Grease Pencil: Add LineArt modifier

This adds the LineArt grease pencil modifier.

It takes objects or collections as input and generates various grease
pencil lines from these objects with the help of the active scene
camera. For example it can generate contour lines, intersection lines
and crease lines to name a few.

This is really useful as artists can then use 3D meshes to automatically
generate grease pencil lines for characters, enviroments or other
visualization purposes.

These lines can then be baked and edited as regular grease pencil lines.

Reviewed By: Sebastian Parborg, Antonio Vazquez, Matias Mendiola

Differential Revision: http://developer.blender.org/D8758

1 files changed, 10 insertions, 0 deletions

diff --git a/source/blender/editors/space_buttons/space_buttons.c b/source/blender/editors/space_buttons/space_buttons.c
index 07bc1d42c3f..43d45db38e2 100644
--- a/source/blender/editors/space_buttons/space_buttons.c
+++ b/source/blender/editors/space_buttons/space_buttons.c
@@ -206,6 +206,14 @@ int ED_buttons_tabs_list(SpaceProperties *sbuts, short *context_tabs_array)
     context_tabs_array[length] = -1;
     length++;
   }
+  if (sbuts->pathflag & (1 << BCONTEXT_VIEW_LAYER)) {
+    context_tabs_array[length] = BCONTEXT_COLLECTION;
+    length++;
+  }
+  if (length != 0) {
+    context_tabs_array[length] = -1;
+    length++;
+  }
   if (sbuts->pathflag & (1 << BCONTEXT_OBJECT)) {
     context_tabs_array[length] = BCONTEXT_OBJECT;
     length++;
@@ -271,6 +279,8 @@ static const char *buttons_main_region_context_string(const short mainb)
       return "view_layer";
     case BCONTEXT_WORLD:
       return "world";
+    case BCONTEXT_COLLECTION:
+      return "collection";
     case BCONTEXT_OBJECT:
       return "object";
     case BCONTEXT_DATA: