OpenSubdiv: Add stub implementation of C-API

C-API is way smaller than the rest of the code which uses it.
So better to conditionally compile stub implementation than
to keep adding ifdef everywhere.

14 files changed, 258 insertions, 140 deletions

diff --git a/intern/CMakeLists.txt b/intern/CMakeLists.txt
index 1459100d415..c7f0f414fb1 100644
--- a/intern/CMakeLists.txt
+++ b/intern/CMakeLists.txt
@@ -31,6 +31,7 @@ add_subdirectory(guardedalloc)
 add_subdirectory(libmv)
 add_subdirectory(memutil)
 add_subdirectory(opencolorio)
+add_subdirectory(opensubdiv)
 add_subdirectory(mikktspace)
 add_subdirectory(glew-mx)
 add_subdirectory(eigen)
@@ -71,10 +72,6 @@ if(WITH_BULLET)
 	add_subdirectory(rigidbody)
 endif()
 
-if(WITH_OPENSUBDIV)
-	add_subdirectory(opensubdiv)
-endif()
-
 # only windows needs utf16 converter
 if(WIN32)
 	add_subdirectory(utfconv)
diff --git a/intern/opensubdiv/CMakeLists.txt b/intern/opensubdiv/CMakeLists.txt
index 887eb399224..f11d9b4613a 100644
--- a/intern/opensubdiv/CMakeLists.txt
+++ b/intern/opensubdiv/CMakeLists.txt
@@ -29,39 +29,9 @@ set(INC
 )
 
 set(INC_SYS
-	${OPENSUBDIV_INCLUDE_DIR}
-	${GLEW_INCLUDE_PATH}
 )
 
 set(SRC
-	internal/opensubdiv.cc
-	internal/opensubdiv_converter_factory.cc
-	internal/opensubdiv_converter_internal.cc
-	internal/opensubdiv_converter_orient.cc
-	internal/opensubdiv_device_context_cuda.cc
-	internal/opensubdiv_device_context_opencl.cc
-	internal/opensubdiv_evaluator.cc
-	internal/opensubdiv_evaluator_internal.cc
-	internal/opensubdiv_gl_mesh.cc
-	internal/opensubdiv_gl_mesh_draw.cc
-	internal/opensubdiv_gl_mesh_fvar.cc
-	internal/opensubdiv_gl_mesh_internal.cc
-	internal/opensubdiv_topology_refiner.cc
-	internal/opensubdiv_topology_refiner_internal.cc
-	internal/opensubdiv_util.cc
-
-	internal/opensubdiv_converter_internal.h
-	internal/opensubdiv_converter_orient.h
-	internal/opensubdiv_converter_orient_impl.h
-	internal/opensubdiv_device_context_cuda.h
-	internal/opensubdiv_device_context_opencl.h
-	internal/opensubdiv_evaluator_internal.h
-	internal/opensubdiv_gl_mesh_fvar.h
-	internal/opensubdiv_gl_mesh_internal.h
-	internal/opensubdiv_internal.h
-	internal/opensubdiv_topology_refiner_internal.h
-	internal/opensubdiv_util.h
-
 	opensubdiv_capi.h
 	opensubdiv_capi_type.h
 	opensubdiv_converter_capi.h
@@ -70,44 +40,88 @@ set(SRC
 	opensubdiv_topology_refiner_capi.h
 )
 
-macro(OPENSUBDIV_DEFINE_COMPONENT component)
-	if(${${component}})
-		add_definitions(-D${component})
-	endif()
-endmacro()
+if(WITH_OPENSUBDIV)
+	macro(OPENSUBDIV_DEFINE_COMPONENT component)
+		if(${${component}})
+			add_definitions(-D${component})
+		endif()
+	endmacro()
 
-OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_OPENMP)
-# TODO(sergey): OpenCL is not tested and totally unstable atm.
-# OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_OPENCL)
-# TODO(sergey): CUDA stays disabled for util it's ported to drievr API.
-# OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_CUDA)
-OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK)
-OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_GLSL_COMPUTE)
+	list(APPEND INC_SYS
+		${OPENSUBDIV_INCLUDE_DIR}
+		${GLEW_INCLUDE_PATH}
+	)
 
