| 152 |
|
rendering an image a piece at a time. |
| 153 |
|
A value of 1 means that the rendered image starts just to the right of |
| 154 |
|
the normal view. |
| 155 |
< |
A value of -1 would be to the left. |
| 155 |
> |
A value of \-1 would be to the left. |
| 156 |
|
Larger or fractional values are permitted as well. |
| 157 |
|
.TP |
| 158 |
|
.BI -vl \ val |
| 263 |
|
.I frac |
| 264 |
|
is too large. |
| 265 |
|
It is usually wise to turn off image sampling when using |
| 266 |
< |
direct jitter by setting -ps to 1. |
| 266 |
> |
direct jitter by setting \-ps to 1. |
| 267 |
|
.TP |
| 268 |
|
.BI -ds \ frac |
| 269 |
|
Set the direct sampling ratio to |
| 555 |
|
.I \-dv |
| 556 |
|
option (above) may be used to override this. |
| 557 |
|
.TP |
| 558 |
+ |
.BR \-u |
| 559 |
+ |
Boolean switch to control uncorrelated random sampling. |
| 560 |
+ |
When "off", a low-discrepancy sequence is used, which reduces |
| 561 |
+ |
variance but can result in a brushed appearance in specular highlights. |
| 562 |
+ |
When "on", pure Monte Carlo sampling is used in all calculations. |
| 563 |
+ |
.TP |
| 564 |
|
.BI -lr \ N |
| 565 |
|
Limit reflections to a maximum of |
| 566 |
|
.I N. |
| 567 |
+ |
If |
| 568 |
+ |
.I N |
| 569 |
+ |
is zero, then Russian roulette is used for ray |
| 570 |
+ |
termination, and the |
| 571 |
+ |
.I -lw |
| 572 |
+ |
setting (below) must be positive. |
| 573 |
+ |
If N is a negative integer, then this sets the upper limit |
| 574 |
+ |
of reflections past which Russian roulette will not be used. |
| 575 |
+ |
In scenes with dielectrics and total internal reflection, |
| 576 |
+ |
a setting of 0 (no limit) may cause a stack overflow. |
| 577 |
|
.TP |
| 578 |
|
.BI -lw \ frac |
| 579 |
|
Limit the weight of each ray to a minimum of |
| 580 |
|
.I frac. |
| 581 |
< |
During ray-tracing, a record is kept of the final contribution |
| 582 |
< |
a ray would have to the image. |
| 583 |
< |
If it is less then the specified minimum, the ray is not traced. |
| 581 |
> |
During ray-tracing, a record is kept of the estimated contribution |
| 582 |
> |
(weight) a ray would have in the image. |
| 583 |
> |
If this weight is less than the specified minimum and the |
| 584 |
> |
.I -lr |
| 585 |
> |
setting (above) is positive, the ray is not traced. |
| 586 |
> |
Otherwise, Russian roulette is used to |
| 587 |
> |
continue rays with a probability equal to the ray weight |
| 588 |
> |
divided by the given |
| 589 |
> |
.I frac. |
| 590 |
|
.TP |
| 591 |
|
.BI -S \ seqstart |
| 592 |
|
Instead of generating a single picture based only on the view |
| 774 |
|
A progress report writes the number of rays traced, the percentage |
| 775 |
|
completed, and the CPU usage to the standard error. |
| 776 |
|
Reports are given either automatically after the specified interval, |
| 777 |
< |
or when the process receives a continue (-CONT) signal (see |
| 777 |
> |
or when the process receives a continue (\-CONT) signal (see |
| 778 |
|
.I kill(1)). |
| 779 |
|
A value of zero turns automatic reporting off. |
| 780 |
|
.TP |
| 788 |
|
The default is to print warnings, so the first appearance of |
| 789 |
|
this option turns them off. |
| 790 |
|
.SH EXAMPLE |
| 791 |
< |
rpict -vp 10 5 3 -vd 1 -.5 0 scene.oct > scene.pic |
| 791 |
> |
rpict \-vp 10 5 3 \-vd 1 \-.5 0 scene.oct > scene.pic |
| 792 |
|
.PP |
| 793 |
< |
rpict -S 1 -o frame%02d.pic scene.oct < keyframes.vf |
| 793 |
> |
rpict \-S 1 \-o frame%02d.pic scene.oct < keyframes.vf |
| 794 |
|
.SH ENVIRONMENT |
| 795 |
|
RAYPATH the directories to check for auxiliary files. |
| 796 |
|
.SH FILES |
