Spectral environment emitter

[UNakade]

Is it possible to have an environment emitter with a spectral specification of radiance instead of an RGB image?

[njroussel]

Currently I do not believe that this is possible.
The envmap plugin will always try to upsample (rgb -> spectrum) the data it has read through the filename property when used with _spectal variant.

[Speierers]

Indeed this is not supported unfortunately.

It isn't currently on our roadmap, but if I were to implement this, here if how I would do it:

• Implement a SpectralBitmap texture plugin that loads a "spectral image file" interpolates between the right channels given the queried wavelength.
• Implement a SpectralEnvmap emitter plugin that uses the SpectralBitmap plugin.

If you give this a try, please open a PR and I will be more than happy to help you with this.

[diiigle]

As a "spectral image file" you could use the proposed OpenEXR layout of @afichet
Comes with code.