NodeExternBase Class

WarningThe scope of applications for UnigineScript is limited to implementing materials-related logic (material expressions, scriptable materials, brush materials). Do not use UnigineScript as a language for application logic, please consider C#/C++ instead, as these APIs are the preferred ones. Availability of new Engine features in UnigineScript (beyond its scope of applications) is not guaranteed, as the current level of support assumes only fixing critical issues.

Inherits from:

Base

The base class that is used to implement logic of custom user-defined nodes. The custom node class should be inherited from NodeExternBase.

Notice

NodeExternBase isn't a node (it isn't inherited from the Node class). So when the engine loads an instance of the custom node class, a NodeExtern node is created. It wraps implementation of the custom node class inherited from the NodeExternBase class.

Usage Example#

To implement logic of a custom node, perform as follows:

NoticeThe custom user-defined node can be implemented on the C++ side only. So the example below shows how to implement such node in C++ and then use in both C++ and UnigineScript.

Inherit your custom node class from NodeExternBase.
Implement constructors, destructor and all required methods.
Register the class via addClassID().
(Optional) If required, export the class and its functions to UnigineScript.

MyNode.h contains implementation of the custom MyNode class inherited from the NodeExternBase class.

Source code (C++)

#include <UnigineNodes.h>

using namespace Unigine;

// inherit a custom class from NodeExternBase
class MyNode : public NodeExternBase
{
public:

	// constructors
	MyNode();
	MyNode(void *node);
	// destructor
	virtual ~MyNode();

	// unique class ID
	virtual int getClassID();

	// save and restore the node state
	virtual int saveState(const StreamPtr &stream);
	virtual int restoreState(const StreamPtr &stream);

	// save and restore the node pointer
	static void savePointer(const StreamPtr &stream, MyNode *node);
	static NodeExternBase *restorePointer(const StreamPtr &stream);

	// set world transformation of the node
	void setWorldTransform(const UNIGINE_MAT4 &transform);
};

MyNode.cpp contains implementation of MyNode's methods.

Source code (C++)

#include "MyNode.h"

// constructor with no arguments
MyNode::MyNode()
{
	Log::warning("MyNode::MyNode(): called\n");
}
// constructor with 1 argument
MyNode::MyNode(void *node)
	: NodeExternBase(node)
{
	Log::warning("MyNode::MyNode(void*): called\n");
}
// destructor
MyNode::~MyNode()
{
	Log::warning("MyNode::~MyNode(): called\n");
}
// returns the class ID of MyNode
int MyNode::getClassID()
{
	return 1;
}
// save the node state
int MyNode::saveState(const StreamPtr &stream)
{
	Log::warning("MyNode::saveState(): called\n");
	return NodeExternBase::saveState(stream);
}
// restore the node state
int MyNode::restoreState(const StreamPtr &stream)
{
	Log::warning("MyNode::restoreState(): called\n");
	return NodeExternBase::restoreState(stream);
}
// save the node pointer
void MyNode::savePointer(const StreamPtr &stream, MyNode *node)
{
	Log::warning("MyNode::savePointer(): called\n");
	return NodeExternBase::savePointer(stream, node);
}
// restore the node pointer
NodeExternBase *MyNode::restorePointer(const StreamPtr &stream)
{
	Log::warning("MyNode::restorePointer(): called\n");
	return NodeExternBase::restorePointer(stream);
}

// set world transformation of the node
void MyNode::setWorldTransform(const UNIGINE_MAT4 &transform)
{
	getNode()->setWorldTransform(transform);
	Log::message("MyNode::setWorldTransform(): called\n");
}

In unigine_project.cpp the MyNode class is registered.

Source code (C++)

#include <UnigineEngine.h>
#include "AppSystemLogic.h"
#include "AppWorldLogic.h"
#include "AppEditorLogic.h"
#include "MyNode.h"

int main(int argc,char *argv[]) {
	
	// register the MyNode class
	NodeExternBase::addClassID<MyNode>(1);

	Unigine::EnginePtr engine(argc,argv);
	
	AppSystemLogic system_logic;
	AppWorldLogic world_logic;
	AppEditorLogic editor_logic;
	
	engine->main(&system_logic,&world_logic,&editor_logic);
	
	return 0;
}

In AppWorldLogic.cpp, approaches to work with the MyNode class are shown: you can directly create an instance of the MyNode class, or you can create an instance of the NodeExtern class by using MyNode's class ID. In both cases, an instance of the MyNode class is created.

