--- ray/doc/man/man1/rpict.1	2019/06/09 17:48:13	1.25
+++ ray/doc/man/man1/rpict.1	2025/06/04 20:32:24	1.33
@@ -1,4 +1,4 @@
-.\" RCSid "$Id: rpict.1,v 1.25 2019/06/09 17:48:13 rschregle Exp $"
+.\" RCSid "$Id: rpict.1,v 1.33 2025/06/04 20:32:24 greg Exp $"
 .TH RPICT 1 2/26/99 RADIANCE
 .SH NAME
 rpict - generate a RADIANCE picture
@@ -18,6 +18,8 @@ rpict - generate a RADIANCE picture
 ]
 .br
 .B "rpict [ options ] \-defaults"
+.br
+.B "rpict \-features [feat1 ..]"
 .SH DESCRIPTION
 .I Rpict
 generates a picture from the RADIANCE scene given in
@@ -41,6 +43,21 @@ In the second form shown above, the default values
 for the options (modified by those options present)
 are printed with a brief explanation.
 .PP
+In the third form, a list of supported features is sent
+to the standard output, one per line.
+If additional arguments follow, they are checked for presence in
+this list.
+If a feature includes subfeatures, these may be checked as well by
+specifying:
+.nf
+
+	rpict -features FeatName=subfeat1,subfeat2
+
+.fi
+If any named feature or subfeature is missing, an error is
+reported and the program returns an error status.
+If all of the named features are present, a zero status is returned.
+.PP
 Most options are followed by one or more arguments, which must be
 separated from the option and each other by white space.
 The exceptions to this rule are the 
@@ -211,10 +228,10 @@ Set the pixel sample jitter to
 Distributed ray-tracing performs anti-aliasing by randomly sampling
 over pixels.
 A value of one will randomly distribute samples over full
-pixels.
+pixels, and is not really recommended due to the tendency of
+samples to (nearly) coincide.
 A value of zero samples pixel centers only.
-A value between zero and one is usually best
-for low-resolution images.
+A value around 0.5-0.8 is typical.
 .TP
 .BI -pm \ frac
 Set the pixel motion blur to
@@ -254,6 +271,28 @@ to use a very small fraction with the
 .I \-pd
 option, to avoid the ghosting effect of too few samples.
 .TP
+.BI -pc " xr yr xg yg xb yb xw yw"
+Use the specified chromaticity pairs for output primaries and white
+point rather than the standard RGB color space.
+.TP
+.BR \-pRGB
+Output standard RGB values (the default).
+.TP
+.BR \-pXYZ
+Output standard CIE XYZ tristimulus values rather than RGB.
+.TP
+.BI -f \ source
+Load definitions from the file
+.I source
+and assign at the global level.
+The usual set of library directories is searched based on the
+.I RAYPATH
+environment variable.
+.TP
+.BI -e \ expr
+Set additional definitions from
+.I expr.
+.TP
 .BI -dj \ frac
 Set the direct jittering to
 .I frac.
@@ -310,21 +349,21 @@ change greater than the
 specification will be calculated.
 .TP
 .BI -dr \ N
-Set the number of relays for secondary sources to
+Set the number of relays for virtual sources to
 .I N.
-A value of 0 means that secondary sources will be ignored.
+A value of 0 means that virtual sources will be ignored.
 A value of 1 means that sources will be made into first generation
-secondary sources; a value of 2 means that first generation
-secondary sources will also be made into second generation secondary
+virtual sources; a value of 2 means that first generation
+virtual sources will also be made into second generation virtual
 sources, and so on.
 .TP
 .BI -dp \ D
-Set the secondary source presampling density to D.
+Set the virtual source presampling density to D.
 This is the number of samples per steradian 
 that will be used to determine ahead of time whether or not
 it is worth following shadow rays through all the reflections and/or
-transmissions associated with a secondary source path.
-A value of 0 means that the full secondary source path will always
+transmissions associated with a virtual source path.
+A value of 0 means that the full virtual source path will always
 be tested for shadows if it is tested at all.
 .TP
 .BR \-dv
@@ -439,14 +478,14 @@ A value of zero is interpreted as unlimited resolution
 Set the ambient accuracy to
 .I acc.
 This value will approximately equal the error
-from indirect illuminance interpolation.
+from indirect irradiance interpolation.
 A value of zero implies no interpolation.
 .TP
 .BI -ad \ N
 Set the number of ambient divisions to
 .I N.
 The error in the Monte Carlo calculation of indirect
-illuminance will be inversely proportional to the square
+irradiance will be inversely proportional to the square
 root of this number.
 A value of zero implies no indirect calculation.
 .TP
@@ -459,13 +498,15 @@ show a significant change.
 .BI -af \ fname
 Set the ambient file to
 .I fname.
-This is where indirect illuminance will be stored and retrieved.
-Normally, indirect illuminance values are kept in memory and
+This is where indirect irradiance will be stored and retrieved.
+Normally, indirect irradiance values are kept in memory and
 lost when the program finishes or dies.
-By using a file, different invocations can share illuminance
+By using a file, different invocations can share irradiance
 values, saving time in the computation.
-Also, by creating an ambient file during a low resolution rendering,
-better results can be obtained in a second high resolution pass.
+Also, by creating an ambient file during a low-resolution rendering,
+better results can be obtained in a second high-resolution pass.
+(It is a good idea to keep all of the calculation parameters the same,
+changing only the dimensions of the output picture.)\0
 The ambient file is in a machine-independent binary format
 which may be examined with
 .I lookamb(1).
@@ -680,6 +721,19 @@ continue rays with a probability equal to the ray weig
 divided by the given
 .I frac.
 .TP
+.BI -cs \ Ns
+Use
+.I Ns
+bands for spectral sampling rather than the default RGB calculation space.
+The maximum setting is controlled by the compiler macro MAXCSAMP, and
+defaults to 24.
+Larger values for Ns will be reduced to MAXCSAMP.
+.TP
+.BI -cw " nmA nmB"
+Set extrema to the given wavelengths for spectral sampling.
+The default is 380 and 780 nanometers.
+The order specified does not matter.
+.TP
 .BI -S \ seqstart
 Instead of generating a single picture based only on the view
 parameters given on the command line, this option causes
@@ -874,6 +928,8 @@ A value of zero turns automatic reporting off.
 Send error messages and progress reports to
 .I efile
 instead of the standard error.
+(Note this option overlaps with "-e expr" above, so file paths
+with '=' or ':' in them are not allowed on this option.)
 .TP
 .BR \-w
 Boolean switch for warning messages.
@@ -884,7 +940,7 @@ rpict \-vp 10 5 3 \-vd 1 \-.5 0 scene.oct > scene.hdr
 .PP
 rpict \-S 1 \-o frame%02d.hdr scene.oct < keyframes.vf
 .PP
-To render ambient illuminance in photon mapping mode from a global photon 
+To render ambient irradiance in photon mapping mode from a global photon 
 map global.pm via one ambient bounce, and from a caustic photon map 
 caustic.pm:
 .IP "" .2i
@@ -910,4 +966,4 @@ option.
 Greg Ward
 .SH "SEE ALSO"
 getinfo(1), lookamb(1), mkpmap(1), oconv(1), pdfblur(1), pfilt(1), 
-pinterp(1), pmblur(1), printf(3), ra_rgbe(1), rad(1), rpiece(1), rtpict(1), rtrace(1), rvu(1)
+pinterp(1), pmblur(1), printf(3), ra_rgbe(1), rad(1), rpiece(1), rtpict(1), rtrace(1), rvu(1), rxpiece(1)