. |
| 872 |
+ |
If "void" is given for <I>rs_mod</I>, |
| 873 |
+ |
then the specular reflection color will be white. |
| 874 |
+ |
The special "inherit" keyword may also be given, in which case |
| 875 |
+ |
specular reflectance will share the main modifier. |
| 876 |
+ |
This behavior is replicated for the specular transmittance modifier |
| 877 |
+ |
<I>ts_mod</I>, which also has its own independent roughness expressions. |
| 878 |
+ |
Finally, the diffuse transmittance modifier is given as |
| 879 |
+ |
<I>td_mod</I>, which may also be "void" or "inherit". |
| 880 |
+ |
Note that any spectra or color for specular components must be |
| 881 |
+ |
carried by the named modifier(s). |
| 882 |
+ |
|
| 883 |
+ |
<p> |
| 884 |
+ |
|
| 885 |
+ |
The main advantage to this material over |
| 886 |
+ |
<a HREF="#BRTDfunc">BRTDfunc</a> and |
| 887 |
+ |
other programmable types described below is that the specular sampling is |
| 888 |
+ |
well-defined, so that all components are fully computed. |
| 889 |
+ |
|
| 890 |
+ |
<p> |
| 891 |
+ |
|
| 892 |
+ |
<dt> |
| 893 |
|
<a NAME="Dielectric"> |
| 894 |
|
<b>Dielectric</b> |
| 895 |
|
</a> |
