1 files changed, 26 insertions, 0 deletions
diff --git a/intern/cycles/render/mesh.cpp b/intern/cycles/render/mesh.cpp
index f99454ee1bb..5445fd3c29c 100644
--- a/intern/cycles/render/mesh.cpp
+++ b/intern/cycles/render/mesh.cpp
@@ -584,6 +584,28 @@ void Mesh::add_vertex_normals()
 	}
 }
 
+void Mesh::add_undisplaced()
+{
+	AttributeSet& attrs = (subdivision_type == SUBDIVISION_NONE) ? attributes : subd_attributes;
+
+	/* don't compute if already there */
+	if(attrs.find(ATTR_STD_POSITION_UNDISPLACED)) {
+		return;
+	}
+
+	/* get attribute */
+	Attribute *attr = attrs.add(ATTR_STD_POSITION_UNDISPLACED);
+	attr->flags |= ATTR_SUBDIVIDED;
+
+	float3 *data = attr->data_float3();
+
+	/* copy verts */
+	size_t size = attr->buffer_size(this, (subdivision_type == SUBDIVISION_NONE) ? ATTR_PRIM_TRIANGLE : ATTR_PRIM_SUBD);
+	if(size) {
+		memcpy(data, verts.data(), size);
+	}
+}
+
 void Mesh::pack_normals(Scene *scene, uint *tri_shader, float4 *vnormal)
 {
 	Attribute *attr_vN = attributes.find(ATTR_STD_VERTEX_NORMAL);
@@ -1682,6 +1704,10 @@ void MeshManager::device_update(Device *device, DeviceScene *dscene, Scene *scen
 			mesh->add_face_normals();
 			mesh->add_vertex_normals();
 
+			if(mesh->need_attribute(scene, ATTR_STD_POSITION_UNDISPLACED)) {
+				mesh->add_undisplaced();
+			}
+
 			if(progress.get_cancel()) return;
 		}
 	}