2 files changed, 38 insertions, 16 deletions

diff --git a/source/blender/blenkernel/intern/gpencil.c b/source/blender/blenkernel/intern/gpencil.c
index d4bf76ea44a..456bc0c88f9 100644
--- a/source/blender/blenkernel/intern/gpencil.c
+++ b/source/blender/blenkernel/intern/gpencil.c
@@ -1161,38 +1161,34 @@ Material *BKE_gpencil_object_material_ensure_from_active_input_brush(Main *bmain
       brush->gpencil_settings->flag &= ~GP_BRUSH_MATERIAL_PINNED;
     }
   }
-  return BKE_gpencil_object_material_ensure_from_active_input_material(bmain, ob);
+  return BKE_gpencil_object_material_ensure_from_active_input_material(ob);
 }
 
 /**
  * Guaranteed to return a material assigned to object. Returns never NULL.
  * Only use this for materials unrelated to user input.
  */
-Material *BKE_gpencil_object_material_ensure_from_active_input_material(Main *bmain, Object *ob)
+Material *BKE_gpencil_object_material_ensure_from_active_input_material(Object *ob)
 {
   Material *ma = give_current_material(ob, ob->actcol);
   if (ma) {
     return ma;
   }
-  /* If the slot is empty, remove because will be added again,
-   * if not, we will get an empty slot. */
-  if ((ob->totcol > 0) && (ob->actcol == ob->totcol)) {
-    BKE_object_material_slot_remove(bmain, ob);
-  }
-  return BKE_gpencil_object_material_new(bmain, ob, "Material", NULL);
+
+  return &defgpencil_material;
 }
 
 /* Get active color, and add all default settings if we don't find anything */
-Material *BKE_gpencil_object_material_ensure_active(Main *bmain, Object *ob)
+Material *BKE_gpencil_object_material_ensure_active(Object *ob)
 {
   Material *ma = NULL;
 
   /* sanity checks */
-  if (ELEM(NULL, bmain, ob)) {
+  if (ob == NULL) {
     return NULL;
   }
 
-  ma = BKE_gpencil_object_material_ensure_from_active_input_material(bmain, ob);
+  ma = BKE_gpencil_object_material_ensure_from_active_input_material(ob);
   if (ma->gp_style == NULL) {
     BKE_material_init_gpencil_settings(ma);
   }
@@ -2008,6 +2004,7 @@ void BKE_gpencil_material_index_reassign(bGPdata *gpd, int totcol, int index)
         /* reassign strokes */
         if ((gps->mat_nr > index) || (gps->mat_nr > totcol - 1)) {
           gps->mat_nr--;
+          CLAMP_MIN(gps->mat_nr, 0);
         }
       }
     }
diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index 1545ae4f48f..cc9be2c5dda 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -71,6 +71,7 @@
 
 /* used in UI and render */
 Material defmaterial;
+Material defgpencil_material;
 
 static CLG_LogRef LOG = {"bke.material"};
 
@@ -78,6 +79,13 @@ static CLG_LogRef LOG = {"bke.material"};
 void init_def_material(void)
 {
   BKE_material_init(&defmaterial);
+  BKE_material_gpencil_init(&defgpencil_material);
+}
+
+/* Free the GPencil data of the deafult material, creator.c */
+void BKE_material_gpencil_default_free(void)
+{
+  MEM_SAFE_FREE(defgpencil_material.gp_style);
 }
 
 /** Free (or release) any data used by this material (does not free the material itself). */
@@ -144,6 +152,16 @@ void BKE_material_init(Material *ma)
   ma->blend_shadow = MA_BS_SOLID;
 }
 
+void BKE_material_gpencil_init(Material *ma)
+{
+  BKE_material_init(ma);
+
+  /* grease pencil settings */
+  strcpy(ma->id.name, "MADefault GPencil");
+  BKE_material_init_gpencil_settings(ma);
+  add_v3_fl(&ma->gp_style->stroke_rgba[0], 0.6f);
+}
+
 Material *BKE_material_add(Main *bmain, const char *name)
 {
   Material *ma;
@@ -580,6 +598,17 @@ Material *give_current_material(Object *ob, short act)
   return ma_p ? *ma_p : NULL;
 }
 
+Material *BKE_material_gpencil_get(Object *ob, short act)
+{
+  Material *ma = give_current_material(ob, act);
+  if (ma != NULL) {
+    return ma;
+  }
+  else {
+    return &defgpencil_material;
+  }
+}
+
 MaterialGPencilStyle *BKE_material_gpencil_settings_get(Object *ob, short act)
 {
   Material *ma = give_current_material(ob, act);
@@ -591,7 +620,7 @@ MaterialGPencilStyle *BKE_material_gpencil_settings_get(Object *ob, short act)
     return ma->gp_style;
   }
   else {
-    return NULL;
+    return defgpencil_material.gp_style;
   }
 }
 
@@ -1070,10 +1099,6 @@ bool BKE_object_material_slot_remove(Main *bmain, Object *ob)
   }
   /* check indices from gpencil */
   else if (ob->type == OB_GPENCIL) {
-    /* need one color */
-    if (ob->totcol == 0) {
-      BKE_gpencil_object_material_ensure_from_active_input_material(bmain, ob);
-    }
     BKE_gpencil_material_index_reassign((bGPdata *)ob->data, ob->totcol, actcol - 1);
   }