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Comparing ray/doc/man/man1/rcontrib.1 (file contents):
Revision 1.3 by greg, Thu Jun 14 22:45:23 2012 UTC vs.
Revision 1.18 by greg, Wed Sep 9 21:28:19 2020 UTC

# Line 9 | Line 9 | rcontrib - compute contribution coefficients in a RADI
9   ][
10   .B \-V
11   ][
12 + .B "\-t secs"
13 + ][
14   .B "\-c count"
15   ][
16   .B \-fo
# Line 21 | Line 23 | rcontrib - compute contribution coefficients in a RADI
23   ][
24   .B "\-o ospec"
25   ][
26 + .B "\-p p1=V1,p2=V2"
27 + ][
28   .B "\-b binv"
29   ][
30   .B "\-bn nbins"
# Line 61 | Line 65 | character.)\0
65   If the
66   .I \-n
67   option is specified with a value greater than 1, multiple
64 – .I rtrace
68   processes will be used to accelerate computation on a shared
69   memory machine.
70   Note that there is no benefit to using more processes
# Line 102 | Line 105 | The
105   option tells
106   .I rcontrib
107   how many rays to accumulate for each record.
108 < The default value is 1, meaning a full record will be produced for
108 > The default value is one, meaning a full record will be produced for
109   each input ray.
110 < For values greater than 1, contributions will be averaged together
110 > For values greater than one, contributions will be averaged together
111   over the given number of input rays.
112   If set to zero, only a single record will be produced at the very
113   end, corresponding to the sum of all rays given on the input
# Line 114 | Line 117 | This is equivalent to passing all the output records t
117   to sum RGB values together, but is much more efficient.
118   Using this option, it is possible to reverse sampling, sending rays from
119   a parallel source such as the sun to a diffuse surface, for example.
120 < Note that output flushing via zero-direction rays is disabled
121 < for accumulated evaluations.
120 > Note that output flushing via zero-direction rays is disabled with
121 > .I \-c
122 > set to zero.
123   .PP
124 + If progress reports are desired, the
125 + .I \-t
126 + option specifies a time interval in seconds for reports sent to
127 + standard error.
128 + .PP
129   The output of
130   .I rcontrib
131   has many potential uses.
# Line 129 | Line 138 | can be used to compute arbitrary input-output relation
138   systems, such as luminaires, light pipes, and shading devices.
139   .PP
140   .I Rcontrib
141 < calls
142 < .I rtrace(1)
134 < with the \-oTW (or \-oTV) option to calculate the daughter ray
135 < contributions for each input ray, and the output tallies
136 < are sent to one or more destinations according to the given
141 > sends the accumulated rays tallies
142 > to one or more destinations according to the given
143   .I \-o
144   specification.
145   If a destination begins with an exclamation mark ('!'), then
# Line 159 | Line 165 | The
165   option may be used to further define
166   a "bin number" within each object if finer resolution is needed, and
167   this will be applied to a "%d" format in the output file
168 < specification if present.
168 > specification if present.
169 > (The final integer will be offset incrementally
170 > if the output is a RADIANCE picture and more than one modifier has
171 > the same format specification.)\0
172   The actual bin number is computed at run time based on ray direction
173   and surface intersection, as described below.
174 < If the number of bins is known in advance, it should be specified with the
174 > The number of bins must be specified in advance with the
175   .I \-bn
176   option, and this is critical for output files containing multiple values
177   per record.
# Line 172 | Line 181 | it has been defined via a previous
181   or
182   .I \-e
183   option.
184 < Since bin numbers start from 0, the bin count is always equal to
185 < the last bin plus 1.
177 < Set the this value to 0 if the bin count is unknown (the default).
184 > Since bin numbers start from zero, the bin count is always equal to
185 > the last bin plus one.
186   The most recent
187 + .I \-p,
188   .I \-b,
189   .I \-bn
190   and
# Line 189 | Line 198 | and
198   .I \-y
199   if the
200   .I \-c
201 < is 0, when they control the resolution string
201 > is zero, when they control the resolution string
202   produced in the corresponding output.
203   .PP
204   If a
205   .I \-b
206   expression is defined for a particular modifier,
207   the bin number will be evaluated at run time for each
208 < ray contribution from
200 < .I rtrace.
