GPv3: Getter and setter for active node

This adds the functions `get_active_node` and `set_active_node`.
It also changes the the parameter of the `set_active_layer` to be
non-const.

Requested in !121970.

Pull Request: https://projects.blender.org/blender/blender/pulls/122006

source/blender/blenkernel/intern/grease_pencil.cc

@@ -87,7 +87,7 @@ static void grease_pencil_init_data(ID *id)
   MEMCPY_STRUCT_AFTER(grease_pencil, DNA_struct_default_get(GreasePencil), id);
 
   grease_pencil->root_group_ptr = MEM_new<greasepencil::LayerGroup>(__func__);
-  grease_pencil->active_node = nullptr;
+  grease_pencil->set_active_node(nullptr);
 
   CustomData_reset(&grease_pencil->layers_data);
 
@@ -116,11 +116,11 @@ static void grease_pencil_copy_data(Main * /*bmain*/,
       __func__, grease_pencil_src->root_group());
 
   /* Set active node. */
-  if (grease_pencil_src->active_node) {
+  if (grease_pencil_src->get_active_node()) {
     bke::greasepencil::TreeNode *active_node = grease_pencil_dst->find_node_by_name(
-        grease_pencil_src->active_node->wrap().name());
+        grease_pencil_src->get_active_node()->name());
     BLI_assert(active_node);
-    grease_pencil_dst->active_node = active_node;
+    grease_pencil_dst->set_active_node(active_node);
   }
 
   CustomData_copy(&grease_pencil_src->layers_data,
@@ -2625,12 +2625,11 @@ const blender::bke::greasepencil::Layer *GreasePencil::get_active_layer() const
   if (this->active_node == nullptr) {
     return nullptr;
   }
-
+  const blender::bke::greasepencil::TreeNode &active_node = *this->get_active_node();
-  if (!this->active_node->wrap().is_layer()) {
+  if (!active_node.is_layer()) {
     return nullptr;
   }
-
+  return &active_node.as_layer();
-  return &this->active_node->wrap().as_layer();
 }
 
 blender::bke::greasepencil::Layer *GreasePencil::get_active_layer()
@@ -2638,17 +2637,16 @@ blender::bke::greasepencil::Layer *GreasePencil::get_active_layer()
   if (this->active_node == nullptr) {
     return nullptr;
   }
-
+  blender::bke::greasepencil::TreeNode &active_node = *this->get_active_node();
-  if (!this->active_node->wrap().is_layer()) {
+  if (!active_node.is_layer()) {
     return nullptr;
   }
-
+  return &active_node.as_layer();
-  return &this->active_node->wrap().as_layer();
 }
 
-void GreasePencil::set_active_layer(const blender::bke::greasepencil::Layer *layer)
+void GreasePencil::set_active_layer(blender::bke::greasepencil::Layer *layer)
 {
-  this->active_node = const_cast<GreasePencilLayerTreeNode *>(&layer->base);
+  this->active_node = reinterpret_cast<GreasePencilLayerTreeNode *>(&layer->as_node());
 
   if (this->flag & GREASE_PENCIL_AUTOLOCK_LAYERS) {
     this->autolock_inactive_layers();
@@ -2681,12 +2679,11 @@ const blender::bke::greasepencil::LayerGroup *GreasePencil::get_active_group() c
   if (this->active_node == nullptr) {
     return nullptr;
   }
-
+  const blender::bke::greasepencil::TreeNode &active_node = *this->get_active_node();
-  if (!this->active_node->wrap().is_group()) {
+  if (!active_node.is_group()) {
     return nullptr;
   }
-
+  return &active_node.as_group();
-  return &this->active_node->wrap().as_group();
 }
 
 blender::bke::greasepencil::LayerGroup *GreasePencil::get_active_group()
@@ -2694,12 +2691,36 @@ blender::bke::greasepencil::LayerGroup *GreasePencil::get_active_group()
   if (this->active_node == nullptr) {
     return nullptr;
   }
-
+  blender::bke::greasepencil::TreeNode &active_node = *this->get_active_node();
-  if (!this->active_node->wrap().is_group()) {
+  if (!active_node.is_group()) {
     return nullptr;
   }
+  return &active_node.as_group();
+}
 
-  return &this->active_node->wrap().as_group();
+const blender::bke::greasepencil::TreeNode *GreasePencil::get_active_node() const
+{
+  if (this->active_node == nullptr) {
+    return nullptr;
+  }
+  return &this->active_node->wrap();
+}
+
+blender::bke::greasepencil::TreeNode *GreasePencil::get_active_node()
+{
+  if (this->active_node == nullptr) {
+    return nullptr;
+  }
+  return &this->active_node->wrap();
+}
+
+void GreasePencil::set_active_node(blender::bke::greasepencil::TreeNode *node)
+{
+  this->active_node = reinterpret_cast<GreasePencilLayerTreeNode *>(node);
+
+  if (this->flag & GREASE_PENCIL_AUTOLOCK_LAYERS) {
+    this->autolock_inactive_layers();
+  }
 }
 
 static blender::VectorSet<blender::StringRefNull> get_node_names(const GreasePencil &grease_pencil)
@@ -3016,10 +3037,10 @@ static void update_active_node(GreasePencil &grease_pencil,
                                const blender::bke::greasepencil::TreeNode &node)
 {
   using namespace blender::bke::greasepencil;
-  if (grease_pencil.active_node == nullptr) {
+  if (grease_pencil.get_active_node() == nullptr) {
     return;
   }
-  const TreeNode &active_node = grease_pencil.active_node->wrap();
+  TreeNode &active_node = *grease_pencil.get_active_node();
   if (&active_node != &node) {
     return;
   }
@@ -3029,7 +3050,7 @@ static void update_active_node(GreasePencil &grease_pencil,
     return;
   }
 