Source code (C++)

#include "AppWorldLogic.h"
#include "MyNode.h"

int AppWorldLogic::init() {
	
	// create a MyNode pointer directly
	MyNode *my_node_0 = new MyNode();
	// call a member function
	my_node_0->setWorldTransform(Math::translate(Math::Vec3(0.5)));
	
	// create a NodeExtern instance by MyNode's class ID
	NodeExternPtr my_node_1 = NodeExtern::create(1);
	// obtain the MyNode pointer
	MyNode *my_node_2 = (MyNode*)my_node_1->getNodeExtern();
	// call the MyNode member function
	my_node_2->setWorldTransform(Math::translate(Math::Vec3(1.0)));

	return 1;
}

Output

MyNode::MyNode(): called
MyNode::setWorldTransform(): called
MyNode::MyNode(void*): called
MyNode::setWorldTransform(): called
MyNode::~MyNode(): called

Exporting to UnigineScript#

To use the custom node on the UnigineScript side, export the class and its functions to UnigineScript.

unigine_project.cpp:

Source code (C++)

#include <UnigineEngine.h>
#include <UnigineInterface.h>
#include "AppSystemLogic.h"
#include "AppWorldLogic.h"
#include "AppEditorLogic.h"
#include "MyNode.h"

int main(int argc,char *argv[]) {
	
	// register the MyNode class
	NodeExternBase::addClassID<MyNode>(1);
	
	// export the MyNode class
	ExternClass<MyNode> *my_node = MakeExternClassSaveRestoreStatePointer<MyNode>();
	my_node->addConstructor();
	my_node->addFunction("grab", &MyNode::grab);
	my_node->addFunction("release", &MyNode::release);
	my_node->addFunction("getNode", &MyNode::getNode);
	my_node->addFunction("setWorldTransform", &MyNode::setWorldTransform);
	Interpreter::addExternClass("MyNode", my_node);
	
	Unigine::EnginePtr engine(argc,argv);
	
	AppSystemLogic system_logic;
	AppWorldLogic world_logic;
	AppEditorLogic editor_logic;
	
	engine->main(&system_logic,&world_logic,&editor_logic);
	
	return 0;
}

And then use the MyNode class on the UnigineScript side:

Source code (UnigineScript)

#include <core/unigine.h>

int init() {

	// create MyNode
	MyNode my_node_0 = new MyNode();
	my_node_0.setWorldTransform(Mat4(translate(0.0f, 0.0f, 1.0f)));

	// create NodeExtern by class ID
	NodeExtern node = new NodeExtern(1);
	MyNode my_node_1 = class_cast("MyNode", node.getNodeExtern());
	my_node_1.setWorldTransform(Mat4(translate(0.0f, 0.0f, -1.0f)));

	return 1;
}

Methods:

Name	Description View: Sort by:
getClassID	Returns a unique class ID.
getNode	Returns the Node instance.
getNodeExtern	Returns the NodeExtern instance that is created on loading the custom node.
loadWorld	Loads a node state from the Xml.
renderHandler	Renders the handler for the custom user-defined node.
renderVisualizer	Renders the visualizer for the custom user-defined node.
saveState	Saves a node state into the stream.
restoreState	Restores a node state from the stream.
saveWorld	Saves a node state into the Xml.
updateEnabled	Updates enabled.
updatePosition	Updates a position of the custom node.
updateTransform	Updates transformation matrix of the custom node.

NodeExternBase Class

Members

int getClassID ( ) #

Returns a unique class ID.

Return value

Unique class ID.

Node getNode ( ) #

Returns the Node instance.

Return value

Node.

NodeExtern getNodeExtern ( ) #

Returns the NodeExtern instance that is created on loading the custom node.

Return value

NodeExtern.

int loadWorld ( Xml xml ) #

Loads a node state from the Xml.

Arguments

Xml xml - Xml smart pointer.

Return value

Returns 1 if the node state was successfully loaded; otherwise, 0 is returned.

void renderHandler ( ) #

Renders the handler for the custom user-defined node.

void renderVisualizer ( ) #

Renders the visualizer for the custom user-defined node.

NoticeYou should enable the engine visualizer by the show_visualizer 1 console command.

int saveState ( Stream stream ) #

Saves a node state into the stream.

Saving into the stream requires creating a blob to save into. To restore the saved state the restoreState() method is used:

Source code (UnigineScript)

// initialize a node and set its state
//...//

// save state
Blob blob_state = new Blob();
node.saveState(blob_state);

// change state
//...//

// restore state
blob_state.seekSet(0); // returning the carriage to the start of the blob
node.restoreState(blob_state);

Arguments

Stream stream - Stream smart pointer.

Return value

1 on success; otherwise, 0.

int restoreState ( Stream stream ) #

Restores a node state from the stream.

Restoring from the stream requires creating a blob to save into and saving the state using the saveState() method:

Source code (UnigineScript)

// initialize a node and set its state
//...//

// save state
Blob blob_state = new Blob();
node.saveState(blob_state);

// change state
//...//

// restore state
blob_state.seekSet(0); // returning the carriage to the start of the blob
node.restoreState(blob_state);

Arguments

Stream stream - Stream smart pointer.

Return value

1 on success; otherwise, 0.

int saveWorld ( Xml xml ) #

Saves a node state into the Xml.

Arguments

Xml xml - Xml smart pointer.

Return value

Returns 1 if the node state was successfully saved; otherwise, 0 is returned.

void updateEnabled ( ) #

Updates enabled.

void updatePosition ( ) #

Updates a position of the custom node.

void updateTransform ( ) #

Updates transformation matrix of the custom node.

Last update: 2021-12-13

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