-data_to_c_simple(shader/gpu_shader_opensubdiv_vertex.glsl SRC)
-data_to_c_simple(shader/gpu_shader_opensubdiv_geometry.glsl SRC)
-data_to_c_simple(shader/gpu_shader_opensubdiv_fragment.glsl SRC)
+	list(APPEND SRC
+		internal/opensubdiv.cc
+		internal/opensubdiv_converter_factory.cc
+		internal/opensubdiv_converter_internal.cc
+		internal/opensubdiv_converter_orient.cc
+		internal/opensubdiv_device_context_cuda.cc
+		internal/opensubdiv_device_context_opencl.cc
+		internal/opensubdiv_evaluator.cc
+		internal/opensubdiv_evaluator_internal.cc
+		internal/opensubdiv_gl_mesh.cc
+		internal/opensubdiv_gl_mesh_draw.cc
+		internal/opensubdiv_gl_mesh_fvar.cc
+		internal/opensubdiv_gl_mesh_internal.cc
+		internal/opensubdiv_topology_refiner.cc
+		internal/opensubdiv_topology_refiner_internal.cc
+		internal/opensubdiv_util.cc
 
-add_definitions(-DGLEW_STATIC)
+		internal/opensubdiv_converter_internal.h
+		internal/opensubdiv_converter_orient.h
+		internal/opensubdiv_converter_orient_impl.h
+		internal/opensubdiv_device_context_cuda.h
+		internal/opensubdiv_device_context_opencl.h
+		internal/opensubdiv_evaluator_internal.h
+		internal/opensubdiv_gl_mesh_fvar.h
+		internal/opensubdiv_gl_mesh_internal.h
+		internal/opensubdiv_internal.h
+		internal/opensubdiv_topology_refiner_internal.h
+		internal/opensubdiv_util.h
+	)
 
-if(WIN32)
-	add_definitions(-DNOMINMAX)
-	add_definitions(-D_USE_MATH_DEFINES)
-endif()
+	OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_OPENMP)
+	# TODO(sergey): OpenCL is not tested and totally unstable atm.
+	# OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_OPENCL)
+	# TODO(sergey): CUDA stays disabled for util it's ported to drievr API.
+	# OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_CUDA)
+	OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK)
+	OPENSUBDIV_DEFINE_COMPONENT(OPENSUBDIV_HAS_GLSL_COMPUTE)
 
-# TODO(sergey): Put CUEW back when CUDA is officially supported by OSD.
-#if(OPENSUBDIV_HAS_CUDA)
-#	list(APPEND INC
-#		../../extern/cuew/include
-#	)
-#	add_definitions(-DOPENSUBDIV_HAS_CUEW)
-#endif()
+	data_to_c_simple(shader/gpu_shader_opensubdiv_vertex.glsl SRC)
+	data_to_c_simple(shader/gpu_shader_opensubdiv_geometry.glsl SRC)
+	data_to_c_simple(shader/gpu_shader_opensubdiv_fragment.glsl SRC)
 
-if(OPENSUBDIV_HAS_OPENCL)
-	list(APPEND INC
-		../../extern/clew/include
+	add_definitions(-DGLEW_STATIC)
+
+	if(WIN32)
+		add_definitions(-DNOMINMAX)
+		add_definitions(-D_USE_MATH_DEFINES)
+	endif()
+
+	# TODO(sergey): Put CUEW back when CUDA is officially supported by OSD.
+	#if(OPENSUBDIV_HAS_CUDA)
+	#	list(APPEND INC
+	#		../../extern/cuew/include
+	#	)
+	#	add_definitions(-DOPENSUBDIV_HAS_CUEW)
+	#endif()
+
+	if(OPENSUBDIV_HAS_OPENCL)
+		list(APPEND INC
+			../../extern/clew/include
+		)
+		add_definitions(-DOPENSUBDIV_HAS_CLEW)
+	endif()
+else()
+	list(APPEND SRC
+		stub/opensubdiv_stub.cc
+		stub/opensubdiv_evaluator_stub.cc
+		stub/opensubdiv_gl_mesh_stub.cc
+		stub/opensubdiv_topology_refiner_stub.cc
 	)
-	add_definitions(-DOPENSUBDIV_HAS_CLEW)
 endif()
 
