feat: implemented adding primitive with UI

modules/terrain_editor/add_primitive_button.cpp

@@ -0,0 +1,31 @@
+#include "add_primitive_button.h"
+#include "terrain_editor/edit_history.h"
+#include "terrain_editor/terrain_mesh_generator.h"
+
+void AddPrimitiveButton::_bind_methods() {
+	BIND_HPROPERTY(Variant::OBJECT, primitive_blueprint, PROPERTY_HINT_RESOURCE_TYPE, "TerrainPrimitive");
+	BIND_HPROPERTY(Variant::OBJECT, terrain, PROPERTY_HINT_NODE_TYPE, "TerrainMeshGenerator");
+}
+
+void AddPrimitiveButton::pressed() {
+	if (this->terrain) {
+		Ref<TerrainPrimitive> copy{ this->primitive_blueprint->duplicate(true) };
+		EditHistory::get_singleton()->push_action(callable_mp(this->terrain, &TerrainMeshGenerator::add_primitive).bind(copy), callable_mp(this->terrain, &TerrainMeshGenerator::remove_primitive).bind(copy));
+	}
+}
+
+void AddPrimitiveButton::set_primitive_blueprint(Ref<TerrainPrimitive> blueprint) {
+	this->primitive_blueprint = blueprint;
+}
+
+Ref<TerrainPrimitive> AddPrimitiveButton::get_primitive_blueprint() const {
+	return this->primitive_blueprint;
+}
+
+void AddPrimitiveButton::set_terrain(TerrainMeshGenerator *terrain) {
+	this->terrain = terrain;
+}
+
+TerrainMeshGenerator *AddPrimitiveButton::get_terrain() const {
+	return this->terrain;
+}

modules/terrain_editor/add_primitive_button.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "scene/gui/button.h"
+#include "terrain_editor/terrain_mesh_generator.h"
+#include "terrain_editor/terrain_primitive.h"
+
+class AddPrimitiveButton : public Button {
+	GDCLASS(AddPrimitiveButton, Button);
+	static void _bind_methods();
+	void pressed() override;
+
+public:
+	void set_primitive_blueprint(Ref<TerrainPrimitive> primitive);
+	Ref<TerrainPrimitive> get_primitive_blueprint() const;
+	void set_terrain(TerrainMeshGenerator *terrain);
+	TerrainMeshGenerator *get_terrain() const;
+
+private:
+	Ref<TerrainPrimitive> primitive_blueprint{};
+	TerrainMeshGenerator *terrain{ nullptr };
+};

modules/terrain_editor/register_types.cpp

@@ -2,7 +2,7 @@
 
 #include "core/config/engine.h"
 #include "core/object/class_db.h"
-#include "scene/main/scene_tree.h"
+#include "terrain_editor/add_primitive_button.h"
 #include "terrain_editor/edit_history.h"
 #include "terrain_editor/point_primitive_node.h"
 #include "terrain_editor/primitive_layer_list.h"
@@ -28,6 +28,7 @@ void initialize_terrain_editor_module(ModuleInitializationLevel p_level) {
 	ClassDB::register_class<EditHistory>();
 	Engine::get_singleton()->add_singleton(Engine::Singleton("EditHistory", (EditHistory::singleton_instance = memnew(EditHistory)), "EditHistory"));
 	ClassDB::register_class<PrimitiveLayerList>();
+	ClassDB::register_class<AddPrimitiveButton>();
 }
 
 void uninitialize_terrain_editor_module(ModuleInitializationLevel p_level) {

modules/terrain_editor/terrain_mesh_generator.cpp

@@ -258,6 +258,21 @@ void TerrainMeshGenerator::push_task(Rect2 area, Ref<ArrayMesh> mesh, size_t poi
 	this->input_lock.unlock();
 }
 
+void TerrainMeshGenerator::add_primitive(Ref<TerrainPrimitive> primitive) {
+	Array list = get_primitives();
+	list.push_front(primitive);
+	set_primitives(list);
+}
+
+void TerrainMeshGenerator::remove_primitive(Ref<TerrainPrimitive> primitive) {
+	Array list = get_primitives();
+	int idx{ list.find(primitive) };
+	if (idx >= 0 && idx < list.size()) {
+		list.remove_at(idx);
+	}
+	set_primitives(list);
+}
+
 void TerrainMeshGenerator::set_primitives(Array primitives) {
 	// synchronise primitives
 	for (Variant var : this->primitives_buffer) {

modules/terrain_editor/terrain_mesh_generator.h

@@ -37,6 +37,8 @@ protected:
 
 public:
 	void push_task(Rect2 area, Ref<ArrayMesh> mesh, size_t side_points, Callable callback = Callable());
+	void add_primitive(Ref<TerrainPrimitive> primitive);
+	void remove_primitive(Ref<TerrainPrimitive> primitive);
 	void set_primitives(Array array);
 	Array get_primitives() const;
 	void set_vertex_color_gradient(Ref<Gradient> gradient);