[Bf-blender-cvs] [1579dc8c3b3] master: Multires: Prepare for cached topology

[Sergey Sharybin]

Commit: 1579dc8c3b3974e98c513cffb2e407c11c32d11c
Author: Sergey Sharybin
Date:   Wed Jan 16 10:58:35 2019 +0100
Branches: master
https://developer.blender.org/rB1579dc8c3b3974e98c513cffb2e407c11c32d11c

Multires: Prepare for cached topology

Note that the actual caching is still disabled, since
more tests is needed with more production-looking files.

===================================================================

M	source/blender/blenloader/intern/readfile.c
M	source/blender/makesdna/DNA_modifier_types.h
M	source/blender/modifiers/intern/MOD_multires.c

===================================================================

diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 0094a6a2f57..ff79ba056e1 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -5393,6 +5393,10 @@ static void direct_link_modifiers(FileData *fd, ListBase *lb)
 			BevelModifierData *bmd = (BevelModifierData *)md;
 			bmd->clnordata.faceHash = NULL;
 		}
+		else if (md->type == eModifierType_Multires) {
+			MultiresModifierData *mmd = (MultiresModifierData *)md;
+			mmd->subdiv = NULL;
+		}
 	}
 }
 
diff --git a/source/blender/makesdna/DNA_modifier_types.h b/source/blender/makesdna/DNA_modifier_types.h
index 30c093ab3a8..101d655ded5 100644
--- a/source/blender/makesdna/DNA_modifier_types.h
+++ b/source/blender/makesdna/DNA_modifier_types.h
@@ -949,6 +949,8 @@ typedef struct MultiresModifierData {
 	short quality;
 	short uv_smooth;
 	short pad2[2];
+	struct Subdiv *subdiv;
+	void *pad3;
 } MultiresModifierData;
 
 typedef enum {
diff --git a/source/blender/modifiers/intern/MOD_multires.c b/source/blender/modifiers/intern/MOD_multires.c
index fc8a376d2d7..9775a536e99 100644
--- a/source/blender/modifiers/intern/MOD_multires.c
+++ b/source/blender/modifiers/intern/MOD_multires.c
@@ -67,6 +67,28 @@ static void initData(ModifierData *md)
 	mmd->quality = 3;
 }
 
+static void freeData(ModifierData *md)
+{
+	MultiresModifierData *mmd = (MultiresModifierData *) md;
+	if (mmd->subdiv != NULL) {
+		BKE_subdiv_free(mmd->subdiv);
+	}
+}
+
+/* Main goal of this function is to give usable subdivision surface descriptor
+ * which matches settings and topology. */
+static Subdiv *subdiv_descriptor_ensure(MultiresModifierData *mmd,
+                                        const SubdivSettings *subdiv_settings,
+                                        const Mesh *mesh)
+{
+	Subdiv *subdiv = BKE_subdiv_update_from_mesh(
+	        mmd->subdiv, subdiv_settings, mesh);
+	if (false) {
+		mmd->subdiv = subdiv;
+	}
+	return subdiv;
+}
+
 /* Subdivide into fully qualified mesh. */
 
 static Mesh *multires_as_mesh(MultiresModifierData *mmd,
@@ -137,16 +159,14 @@ static Mesh *applyModifier(ModifierData *md,
 	if (subdiv_settings.level == 0) {
 		return result;
 	}
-	/* TODO(sergey): Try to re-use subdiv when possible. */
-	Subdiv *subdiv = BKE_subdiv_new_from_mesh(&subdiv_settings, mesh);
+	Subdiv *subdiv = subdiv_descriptor_ensure(mmd, &subdiv_settings, mesh);
 	if (subdiv == NULL) {
 		/* Happens on bad topology, ut also on empty input mesh. */
 		return result;
 	}
 	/* NOTE: Orco needs final coordinates on CPU side, which are expected to be
 	 * accessible via MVert. For this reason we do not evaluate multires to
-	 * grids when orco is requested.
-	 */
+	 * grids when orco is requested. */
 	const bool for_orco = (ctx->flag & MOD_APPLY_ORCO) != 0;
 	if ((ctx->object->mode & OB_MODE_SCULPT) && !for_orco) {
 		/* NOTE: CCG takes ownership over Subdiv. */
@@ -156,9 +176,10 @@ static Mesh *applyModifier(ModifierData *md,
 	}
 	else {
 		result = multires_as_mesh(mmd, ctx, mesh, subdiv);
-		/* TODO(sergey): Cache subdiv somehow. */
 		// BKE_subdiv_stats_print(&subdiv->stats);
-		BKE_subdiv_free(subdiv);
+		if (subdiv != mmd->subdiv) {
+			BKE_subdiv_free(subdiv);
+		}
 	}
 	return result;
 }
@@ -188,7 +209,7 @@ ModifierTypeInfo modifierType_Multires = {
 
 	/* initData */          initData,
 	/* requiredDataMask */  NULL,
-	/* freeData */          NULL,
+	/* freeData */          freeData,
 	/* isDisabled */        NULL,
 	/* updateDepsgraph */   NULL,
 	/* dependsOnTime */     NULL,