Fix: Grease Pencil sculpting crashes when sculpting on layers without any strokes

Reported by @loochmunz. I've also gone through checking for and fixing other places
where this was also occurring.


To be included in 2.78

2 files changed, 12 insertions, 4 deletions

diff --git a/source/blender/editors/gpencil/gpencil_brush.c b/source/blender/editors/gpencil/gpencil_brush.c
index fcb2ce02bde..8576cbca239 100644
--- a/source/blender/editors/gpencil/gpencil_brush.c
+++ b/source/blender/editors/gpencil/gpencil_brush.c
@@ -1350,6 +1350,10 @@ static bool gpsculpt_brush_apply_standard(bContext *C, tGP_BrushEditData *gso)
 
 	CTX_DATA_BEGIN(C, bGPDlayer *, gpl, editable_gpencil_layers)
 	{
+		bGPDframe *gpf = gpl->actframe;
+		if (gpf == NULL)
+			continue;
+		
 		/* calculate difference matrix if parent object */
 		if (gpl->parent != NULL) {
 			ED_gpencil_parent_location(gpl, diff_mat);
@@ -1358,10 +1362,8 @@ static bool gpsculpt_brush_apply_standard(bContext *C, tGP_BrushEditData *gso)
 		else {
 			parented = false;
 		}
-
-		bGPDframe *gpf = gpl->actframe;
-		bGPDstroke *gps;
-		for (gps = gpf->strokes.first; gps; gps = gps->next) {
+		
+		for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
 			/* skip strokes that are invalid for current view */
 			if (ED_gpencil_stroke_can_use(C, gps) == false)
 				continue;
diff --git a/source/blender/editors/gpencil/gpencil_edit.c b/source/blender/editors/gpencil/gpencil_edit.c
index 7175ec3e83d..12d837dfb29 100644
--- a/source/blender/editors/gpencil/gpencil_edit.c
+++ b/source/blender/editors/gpencil/gpencil_edit.c
@@ -1504,6 +1504,9 @@ static int gp_stroke_cyclical_set_exec(bContext *C, wmOperator *op)
 	/* loop all selected strokes */
 	CTX_DATA_BEGIN(C, bGPDlayer *, gpl, editable_gpencil_layers)
 	{
+		if (gpl->actframe == NULL)
+			continue;
+			
 		for (bGPDstroke *gps = gpl->actframe->strokes.last; gps; gps = gps->prev) {
 			bGPDpalettecolor *palcolor = gps->palcolor;
 			
@@ -1724,6 +1727,9 @@ static int gp_stroke_join_exec(bContext *C, wmOperator *op)
 	CTX_DATA_BEGIN(C, bGPDlayer *, gpl, editable_gpencil_layers)
 	{
 		bGPDframe *gpf = gpl->actframe;
+		if (gpf == NULL)
+			continue;
+		
 		for (gps = gpf->strokes.first; gps; gps = gpsn) {
 			gpsn = gps->next;
 			if (gps->flag & GP_STROKE_SELECT) {