On 2025-05-02 19:47 (-4), netfoot wrote:
> 
> I last used POV-ray about 25 years ago and I'm giving it another whirl. It sure
> has changed since I was using DOS on an i386!

Welcome back!

These are the main changes that you need to know:

 - Scene description files are expected to start with a #version
   statement.

 - Scene description files are expected to have an assumed_gamma in the
   global_settings{} block.  The default is 1.0, but this has
   implications for the appearance of your scenes.  (See below.)

 - If you're using version 3.8 beta, the default finish ambient is
   changed to 0.0, making shadows completely black.

 - Using radiosity disables all finish ambients.  If you wish to define
   a glowing object, use the new 'emission' keyword in the finish block.

If your POV-Ray version was up-to-date as of 25 years ago, the following
features may be familiar; but these were new at the time.

 - All declarations of floats and vectors require a terminating semi-
   colon.

 - Refraction is no longer a finish feature; it is now handled by the
   interior{} block.

 - Halos are obsolete, and are replaced with media.

There are more neat toys--most notably, true caustics using photon
mapping--but you can ease into these at your leisure.

More remarks are apropos about assumed_gamma--a lot more.  Be sure to
read the documentation on gamma handling very carefully.  Prior to
version 3.7, there was no default assumed_gamma, meaning that the scene
defaulted to your monitor's gamma, typically around 2.2; and colors to
this day are typically defined with this assumption[1].  To correct the
mismatch with assumed_gamma 1.0, such colors will need to be defined
with the 'srgb' keyword or, in the case of the named colors in
colors.inc, prefixed with the 'srgbft' keyword.

Introduction to Gamma:
https://blog.johnnovak.net/2016/09/21/what-every-coder-should-know-about-gamma/

Gamma handling documentation:
https://wiki.povray.org/content/Documentation:Tutorial_Section_3.3#Gamma_Handling

How to use the sRGB keywords: https://github.com/CousinRicky/POV-Gamma-sRGB

_________________
[1] Actually, they tend to assume sRGB nowadays rather than 2.2, but the
principle is the same.

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