- particle drawing was using invalid memory with weights.

- particle set weight operator (Shift + K) and from the menu.
- mirror vertex groups operator can also flip weight group names.

a number of utility functions for weight groups added
 int *get_defgroup_flip_map(struct Object *ob);
 void flip_vertexgroup_name (char *name_r, const char *name, int strip_number); // moved from modifier.c 
 void copy_defvert (struct MDeformVert *dvert_r, const struct MDeformVert *dvert);
 void flip_defvert (struct MDeformVert *dvert, int *flip_map);

3 files changed, 187 insertions, 124 deletions

diff --git a/source/blender/blenkernel/intern/deform.c b/source/blender/blenkernel/intern/deform.c
index c1e45243bb5..620e114bad2 100644
--- a/source/blender/blenkernel/intern/deform.c
+++ b/source/blender/blenkernel/intern/deform.c
@@ -34,6 +34,7 @@
 
 #include <string.h>
 #include <math.h>
+#include "ctype.h"
 
 #include "MEM_guardedalloc.h"
 
@@ -95,6 +96,36 @@ bDeformGroup *copy_defgroup (bDeformGroup *ingroup)
 	return outgroup;
 }
 
+void copy_defvert (MDeformVert *dvert_r, const MDeformVert *dvert)
+{
+	if(dvert_r->totweight == dvert->totweight) {
+		if(dvert->totweight)
+			memcpy(dvert_r->dw, dvert->dw, dvert->totweight * sizeof(MDeformWeight));
+	}
+	else {
+		if(dvert_r->dw)
+			MEM_freeN(dvert_r->dw);
+
+		if(dvert->totweight)
+			dvert_r->dw= MEM_dupallocN(dvert->dw);
+		else
+			dvert_r->dw= NULL;
+
+		dvert_r->totweight = dvert->totweight;
+	}
+}
+
+void flip_defvert (MDeformVert *dvert, int *flip_map)
+{
+	MDeformWeight *dw;
+	int i;
+
+	for(dw= dvert->dw, i=0; i<dvert->totweight; dw++, i++)
+		if(flip_map[dw->def_nr] >= 0)
+			dw->def_nr= flip_map[dw->def_nr];
+}
+
+
 bDeformGroup *get_named_vertexgroup (Object *ob, char *name)
 {
 	/* return a pointer to the deform group with this name
@@ -167,6 +198,36 @@ int get_defgroup_num (Object *ob, bDeformGroup *dg)
     
 }
 
+/* note, must be freed */
+int *get_defgroup_flip_map(Object *ob)
+{
+	bDeformGroup *dg;
+	int totdg= BLI_countlist(&ob->defbase);
+
+	if(totdg==0) {
+		return NULL;
+	}
+	else {
+		char name[sizeof(dg->name)];
+		int i, flip_num, *map= MEM_mallocN(totdg * sizeof(int), "get_defgroup_flip_map");
+		memset(map, -1, totdg * sizeof(int));
+
+		for (dg=ob->defbase.first, i=0; dg; dg=dg->next, i++) {
+			if(map[i] == -1) { /* may be calculated previously */
+				flip_vertexgroup_name(name, dg->name, 0);
+				if(strcmp(name, dg->name)) {
+					flip_num= get_named_vertexgroup_num(ob, name);
+					if(flip_num > -1) {
+						map[i]= flip_num;
+						map[flip_num]= i; /* save an extra lookup */
+					}
+				}
+			}
+		}
+		return map;
+	}
+}
+
 void unique_vertexgroup_name (bDeformGroup *dg, Object *ob)
 {
 	bDeformGroup *curdef;
@@ -221,6 +282,121 @@ void unique_vertexgroup_name (bDeformGroup *dg, Object *ob)
 	}	
 }
 
