Preamble

Ray Studio is a simple script for creating effect of light rays (or volume light). This script is a some kind of wrapper around standard radial blur filter in GIMP but it allowes to get result for several seconds instead of dozens of minutes. This script use only GIMP procedures and don't require any external scripts or plug-ins. Script doesn't has any license, so you may use it's code for any purpose.



First step: source point defination

Before launching of the Ray Studio you have to define source point of ray "emmision". Unfortunately this is a first work version of this script so there is no any "comfortable" method of source point defination, so that source point has to be defined manually. You need to load image to GIMP and point mouse cursor at the place which you desire to define as source point; in left-buttom corner of GIMP should appear display of current cursor's coordinate (first digit is X coordinate, second - Y). This digits is needed for script configuration (options "X" and "Y"). Detail decription of script option see below.

Cursor coordinates

Second step: launching Ray Studio

Launch Ray Studio script by using GIMP menu (Filters - RSS - Ray Studio).

Script interface

Third step: script settings

Lightning edge - option of cutting levels of image to light side. Default value is 0.0 which does'nt affect on light stream, offset mean levels cut by using specified value. Option allow to regulate brightness range of image from which rays will be emmited.

Ray's tone color - option specifies tone color which will be applied to result rays.

Ray toning opacity - option specifies opacity of the tone layer which will be blended with result rays.

X and Y - specifies position of the source point. Insted of standard radial blur filter Ray Studio allow to specife negative values for coordinates of source point.

Blur size - specifies blur size for radial blur filter.

Degrade resolution - defines a degrade value for image resolution while processing. Degrade resolution is the only way to achieve radical increasement of script execution speed. Default degrade value is 1: image processing in original resolution. ATTENTION: processing in original resolution will not give any increase of speed and may take too much time! Recommended value is 1/4, processing time will be acceptable without quality loss. Value 1/8 and 1/16 reccomended only for preview. Also if source point is out of canvas then recommended value will be 1/2.


Fourth step: script execution

After setting up script's options press OK button to begin execution.

Original image	Result image (1/4)

All good scripts are created by need. This script is not exception. Usually to achieve simular effect I spent very much processor's time for computing radial blur, after I experemented with blending modes. On large images (with powerfull quad-core processor) processing may took about one hour. Recently I found how solve this with Script-Fu. Idea with resolution degradation was taken from commercial plugin package Saphire for Adobe After Effects. This technique applied in this script so anyone may achieve this effect much faster than before.

Script is under developing, until some guy willn't write faster plugin or GEGL operation.



e-mail: spoilt.exile@gmail.com
jabber: spoilt_exile@draugr.de