Blackboard: Add variable-to-property binding interface

blackboard/bb_variable.cpp

@@ -20,19 +20,35 @@ void BBVariable::unref() {
 	data = nullptr;
 }
 
-// void BBVariable::init_ref() {
-// 	if (data) {
-// 		unref();
-// 	}
-// 	data = memnew(Data);
-// 	data->refcount.init();
-// }
-
 void BBVariable::set_value(const Variant &p_value) {
-	data->value = p_value;
+	data->value = p_value; // Setting value even when bound as a fallback in case the binding fails.
+
+	if (is_bound()) {
+		Object *obj = ObjectDB::get_instance(ObjectID(data->bound_object));
+		ERR_FAIL_COND_MSG(!obj, "Blackboard: Failed to get bound object.");
+#ifdef LIMBOAI_MODULE
+		bool r_valid;
+		obj->set(data->bound_property, p_value, &r_valid);
+		ERR_FAIL_COND_MSG(!r_valid, vformat("Blackboard: Failed to set bound property `%s` on %s", data->bound_property, obj));
+#elif LIMBOAI_GDEXTENSION
+		obj->set(data->bound_property, p_value);
+#endif
+	}
 }
 
 Variant BBVariable::get_value() const {
+	if (is_bound()) {
+		Object *obj = ObjectDB::get_instance(ObjectID(data->bound_object));
+		ERR_FAIL_COND_V_MSG(!obj, data->value, "Blackboard: Failed to get bound object.");
+#ifdef LIMBOAI_MODULE
+		bool r_valid;
+		Variant ret = obj->get(data->bound_property, &r_valid);
+		ERR_FAIL_COND_V_MSG(!r_valid, data->value, vformat("Blackboard: Failed to get bound property `%s` on %s", data->bound_property, obj));
+#elif LIMBOAI_GDEXTENSION
+		Variant ret = obj->get(data->bound_property);
+#endif
+		return ret;
+	}
 	return data->value;
 }
 
@@ -89,6 +105,19 @@ void BBVariable::copy_prop_info(const BBVariable &p_other) {
 	data->hint_string = p_other.data->hint_string;
 }
 
+void BBVariable::bind(Object *p_object, const StringName &p_property) {
+	ERR_FAIL_NULL_MSG(p_object, "Blackboard: Binding failed - object is null.");
+	ERR_FAIL_COND_MSG(p_property == StringName(), "Blackboard: Binding failed - property name is empty.");
+	ERR_FAIL_COND_MSG(!OBJECT_HAS_PROPERTY(p_object, p_property), vformat("Blackboard: Binding failed - %s has no property `%s`.", p_object, p_property));
+	data->bound_object = p_object->get_instance_id();
+	data->bound_property = p_property;
+}
+
+void BBVariable::unbind() {
+	data->bound_object = 0;
+	data->bound_property = StringName();
+}
+
 bool BBVariable::operator==(const BBVariable &p_var) const {
 	if (data == p_var.data) {
 		return true;

blackboard/bb_variable.h

@@ -14,14 +14,10 @@
 
 #ifdef LIMBOAI_MODULE
 #include "core/object/object.h"
-#include "core/templates/safe_refcount.h"
-#include "core/variant/variant.h"
 #endif // LIMBOAI_MODULE
 
 #ifdef LIMBOAI_GDEXTENSION
-#include "godot_cpp/core/defs.hpp"
+#include "godot_cpp/core/object.hpp"
-#include "godot_cpp/templates/safe_refcount.hpp"
-#include "godot_cpp/variant/variant.hpp"
 using namespace godot;
 #endif // LIMBOAI_GDEXTENSION
 
@@ -33,14 +29,14 @@ private:
 		Variant::Type type = Variant::NIL;
 		PropertyHint hint = PropertyHint::PROPERTY_HINT_NONE;
 		String hint_string;
-		// bool bound = false;
+
-		// uint64_t bound_object = 0;
+		NodePath binding_path;
-		// StringName bound_property;
+		uint64_t bound_object = 0;
+		StringName bound_property;
 	};
 
 	Data *data = nullptr;
 	void unref();
-	// void init_ref();
 
 public:
 	void set_value(const Variant &p_value);
@@ -60,10 +56,15 @@ public:
 	bool is_same_prop_info(const BBVariable &p_other) const;
 	void copy_prop_info(const BBVariable &p_other);
 
-	// bool is_bound() { return bound; }
+	// * Editor binding methods
+	String get_binding_path() const { return data->binding_path; }
+	void set_binding_path(const String &p_binding_path) { data->binding_path = p_binding_path; }
+	bool has_binding() { return data->binding_path.is_empty(); }
 
