make materials.pop() and more like pythons list.pop

- allow negative index values.
- error when invalid index value are passed in.
- remove last item if no index argument is given.

also change behavior to remove the material slot, it was only clearning by default but the list length remained the same.

3 files changed, 45 insertions, 32 deletions

diff --git a/source/blender/blenkernel/BKE_material.h b/source/blender/blenkernel/BKE_material.h
index 7c47380f838..5d8406ba76f 100644
--- a/source/blender/blenkernel/BKE_material.h
+++ b/source/blender/blenkernel/BKE_material.h
@@ -88,7 +88,7 @@ int object_remove_material_slot(struct Object *ob);
 
 /* rna api */
 void material_append_id(struct ID *id, struct Material *ma);
-struct Material *material_pop_id(struct ID *id, int index, int remove_material_slot); /* index is an int because of RNA */
+struct Material *material_pop_id(struct ID *id, int index, bool remove_material_slot); /* index is an int because of RNA */
 
 /* rendering */
 
diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index 6dc3c6d7bc6..b9114c24091 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -572,7 +572,7 @@ void material_append_id(ID *id, Material *ma)
 	}
 }
 
-Material *material_pop_id(ID *id, int index_i, int remove_material_slot)
+Material *material_pop_id(ID *id, int index_i, bool remove_material_slot)
 {
 	short index = (short)index_i;
 	Material *ret = NULL;
@@ -583,34 +583,24 @@ Material *material_pop_id(ID *id, int index_i, int remove_material_slot)
 			ret = (*matar)[index];
 			id_us_min((ID *)ret);
 
-			if (remove_material_slot) {
-				if (*totcol <= 1) {
-					*totcol = 0;
-					MEM_freeN(*matar);
-					*matar = NULL;
-				}
-				else {
-					Material **mat;
-					if (index + 1 != (*totcol))
-						memmove((*matar) + index, (*matar) + (index + 1), sizeof(void *) * ((*totcol) - (index + 1)));
-
-					(*totcol)--;
-					
-					mat = MEM_callocN(sizeof(void *) * (*totcol), "newmatar");
-					memcpy(mat, *matar, sizeof(void *) * (*totcol));
-					MEM_freeN(*matar);
-
-					*matar = mat;
-					test_object_materials(G.main, id);
-				}
+			if (*totcol <= 1) {
+				*totcol = 0;
+				MEM_freeN(*matar);
+				*matar = NULL;
+			}
+			else {
+				if (index + 1 != (*totcol))
+					memmove((*matar) + index, (*matar) + (index + 1), sizeof(void *) * ((*totcol) - (index + 1)));
+
+				(*totcol)--;
+				*matar = MEM_reallocN(*matar, sizeof(void *) * (*totcol));
+				test_object_materials(G.main, id);
+			}
 
+			if (remove_material_slot) {
 				/* decrease mat_nr index */
 				data_delete_material_index_id(id, index);
 			}
-
-			/* don't remove material slot, only clear it*/
-			else
-				(*matar)[index] = NULL;
 		}
 	}
 	
@@ -1840,8 +1830,14 @@ static void convert_tfacematerial(Main *main, Material *ma)
 			mf->mat_nr = mat_nr;
 		}
 		/* remove material from mesh */
-		for (a = 0; a < me->totcol; )
-			if (me->mat[a] == ma) material_pop_id(&me->id, a, 1); else a++;
+		for (a = 0; a < me->totcol; ) {
+			if (me->mat[a] == ma) {
+				material_pop_id(&me->id, a, true);
+			}
+			else {
+				a++;
+			}
+		}
 	}
 }
 
diff --git a/source/blender/makesrna/intern/rna_ID.c b/source/blender/makesrna/intern/rna_ID.c
index 0489f85a37f..76337da3261 100644
--- a/source/blender/makesrna/intern/rna_ID.c
+++ b/source/blender/makesrna/intern/rna_ID.c
@@ -353,9 +353,26 @@ static void rna_IDMaterials_append_id(ID *id, Material *ma)
 	WM_main_add_notifier(NC_OBJECT | ND_OB_SHADING, id);
 }
 
-static Material *rna_IDMaterials_pop_id(ID *id, int index_i, int remove_material_slot)
+static Material *rna_IDMaterials_pop_id(ID *id, ReportList *reports, int index_i, int remove_material_slot)
 {
-	Material *ma = material_pop_id(id, index_i, remove_material_slot);
+	Material *ma;
+	short *totcol = give_totcolp_id(id);
+	const short totcol_orig = *totcol;
+	if (index_i < 0) {
+		index_i += (*totcol);
+	}
+
+	if ((index_i < 0) || (index_i >= (*totcol))) {
+		BKE_report(reports, RPT_ERROR, "Index out of range");
+		return NULL;
+	}
+
+	ma = material_pop_id(id, index_i, remove_material_slot);
+
+	if (*totcol == totcol_orig) {
+		BKE_report(reports, RPT_ERROR, "No material to removed");
+		return NULL;
+	}
 
 	DAG_id_tag_update(id, OB_RECALC_DATA);
 	WM_main_add_notifier(NC_OBJECT | ND_DRAW, id);
@@ -476,9 +493,9 @@ static void rna_def_ID_materials(BlenderRNA *brna)
 	RNA_def_property_flag(parm, PROP_REQUIRED);
 
 	func = RNA_def_function(srna, "pop", "rna_IDMaterials_pop_id");
+	RNA_def_function_flag(func, FUNC_USE_REPORTS);
 	RNA_def_function_ui_description(func, "Remove a material from the data block");
-	parm = RNA_def_int(func, "index", 0, 0, MAXMAT, "", "Index of material to remove", 0, MAXMAT);
-	RNA_def_property_flag(parm, PROP_REQUIRED);
+	parm = RNA_def_int(func, "index", -1, -MAXMAT, MAXMAT, "", "Index of material to remove", 0, MAXMAT);
 	RNA_def_boolean(func, "update_data", 0, "", "Update data by re-adjusting the material slots assigned");
 	parm = RNA_def_pointer(func, "material", "Material", "", "Material to remove");
 	RNA_def_function_return(func, parm);