208 > ray contribution.
209   Specifically, each ray's world intersection point will be assigned to
210   the variables Px, Py, and Pz, and the normalized ray direction
211   will be assigned to Dx, Dy, and Dz.
# Line 206 | Line 214 | These parameters may be combined with definitions give
214   arguments and files read using the
215   .I \-f
216   option.
217 + Additional parameter values that apply only to this modifier may be specified
218 + with a
219 + .I \-p
220 + option, which contains a list of variable names and assigned values, separated
221 + by commas, colons, or semicolons.
222   The computed bin value will be
223   rounded to the nearest whole number.
224 + (Negative bin values will be silently ignored.)\0
225 + For a single bin, you may specify
226 + .I "\-b 0",
227 + which is the default.
228   This mechanism allows the user to define precise regions or directions
229   they wish to accumulate, such as the Tregenza sky discretization,
230   which would be otherwise impossible to specify
# Line 216 | Line 233 | The rules and predefined functions available for these
233   described in the
234   .I rcalc(1)
235   man page.
236 < Unlike
236 > Like
237   .I rcalc,
238   .I rcontrib
239   will search the RADIANCE library directories for each file given in a
# Line 271 | Line 288 | A command argument beginning with a dollar sign ('$')
288   replaced by the contents of the given environment variable.
289   A command argument beginning with an at sign ('@') is immediately
290   replaced by the contents of the given file.
291 + .PP
292 + .I Rcontrib
293 + supports light source contributions from photon maps generated by
294 + .I mkpmap(1)
295 + with its
296 + .I -apC
297 + option. Enabling photon mapping is described in the
298 + .I rtrace
299 + man page along with its relevant settings. In photon mapping mode,
300 + .I rcontrib
301 + only supports contributions from light sources, not arbitrary modifiers.
302 + The
303 + .I -b
304 + option is supported along with its associated ray variables, as
305 + discussed above. Ray coefficients are also supported via the
306 + .I \-V-
307 + option. Using fewer photons than there are light sources for the photon
308 + density estimates results in omitted contributions, thus the bandwidth
309 + is clamped accordingly and a warning is issued.
310   .SH EXAMPLES
311   To compute the proportional contributions from sources modified
312   by "light1" vs. "light2" on a set of illuminance values:
# Line 291 | Line 327 | pcomb \-c 100 90 75 c_light1.hdr \-c 50 55 57 c_light2
327   .PP
328   To compute an array of illuminance contributions according to a Tregenza sky:
329   .IP "" .2i
330 < rcontrib \-I+ \-b tbin \-o sky.dat \-m skyglow \-b 0 \-o ground.dat \-m groundglow
331 < @render.opt \-f tregenza.cal scene.oct < test.dat
330 > rcontrib \-I+ \-f tregenza.cal \-b tbin \-bn Ntbins \-o sky.dat \-m skyglow
331 > \-b 0 \-o ground.dat \-m groundglow @render.opt scene.oct < test.dat
332 > .PP
333 > To perform an annual simulation of 365 daily sun positions in photon mapping
334 > mode:
335 > .IP "" .2i
336 > rcontrib \-I+ \-h \-V \-fo \-o c_%s.dat \-M lights \-ap contrib.pm 365
337 > scene.oct < test.dat,
338   .SH ENVIRONMENT
339   RAYPATH         path to search for \-f and \-M files
340 + .SH BUGS
341 + We do not currently compute contributions or coefficients properly
342 + in scenes with participating media.
343 + A single warning will be issued if a scattering or absorbing medium
344 + is detected.
345   .SH AUTHOR
346   Greg Ward
347   .SH "SEE ALSO"
348 < cnt(1), genklemsamp(1), getinfo(1), pcomb(1), pfilt(1), ra_rgbe(1),
349 < rcalc(1), rpict(1), rsensor(1), rtrace(1), total(1), vwrays(1), ximage(1)
348 > cnt(1), genklemsamp(1), getinfo(1), mkpmap(1), pcomb(1), pfilt(1),
349 > ra_rgbe(1), rcalc(1), rfluxmtx(1), rmtxop(1), rpict(1), rsensor(1),
350 > rtrace(1), total(1), vwrays(1), ximage(1)
351 >

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