Multires: Begin hooking it up to the new subdiv code

Currently behaves same as subsurf, support of displacement is the
next task in the line to tackle!

6 files changed, 104 insertions, 35 deletions

diff --git a/source/blender/blenkernel/BKE_multires.h b/source/blender/blenkernel/BKE_multires.h
index 3a70e145744..08feaec6644 100644
--- a/source/blender/blenkernel/BKE_multires.h
+++ b/source/blender/blenkernel/BKE_multires.h
@@ -82,6 +82,8 @@ struct DerivedMesh *multires_make_derived_from_derived(struct DerivedMesh *dm,
 struct MultiresModifierData *find_multires_modifier_before(struct Scene *scene,
                                                            struct ModifierData *lastmd);
 struct MultiresModifierData *get_multires_modifier(struct Scene *scene, struct Object *ob, bool use_first);
+int multires_get_level(struct Scene *scene, struct Object *ob, const struct MultiresModifierData *mmd,
+                       bool render, bool ignore_simplify);
 struct DerivedMesh *get_multires_dm(struct Depsgraph *depsgraph, struct Scene *scene, struct MultiresModifierData *mmd,
                                     struct Object *ob);
 void multiresModifier_del_levels(struct MultiresModifierData *mmd, struct Scene *scene, struct Object *object, int direction);
diff --git a/source/blender/blenkernel/BKE_subdiv.h b/source/blender/blenkernel/BKE_subdiv.h
index 03d765a154f..c4628cb9da7 100644
--- a/source/blender/blenkernel/BKE_subdiv.h
+++ b/source/blender/blenkernel/BKE_subdiv.h
@@ -111,6 +111,12 @@ typedef struct Subdiv {
 	SubdivStats stats;
 } Subdiv;
 
+/* ================================ HELPERS ================================= */
+
+/* NOTE: uv_smooth is eSubsurfUVSmooth. */
+eSubdivFVarLinearInterpolation
+BKE_subdiv_fvar_interpolation_from_uv_smooth(int uv_smooth);
+
 /* =============================== STATISTICS =============================== */
 
 void BKE_subdiv_stats_init(SubdivStats *stats);
diff --git a/source/blender/blenkernel/intern/multires.c b/source/blender/blenkernel/intern/multires.c
index bb261ec9590..ab0327652cd 100644
--- a/source/blender/blenkernel/intern/multires.c
+++ b/source/blender/blenkernel/intern/multires.c
@@ -337,8 +337,8 @@ MultiresModifierData *get_multires_modifier(Scene *scene, Object *ob, bool use_f
 	return mmd;
 }
 
-static int multires_get_level(Scene *scene, Object *ob, MultiresModifierData *mmd,
-                              bool render, bool ignore_simplify)
+int multires_get_level(Scene *scene, Object *ob, const MultiresModifierData *mmd,
+                       bool render, bool ignore_simplify)
 {
 	if (render)
 		return (scene != NULL) ? get_render_subsurf_level(&scene->r, mmd->renderlvl, true) : mmd->renderlvl;
diff --git a/source/blender/blenkernel/intern/subdiv.c b/source/blender/blenkernel/intern/subdiv.c
index 207fdf43c55..4f630e8c38c 100644
--- a/source/blender/blenkernel/intern/subdiv.c
+++ b/source/blender/blenkernel/intern/subdiv.c
@@ -30,6 +30,7 @@
 #include "BKE_subdiv.h"
 
 #include "DNA_mesh_types.h"
+#include "DNA_modifier_types.h"
 
 #include "BLI_utildefines.h"
 
@@ -42,6 +43,27 @@
 #include "opensubdiv_evaluator_capi.h"
 #include "opensubdiv_topology_refiner_capi.h"
 