+
+/* finds the best possible flipped name. For renaming; check for unique names afterwards */
+/* if strip_number: removes number extensions */
+void flip_vertexgroup_name (char *name_r, const char *name, int strip_number)
+{
+	int     len;
+	char    prefix[sizeof((bDeformGroup *)NULL)->name]={""};   /* The part before the facing */
+	char    suffix[sizeof((bDeformGroup *)NULL)->name]={""};   /* The part after the facing */
+	char    replace[sizeof((bDeformGroup *)NULL)->name]={""};  /* The replacement string */
+	char    number[sizeof((bDeformGroup *)NULL)->name]={""};   /* The number extension string */
+	char    *index=NULL;
+
+	len= strlen(name);
+	if(len<3) return; // we don't do names like .R or .L
+
+	/* We first check the case with a .### extension, let's find the last period */
+	if(isdigit(name[len-1])) {
+		index= strrchr(name, '.'); // last occurrence
+		if (index && isdigit(index[1]) ) { // doesnt handle case bone.1abc2 correct..., whatever!
+			if(strip_number==0)
+				strcpy(number, index);
+			*index= 0;
+			len= strlen(name);
+		}
+	}
+
+	strcpy (prefix, name);
+
+#define IS_SEPARATOR(a) ((a)=='.' || (a)==' ' || (a)=='-' || (a)=='_')
+
+	/* first case; separator . - _ with extensions r R l L  */
+	if( IS_SEPARATOR(name[len-2]) ) {
+		switch(name[len-1]) {
+			case 'l':
+				prefix[len-1]= 0;
+				strcpy(replace, "r");
+				break;
+			case 'r':
+				prefix[len-1]= 0;
+				strcpy(replace, "l");
+				break;
+			case 'L':
+				prefix[len-1]= 0;
+				strcpy(replace, "R");
+				break;
+			case 'R':
+				prefix[len-1]= 0;
+				strcpy(replace, "L");
+				break;
+		}
+	}
+	/* case; beginning with r R l L , with separator after it */
+	else if( IS_SEPARATOR(name[1]) ) {
+		switch(name[0]) {
+			case 'l':
+				strcpy(replace, "r");
+				strcpy(suffix, name+1);
+				prefix[0]= 0;
+				break;
+			case 'r':
+				strcpy(replace, "l");
+				strcpy(suffix, name+1);
+				prefix[0]= 0;
+				break;
+			case 'L':
+				strcpy(replace, "R");
+				strcpy(suffix, name+1);
+				prefix[0]= 0;
+				break;
+			case 'R':
+				strcpy(replace, "L");
+				strcpy(suffix, name+1);
+				prefix[0]= 0;
+				break;
+		}
+	}
+	else if(len > 5) {
+		/* hrms, why test for a separator? lets do the rule 'ultimate left or right' */
+		index = BLI_strcasestr(prefix, "right");
+		if (index==prefix || index==prefix+len-5) {
+			if(index[0]=='r')
+				strcpy (replace, "left");
+			else {
+				if(index[1]=='I')
+					strcpy (replace, "LEFT");
+				else
+					strcpy (replace, "Left");
+			}
+			*index= 0;
+			strcpy (suffix, index+5);
+		}
+		else {
+			index = BLI_strcasestr(prefix, "left");
+			if (index==prefix || index==prefix+len-4) {
+				if(index[0]=='l')
+					strcpy (replace, "right");
+				else {
+					if(index[1]=='E')
+						strcpy (replace, "RIGHT");
+					else
+						strcpy (replace, "Right");
+				}
+				*index= 0;
+				strcpy (suffix, index+4);
+			}
+		}
+	}
+
+#undef IS_SEPARATOR
+
+	sprintf (name_r, "%s%s%s%s", prefix, replace, suffix, number);
+}
+
+
+
 float deformvert_get_weight(const struct MDeformVert *dvert, int group_num)
 {
 	if(dvert)
diff --git a/source/blender/blenkernel/intern/modifier.c b/source/blender/blenkernel/intern/modifier.c
index 7e211f60cd5..3c925e5ff25 100644
--- a/source/blender/blenkernel/intern/modifier.c
+++ b/source/blender/blenkernel/intern/modifier.c
@@ -39,7 +39,6 @@
 #include "stdarg.h"
 #include "math.h"
 #include "float.h"
-#include "ctype.h"
 
 #include "BLI_math.h"
 #include "BLI_blenlib.h"
@@ -1801,118 +1800,6 @@ static void mirrorModifier_updateDepgraph(ModifierData *md, DagForest *forest, S
 	}
 }
 
