re-using old one. New one = 'exp'.
- at first I used the old 'exposure' value, and just mapped it to 0. this
causes a problem with upward compatibility, old blenders then render a
black picture. is too confusing!
- warning; exposure values saved with commit of last week will get lost.
- based at 1.0-exp(-color) trick in Yafray. But to guarantee backwards
compatibility, and some more control, Stefano Selleri hacked a useful
formula for it.
- We now have 2 values to set:
- "exp": the exponential correction value (0-1)
- "range": the light range that maps on color 1.0 (0-5)
- Using exp(x) (is e^x) we can much better prevent overflows from render,
which are currently hard-clipped in Blender. Setting a small 'exp' value
wil efficiently smooth out high energy and map that back to a color for
display.
- total formula:
newcol= linfac*(1.0-exp(col*logfac))
col, newcol are colors
linfac= 1.0 + 1.0/((2.0*wrld.exp +0.5)^10)
logfac= log( (linfac-1.0)/linfac )/wrld.range
wrld.exp and wrld.range are the button values
- default setting: exp=0.0 and range=1.0 give results extremely close to
previous rendering.
- graph: http://www.selleri.org/Blender/buffer/Image1.png for 'exp' setting
ranging from 0-1, and with 'range'=2
Thanks Stefano for the help!
Updated the Make environment to point to the correct location. The include
paths were still pointing to source/blender/bpython/include while it should be
source/blender/python.
I did not encounter the build problems because I'm always working with the
autoconf build environment.
