Added improved exposure calculation

- 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!

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/renderconverter/intern/convertBlenderScene.c b/source/blender/renderconverter/intern/convertBlenderScene.c
index 185e8ca9c05..b8738968db4 100644
--- a/source/blender/renderconverter/intern/convertBlenderScene.c
+++ b/source/blender/renderconverter/intern/convertBlenderScene.c
@@ -1827,7 +1827,7 @@ void RE_add_render_lamp(Object *ob, int doshadbuf)
 	lar->mode= la->mode;
 
 	lar->energy= la->energy;
-	lar->energy= la->energy*R.wrld.exposure;
+	lar->energy= la->energy;
 	if(la->mode & LA_NEG) lar->energy= -lar->energy;
 
 	lar->vec[0]= -mat[2][0];