Bugfix #33667

Mesh had invalid face indices (number too high).
On Separate in Edit Mode it crashed.

Two fixes:

- The Material properties viewer just showed the last material in the index array.
  Now it shows nothing, to indicate it's an invalid selected material.

- Crash was caused by array copy magic, not checking the active index properly.

(No assert, no warning prints, I think cases like this can happen too easily, and this
way user gets notified nicely and can fix it).

1 files changed, 11 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index f0327719372..bf64bd3d093 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -628,11 +628,14 @@ Material *give_current_material(Object *ob, short act)
 	if (totcolp == NULL || ob->totcol == 0) return NULL;
 	
 	if (act < 0) {
-		printf("no!\n");
+		printf("Negative material index!\n");
 	}
 	
-	if (act > ob->totcol) act = ob->totcol;
-	else if (act <= 0) act = 1;
+	/* return NULL for invalid 'act', can happen for mesh face indices */
+	if (act > ob->totcol)
+		return NULL;
+	else if (act <= 0)
+		return NULL;
 
 	if (ob->matbits && ob->matbits[act - 1]) {    /* in object */
 		ma = ob->mat[act - 1];
@@ -1234,6 +1237,11 @@ int object_remove_material_slot(Object *ob)
 
 	if (*matarar == NULL) return FALSE;
 
+	/* can happen on face selection in editmode */
+	if (ob->actcol > ob->totcol) {
+		ob->actcol = ob->totcol;
+	}
+	
 	/* we delete the actcol */
 	mao = (*matarar)[ob->actcol - 1];
 	if (mao) mao->id.us--;