+eSubdivFVarLinearInterpolation
+BKE_subdiv_fvar_interpolation_from_uv_smooth(int uv_smooth)
+{
+	switch (uv_smooth) {
+		case SUBSURF_UV_SMOOTH_NONE:
+			return SUBDIV_FVAR_LINEAR_INTERPOLATION_ALL;
+		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS:
+			return SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_ONLY;
+		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_AND_JUNCTIONS:
+			return SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_AND_JUNCTIONS;
+		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_JUNCTIONS_AND_CONCAVE:
+			return SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_JUNCTIONS_AND_CONCAVE;
+		case SUBSURF_UV_SMOOTH_PRESERVE_BOUNDARIES:
+			return SUBDIV_FVAR_LINEAR_INTERPOLATION_BOUNDARIES;
+		case SUBSURF_UV_SMOOTH_ALL:
+			return SUBDIV_FVAR_LINEAR_INTERPOLATION_NONE;
+	}
+	BLI_assert(!"Unknown uv smooth flag");
+	return SUBSURF_UV_SMOOTH_NONE;
+}
+
 Subdiv *BKE_subdiv_new_from_converter(const SubdivSettings *settings,
                                       struct OpenSubdiv_Converter *converter)
 {
diff --git a/source/blender/modifiers/intern/MOD_multires.c b/source/blender/modifiers/intern/MOD_multires.c
index 36bfa4fcd56..ca60dceb052 100644
--- a/source/blender/modifiers/intern/MOD_multires.c
+++ b/source/blender/modifiers/intern/MOD_multires.c
@@ -37,6 +37,7 @@
 
 #include "DNA_mesh_types.h"
 #include "DNA_object_types.h"
+#include "DNA_scene_types.h"
 
 #include "BLI_utildefines.h"
 
@@ -44,6 +45,7 @@
 #include "BKE_mesh.h"
 #include "BKE_multires.h"
 #include "BKE_modifier.h"
+#include "BKE_subdiv.h"
 #include "BKE_subsurf.h"
 
 #include "DEG_depsgraph_query.h"
@@ -139,6 +141,63 @@ static DerivedMesh *applyModifier(
 	return result;
 }
 
+#ifdef WITH_OPENSUBDIV_MODIFIER
+static int subdiv_levels_for_modifier_get(const MultiresModifierData *mmd,
+                                          const ModifierEvalContext *ctx)
+{
+	Scene *scene = DEG_get_evaluated_scene(ctx->depsgraph);
+	const bool use_render_params = (ctx->flag & MOD_APPLY_RENDER);
+	return multires_get_level(
+	        scene, ctx->object, mmd, use_render_params, false);
+}
+
+static void subdiv_settings_init(SubdivSettings *settings,
+                                 const MultiresModifierData *mmd)
+{
+	settings->is_simple = (mmd->simple != 0);
+	settings->is_adaptive = !settings->is_simple;
+	settings->level = mmd->quality;
+	settings->fvar_linear_interpolation =
+	        BKE_subdiv_fvar_interpolation_from_uv_smooth(mmd->uv_smooth);
+}
+
+static void subdiv_mesh_settings_init(SubdivToMeshSettings *settings,
+                                      const MultiresModifierData *mmd,
+                                      const ModifierEvalContext *ctx)
+{
+	const int level = subdiv_levels_for_modifier_get(mmd, ctx);
+	settings->resolution = (1 << level) + 1;
+}
+
+static Mesh *applyModifier_subdiv(ModifierData *md,
+                                  const ModifierEvalContext *ctx,
+                                  Mesh *mesh)
+{
+	Mesh *result = mesh;
+	MultiresModifierData *mmd = (MultiresModifierData *)md;
+	SubdivSettings subdiv_settings;
+	subdiv_settings_init(&subdiv_settings, mmd);
+	if (subdiv_settings.level == 0) {
+		/* NOTE: Shouldn't really happen, is supposed to be catched by
+		 * isDisabled() callback.
+		 */
+		return result;
+	}
+	/* TODO(sergey): Try to re-use subdiv when possible. */
+	Subdiv *subdiv = BKE_subdiv_new_from_mesh(&subdiv_settings, mesh);
+	if (subdiv == NULL) {
+		/* Happens on bad topology, ut also on empty input mesh. */
+		return result;
+	}
+	SubdivToMeshSettings mesh_settings;
+	subdiv_mesh_settings_init(&mesh_settings, mmd, ctx);
+	result = BKE_subdiv_to_mesh(subdiv, &mesh_settings, mesh);
+	/* TODO(sergey): Cache subdiv somehow. */
+	// BKE_subdiv_stats_print(&subdiv->stats);
+	BKE_subdiv_free(subdiv);
+	return result;
+}
+#endif
 