-/* finds the best possible flipped name. For renaming; check for unique names afterwards */
-/* if strip_number: removes number extensions */
-static void vertgroup_flip_name (char *name, int strip_number)
-{
-	int     len;
-	char    prefix[128]={""};   /* The part before the facing */
-	char    suffix[128]={""};   /* The part after the facing */
-	char    replace[128]={""};  /* The replacement string */
-	char    number[128]={""};   /* The number extension string */
-	char    *index=NULL;
-
-	len= strlen(name);
-	if(len<3) return; // we don't do names like .R or .L
-
-	/* We first check the case with a .### extension, let's find the last period */
-	if(isdigit(name[len-1])) {
-		index= strrchr(name, '.'); // last occurrence
-		if (index && isdigit(index[1]) ) { // doesnt handle case bone.1abc2 correct..., whatever!
-			if(strip_number==0) 
-				strcpy(number, index);
-			*index= 0;
-			len= strlen(name);
-		}
-	}
-
-	strcpy (prefix, name);
-
-#define IS_SEPARATOR(a) ((a)=='.' || (a)==' ' || (a)=='-' || (a)=='_')
-
-	/* first case; separator . - _ with extensions r R l L  */
-	if( IS_SEPARATOR(name[len-2]) ) {
-		switch(name[len-1]) {
-			case 'l':
-				prefix[len-1]= 0;
-				strcpy(replace, "r");
-				break;
-			case 'r':
-				prefix[len-1]= 0;
-				strcpy(replace, "l");
-				break;
-			case 'L':
-				prefix[len-1]= 0;
-				strcpy(replace, "R");
-				break;
-			case 'R':
-				prefix[len-1]= 0;
-				strcpy(replace, "L");
-				break;
-		}
-	}
-	/* case; beginning with r R l L , with separator after it */
-	else if( IS_SEPARATOR(name[1]) ) {
-		switch(name[0]) {
-			case 'l':
-				strcpy(replace, "r");
-				strcpy(suffix, name+1);
-				prefix[0]= 0;
-				break;
-			case 'r':
-				strcpy(replace, "l");
-				strcpy(suffix, name+1);
-				prefix[0]= 0;
-				break;
-			case 'L':
-				strcpy(replace, "R");
-				strcpy(suffix, name+1);
-				prefix[0]= 0;
-				break;
-			case 'R':
-				strcpy(replace, "L");
-				strcpy(suffix, name+1);
-				prefix[0]= 0;
-				break;
-		}
-	}
-	else if(len > 5) {
-		/* hrms, why test for a separator? lets do the rule 'ultimate left or right' */
-		index = BLI_strcasestr(prefix, "right");
-		if (index==prefix || index==prefix+len-5) {
-			if(index[0]=='r') 
-				strcpy (replace, "left");
-			else {
-				if(index[1]=='I') 
-					strcpy (replace, "LEFT");
-				else
-					strcpy (replace, "Left");
-			}
-			*index= 0;
-			strcpy (suffix, index+5);
-		}
-		else {
-			index = BLI_strcasestr(prefix, "left");
-			if (index==prefix || index==prefix+len-4) {
-				if(index[0]=='l') 
-					strcpy (replace, "right");
-				else {
-					if(index[1]=='E') 
-						strcpy (replace, "RIGHT");
-					else
-						strcpy (replace, "Right");
-				}
-				*index= 0;
-				strcpy (suffix, index+4);
-			}
-		}
-	}
-
-#undef IS_SEPARATOR
-
-	sprintf (name, "%s%s%s%s", prefix, replace, suffix, number);
-}
-
 static DerivedMesh *doMirrorOnAxis(MirrorModifierData *mmd,
 		Object *ob,
 		DerivedMesh *dm,
@@ -2022,8 +1909,7 @@ static DerivedMesh *doMirrorOnAxis(MirrorModifierData *mmd,
 							continue;
 						
 						def = vector_def[dvert->dw[j].def_nr];
-						strcpy(tmpname, def->name);
-						vertgroup_flip_name(tmpname,0);
+						flip_vertexgroup_name(tmpname, def->name, 0);
 						
 						for(b = 0, defb = ob->defbase.first; defb;
 						    defb = defb->next, b++)
diff --git a/source/blender/blenkernel/intern/particle.c b/source/blender/blenkernel/intern/particle.c
index 63d681cce0b..006e05370b1 100644
--- a/source/blender/blenkernel/intern/particle.c
+++ b/source/blender/blenkernel/intern/particle.c
@@ -2999,8 +2999,8 @@ void psys_cache_edit_paths(Scene *scene, Object *ob, PTCacheEdit *edit, float cf
 
 		/* should init_particle_interpolation set this ? */
 		if(pset->brushtype==PE_BRUSH_WEIGHT){
-			pind.hkey[0] = pa->hair;
-			pind.hkey[1] = pa->hair + 1;
+			pind.hkey[0] = NULL;
+			pind.hkey[1] = pa->hair;
 		}
 
 
@@ -3036,12 +3036,6 @@ void psys_cache_edit_paths(Scene *scene, Object *ob, PTCacheEdit *edit, float cf
 
 			do_particle_interpolation(psys, i, pa, t, frs_sec, &pind, &result);
 
-			/* should init_particle_interpolation set this ? */
-			if(pset->brushtype==PE_BRUSH_WEIGHT){
-				pind.hkey[0] = pind.hkey[1];
-				pind.hkey[1]++;
-			}
-
 			 /* non-hair points are already in global space */
 			if(psys && !(psys->flag & PSYS_GLOBAL_HAIR)) {
 				mul_m4_v3(hairmat, result.co);
@@ -3099,10 +3093,17 @@ void psys_cache_edit_paths(Scene *scene, Object *ob, PTCacheEdit *edit, float cf
 
 			/* selection coloring in edit mode */
 			if(pset->brushtype==PE_BRUSH_WEIGHT){
-				if(k==steps)
+				if(k==0)
+					weight_to_rgb(pind.hkey[1]->weight, ca->col, ca->col+1, ca->col+2);
+				else if(k >= steps - 1)
 					weight_to_rgb(pind.hkey[0]->weight, ca->col, ca->col+1, ca->col+2);
 				else
 					weight_to_rgb((1.0f - keytime) * pind.hkey[0]->weight + keytime * pind.hkey[1]->weight, ca->col, ca->col+1, ca->col+2);
+
+				/* at the moment this is only used for weight painting.
+				 * will need to move out of this check if its used elsewhere. */
+				pind.hkey[0] = pind.hkey[1];
+				pind.hkey[1]++;
 			}
 			else {
 				if((ekey + (pind.ekey[0] - point->keys))->flag & PEK_SELECT){