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Each entity is given by a short keyword, followed by space- or tab- |
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delimited arguments on a single line. A single entity may be extended |
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over multiple lines using a backslash ('\') character right before the |
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< |
end of line, though no extended line may exceed 512 characters in total |
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< |
length. (Given the current set of entities, even approaching 80 |
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< |
characters would be highly unusual.) |
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> |
end of line, though no extended line may exceed 4096 characters in total |
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length. |
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Entities and Contexts |
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===================== |
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c [id [= [template]]] get/set color context |
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cxy x y set CIE (x,y) chromaticity for current color |
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cspec l_min l_max v1 v2 .. set relative spectrum for current color |
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+ |
cct temperature set spectrum based on black body temperature |
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cmix w1 c1 w2 c2 .. mix named colors to make current color |
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m [id [= [template]]] get/set material context |
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sides {1|2} set number of sides for current material |
| 210 |
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included in the other material parameters. All colors are absolute, |
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e.g. spectral reflectance or transmittance under uniform white light. |
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|
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< |
A CIE xy chromaticity pair is the most basic color specification. |
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< |
A full spectrum is the most general specification, and the starting |
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< |
(i.e. minimum) and ending (i.e. maximum) wavelengths are given along |
| 216 |
< |
with a set of evenly spaced values. Wavelengths are given in nanometers, |
| 217 |
< |
and must be within the range of 380-780. The spectral values themselves |
| 218 |
< |
are located starting at the first wavelength and proceeding at even |
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< |
increments to the ending wavelength. The values in between will be |
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< |
interpolated as necessary, so there must be at least two specified points. |
| 221 |
< |
The color mixing entity is intended not only for the mixing of named |
| 222 |
< |
colors, but also for color specifications using an arbitrary set |
| 223 |
< |
of basis functions. The actual totals for spectral and mixing |
| 224 |
< |
coefficients is irrelevant, since the results will be normalized. |
| 213 |
> |
A CIE xy chromaticity pair is the most basic color specification. A |
| 214 |
> |
full spectrum is the most general specification, and the starting (i.e. |
| 215 |
> |
minimum) and ending (i.e. maximum) wavelengths are given along with a |
| 216 |
> |
set of evenly spaced values. Wavelengths are given in nanometers, and |
| 217 |
> |
should be within the range of 380-780. The spectral values themselves, |
| 218 |
> |
which can be thought of as relative power density per nanometer, start |
| 219 |
> |
at the first wavelength and proceed at even increments to the last |
| 220 |
> |
wavelength. The values in between will be interpolated as necessary, |
| 221 |
> |
so there must be at least two specified points. The color temperature |
| 222 |
> |
entity corresponds to the spectrum of a black body at the specified |
| 223 |
> |
temperature (in degrees Kelvin). The color mixing entity is intended |
| 224 |
> |
not only for the mixing of named colors, but also for color |
| 225 |
> |
specifications using an arbitrary set of basis functions. The mixing |
| 226 |
> |
coefficients are in effect relative luminances for each color |
| 227 |
> |
"primary." The actual total of the mixing coefficients or spectral |
| 228 |
> |
values is irrelevant, since the results will always be normalized. |
| 229 |
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Diffuse emittance is always given in SI units of lumens/meter^2. Note that |
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this is emittance, not exitance, and does not include light reflected or |