 blender_add_lib(bf_intern_opensubdiv "${SRC}" "${INC}" "${INC_SYS}")
diff --git a/intern/opensubdiv/internal/opensubdiv_gl_mesh.cc b/intern/opensubdiv/internal/opensubdiv_gl_mesh.cc
index 34d27591d0b..649c5ce7b7d 100644
--- a/intern/opensubdiv/internal/opensubdiv_gl_mesh.cc
+++ b/intern/opensubdiv/internal/opensubdiv_gl_mesh.cc
@@ -281,7 +281,7 @@ struct OpenSubdiv_GLMesh *openSubdiv_createOsdGLMeshFromTopologyRefiner(
   return gl_mesh;
 }
 
-void openSubdiv_deleteOsdGLMesh(OpenSubdiv_GLMesh *gl_mesh) {
+void openSubdiv_deleteOsdGLMesh(OpenSubdiv_GLMesh* gl_mesh) {
   delete gl_mesh->internal;
   OBJECT_GUARDED_DELETE(gl_mesh, OpenSubdiv_GLMesh);
 }
diff --git a/intern/opensubdiv/stub/opensubdiv_evaluator_stub.cc b/intern/opensubdiv/stub/opensubdiv_evaluator_stub.cc
new file mode 100644
index 00000000000..86c80fe8a54
--- /dev/null
+++ b/intern/opensubdiv/stub/opensubdiv_evaluator_stub.cc
@@ -0,0 +1,29 @@
+// Copyright 2018 Blender Foundation. All rights reserved.
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software Foundation,
+// Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+//
+// Author: Sergey Sharybin
+
+#include "opensubdiv_evaluator_capi.h"
+
+#include <cstddef>
+
+OpenSubdiv_Evaluator* openSubdiv_createEvaluatorFromTopologyRefiner(
+    struct OpenSubdiv_TopologyRefiner* /*topology_refiner*/) {
+  return NULL;
+}
+
+void openSubdiv_deleteEvaluator(OpenSubdiv_Evaluator* /*evaluator*/) {
+}
diff --git a/intern/opensubdiv/stub/opensubdiv_gl_mesh_stub.cc b/intern/opensubdiv/stub/opensubdiv_gl_mesh_stub.cc
new file mode 100644
index 00000000000..8f14a2326dd
--- /dev/null
+++ b/intern/opensubdiv/stub/opensubdiv_gl_mesh_stub.cc
@@ -0,0 +1,37 @@
+// Copyright 2018 Blender Foundation. All rights reserved.
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software Foundation,
+// Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+//
+// Author: Sergey Sharybin
+
+#include "opensubdiv_gl_mesh_capi.h"
+
+#include <cstddef>
+
+struct OpenSubdiv_GLMesh *openSubdiv_createOsdGLMeshFromTopologyRefiner(
+    OpenSubdiv_TopologyRefiner* /*topology_refiner*/,
+    eOpenSubdivEvaluator /*evaluator_type*/) {
+  return NULL;
+}
+
+void openSubdiv_deleteOsdGLMesh(OpenSubdiv_GLMesh* /*gl_mesh*/) {
+}
+
+bool openSubdiv_initGLMeshDrawingResources(void) {
+  return false;
+}
+
+void openSubdiv_deinitGLMeshDrawingResources(void) {
+}
diff --git a/intern/opensubdiv/stub/opensubdiv_stub.cc b/intern/opensubdiv/stub/opensubdiv_stub.cc
new file mode 100644
index 00000000000..f03f0a0ef94
--- /dev/null
+++ b/intern/opensubdiv/stub/opensubdiv_stub.cc
@@ -0,0 +1,35 @@
+// Copyright 2018 Blender Foundation. All rights reserved.
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software Foundation,
+// Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+//
+// Author: Sergey Sharybin
+
+#include "opensubdiv_capi.h"
+
+#include <cstddef>
+
+void openSubdiv_init(void) {
+}
+
+void openSubdiv_cleanup(void) {
+}
+
+int openSubdiv_getAvailableEvaluators(void) {
+  return 0;
+}
+
+int openSubdiv_getVersionHex(void) {
+  return 0;
+}
diff --git a/intern/opensubdiv/stub/opensubdiv_topology_refiner_stub.cc b/intern/opensubdiv/stub/opensubdiv_topology_refiner_stub.cc
new file mode 100644
index 00000000000..de98b0b5eee
--- /dev/null
+++ b/intern/opensubdiv/stub/opensubdiv_topology_refiner_stub.cc
@@ -0,0 +1,37 @@
+// Copyright 2018 Blender Foundation. All rights reserved.
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software Foundation,
+// Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+//
+// Author: Sergey Sharybin
+
+#include "opensubdiv_topology_refiner_capi.h"
+
+#include <cstddef>
+
+OpenSubdiv_TopologyRefiner* openSubdiv_createTopologyRefinerFromConverter(
+    OpenSubdiv_Converter* /*converter*/,
+    const OpenSubdiv_TopologyRefinerSettings* /*settings*/) {
+  return NULL;     
+}
+
+void openSubdiv_deleteTopologyRefiner(
+    OpenSubdiv_TopologyRefiner* /*topology_refiner*/) {
+}
+
+bool openSubdiv_topologyRefinerCompareWithConverter(
+    const OpenSubdiv_TopologyRefiner* /*topology_refiner*/,
+    const OpenSubdiv_Converter* /*converter*/) {
+  return false;
+}
diff --git a/source/blender/blenkernel/BKE_subdiv.h b/source/blender/blenkernel/BKE_subdiv.h
index cd1e3adbc21..d81047563a7 100644
--- a/source/blender/blenkernel/BKE_subdiv.h
+++ b/source/blender/blenkernel/BKE_subdiv.h
@@ -130,8 +130,9 @@ void BKE_subdiv_free(Subdiv *subdiv);
 
