GPencil: Only brushes with pinned materials have materials

Using GP_BRUSH_MATERIAL_PINNED to switch between active material and brush material, instead of updating all brushes on active material changes. This will allow brushes to have no material and therefore to not inflate the user count.

This fix T62465.

Patch contributed by @matc
Reviewers: @brecht @antoniov @billreynish @mendio

1 files changed, 15 insertions, 23 deletions

diff --git a/source/blender/editors/gpencil/gpencil_paint.c b/source/blender/editors/gpencil/gpencil_paint.c
index dd949b21743..cd17f7dc640 100644
--- a/source/blender/editors/gpencil/gpencil_paint.c
+++ b/source/blender/editors/gpencil/gpencil_paint.c
@@ -302,6 +302,12 @@ static bool gpencil_draw_poll(bContext *C)
 			return false;
 		}
 
+		ToolSettings *ts = CTX_data_scene(C)->toolsettings;
+		if (!ts->gp_paint->paint.brush) {
+			CTX_wm_operator_poll_msg_set(C, "Grease Pencil has no active paint tool");
+			return false;
+		}
+
 		return true;
 	}
 	else {
@@ -1217,7 +1223,7 @@ static void gp_stroke_newfrombuffer(tGPsdata *p)
 	}
 
 	/* Save material index */
-	gps->mat_nr = BKE_gpencil_get_material_index(p->ob, p->material) - 1;
+	gps->mat_nr = BKE_gpencil_get_material_index_for_brush(p->ob, p->brush);
 
 	/* calculate UVs along the stroke */
 	ED_gpencil_calc_stroke_uv(obact, gps);
@@ -1834,31 +1840,10 @@ static void gp_init_colors(tGPsdata *p)
 	bGPdata *gpd = p->gpd;
 	Brush *brush = p->brush;
 
-	Material *ma = NULL;
 	MaterialGPencilStyle *gp_style = NULL;
 
 	/* use brush material */
-	ma = BKE_gpencil_get_material_from_brush(brush);
-
-	/* if no brush defaults, get material and color info
-	 * NOTE: Ensures that everything we need will exist...
-	 */
-	if ((ma == NULL) || (ma->gp_style == NULL)) {
-		BKE_gpencil_material_ensure(p->bmain, p->ob);
-
-		/* assign always the first material to the brush */
-		p->material = give_current_material(p->ob, 1);
-		brush->gpencil_settings->material = p->material;
-	}
-	else {
-		p->material = ma;
-	}
-
-	/* check if the material is already on object material slots and add it if missing */
-	if (BKE_gpencil_get_material_index(p->ob, p->material) == 0) {
-		BKE_object_material_slot_add(p->bmain, p->ob);
-		assign_material(p->bmain, p->ob, ma, p->ob->totcol, BKE_MAT_ASSIGN_USERPREF);
-	}
+	p->material = BKE_gpencil_current_input_brush_material(p->bmain, p->ob, brush);
 
 	/* assign color information to temp tGPsdata */
 	gp_style = p->material->gp_style;
@@ -1996,7 +1981,14 @@ static bool gp_session_initdata(bContext *C, wmOperator *op, tGPsdata *p)
 		/* NOTE: This is only done for 3D view, as Materials aren't used for
 		 *       annotations in 2D editors
 		 */
+		int totcol = p->ob->totcol;
+
 		gp_init_colors(p);
+
+		/* check whether the material was newly added */
+		if (totcol != p->ob->totcol) {
+			WM_event_add_notifier(C, NC_SPACE | ND_SPACE_PROPERTIES, NULL);
+		}
 	}
 
 	/* lock axis (in some modes, disable) */