-	// void bind(Node *p_root, NodePath p_path);
+	// * Runtime binding methods
-	// void unbind();
+	bool is_bound() const { return data->bound_object != 0; }
+	void bind(Object *p_object, const StringName &p_property);
+	void unbind();
 
 	bool operator==(const BBVariable &p_var) const;
 	bool operator!=(const BBVariable &p_var) const;

blackboard/blackboard.cpp

@@ -12,7 +12,6 @@
 #include "blackboard.h"
 
 #ifdef LIMBOAI_MODULE
-#include "core/error/error_macros.h"
 #include "core/variant/variant.h"
 #include "scene/main/node.h"
 #endif // LIMBOAI_MODULE
@@ -62,6 +61,16 @@ void Blackboard::erase_var(const String &p_name) {
 	data.erase(p_name);
 }
 
+void Blackboard::bind_var_to_property(const String &p_name, Object *p_object, const StringName &p_property) {
+	ERR_FAIL_COND_MSG(!data.has(p_name), "Blackboard: Binding failed - can't bind variable that doesn't exist.");
+	data[p_name].bind(p_object, p_property);
+}
+
+void Blackboard::unbind_var(const String &p_name) {
+	ERR_FAIL_COND_MSG(data.has(p_name), "Blackboard: Can't unbind variable that doesn't exist.");
+	data[p_name].unbind();
+}
+
 void Blackboard::add_var(const String &p_name, const BBVariable &p_var) {
 	ERR_FAIL_COND(data.has(p_name));
 	data.insert(p_name, p_var);
@@ -89,4 +98,6 @@ void Blackboard::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("erase_var", "p_name"), &Blackboard::erase_var);
 	ClassDB::bind_method(D_METHOD("prefetch_nodepath_vars", "p_node"), &Blackboard::prefetch_nodepath_vars);
 	ClassDB::bind_method(D_METHOD("top"), &Blackboard::top);
+	ClassDB::bind_method(D_METHOD("bind_var_to_property", "p_name", "p_object", "p_property"), &Blackboard::bind_var_to_property);
+	ClassDB::bind_method(D_METHOD("unbind_var", "p_name"), &Blackboard::unbind_var);
 }

blackboard/blackboard.h

@@ -51,6 +51,9 @@ public:
 	bool has_var(const String &p_name) const;
 	void erase_var(const String &p_name);
 
+	void bind_var_to_property(const String &p_name, Object *p_object, const StringName &p_property);
+	void unbind_var(const String &p_name);
+
 	void add_var(const String &p_name, const BBVariable &p_var);
 
 	void prefetch_nodepath_vars(Node *p_node);

doc_classes/Blackboard.xml

@@ -11,6 +11,15 @@
 	<tutorials>
 	</tutorials>
 	<methods>
+		<method name="bind_var_to_property">
+			<return type="void" />
+			<param index="0" name="p_name" type="String" />
+			<param index="1" name="p_object" type="Object" />
+			<param index="2" name="p_property" type="StringName" />
+			<description>
+				Establish a binding between a variable and the object's property specified by [param p_property] and [param p_object]. Changes to the variable update the property, and vice versa.
+			</description>
+		</method>
 		<method name="erase_var">
 			<return type="void" />
 			<param index="0" name="p_name" type="String" />
@@ -67,5 +76,12 @@
 				Returns the topmost [Blackboard] in the scope chain.
 			</description>
 		</method>
+		<method name="unbind_var">
+			<return type="void" />
+			<param index="0" name="p_name" type="String" />
+			<description>
+				Remove binding from a variable.
+			</description>
+		</method>
 	</methods>
 </class>

util/limbo_compat.h

@@ -54,6 +54,11 @@
 #define GET_SCRIPT(m_obj) (m_obj->get_script_instance() ? m_obj->get_script_instance()->get_script() : nullptr)
 #define ADD_STYLEBOX_OVERRIDE(m_control, m_name, m_stylebox) (m_control->add_theme_style_override(m_name, m_stylebox))
 
+_FORCE_INLINE_ bool OBJECT_HAS_PROPERTY(Object *p_obj, const StringName &p_prop) {
+	bool r_valid;
+	return Variant(p_obj).has_key(p_prop, r_valid);
+}
+
 #define VARIANT_EVALUATE(m_op, m_lvalue, m_rvalue, r_ret) r_ret = Variant::evaluate(m_op, m_lvalue, m_rvalue)
 
 // * Virtual calls
@@ -133,6 +138,10 @@ using namespace godot;
 #define GET_SCRIPT(m_obj) (m_obj->get_script())
 #define ADD_STYLEBOX_OVERRIDE(m_control, m_name, m_stylebox) (m_control->add_theme_stylebox_override(m_name, m_stylebox))
 
+_FORCE_INLINE_ bool OBJECT_HAS_PROPERTY(Object *p_obj, const StringName &p_prop) {
+	return Variant(p_obj).has_key(p_prop);
+}
+
 #define VARIANT_EVALUATE(m_op, m_lvalue, m_rvalue, r_ret)            \
 	{                                                                \
 		bool r_valid;                                                \