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, 44 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/collection.c b/source/blender/blenkernel/intern/collection.c
index 28b91dcc8ce..4e4134c7c8f 100644
--- a/source/blender/blenkernel/intern/collection.c
+++ b/source/blender/blenkernel/intern/collection.c
@@ -122,7 +122,9 @@ static void collection_copy_data(Main *bmain, ID *id_dst, const ID *id_src, cons
   }
 
   collection_dst->flag &= ~COLLECTION_HAS_OBJECT_CACHE;
+  collection_dst->flag &= ~COLLECTION_HAS_OBJECT_CACHE_INSTANCED;
   BLI_listbase_clear(&collection_dst->object_cache);
+  BLI_listbase_clear(&collection_dst->object_cache_instanced);
 
   BLI_listbase_clear(&collection_dst->gobject);
   BLI_listbase_clear(&collection_dst->children);
@@ -214,8 +216,10 @@ static void collection_blend_write(BlendWriter *writer, ID *id, const void *id_a
   if (collection->id.us > 0 || BLO_write_is_undo(writer)) {
     /* Clean up, important in undo case to reduce false detection of changed data-blocks. */
     collection->flag &= ~COLLECTION_HAS_OBJECT_CACHE;
+    collection->flag &= ~COLLECTION_HAS_OBJECT_CACHE_INSTANCED;
     collection->tag = 0;
     BLI_listbase_clear(&collection->object_cache);
+    BLI_listbase_clear(&collection->object_cache_instanced);
     BLI_listbase_clear(&collection->parents);
 
     /* write LibData */
@@ -246,8 +250,10 @@ void BKE_collection_blend_read_data(BlendDataReader *reader, Collection *collect
   BKE_previewimg_blend_read(reader, collection->preview);
 
   collection->flag &= ~COLLECTION_HAS_OBJECT_CACHE;
+  collection->flag &= ~COLLECTION_HAS_OBJECT_CACHE_INSTANCED;
   collection->tag = 0;
   BLI_listbase_clear(&collection->object_cache);
+  BLI_listbase_clear(&collection->object_cache_instanced);
   BLI_listbase_clear(&collection->parents);
 
 #ifdef USE_COLLECTION_COMPAT_28
@@ -773,7 +779,10 @@ const char *BKE_collection_ui_name_get(struct Collection *collection)
 /** \name Object List Cache
  * \{ */
 
-static void collection_object_cache_fill(ListBase *lb, Collection *collection, int parent_restrict)
+static void collection_object_cache_fill(ListBase *lb,
+                                         Collection *collection,
+                                         int parent_restrict,
+                                         bool with_instances)
 {
   int child_restrict = collection->flag | parent_restrict;
 
@@ -784,6 +793,10 @@ static void collection_object_cache_fill(ListBase *lb, Collection *collection, i
       base = MEM_callocN(sizeof(Base), "Object Base");
       base->object = cob->ob;
       BLI_addtail(lb, base);
+      if (with_instances && cob->ob->instance_collection) {
+        collection_object_cache_fill(
+            lb, cob->ob->instance_collection, child_restrict, with_instances);
+      }
     }
 
     /* Only collection flags are checked here currently, object restrict flag is checked
@@ -798,7 +811,7 @@ static void collection_object_cache_fill(ListBase *lb, Collection *collection, i
   }
 
   LISTBASE_FOREACH (CollectionChild *, child, &collection->children) {
-    collection_object_cache_fill(lb, child->collection, child_restrict);
+    collection_object_cache_fill(lb, child->collection, child_restrict, with_instances);
   }
 }
 
@@ -809,7 +822,7 @@ ListBase BKE_collection_object_cache_get(Collection *collection)
 
     BLI_mutex_lock(&cache_lock);
     if (!(collection->flag & COLLECTION_HAS_OBJECT_CACHE)) {
-      collection_object_cache_fill(&collection->object_cache, collection, 0);
+      collection_object_cache_fill(&collection->object_cache, collection, 0, false);
       collection->flag |= COLLECTION_HAS_OBJECT_CACHE;
     }
     BLI_mutex_unlock(&cache_lock);
@@ -818,11 +831,29 @@ ListBase BKE_collection_object_cache_get(Collection *collection)
   return collection->object_cache;
 }
 
+ListBase BKE_collection_object_cache_instanced_get(Collection *collection)
+{
+  if (!(collection->flag & COLLECTION_HAS_OBJECT_CACHE_INSTANCED)) {
+    static ThreadMutex cache_lock = BLI_MUTEX_INITIALIZER;
+
+    BLI_mutex_lock(&cache_lock);
+    if (!(collection->flag & COLLECTION_HAS_OBJECT_CACHE_INSTANCED)) {
+      collection_object_cache_fill(&collection->object_cache_instanced, collection, 0, true);
+      collection->flag |= COLLECTION_HAS_OBJECT_CACHE_INSTANCED;
+    }
+    BLI_mutex_unlock(&cache_lock);
+  }
+
+  return collection->object_cache_instanced;
+}
+
 static void collection_object_cache_free(Collection *collection)
 {
   /* Clear own cache an for all parents, since those are affected by changes as well. */
   collection->flag &= ~COLLECTION_HAS_OBJECT_CACHE;
+  collection->flag &= ~COLLECTION_HAS_OBJECT_CACHE_INSTANCED;
   BLI_freelistN(&collection->object_cache);
+  BLI_freelistN(&collection->object_cache_instanced);
 
   LISTBASE_FOREACH (CollectionParent *, parent, &collection->parents) {
     collection_object_cache_free(parent->collection);
@@ -928,6 +959,16 @@ bool BKE_collection_has_object_recursive(Collection *collection, Object *ob)
   return (BLI_findptr(&objects, ob, offsetof(Base, object)));
 }
 
+bool BKE_collection_has_object_recursive_instanced(Collection *collection, Object *ob)
+{
+  if (ELEM(NULL, collection, ob)) {
+    return false;
+  }
+
+  const ListBase objects = BKE_collection_object_cache_instanced_get(collection);
+  return (BLI_findptr(&objects, ob, offsetof(Base, object)));
+}
+
 static Collection *collection_next_find(Main *bmain, Scene *scene, Collection *collection)
 {
   if (scene && collection == scene->master_collection) {