 /* ============================= EVALUATION API ============================= */
 
-void BKE_subdiv_eval_begin(Subdiv *subdiv);
-void BKE_subdiv_eval_update_from_mesh(Subdiv *subdiv, const struct Mesh *mesh);
+/* Returns true if evaluator is ready for use. */
+bool BKE_subdiv_eval_begin(Subdiv *subdiv);
+bool BKE_subdiv_eval_update_from_mesh(Subdiv *subdiv, const struct Mesh *mesh);
 
 /* Single point queries. */
 
diff --git a/source/blender/blenkernel/CMakeLists.txt b/source/blender/blenkernel/CMakeLists.txt
index 7169597f100..646665cdec2 100644
--- a/source/blender/blenkernel/CMakeLists.txt
+++ b/source/blender/blenkernel/CMakeLists.txt
@@ -53,6 +53,7 @@ set(INC
 	../../../intern/atomic
 	../../../intern/clog
 	../../../intern/libmv
+	../../../intern/opensubdiv
 	../../../extern/curve_fit_nd
 )
 
@@ -530,7 +531,6 @@ endif()
 if(WITH_OPENSUBDIV)
 	add_definitions(-DWITH_OPENSUBDIV)
 	list(APPEND INC_SYS
-		../../../intern/opensubdiv
 		${OPENSUBDIV_INCLUDE_DIRS}
 	)
 endif()
diff --git a/source/blender/blenkernel/intern/subdiv.c b/source/blender/blenkernel/intern/subdiv.c
index bae5491c079..207fdf43c55 100644
--- a/source/blender/blenkernel/intern/subdiv.c
+++ b/source/blender/blenkernel/intern/subdiv.c
@@ -37,17 +37,14 @@
 
 #include "subdiv_converter.h"
 
