| 9 |
|
][ |
| 10 |
|
.B \-V |
| 11 |
|
][ |
| 12 |
+ |
.B \-c |
| 13 |
+ |
][ |
| 14 |
|
.B \-fo |
| 15 |
|
| |
| 16 |
|
.B \-r |
| 97 |
|
can be used to compute arbitrary input-output relationships in optical |
| 98 |
|
systems, such as luminaires, light pipes, and shading devices. |
| 99 |
|
.PP |
| 100 |
+ |
Setting the |
| 101 |
+ |
.I \-c |
| 102 |
+ |
option instructs |
| 103 |
+ |
.I rtcontrib |
| 104 |
+ |
to accumulate values rather than reporting one record per ray. |
| 105 |
+ |
With this option, only a single record will be produced at the very |
| 106 |
+ |
end, corresponding to the sum of all rays given on the input. |
| 107 |
+ |
This is equivalent to passing all the output records through a program like |
| 108 |
+ |
.I total(1) |
| 109 |
+ |
to sum RGB values together, but is much more efficient. |
| 110 |
+ |
Using this option, it is possible to reverse sampling, sending rays from |
| 111 |
+ |
a parallel source such as the sun to a diffuse surface, for example. |
| 112 |
+ |
Care must be taken to perform normalization based on the |
| 113 |
+ |
radiation density and the number of rays sampled. |
| 114 |
+ |
.PP |
| 115 |
|
.I Rtcontrib |
| 116 |
|
calls |
| 117 |
|
.I rtrace(1) |
| 129 |
|
If instead the |
| 130 |
|
.I \-r |
| 131 |
|
option is specified, data recovery is attempted on existing files. |
| 132 |
+ |
(If |
| 133 |
+ |
.I \-c |
| 134 |
+ |
is used together with the |
| 135 |
+ |
.I \-r |
| 136 |
+ |
option, existing files are read in and new ray evaluations are added |
| 137 |
+ |
to the previous results, providing a convenient means for |
| 138 |
+ |
progressive simulation.)\0 |
| 139 |
|
If an output specification contains a "%s" format, this will be |
| 140 |
|
replaced by the modifier name. |
| 141 |
|
The |
| 161 |
|
options to the left of each |
| 162 |
|
.I \-m |
| 163 |
|
setting affect only that modifier. |
| 164 |
< |
(The ordering of other options is unimportant.)\0 |
| 164 |
> |
The ordering of other options is unimportant, except for |
| 165 |
> |
.I \-x |
| 166 |
> |
and |
| 167 |
> |
.I \-y |
| 168 |
> |
if the |
| 169 |
> |
.I \-c |
| 170 |
> |
is present, when they control the resolution string |
| 171 |
> |
produced in the corresponding output. |
| 172 |
|
.PP |
| 173 |
|
If a |
| 174 |
|
.I \-b |
| 288 |
|
Greg Ward |
| 289 |
|
.SH "SEE ALSO" |
| 290 |
|
cnt(1), getinfo(1), pcomb(1), pfilt(1), ra_rgbe(1), |
| 291 |
< |
rcalc(1), rpict(1), rtrace(1), vwrays(1), ximage(1) |
| 291 |
> |
rcalc(1), rpict(1), rtrace(1), total(1), vwrays(1), ximage(1) |
