[Bf-blender-cvs] [6d0835eca7e] blender2.8: GP: Fix NULL pointer when preview is not ready

[Antonioya]

Commit: 6d0835eca7e6bdec9f19bbb5fb194146225164c7
Author: Antonioya
Date:   Sun Aug 5 11:06:20 2018 +0200
Branches: blender2.8
https://developer.blender.org/rB6d0835eca7e6bdec9f19bbb5fb194146225164c7

GP: Fix NULL pointer when preview is not ready

The preview cannot be ready when create a material with python

===================================================================

M	source/blender/makesrna/intern/rna_material.c

===================================================================

diff --git a/source/blender/makesrna/intern/rna_material.c b/source/blender/makesrna/intern/rna_material.c
index 56f5a12516b..b6250a81b3b 100644
--- a/source/blender/makesrna/intern/rna_material.c
+++ b/source/blender/makesrna/intern/rna_material.c
@@ -114,10 +114,11 @@ static void rna_MaterialGpencil_update(Main *bmain, Scene *scene, PointerRNA *pt
 	rna_Material_update(bmain, scene, ptr);
 
 	/* update previews (icon and thumbnail) */
-	preview->flag[ICON_SIZE_ICON] |= PRV_CHANGED;
-	preview->flag[ICON_SIZE_PREVIEW] |= PRV_CHANGED;
-	WM_main_add_notifier(NC_MATERIAL | ND_SHADING_PREVIEW, ma);
-
+	if (preview != NULL) {
+		preview->flag[ICON_SIZE_ICON] |= PRV_CHANGED;
+		preview->flag[ICON_SIZE_PREVIEW] |= PRV_CHANGED;
+		WM_main_add_notifier(NC_MATERIAL | ND_SHADING_PREVIEW, ma);
+	}
 	WM_main_add_notifier(NC_GPENCIL | ND_DATA, ma);
 }