-  Span<const Layer *> layers = grease_pencil.layers();
+  Span<Layer *> layers = grease_pencil.layers_for_write();
   /* If there is no other layer available, unset the active layer. */
   if (layers.size() == 1) {
     grease_pencil.set_active_layer(nullptr);
@@ -3253,7 +3274,7 @@ static void read_layer_tree(GreasePencil &grease_pencil, BlendDataReader *reader
    * and create an empty root group to avoid crashes. */
   if (grease_pencil.root_group_ptr == nullptr) {
     grease_pencil.root_group_ptr = MEM_new<blender::bke::greasepencil::LayerGroup>(__func__);
-    grease_pencil.active_node = nullptr;
+    grease_pencil.set_active_node(nullptr);
     return;
   }
   /* Read active layer. */

source/blender/editors/grease_pencil/intern/grease_pencil_layers.cc

@@ -212,7 +212,7 @@ static int grease_pencil_layer_active_exec(bContext *C, wmOperator *op)
   GreasePencil &grease_pencil = *static_cast<GreasePencil *>(object->data);
   int layer_index = RNA_int_get(op->ptr, "layer");
 
-  const Layer &layer = *grease_pencil.layer(layer_index);
+  Layer &layer = *grease_pencil.layer(layer_index);
   if (grease_pencil.is_layer_active(&layer)) {
     return OPERATOR_CANCELLED;
   }

source/blender/editors/grease_pencil/intern/grease_pencil_undo.cc

@@ -280,8 +280,8 @@ class StepObject {
     BLI_assert(layers_num_ == grease_pencil.layers().size());
 
     if (!active_layer_name_.empty()) {
-      const bke::greasepencil::TreeNode *active_node =
+      bke::greasepencil::TreeNode *active_node = grease_pencil.root_group().find_node_by_name(
-          grease_pencil.root_group().find_node_by_name(active_layer_name_);
+          active_layer_name_);
       if (active_node && active_node->is_layer()) {
         grease_pencil.set_active_layer(&active_node->as_layer());
       }

source/blender/editors/interface/templates/interface_template_grease_pencil_layer_tree.cc

@@ -170,7 +170,7 @@ class LayerViewItemDragController : public AbstractViewItemDragController {
 
   void on_drag_start() override
   {
-    grease_pencil_.active_node = &dragged_node_;
+    grease_pencil_.set_active_node(&dragged_node_);
   }
 };
 

source/blender/makesdna/DNA_grease_pencil_types.h

@@ -508,7 +508,7 @@ typedef struct GreasePencil {
   bool has_active_layer() const;
   const blender::bke::greasepencil::Layer *get_active_layer() const;
   blender::bke::greasepencil::Layer *get_active_layer();
-  void set_active_layer(const blender::bke::greasepencil::Layer *layer);
+  void set_active_layer(blender::bke::greasepencil::Layer *layer);
   bool is_layer_active(const blender::bke::greasepencil::Layer *layer) const;
   void autolock_inactive_layers();
 
@@ -517,6 +517,11 @@ typedef struct GreasePencil {
   const blender::bke::greasepencil::LayerGroup *get_active_group() const;
   blender::bke::greasepencil::LayerGroup *get_active_group();
 
+  /* Active node functions. */
+  const blender::bke::greasepencil::TreeNode *get_active_node() const;
+  blender::bke::greasepencil::TreeNode *get_active_node();
+  void set_active_node(blender::bke::greasepencil::TreeNode *node);
+
   /* Adding layers and layer groups. */
   /** Adds a new layer with the given name to the top of root group. */
   blender::bke::greasepencil::Layer &add_layer(blender::StringRefNull name);

source/blender/makesrna/intern/rna_grease_pencil.cc

@@ -251,10 +251,11 @@ static void rna_GreasePencil_active_group_set(PointerRNA *ptr,
                                               PointerRNA value,
                                               ReportList * /*reports*/)
 {
+  using namespace blender::bke::greasepencil;
   GreasePencil *grease_pencil = rna_grease_pencil(ptr);
-  GreasePencilLayerTreeNode *node = static_cast<GreasePencilLayerTreeNode *>(value.data);
+  TreeNode *node = static_cast<TreeNode *>(value.data);
-  if (node->wrap().is_group()) {
+  if (node->is_group()) {
-    grease_pencil->active_node = node;
+    grease_pencil->set_active_node(node);
     WM_main_add_notifier(NC_GPENCIL | NA_EDITED, nullptr);
   }
 }