[Bf-blender-cvs] [e39af08] gooseberry: Ugly hack for caching code to deal with quirky modifier stack behavior.

[Lukas Tönne]

Commit: e39af0806ddb7cc28355a7ed6dc32833f4d9cd81
Author: Lukas Tönne
Date:   Mon Mar 9 09:44:40 2015 +0100
Branches: gooseberry
https://developer.blender.org/rBe39af0806ddb7cc28355a7ed6dc32833f4d9cd81

Ugly hack for caching code to deal with quirky modifier stack behavior.

CustomData layers are pruned by the CDDM_copy function when they have
CD_FLAG_NOCOPY set. This is based on later modifiers in the stack, which
can specify that they require certain data layers - but the caching
modifier itself should store only what is needed by later modifiers.
It means we cannot easily keep a full copy of the DM in the cache
modifier to writing into caches later.

For now the hackish solution is to temporarily disable NOCOPY flags when
copying the DM. This is really not nice and needs a better solution.

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

M	source/blender/modifiers/intern/MOD_cache.c

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

diff --git a/source/blender/modifiers/intern/MOD_cache.c b/source/blender/modifiers/intern/MOD_cache.c
index 70b434c..a2650d0 100644
--- a/source/blender/modifiers/intern/MOD_cache.c
+++ b/source/blender/modifiers/intern/MOD_cache.c
@@ -27,15 +27,18 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "BLI_listbase.h"
 #include "BLI_utildefines.h"
 #include "BLI_string.h"
 
+#include "DNA_customdata_types.h"
 #include "DNA_scene_types.h"
 #include "DNA_object_types.h"
 #include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
 
 #include "BKE_cdderivedmesh.h"
+#include "BKE_customdata.h"
 #include "BKE_DerivedMesh.h"
 #include "BKE_scene.h"
 #include "BKE_global.h"
@@ -81,15 +84,87 @@ static void freeData(ModifierData *md)
 	}
 }
 
+static bool *store_nocopy_flags(CustomData *cdata)
+{
+	if (cdata) {
+		int totlayer = cdata->totlayer;
+		bool *nocopy = MEM_mallocN(sizeof(bool) * totlayer, "customdata nocopy flags");
+		CustomDataLayer *layer;
+		int i;
+		
+		for (i = 0, layer = cdata->layers; i < totlayer; ++i, ++layer) {
+			nocopy[i] = layer->flag & CD_FLAG_NOCOPY;
+			layer->flag &= ~CD_FLAG_NOCOPY;
+		}
+		
+		return nocopy;
+	}
+	else
+		return NULL;
+}
+
+static void restore_nocopy_flags(CustomData *cdata, bool *nocopy)
+{
+	if (cdata && nocopy) {
+		int totlayer = cdata->totlayer;
+		CustomDataLayer *layer;
+		int i;
+		
+		for (i = 0, layer = cdata->layers; i < totlayer; ++i, ++layer) {
+			if (nocopy[i])
+				layer->flag |= CD_FLAG_NOCOPY;
+			else
+				layer->flag &= ~CD_FLAG_NOCOPY;
+		}
+	}
+	
+	if (nocopy)
+		MEM_freeN(nocopy);
+}
+
 static DerivedMesh *pointcache_do(CacheModifierData *pcmd, Object *UNUSED(ob), DerivedMesh *dm, ModifierApplyFlag flag)
 {
-	bool use_output = (flag & MOD_APPLY_RENDER) ? (pcmd->flag & MOD_CACHE_USE_OUTPUT_RENDER) : (pcmd->flag & MOD_CACHE_USE_OUTPUT_REALTIME);
+	bool use_output;
+	
+	if (!(flag & MOD_APPLY_USECACHE))
+		return dm;
+	
+	use_output = (flag & MOD_APPLY_RENDER) ? (pcmd->flag & MOD_CACHE_USE_OUTPUT_RENDER) : (pcmd->flag & MOD_CACHE_USE_OUTPUT_REALTIME);
 	if (use_output) {
 		if (pcmd->output_dm) {
 			pcmd->output_dm->release(pcmd->output_dm);
 		}
 		
-		pcmd->output_dm = CDDM_copy(dm);
+		/* XXX HACK!
+		 * DM copy will ignore all layers with CD_FLAG_NOCOPY set.
+		 * This include layers that are needed by subsequent modifiers,
+		 * which works for the modifier stack eval because DMs are passed
+		 * down the chain directly. Making a copy for keeping the DM for the
+		 * writer will discard those layers, so we have to temporarily disable
+		 * the NOCOPY flags ...
+		 * 
+		 * Probably a better way of writing out temporary data could help
+		 */
+		{
+			CustomData *vdata = dm->getVertDataLayout(dm);
+			CustomData *edata = dm->getEdgeDataLayout(dm);
+			CustomData *fdata = dm->getTessFaceDataLayout(dm);
+			CustomData *pdata = dm->getPolyDataLayout(dm);
+			CustomData *ldata = dm->getLoopDataLayout(dm);
+			bool *vdata_nocopy = store_nocopy_flags(vdata);
+			bool *edata_nocopy = store_nocopy_flags(edata);
+			bool *fdata_nocopy = store_nocopy_flags(fdata);
+			bool *pdata_nocopy = store_nocopy_flags(pdata);
+			bool *ldata_nocopy = store_nocopy_flags(ldata);
+			
+			pcmd->output_dm = CDDM_copy(dm);
+			
+			restore_nocopy_flags(vdata, vdata_nocopy);
+			restore_nocopy_flags(edata, edata_nocopy);
+			restore_nocopy_flags(fdata, fdata_nocopy);
+			restore_nocopy_flags(pdata, pdata_nocopy);
+			restore_nocopy_flags(ldata, ldata_nocopy);
+		}
 	}
 	else {
 		/* unused cache output? clean up! */