[Bf-blender-cvs] [dae8326] master: Fix T47356: Too sharp falloww with Burley BSSRDF

[Sergey Sharybin]

Commit: dae8326d1e98632be42e525011c061d46c1d0e2a
Author: Sergey Sharybin
Date:   Mon Feb 8 14:51:57 2016 +0100
Branches: master
https://developer.blender.org/rBdae8326d1e98632be42e525011c061d46c1d0e2a

Fix T47356: Too sharp falloww with Burley BSSRDF

After the clamping commit we need to bump BURLEY_TRUNCATE
constant a bit, otherwise mean free path does not really
match the disk radius needed for importance sampling.

===================================================================

M	intern/cycles/kernel/closure/bssrdf.h

===================================================================

diff --git a/intern/cycles/kernel/closure/bssrdf.h b/intern/cycles/kernel/closure/bssrdf.h
index a53fedb..2e32795 100644
--- a/intern/cycles/kernel/closure/bssrdf.h
+++ b/intern/cycles/kernel/closure/bssrdf.h
@@ -181,7 +181,7 @@ ccl_device void bssrdf_cubic_sample(ShaderClosure *sc, float xi, float *r, float
  * the mean free length, but still not too big so sampling is still
  * effective. Might need some further tweaks.
  */
-#define BURLEY_TRUNCATE     10.0f
+#define BURLEY_TRUNCATE     30.0f
 #define BURLEY_TRUNCATE_CDF 0.973233f // cdf(BURLEY_TRUNCATE)
 
 ccl_device_inline float bssrdf_burley_fitting(float A)