8 files changed, 21 insertions, 22 deletions
diff --git a/intern/cycles/kernel/geom/geom_motion_triangle.h b/intern/cycles/kernel/geom/geom_motion_triangle.h
index 5ab0b731bdd..7409aa0d014 100644
--- a/intern/cycles/kernel/geom/geom_motion_triangle.h
+++ b/intern/cycles/kernel/geom/geom_motion_triangle.h
@@ -272,7 +272,11 @@ ccl_device_noinline void motion_triangle_shader_setup(KernelGlobals *kg, ShaderD
 #endif
 
 	/* compute face normal */
-	float3 Ng = normalize(cross(verts[1] - verts[0], verts[2] - verts[0]));
+	float3 Ng;
+	if(sd->flag & SD_NEGATIVE_SCALE_APPLIED)
+		Ng = normalize(cross(verts[2] - verts[0], verts[1] - verts[0]));
+	else
+		Ng = normalize(cross(verts[1] - verts[0], verts[2] - verts[0]));
 
 	sd->Ng = Ng;
 	sd->N = Ng;
diff --git a/intern/cycles/kernel/geom/geom_triangle.h b/intern/cycles/kernel/geom/geom_triangle.h
index 27d1351568a..35dd5b2324e 100644
--- a/intern/cycles/kernel/geom/geom_triangle.h
+++ b/intern/cycles/kernel/geom/geom_triangle.h
@@ -127,11 +127,14 @@ ccl_device_inline float3 triangle_normal(KernelGlobals *kg, ShaderData *sd)
 	float3 v2 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.z)));
 	
 	/* return normal */
-	return normalize(cross(v1 - v0, v2 - v0));
+	if(sd->flag & SD_NEGATIVE_SCALE_APPLIED)
+		return normalize(cross(v2 - v0, v1 - v0));
+	else
+		return normalize(cross(v1 - v0, v2 - v0));
 }
 
 /* point and normal on triangle  */
-ccl_device_inline void triangle_point_normal(KernelGlobals *kg, int prim, float u, float v, float3 *P, float3 *Ng, int *shader)
+ccl_device_inline void triangle_point_normal(KernelGlobals *kg, int object, int prim, float u, float v, float3 *P, float3 *Ng, int *shader)
 {
 	/* load triangle vertices */
 	float3 tri_vindex = float4_to_float3(kernel_tex_fetch(__tri_vindex, prim));
@@ -145,7 +148,11 @@ ccl_device_inline void triangle_point_normal(KernelGlobals *kg, int prim, float
 	*P = (u*v0 + v*v1 + t*v2);
 
 	/* compute normal */
-	*Ng = normalize(cross(v1 - v0, v2 - v0));
+	int object_flag = kernel_tex_fetch(__object_flag, object);
+	if(object_flag & SD_NEGATIVE_SCALE_APPLIED)
+		*Ng = normalize(cross(v2 - v0, v1 - v0));
+	else
+		*Ng = normalize(cross(v1 - v0, v2 - v0));
 
 	/* shader`*/
 	*shader = __float_as_int(kernel_tex_fetch(__tri_shader, prim));
diff --git a/intern/cycles/kernel/kernel_bake.h b/intern/cycles/kernel/kernel_bake.h
index c2d14b7f835..0df1725edbe 100644
--- a/intern/cycles/kernel/kernel_bake.h
+++ b/intern/cycles/kernel/kernel_bake.h
@@ -215,7 +215,7 @@ ccl_device void kernel_bake_evaluate(KernelGlobals *kg, ccl_global uint4 *input,
 	int shader;
 	float3 P, Ng;
 
-	triangle_point_normal(kg, prim, u, v, &P, &Ng, &shader);
+	triangle_point_normal(kg, object, prim, u, v, &P, &Ng, &shader);
 
 	/* dummy initilizations copied from SHADER_EVAL_DISPLACE */
 	float3 I = Ng;
diff --git a/intern/cycles/kernel/kernel_light.h b/intern/cycles/kernel/kernel_light.h
index ac432d3fe04..3832631e02d 100644
--- a/intern/cycles/kernel/kernel_light.h
+++ b/intern/cycles/kernel/kernel_light.h
@@ -457,7 +457,7 @@ ccl_device void triangle_light_sample(KernelGlobals *kg, int prim, int object,
 	v = randv*randu;
 