-#ifdef WITH_OPENSUBDIV
-#  include "opensubdiv_capi.h"
-#  include "opensubdiv_converter_capi.h"
-#  include "opensubdiv_evaluator_capi.h"
-#  include "opensubdiv_topology_refiner_capi.h"
-#endif
+#include "opensubdiv_capi.h"
+#include "opensubdiv_converter_capi.h"
+#include "opensubdiv_evaluator_capi.h"
+#include "opensubdiv_topology_refiner_capi.h"
 
 Subdiv *BKE_subdiv_new_from_converter(const SubdivSettings *settings,
                                       struct OpenSubdiv_Converter *converter)
 {
-#ifdef WITH_OPENSUBDIV
 	SubdivStats stats;
 	BKE_subdiv_stats_init(&stats);
 	BKE_subdiv_stats_begin(&stats, SUBDIV_STATS_TOPOLOGY_REFINER_CREATION_TIME);
@@ -74,16 +71,11 @@ Subdiv *BKE_subdiv_new_from_converter(const SubdivSettings *settings,
 	BKE_subdiv_stats_end(&stats, SUBDIV_STATS_TOPOLOGY_REFINER_CREATION_TIME);
 	subdiv->stats = stats;
 	return subdiv;
-#else
-	UNUSED_VARS(settings, converter);
-	return NULL;
-#endif
 }
 
 Subdiv *BKE_subdiv_new_from_mesh(const SubdivSettings *settings,
                                  struct Mesh *mesh)
 {
-#ifdef WITH_OPENSUBDIV
 	if (mesh->totvert == 0) {
 		return NULL;
 	}
@@ -92,15 +84,10 @@ Subdiv *BKE_subdiv_new_from_mesh(const SubdivSettings *settings,
 	Subdiv *subdiv = BKE_subdiv_new_from_converter(settings, &converter);
 	BKE_subdiv_converter_free(&converter);
 	return subdiv;
-#else
-	UNUSED_VARS(settings, mesh);
-	return NULL;
-#endif
 }
 
 void BKE_subdiv_free(Subdiv *subdiv)
 {
-#ifdef WITH_OPENSUBDIV
 	if (subdiv->evaluator != NULL) {
 		openSubdiv_deleteEvaluator(subdiv->evaluator);
 	}
@@ -108,7 +95,4 @@ void BKE_subdiv_free(Subdiv *subdiv)
 		openSubdiv_deleteTopologyRefiner(subdiv->topology_refiner);
 	}
 	MEM_freeN(subdiv);
-#else
-	UNUSED_VARS(subdiv);
-#endif
 }
diff --git a/source/blender/blenkernel/intern/subdiv_converter.c b/source/blender/blenkernel/intern/subdiv_converter.c
index f6dabfa1c80..0ef32200bd3 100644
--- a/source/blender/blenkernel/intern/subdiv_converter.c
+++ b/source/blender/blenkernel/intern/subdiv_converter.c
@@ -27,25 +27,18 @@
 
 #include "BLI_utildefines.h"
 
-#ifdef WITH_OPENSUBDIV
-#  include "opensubdiv_converter_capi.h"
-#endif
+#include "opensubdiv_converter_capi.h"
 
 void BKE_subdiv_converter_free(struct OpenSubdiv_Converter *converter)
 {
-#ifdef WITH_OPENSUBDIV
 	if (converter->freeUserData) {
 		converter->freeUserData(converter);
 	}
-#else
-	UNUSED_VARS(converter);
-#endif
 }
 
 /*OpenSubdiv_FVarLinearInterpolation*/ int
 BKE_subdiv_converter_fvar_linear_from_settings(const SubdivSettings *settings)
 {
-#ifdef WITH_OPENSUBDIV
 	switch (settings->fvar_linear_interpolation) {
 		case SUBDIV_FVAR_LINEAR_INTERPOLATION_NONE:
 			return OSD_FVAR_LINEAR_INTERPOLATION_NONE;
@@ -58,8 +51,4 @@ BKE_subdiv_converter_fvar_linear_from_settings(const SubdivSettings *settings)
 	}
 	BLI_assert(!"Unknown fvar linear interpolation");
 	return OSD_FVAR_LINEAR_INTERPOLATION_NONE;
-#else
-	UNUSED_VARS(settings);
-	return 0;
-#endif
 }
diff --git a/source/blender/blenkernel/intern/subdiv_converter_mesh.c b/source/blender/blenkernel/intern/subdiv_converter_mesh.c
index c5fb8afb6cd..32e829a9439 100644
--- a/source/blender/blenkernel/intern/subdiv_converter_mesh.c
+++ b/source/blender/blenkernel/intern/subdiv_converter_mesh.c
@@ -40,12 +40,9 @@
 
