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.B octree |
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.br |
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.B "rtrace [ options ] \-defaults" |
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+ |
.br |
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.B "rtrace \-features [feat1 ..]" |
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.SH DESCRIPTION |
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.I Rtrace |
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traces rays from the standard input through the RADIANCE scene given by |
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This may be useful for programs that run |
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.I rtrace |
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as a separate process. |
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< |
In the second form, the default values |
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> |
.PP |
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> |
In the second form shown above, the default values |
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for the options (modified by those options present) |
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are printed with a brief explanation. |
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.PP |
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In the third form, a list of supported features is sent |
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to the standard output, one per line. |
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If additional arguments follow, they are checked for presence in |
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this list. |
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If a feature includes subfeatures, these may be checked as well by |
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specifying: |
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+ |
.nf |
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+ |
|
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rtrace -features FeatName=subfeat1,subfeat2 |
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+ |
|
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.fi |
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If any named feature or subfeature is missing, an error is |
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reported and the program returns an error status. |
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If all of the named features are present, a zero status is returned. |
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.PP |
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Options may be given on the command line and/or read from the |
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environment and/or read from a file. |
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A command argument beginning with a dollar sign ('$') is immediately |
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ascii, 'f' for single-precision floating point, |
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and 'd' for double-precision floating point. |
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In addition to these three choices, the character 'c' may be used |
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to denote 4-byte floating point (Radiance) color format |
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for the output of values only |
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< |
.I (\-ov |
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option, below). |
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to denote 4-byte RGBE (Radiance) color format |
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for the output of individual color values only, and the |
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> |
.I \-x |
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> |
and |
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> |
.I \-y |
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> |
options should also be specified to create a valid output picture. |
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If the output character is missing, the input format is used. |
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.IP |
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Note that there is no space between this option and its argument. |
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.IP |
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M material name |
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.IP |
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r mirrored value contribution |
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.IP |
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x unmirrored value contribution |
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+ |
.IP |
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+ |
R mirrored ray length |
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+ |
.IP |
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+ |
X unmirrored ray length |
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+ |
.IP |
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~ tilde (end of trace marker) |
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.IP |
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If the letter 't' appears in |
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.I \-dv |
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option (below) may be used to override this. |
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This option is especially useful in |
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conjunction with ximage(1) for computing illuminance at scene points. |
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conjunction with ximage(1) for computing irradiance at scene points. |
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.TP |
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.BR \-u |
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Boolean switch to control uncorrelated random sampling. |
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specification will be calculated. |
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.TP |
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.BI -dr \ N |
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Set the number of relays for secondary sources to |
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> |
Set the number of relays for virtual sources to |
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.I N. |
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< |
A value of 0 means that secondary sources will be ignored. |
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> |
A value of 0 means that virtual sources will be ignored. |
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A value of 1 means that sources will be made into first generation |
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secondary sources; a value of 2 means that first generation |
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secondary sources will also be made into second generation secondary |
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virtual sources; a value of 2 means that first generation |
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> |
virtual sources will also be made into second generation virtual |
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sources, and so on. |
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|
.TP |
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.BI -dp \ D |
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< |
Set the secondary source presampling density to D. |
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> |
Set the virtual source presampling density to D. |
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This is the number of samples per steradian |
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|
that will be used to determine ahead of time whether or not |
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|
it is worth following shadow rays through all the reflections and/or |
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< |
transmissions associated with a secondary source path. |
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< |
A value of 0 means that the full secondary source path will always |
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> |
transmissions associated with a virtual source path. |
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> |
A value of 0 means that the full virtual source path will always |
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|
be tested for shadows if it is tested at all. |
