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

7 files changed, 101 insertions, 8 deletions

diff --git a/source/blender/blenkernel/BKE_collection.h b/source/blender/blenkernel/BKE_collection.h
index d15aebfe03d..d0fca5e3796 100644
--- a/source/blender/blenkernel/BKE_collection.h
+++ b/source/blender/blenkernel/BKE_collection.h
@@ -82,6 +82,8 @@ struct Collection *BKE_collection_master_add(void);
 
 bool BKE_collection_has_object(struct Collection *collection, const struct Object *ob);
 bool BKE_collection_has_object_recursive(struct Collection *collection, struct Object *ob);
+bool BKE_collection_has_object_recursive_instanced(struct Collection *collection,
+                                                   struct Object *ob);
 struct Collection *BKE_collection_object_find(struct Main *bmain,
                                               struct Scene *scene,
                                               struct Collection *collection,
@@ -123,6 +125,7 @@ bool BKE_collection_object_cyclic_check(struct Main *bmain,
 /* Object list cache. */
 
 struct ListBase BKE_collection_object_cache_get(struct Collection *collection);
+ListBase BKE_collection_object_cache_instanced_get(struct Collection *collection);
 void BKE_collection_object_cache_free(struct Collection *collection);
 
 struct Base *BKE_collection_or_layer_objects(const struct ViewLayer *view_layer,
diff --git a/source/blender/blenkernel/BKE_global.h b/source/blender/blenkernel/BKE_global.h
index b3d0e0c9f98..9e237679795 100644
--- a/source/blender/blenkernel/BKE_global.h
+++ b/source/blender/blenkernel/BKE_global.h
@@ -77,6 +77,7 @@ typedef struct Global {
    *   *   1112: Disable new Cloth internal springs handling (09/2014).
    *   *   1234: Disable new dyntopo code fixing skinny faces generation (04/2015).
    *   *   3001: Enable additional Fluid modifier (Mantaflow) options (02/2020).
+   *   *   4000: Line Art state output and debugging logs (03/2021).
    *   * 16384 and above: Reserved for python (add-ons) usage.
    */
   short debug_value;
diff --git a/source/blender/blenkernel/BKE_gpencil.h b/source/blender/blenkernel/BKE_gpencil.h
index 5cfdcf241d1..a0a3f30d6d8 100644
--- a/source/blender/blenkernel/BKE_gpencil.h
+++ b/source/blender/blenkernel/BKE_gpencil.h
@@ -212,6 +212,10 @@ void BKE_gpencil_layer_mask_sort(struct bGPdata *gpd, struct bGPDlayer *gpl);
 void BKE_gpencil_layer_mask_sort_all(struct bGPdata *gpd);
 void BKE_gpencil_layer_frames_sort(struct bGPDlayer *gpl, bool *r_has_duplicate_frames);
 
+struct bGPDlayer *BKE_gpencil_layer_get_by_name(struct bGPdata *gpd,
+                                                char *name,
+                                                int first_if_not_found);
+
 /* Brush */
 struct Material *BKE_gpencil_brush_material_get(struct Brush *brush);
 void BKE_gpencil_brush_material_set(struct Brush *brush, struct Material *material);
@@ -231,6 +235,7 @@ struct Material *BKE_gpencil_object_material_new(struct Main *bmain,
                                                  int *r_index);
 
 int BKE_gpencil_object_material_index_get(struct Object *ob, struct Material *ma);
+int BKE_gpencil_object_material_get_index_name(struct Object *ob, char *name);
 
 struct Material *BKE_gpencil_object_material_from_brush_get(struct Object *ob,
                                                             struct Brush *brush);
diff --git a/source/blender/blenkernel/BKE_gpencil_modifier.h b/source/blender/blenkernel/BKE_gpencil_modifier.h
index c066c161f46..c6406c8478c 100644
--- a/source/blender/blenkernel/BKE_gpencil_modifier.h
+++ b/source/blender/blenkernel/BKE_gpencil_modifier.h
@@ -206,7 +206,8 @@ typedef struct GpencilModifierTypeInfo {
    * This function is optional.
    */
   void (*updateDepsgraph)(struct GpencilModifierData *md,
-                          const struct ModifierUpdateDepsgraphContext *ctx);
+                          const struct ModifierUpdateDepsgraphContext *ctx,
+                          const int mode);
 
