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, 27 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_collection.c b/source/blender/makesrna/intern/rna_collection.c
index 20a455f5312..90e969560b7 100644
--- a/source/blender/makesrna/intern/rna_collection.c
+++ b/source/blender/makesrna/intern/rna_collection.c
@@ -22,6 +22,8 @@
 
 #include "DNA_collection_types.h"
 
+#include "DNA_lineart_types.h"
+
 #include "BLI_utildefines.h"
 
 #include "RNA_define.h"
@@ -517,6 +519,31 @@ void RNA_def_collections(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Disable in Renders", "Globally disable in renders");
   RNA_def_property_update(prop, NC_SCENE | ND_LAYER_CONTENT, "rna_Collection_flag_update");
 
+  static const EnumPropertyItem rna_collection_lineart_usage[] = {
+      {COLLECTION_LRT_INCLUDE, "INCLUDE", 0, "Include", "Collection will produce feature lines"},
+      {COLLECTION_LRT_OCCLUSION_ONLY,
+       "OCCLUSION_ONLY",
+       0,
+       "Occlusion Only",
+       "Only use the collection to produce occlusion"},
+      {COLLECTION_LRT_EXCLUDE, "EXCLUDE", 0, "Exclude", "Don't use this collection in LRT"},
+      {COLLECTION_LRT_INTERSECTION_ONLY,
+       "INTERSECTION_ONLY",
+       0,
+       "Intersection Only",
+       "Only generate intersection lines with this collection"},
+      {COLLECTION_LRT_NO_INTERSECTION,
+       "NO_INTERSECTION",
+       0,
+       "No Intersection",
+       "Do not generate intersection lines for this collection"},
+      {0, NULL, 0, NULL, NULL}};
+
+  prop = RNA_def_property(srna, "lineart_usage", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, rna_collection_lineart_usage);
+  RNA_def_property_ui_text(prop, "Usage", "How to use this collection in LRT");
+  RNA_def_property_update(prop, NC_SCENE, NULL);
+
   prop = RNA_def_property(srna, "color_tag", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_sdna(prop, NULL, "color_tag");
   RNA_def_property_enum_funcs(