[Bf-blender-cvs] [a950af8e24d] master: Fix T53012: Shadow catcher creates artifacts on contact area

[Sergey Sharybin]

Commit: a950af8e24dd22e93bbf13a7931c175d0037df66
Author: Sergey Sharybin
Date:   Fri Oct 6 17:27:34 2017 +0500
Branches: master
https://developer.blender.org/rBa950af8e24dd22e93bbf13a7931c175d0037df66

Fix T53012: Shadow catcher creates artifacts on contact area

The issue was caused by light sample being evaluated to nan at some point.
This is root of the cause which is to be fixed, but is very hard to trace down
especially via ssh (the issue only happens on AVX2 release build). Will give it
a closer look when back to my AVX2 machine.

For until then this is a good check to have anyway, it corresponds to what's
happening in regular radiance sum.

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

M	intern/cycles/kernel/kernel_accumulate.h

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

diff --git a/intern/cycles/kernel/kernel_accumulate.h b/intern/cycles/kernel/kernel_accumulate.h
index ae5f6e5e070..366f25422fd 100644
--- a/intern/cycles/kernel/kernel_accumulate.h
+++ b/intern/cycles/kernel/kernel_accumulate.h
@@ -557,7 +557,11 @@ ccl_device_inline void path_radiance_sum_shadowcatcher(KernelGlobals *kg,
 	float path_total = average(L->path_total);
 	float shadow;
 
-	if(path_total == 0.0f) {
+	if(UNLIKELY(!isfinite_safe(path_total))) {
+		kernel_assert(!"Non-finite total radiance along the path");
+		shadow = 0.0f;
+	}
+	else if(path_total == 0.0f) {
 		shadow = L->shadow_transparency;
 	}
 	else {