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) |