The Persistence of Vision Raytracer (POV-Ray).
This is the legacy Bug Tracking System for the POV-Ray project. Bugs listed here are being migrated to our github issue tracker. Please refer to that for new reports or updates to existing ones on this system.
FS#88 - File output code does not properly handle negative color values
Opened by Christoph Lipka (clipka) - Tuesday, 23 March 2010, 14:45 GMT
Last edited by Christoph Lipka (clipka) - Saturday, 19 June 2010, 12:46 GMT
File output code for virtually all file formats performs gamma correction on unclipped color values, which leads to issues when color values happen to be negative for some reason and gamma does not happen to be an integer value such as 1.0 or 2.0. As a consequence, subsequent steps (clipping and converting to integer) apparently produce compiler-dependent results. Compiled with Microsift or Intel compilers, POV-Ray seems to write zero brightness in such cases, while compiled with g++ 4.4 (and possibly other compilers) it seems to write full brightness instead.
(See thread news://news.povray.org:firstname.lastname@example.org for examples.)
The proper solution should be to apply gamma correction after clipping.
Saturday, 19 June 2010, 12:46 GMT
Reason for closing: Fixed