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.

5 files changed, 39 insertions, 71 deletions

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;