 #include "MEM_guardedalloc.h"
 
-#ifdef WITH_OPENSUBDIV
-#  include "opensubdiv_capi.h"
-#  include "opensubdiv_converter_capi.h"
-#endif
+#include "opensubdiv_capi.h"
+#include "opensubdiv_converter_capi.h"
 
-#ifdef WITH_OPENSUBDIV
 typedef struct ConverterStorage {
 	SubdivSettings settings;
 	const Mesh *mesh;
@@ -391,16 +388,11 @@ static void init_user_data(OpenSubdiv_Converter *converter,
 	initialize_manifold_indices(user_data);
 	converter->user_data = user_data;
 }
-#endif
 
 void BKE_subdiv_converter_init_for_mesh(struct OpenSubdiv_Converter *converter,
                                         const SubdivSettings *settings,
                                         const Mesh *mesh)
 {
-#ifdef WITH_OPENSUBDIV
 	init_functions(converter);
 	init_user_data(converter, settings, mesh);
-#else
-	UNUSED_VARS(converter, settings, mesh);
-#endif
 }
diff --git a/source/blender/blenkernel/intern/subdiv_eval.c b/source/blender/blenkernel/intern/subdiv_eval.c
index e23be84ee26..e3754655ea6 100644
--- a/source/blender/blenkernel/intern/subdiv_eval.c
+++ b/source/blender/blenkernel/intern/subdiv_eval.c
@@ -40,32 +40,32 @@
 
 #include "MEM_guardedalloc.h"
 
-#ifdef WITH_OPENSUBDIV
-#  include "opensubdiv_evaluator_capi.h"
-#  include "opensubdiv_topology_refiner_capi.h"
-#endif
+#include "opensubdiv_evaluator_capi.h"
+#include "opensubdiv_topology_refiner_capi.h"
 
-void BKE_subdiv_eval_begin(Subdiv *subdiv)
+bool BKE_subdiv_eval_begin(Subdiv *subdiv)
 {
-#ifdef WITH_OPENSUBDIV
 	if (subdiv->topology_refiner == NULL) {
-		/* Happens on input mesh with just loose geometry. */
+		/* Happens on input mesh with just loose geometry,
+		 * or when OpenSubdiv is disabled
+		 */
+		return false;
 	}
 	else if (subdiv->evaluator == NULL) {
 		BKE_subdiv_stats_begin(&subdiv->stats, SUBDIV_STATS_EVALUATOR_CREATE);
 		subdiv->evaluator = openSubdiv_createEvaluatorFromTopologyRefiner(
 		        subdiv->topology_refiner);
 		BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_EVALUATOR_CREATE);
+		if (subdiv->evaluator == NULL) {
+			return false;
+		}
 	}
 	else {
 		/* TODO(sergey): Check for topology change. */
 	}
-#else
-	UNUSED_VARS(subdiv);
-#endif
+	return true;
 }
 
-#ifdef WITH_OPENSUBDIV
 static void set_coarse_positions(Subdiv *subdiv, const Mesh *mesh)
 {
 	const MVert *mvert = mesh->mvert;
@@ -130,14 +130,16 @@ static void set_face_varying_data_from_uv(Subdiv *subdiv,
 		}
 	}
 }
-#endif
 