 ModifierTypeInfo modifierType_Multires = {
 	/* name */              "Multires",
@@ -162,7 +221,11 @@ ModifierTypeInfo modifierType_Multires = {
 	/* deformMatrices */    NULL,
 	/* deformVertsEM */     NULL,
 	/* deformMatricesEM */  NULL,
+#ifdef WITH_OPENSUBDIV_MODIFIER
+	/* applyModifier */     applyModifier_subdiv,
+#else
 	/* applyModifier */     NULL,
+#endif
 	/* applyModifierEM */   NULL,
 
 	/* initData */          initData,
diff --git a/source/blender/modifiers/intern/MOD_subsurf.c b/source/blender/modifiers/intern/MOD_subsurf.c
index 4cf830f9787..38683cff42a 100644
--- a/source/blender/modifiers/intern/MOD_subsurf.c
+++ b/source/blender/modifiers/intern/MOD_subsurf.c
@@ -150,13 +150,13 @@ static DerivedMesh *applyModifierEM(
 static int subdiv_levels_for_modifier_get(const SubsurfModifierData *smd,
                                           const ModifierEvalContext *ctx)
 {
-       Scene *scene = DEG_get_evaluated_scene(ctx->depsgraph);
-       const bool use_render_params = (ctx->flag & MOD_APPLY_RENDER);
-       const int requested_levels = (use_render_params) ? smd->renderLevels
-                                                        : smd->levels;
-       return get_render_subsurf_level(&scene->r,
-                                       requested_levels,
-                                       use_render_params);
+	Scene *scene = DEG_get_evaluated_scene(ctx->depsgraph);
+	const bool use_render_params = (ctx->flag & MOD_APPLY_RENDER);
+	const int requested_levels = (use_render_params) ? smd->renderLevels
+	                                                 : smd->levels;
+	return get_render_subsurf_level(&scene->r,
+	                                requested_levels,
+	                                use_render_params);
 }
 
 static void subdiv_settings_init(SubdivSettings *settings,
@@ -165,32 +165,8 @@ static void subdiv_settings_init(SubdivSettings *settings,
 	settings->is_simple = (smd->subdivType == SUBSURF_TYPE_SIMPLE);
 	settings->is_adaptive = !settings->is_simple;
 	settings->level = smd->quality;
-	switch (smd->uv_smooth) {
-		case SUBSURF_UV_SMOOTH_NONE:
-			settings->fvar_linear_interpolation =
-			        SUBDIV_FVAR_LINEAR_INTERPOLATION_ALL;
-			break;
-		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS:
-			settings->fvar_linear_interpolation =
-			        SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_ONLY;
-			break;
-		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_AND_JUNCTIONS:
-			settings->fvar_linear_interpolation =
-			        SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_AND_JUNCTIONS;
-			break;
-		case SUBSURF_UV_SMOOTH_PRESERVE_CORNERS_JUNCTIONS_AND_CONCAVE:
-			settings->fvar_linear_interpolation =
-			        SUBDIV_FVAR_LINEAR_INTERPOLATION_CORNERS_JUNCTIONS_AND_CONCAVE;
-			break;
-		case SUBSURF_UV_SMOOTH_PRESERVE_BOUNDARIES:
-			settings->fvar_linear_interpolation =
-			        SUBDIV_FVAR_LINEAR_INTERPOLATION_BOUNDARIES;
-			break;
-		case SUBSURF_UV_SMOOTH_ALL:
-			settings->fvar_linear_interpolation =
-			        SUBDIV_FVAR_LINEAR_INTERPOLATION_NONE;
-			break;
-	}
+	settings->fvar_linear_interpolation =
+	        BKE_subdiv_fvar_interpolation_from_uv_smooth(smd->uv_smooth);
 }
 
 static void subdiv_mesh_settings_init(SubdivToMeshSettings *settings,