   /**
    * Should return true if the modifier needs to be recalculated on time
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) {
diff --git a/source/blender/blenkernel/intern/gpencil.c b/source/blender/blenkernel/intern/gpencil.c
index 00dcaad83db..3b46672f9cd 100644
--- a/source/blender/blenkernel/intern/gpencil.c
+++ b/source/blender/blenkernel/intern/gpencil.c
@@ -1663,6 +1663,31 @@ bGPDlayer *BKE_gpencil_layer_active_get(bGPdata *gpd)
   return NULL;
 }
 
+bGPDlayer *BKE_gpencil_layer_get_by_name(bGPdata *gpd, char *name, int first_if_not_found)
+{
+  bGPDlayer *gpl;
+  int i = 0;
+
+  /* error checking */
+  if (ELEM(NULL, gpd, gpd->layers.first)) {
+    return NULL;
+  }
+
+  /* loop over layers until found (assume only one active) */
+  for (gpl = gpd->layers.first; gpl; gpl = gpl->next) {
+    if (STREQ(name, gpl->info)) {
+      return gpl;
+    }
+    i++;
+  }
+
+  /* no such layer */
+  if (first_if_not_found) {
+    return gpd->layers.first;
+  }
+  return NULL;
+}
+
 /**
  * Set active grease pencil layer.
  * \param gpd: Grease pencil data-block
@@ -2421,6 +2446,21 @@ int BKE_gpencil_object_material_index_get(Object *ob, Material *ma)
   return -1;
 }
 
+int BKE_gpencil_object_material_get_index_name(Object *ob, char *name)
+{
+  short *totcol = BKE_object_material_len_p(ob);
+  Material *read_ma = NULL;
+  for (short i = 0; i < *totcol; i++) {
+    read_ma = BKE_object_material_get(ob, i + 1);
+    /* Material names are like "MAMaterial.001" */
+    if (STREQ(name, &read_ma->id.name[2])) {
+      return i;
+    }
+  }
+
+  return -1;
+}
+
 /**
  * Create a default palette.
  * \param bmain: Main pointer
diff --git a/source/blender/blenkernel/intern/object_update.c b/source/blender/blenkernel/intern/object_update.c
index 69442b7646c..1e6a099040f 100644
--- a/source/blender/blenkernel/intern/object_update.c
+++ b/source/blender/blenkernel/intern/object_update.c
@@ -176,12 +176,14 @@ void BKE_object_handle_data_update(Depsgraph *depsgraph, Scene *scene, Object *o
 
       CustomData_MeshMasks cddata_masks = scene->customdata_mask;
       CustomData_MeshMasks_update(&cddata_masks, &CD_MASK_BAREMESH);
-      if (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER) {
-        /* Make sure Freestyle edge/face marks appear in DM for render (see T40315). */
+      /* Make sure Freestyle edge/face marks appear in DM for render (see T40315). Due to Line Art
+       * impementation, edge marks should also be shown in viewport. */
 #ifdef WITH_FREESTYLE
-        cddata_masks.emask |= CD_MASK_FREESTYLE_EDGE;
-        cddata_masks.pmask |= CD_MASK_FREESTYLE_FACE;
+      cddata_masks.emask |= CD_MASK_FREESTYLE_EDGE;
+      cddata_masks.pmask |= CD_MASK_FREESTYLE_FACE;
+      cddata_masks.vmask |= CD_MASK_MDEFORMVERT;
 #endif
+      if (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER) {
         /* Always compute UVs, vertex colors as orcos for render. */
         cddata_masks.lmask |= CD_MASK_MLOOPUV | CD_MASK_MLOOPCOL;
         cddata_masks.vmask |= CD_MASK_ORCO | CD_MASK_PROP_COLOR;