From 5e5ec4c138de49005ea711d280e3e18794c9473d Mon Sep 17 00:00:00 2001
From: Brecht Van Lommel <brechtvanlommel@gmail.com>
Date: Thu, 3 Apr 2014 15:51:43 +0200
Subject: [PATCH] Fix T39577: cycles issue mixing anisotropic BSDFs with
 branched path tracer.

---
 intern/cycles/kernel/kernel_shader.h | 35 +++++++++++++++++-----------
 intern/cycles/kernel/svm/svm_types.h |  2 ++
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/intern/cycles/kernel/kernel_shader.h b/intern/cycles/kernel/kernel_shader.h
index 716dd5127c1..7aa9cfbcccc 100644
--- a/intern/cycles/kernel/kernel_shader.h
+++ b/intern/cycles/kernel/kernel_shader.h
@@ -453,23 +453,32 @@ ccl_device void shader_merge_closures(ShaderData *sd)
 			ShaderClosure *scj = &sd->closure[j];
 
 #ifdef __OSL__
-			if(!sci->prim && !scj->prim && sci->type == scj->type && sci->data0 == scj->data0 && sci->data1 == scj->data1) {
-#else
-			if(sci->type == scj->type && sci->data0 == scj->data0 && sci->data1 == scj->data1) {
+			if(sci->prim || scj->prim)
+				continue;
 #endif
-				sci->weight += scj->weight;
-				sci->sample_weight += scj->sample_weight;
 
-				int size = sd->num_closure - (j+1);
-				if(size > 0) {
-					for(int k = 0; k < size; k++) {
-						scj[k] = scj[k+1];
-					}
-				}
+			if(!(sci->type == scj->type && sci->data0 == scj->data0 && sci->data1 == scj->data1))
+				continue;
 
-				sd->num_closure--;
-				j--;
+			if(CLOSURE_IS_BSDF_OR_BSSRDF(sci->type)) {
+				if(sci->N != scj->N)
+					continue;
+				else if(CLOSURE_IS_BSDF_ANISOTROPIC(sci->type) && sci->T != scj->T)
+					continue;
 			}
+
+			sci->weight += scj->weight;
+			sci->sample_weight += scj->sample_weight;
+
+			int size = sd->num_closure - (j+1);
+			if(size > 0) {
+				for(int k = 0; k < size; k++) {
+					scj[k] = scj[k+1];
+				}
+			}
+
+			sd->num_closure--;
+			j--;
 		}
 	}
 }
diff --git a/intern/cycles/kernel/svm/svm_types.h b/intern/cycles/kernel/svm/svm_types.h
index 3285ea5cd31..4381bfe0996 100644
--- a/intern/cycles/kernel/svm/svm_types.h
+++ b/intern/cycles/kernel/svm/svm_types.h
@@ -402,6 +402,8 @@ typedef enum ClosureType {
 #define CLOSURE_IS_BSDF_GLOSSY(type) (type >= CLOSURE_BSDF_GLOSSY_ID && type <= CLOSURE_BSDF_HAIR_REFLECTION_ID)
 #define CLOSURE_IS_BSDF_TRANSMISSION(type) (type >= CLOSURE_BSDF_TRANSMISSION_ID && type <= CLOSURE_BSDF_HAIR_TRANSMISSION_ID)
 #define CLOSURE_IS_BSDF_BSSRDF(type) (type == CLOSURE_BSDF_BSSRDF_ID)
+#define CLOSURE_IS_BSDF_ANISOTROPIC(type) (type == CLOSURE_BSDF_WARD_ID)
+#define CLOSURE_IS_BSDF_OR_BSSRDF(type) (type <= CLOSURE_BSSRDF_GAUSSIAN_ID)
 #define CLOSURE_IS_BSSRDF(type) (type >= CLOSURE_BSSRDF_CUBIC_ID && type <= CLOSURE_BSSRDF_GAUSSIAN_ID)
 #define CLOSURE_IS_VOLUME(type) (type >= CLOSURE_VOLUME_ID && type <= CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID)
 #define CLOSURE_IS_EMISSION(type) (type == CLOSURE_EMISSION_ID)