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|
.TP |
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|
.BR \-dv |
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Set the ambient accuracy to |
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.I acc. |
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|
This value will approximately equal the error |
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< |
from indirect illuminance interpolation. |
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> |
from indirect irradiance interpolation. |
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A value of zero implies no interpolation. |
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.TP |
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|
.BI -ad \ N |
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Set the number of ambient divisions to |
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.I N. |
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|
The error in the Monte Carlo calculation of indirect |
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< |
illuminance will be inversely proportional to the square |
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> |
irradiance will be inversely proportional to the square |
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root of this number. |
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A value of zero implies no indirect calculation. |
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.TP |
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.BI -af \ fname |
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Set the ambient file to |
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|
.I fname. |
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< |
This is where indirect illuminance will be stored and retrieved. |
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< |
Normally, indirect illuminance values are kept in memory and |
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> |
This is where indirect irradiance will be stored and retrieved. |
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> |
Normally, indirect irradiance values are kept in memory and |
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|
lost when the program finishes or dies. |
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< |
By using a file, different invocations can share illuminance |
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> |
By using a file, different invocations can share irradiance |
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|
values, saving time in the computation. |
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The ambient file is in a machine-independent binary format |
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|
which can be examined with |
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termination, and the |
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|
.I -lw |
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|
setting (below) must be positive. |
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< |
If N is a negative integer, then this sets the upper limit |
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< |
of reflections past which Russian roulette will be used. |
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> |
If N is a negative integer, then this limits the maximum |
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> |
number of reflections even with Russian roulette. |
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In scenes with dielectrics and total internal reflection, |
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a setting of 0 (no limit) may cause a stack overflow. |
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|
.TP |
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divided by the given |
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|
.I frac. |
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|
.TP |
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< |
.BR -ld |
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> |
.BR \-ld |
| 693 |
|
Boolean switch to limit ray distance. |
| 694 |
|
If this option is set, then rays will only be traced as far as the |
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|
magnitude of each direction vector. |
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Otherwise, vector magnitude is ignored and rays are traced to infinity. |
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|
.TP |
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+ |
.BI -cs \ Ns |
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+ |
Use |
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+ |
.I Ns |
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+ |
bands for spectral sampling rather than the default RGB calculation space. |
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+ |
The maximum setting is controlled by the compiler macro MAXCSAMP, and |
| 703 |
+ |
defaults to 24. |
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+ |
Larger values for Ns will be reduced to MAXCSAMP. |
| 705 |
+ |
.TP |
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+ |
.BI -cw " nmA nmB" |
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+ |
Set extrema to the given wavelengths for spectral sampling. |
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+ |
The default is 380 and 780 nanometers. |
| 709 |
+ |
The order specified does not matter. |
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+ |
.TP |
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+ |
.BR \-co |
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+ |
Boolean switch turns on spectral data output if selected. |
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+ |
The default is to reduce spectral results to RGB, but see the related |
| 714 |
+ |
.I \-p* |
| 715 |
+ |
options, below. |
| 716 |
+ |
.TP |
| 717 |
+ |
.BI -pc " xr yr xg yg xb yb xw yw" |
| 718 |
+ |
Use the specified chromaticity pairs for output primaries and white |
| 719 |
+ |
point rather than the standard RGB color space. |
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+ |
.TP |
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+ |
.BR \-pRGB |
| 722 |
+ |
Output standard RGB values (the default). |
| 723 |
+ |
.TP |
| 724 |
+ |
.BR \-pXYZ |
| 725 |
+ |
Output standard CIE XYZ tristimulus values rather than RGB. |
| 726 |
+ |
.TP |
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+ |
.BR \-pY |
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+ |
Produce a single output channel corresponding to photopic luminance. |
| 729 |
+ |
.TP |
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+ |
.BR \-pS |
| 731 |
+ |
Produce a single output channel corresponding to scotopic luminance. |
| 732 |
+ |
.TP |
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+ |
.BR \-pM |
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+ |
Produce a single output channel corresponding to melanopic luminance. |
| 735 |
+ |
.TP |
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|
.BI -e \ efile |
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|
Send error messages and progress reports to |
| 738 |
|
.I efile |
| 795 |
|
.IP "" .2i |
| 796 |
|
rtrace \-ov scene.oct < samples.inp > radiance.out |
| 797 |
|
.PP |
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< |
To compute illuminance values at locations selected with the 't' |
| 798 |
> |
To compute irradiance values at locations selected with the 't' |
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|
command of |
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|
.I ximage(1): |
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|
.IP "" .2i |
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|
cnt 480 640 | rcalc \-e 'xr:640;yr:480' \-f unusual_view.cal | rtrace |
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|
\-x 640 \-y 480 \-fac scene.oct > unusual.hdr |
| 812 |
|
.PP |
| 813 |
< |
To compute ambient illuminance in photon mapping mode from a global photon |
| 813 |
> |
To compute ambient irradiance in photon mapping mode from a global photon |
| 814 |
|
map global.pm via one ambient bounce, and from a caustic photon map |
| 815 |
|
caustic.pm at sensor positions in samples.inp: |
| 816 |
|
.IP "" .2i |
| 833 |
|
.SH AUTHOR |
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|
Greg Ward |
| 835 |
|
.SH "SEE ALSO" |
| 836 |
< |
getinfo(1), lookamb(1), mkpmap(1), oconv(1), pfilt(1), pinterp(1), |
| 837 |
< |
pvalue(1), rcontrib(1), rpict(1), rtpict(1), rvu(1), vwrays(1), ximage(1) |
| 836 |
> |
dctimestep(1), getinfo(1), lookamb(1), |
| 837 |
> |
mkpmap(1), oconv(1), pfilt(1), pinterp(1), |
| 838 |
> |
pvalue(1), rcalc(1), rcomb(1), rcontrib(1), rcrop(1), |
| 839 |
> |
rmtxop(1), rsplit(1), |
| 840 |
> |
rpict(1), rtpict(1), rvu(1), vwrays(1), ximage(1) |