-void BKE_subdiv_eval_update_from_mesh(Subdiv *subdiv, const Mesh *mesh)
+bool BKE_subdiv_eval_update_from_mesh(Subdiv *subdiv, const Mesh *mesh)
 {
-#ifdef WITH_OPENSUBDIV
-	BKE_subdiv_eval_begin(subdiv);
+	if (!BKE_subdiv_eval_begin(subdiv)) {
+		return false;
+	}
 	if (subdiv->evaluator == NULL) {
-		return;
+		/* NOTE: This situation is supposed to be handled by begin(). */
+		BLI_assert(!"Is not supposed to happen");
+		return false;
 	}
 	/* Set coordinates of base mesh vertices. */
 	set_coarse_positions(subdiv, mesh);
@@ -153,9 +155,7 @@ void BKE_subdiv_eval_update_from_mesh(Subdiv *subdiv, const Mesh *mesh)
 	BKE_subdiv_stats_begin(&subdiv->stats, SUBDIV_STATS_EVALUATOR_REFINE);
 	subdiv->evaluator->refine(subdiv->evaluator);
 	BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_EVALUATOR_REFINE);
-#else
-	UNUSED_VARS(subdiv, mesh);
-#endif
+	return true;
 }
 
 /* ========================== Single point queries ========================== */
@@ -178,14 +178,10 @@ void BKE_subdiv_eval_limit_point_and_derivatives(
         const float u, const float v,
         float P[3], float dPdu[3], float dPdv[3])
 {
-#ifdef WITH_OPENSUBDIV
 	subdiv->evaluator->evaluateLimit(subdiv->evaluator,
 	                                 ptex_face_index,
 	                                 u, v,
 	                                 P, dPdu, dPdv);
-#else
-	UNUSED_VARS(subdiv, ptex_face_index, u, v, P, dPdu, dPdv);
-#endif
 }
 
 void BKE_subdiv_eval_limit_point_and_normal(
@@ -224,15 +220,11 @@ void BKE_subdiv_eval_face_varying(
         const float u, const float v,
         float face_varying[2])
 {
-#ifdef WITH_OPENSUBDIV
 	subdiv->evaluator->evaluateFaceVarying(subdiv->evaluator,
 	                                       face_varying_channel,
 	                                       ptex_face_index,
 	                                       u, v,
 	                                       face_varying);
-#else
-	UNUSED_VARS(subdiv, face_varying_channel, ptex_face_index, u, v, face_varying);
-#endif
 }
 
 /* ===================  Patch queries at given resolution =================== */
diff --git a/source/blender/blenkernel/intern/subdiv_mesh.c b/source/blender/blenkernel/intern/subdiv_mesh.c
index bb27cb6a31e..3bc39732118 100644
--- a/source/blender/blenkernel/intern/subdiv_mesh.c
+++ b/source/blender/blenkernel/intern/subdiv_mesh.c
@@ -227,7 +227,7 @@ static void subdiv_mesh_ctx_count(SubdivMeshContext *ctx)
 			        num_polys_per_ptex_get(no_quad_patch_resolution);
 		}
 	}
-	/* Calculate extra edges createdd by loose edges. */
+	/* Calculate extra vertices createdd by loose edges. */
 	for (int edge_index = 0; edge_index < coarse_mesh->totedge; edge_index++) {
 		if (!BLI_BITMAP_TEST_BOOL(ctx->coarse_edges_used_map, edge_index)) {
 			ctx->num_subdiv_vertices += num_subdiv_vertices_per_coarse_edge;
@@ -2388,7 +2388,18 @@ Mesh *BKE_subdiv_to_mesh(
 	/* Make sure evaluator is up to date with possible new topology, and that
 	 * is is refined for the new positions of coarse vertices.
 	 */
-	BKE_subdiv_eval_update_from_mesh(subdiv, coarse_mesh);
+	if (!BKE_subdiv_eval_update_from_mesh(subdiv, coarse_mesh)) {
+		/* This could happen in two situations:
+		 * - OpenSubdiv is disabled.
+		 * - Something totally bad happened, and OpenSubdiv rejected our
+		 *   topology.
+		 * In either way, we can't safely continue.
+		 */
+		if (coarse_mesh->totpoly) {
+			BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH);
+			return NULL;
+		}
+	}
 	SubdivMeshContext ctx = {0};
 	ctx.coarse_mesh = coarse_mesh;
 	ctx.subdiv = subdiv;