# Unigine.WorldExternBase Class (CPP)

**Header:** #include <UnigineWorld.h>

**Inherits from:** Base


UNIGINE Base WorldExtern class.


## WorldExternBase Class

---

## template < class Type >

## static addClassID ( int class_id )


Registers the custom world class with a unique class ID.


```cpp
// register the MyWorld class
WorldExternBase::addClassID<MyWorld>(1);

```


### Arguments

- *int* **class_id** - Unique class ID.

## int getClassID ( )

Returns a unique class ID.
### Return value

Unique class ID.
## Ptr < Node > getNode ( ) const

Returns the Node smart pointer.
### Return value

Node smart pointer.
## Ptr < WorldExtern > getWorldExtern ( ) const

Returns the WorldExtern smart pointer.
### Return value

WorldExtern smart pointer.
## int loadWorld ( const Ptr < Xml > & xml )

Loads a world state from the Xml.
### Arguments

- *const [Ptr](../../../api/library/common/class.ptr_cpp.md)<[Xml](../../../api/library/common/class.xml_cpp.md)> &* **xml** - Xml smart pointer.

### Return value

1 if the world state was successfully loaded; otherwise, 0.
## void preRender ( float ifps )

Pre-render function, i.e. after the *update()* and before the *render()* function.
### Arguments

- *float* **ifps** - Inverse FPS value.

## void renderHandler ( )

Renders the handler for the external world.
## void renderVisualizer ( )


Renders the visualizer.


> **Notice:** You should enable the engine visualizer by the **show_visualizer 1** console command.


## bool saveState ( const Ptr < Stream > & stream )


Saves a world state into the stream. Saving into the stream requires creating a blob to save into. To restore the saved state the *[restoreState()](#restoreState_Stream_int)* method is used:


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

// save state
BlobPtr blob_state = Blob::create();
worldExtern1->saveState(blob_state);

// change state
//...//

// restore state
blob_state->seekSet(0);				// returning the carriage to the start of the blob
worldExtern1->restoreState(blob_state);

```


### Arguments

- *const [Ptr](../../../api/library/common/class.ptr_cpp.md)<[Stream](../../../api/library/common/class.stream_cpp.md)> &* **stream** - Stream smart pointer.

### Return value

true on success; otherwise, false.
## bool restoreState ( const Ptr < Stream > & stream )


Restores a world state from the stream. Restoring from the stream requires creating a blob to save into and saving the state using the *[saveState()](#saveState_Stream_int)* method:


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

// save state
BlobPtr blob_state = Blob::create();
worldExtern1->saveState(blob_state);

// change state
//...//

// restore state
blob_state->seekSet(0);				// returning the carriage to the start of the blob
worldExtern1->restoreState(blob_state);

```


### Arguments

- *const [Ptr](../../../api/library/common/class.ptr_cpp.md)<[Stream](../../../api/library/common/class.stream_cpp.md)> &* **stream** - Stream smart pointer.

### Return value

true on success; otherwise, false.
## int saveWorld ( const Ptr < Xml > & xml )

Saves a world state into the Xml.
### Arguments

- *const [Ptr](../../../api/library/common/class.ptr_cpp.md)<[Xml](../../../api/library/common/class.xml_cpp.md)> &* **xml** - Xml smart pointer.

### Return value

1 if the world state was successfully saved; otherwise, 0.
## void update ( float ifps )

Update function. It is called when the node is visible.
### Arguments

- *float* **ifps** - Inverse FPS value.

## void updateEnabled ( )

Updates enabled.
## void updateTransform ( )

Updates transformation matrix of the external world.
## void setUpdateDistanceLimit ( float distance )

Sets the distance from the camera within which the external world should be updated.
### Arguments

- *float* **distance** - Distance from the camera within which the external world should be updated (in units).

## float getUpdateDistanceLimit ( )

Returns the distance from the camera within which the external world should be updated.
### Return value

Distance from the camera within which the external world should be updated (in units).
## void setUpdate ( bool enabled )

Sets a value indicating if the external world should be constantly updated each frame, regardless of the [update distance](#setUpdateDistanceLimit_float_void).
### Arguments

- *bool* **enabled** - true to enable forced updating for the external world; false - to disable forced updating and take the [update distance](#setUpdateDistanceLimit_float_void) into account.

## bool isUpdate ( )

Returns a value indicating if the external world should be constantly updated each frame, regardless of the [update distance](#setUpdateDistanceLimit_float_void).
### Return value

true if the external world is constantly updated each frame; otherwise, false