 	/* triangle, so get position, normal, shader */
-	triangle_point_normal(kg, prim, u, v, &ls->P, &ls->Ng, &ls->shader);
+	triangle_point_normal(kg, object, prim, u, v, &ls->P, &ls->Ng, &ls->shader);
 	ls->object = object;
 	ls->prim = prim;
 	ls->lamp = LAMP_NONE;
diff --git a/intern/cycles/kernel/kernel_shader.h b/intern/cycles/kernel/kernel_shader.h
index 3b95d7055ac..fc61f1a9c2c 100644
--- a/intern/cycles/kernel/kernel_shader.h
+++ b/intern/cycles/kernel/kernel_shader.h
@@ -340,7 +340,7 @@ ccl_device void shader_setup_from_displace(KernelGlobals *kg, ShaderData *sd,
 	float3 P, Ng, I = make_float3(0.0f, 0.0f, 0.0f);
 	int shader;
 
-	triangle_point_normal(kg, prim, u, v, &P, &Ng, &shader);
+	triangle_point_normal(kg, object, prim, u, v, &P, &Ng, &shader);
 
 	/* force smooth shading for displacement */
 	shader |= SHADER_SMOOTH_NORMAL;
diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
index f60d813edad..0ee7e60f4f6 100644
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -592,6 +592,7 @@ enum ShaderDataFlag {
 	SD_HOLDOUT_MASK = 524288,			/* holdout for camera rays */
 	SD_OBJECT_MOTION = 1048576,			/* has object motion blur */
 	SD_TRANSFORM_APPLIED = 2097152,		/* vertices have transform applied */
+	SD_NEGATIVE_SCALE_APPLIED = 4194304,	/* vertices have negative scale applied */
 
 	SD_OBJECT_FLAGS = (SD_HOLDOUT_MASK|SD_OBJECT_MOTION|SD_TRANSFORM_APPLIED)
 };
diff --git a/intern/cycles/render/mesh.cpp b/intern/cycles/render/mesh.cpp
index 295c934537a..273443034c5 100644
--- a/intern/cycles/render/mesh.cpp
+++ b/intern/cycles/render/mesh.cpp
@@ -341,13 +341,6 @@ void Mesh::add_vertex_normals()
 				vN[i] = -vN[i];
 		}
 	}
-	else if(flip) {
-		Attribute *attr_vN = attributes.find(ATTR_STD_VERTEX_NORMAL);
-		float3 *vN = attr_vN->data_float3();
-		for(size_t i = 0; i < verts_size; i++) {
-			vN[i] = -vN[i];
-		}
-	}
 
 	/* motion vertex normals */
 	Attribute *attr_mP = attributes.find(ATTR_STD_MOTION_VERTEX_POSITION);
@@ -382,14 +375,6 @@ void Mesh::add_vertex_normals()
 			}
 		}
 	}
-	else if(has_motion_blur() && attr_mN && flip) {
-		for(int step = 0; step < motion_steps - 1; step++) {
-			float3 *mN = attr_mN->data_float3() + step*verts.size();
-			for(size_t i = 0; i < verts_size; i++) {
-				mN[i] = -mN[i];
-			}
-		}
-	}
 }
 
 void Mesh::pack_normals(Scene *scene, float *tri_shader, float4 *vnormal)
diff --git a/intern/cycles/render/object.cpp b/intern/cycles/render/object.cpp
index 027bfd71931..1f148d34ea6 100644
--- a/intern/cycles/render/object.cpp
+++ b/intern/cycles/render/object.cpp
@@ -449,6 +449,8 @@ void ObjectManager::apply_static_transforms(DeviceScene *dscene, Scene *scene, u
 				}
 
 				object_flag[i] |= SD_TRANSFORM_APPLIED;
+				if(object->mesh->transform_negative_scaled)
+					object_flag[i] |= SD_NEGATIVE_SCALE_APPLIED;
 			}
 			else
 				have_instancing = true;