Unigine::NodeTrigger Class
| Header: | #include <UnigineNodes.h> |
| Inherits from: | Node |
A trigger node is a zero-sized node that has no visual representation and fires callbacks when:
- It is enabled/disabled (the enabled callback function is called).
- Its transformation is changed (the position callback function is called).
For example, to detect if some node has been enabled (for example, a world clutter node that renders nodes only around the camera has enabled it), the trigger node is added as a child to this node and fires the corresponding callback.
Creating a Trigger Node#
To create a trigger node, simply call the NodeTrigger constructor and then add the node as a child to another node, for which callbacks should be fired.
Source code (C++)
// AppWorldLogic.h
#include <UnigineLogic.h>
#include <UnigineStreams.h>
#include <UnigineObjects.h>
#include <UnigineNodes.h>
#include <UnigineCallback.h>
#include <UnigineLog.h>
using namespace Unigine;
class AppWorldLogic : public Unigine::WorldLogic {
public:
virtual int init();
virtual int update();
virtual int postUpdate();
virtual int updatePhysics();
virtual int shutdown();
virtual int save(const Unigine::StreamPtr &stream);
virtual int restore(const Unigine::StreamPtr &stream);
private:
ObjectMeshStaticPtr object;
NodeTriggerPtr trigger;
};Source code (C++)
// AppWorldLogic.cpp
#include "AppWorldLogic.h"
using namespace Math;
int AppWorldLogic::init() {
// create a mesh
MeshPtr mesh = Mesh::create();
mesh->addBoxSurface("box_0", vec3(1.0f));
// create a node (e.g. an instance of the ObjectMeshStatic class)
object = ObjectMeshStatic::create(mesh);
// change material albedo color
object->setMaterialParameterFloat4("albedo_color", vec4(1.0f, 0.0f, 0.0f, 1.0f), 0);
// create a trigger node
trigger = NodeTrigger::create();
// add it as a child to the static mesh
object->addWorldChild(trigger);
return 1;
}Editing a Trigger Node#
Editing a trigger node includes implementing and specifying the enabled and position callbacks that are fired on enabling or positioning the trigger node correspondingly.
The callback function must receive at least 1 argument of the NodeTrigger type. In addition, it can also take another 2 arguments of any type.
The callback functions can be set by callback pointers or names:
- AddEnabledCallback() and AddPositionCallback() receive pointers to the callback functions.
- SetEnabledCallbackName() and SetPositionCallbackName() receive names of the callback functions implemented in the world script (on the UnigineScript side). In this case, the callback functions can receive no arguments or 1 argument of the Node or NodeTrigger type.
NoticeThese methods allow for setting callbacks with 0 or 1 argument only. To set callbacks with additional arguments, use addEnabledCallback()/addPositionCallback().
Setting the callback functions by pointers:
Source code (C++)
// AppWorldLogic.h
#include <UnigineLogic.h>
#include <UnigineGame.h>
using namespace Unigine;
class AppWorldLogic : public Unigine::WorldLogic {
public:
virtual int init();
virtual int update();
private:
ObjectMeshStaticPtr object;
NodeTriggerPtr trigger;
void position_callback(NodeTriggerPtr trigger)
{
Log::message("Object position has been changed. New position is: (%f %f %f)\n", trigger->getWorldPosition().x, trigger->getWorldPosition().y, trigger->getWorldPosition().z);
}
void enabled_callback(NodeTriggerPtr trigger)
{
Log::message("The enabled flag is %d\n", trigger->isEnabled());
}
};Source code (C++)
// AppWorldLogic.cpp
#include "AppWorldLogic.h"
using namespace Math;
int AppWorldLogic::init() {
// create a mesh
MeshPtr mesh = Mesh::create();
mesh->addBoxSurface("box_0", vec3(1.0f));
// create a node (e.g. an instance of the ObjectMeshStatic class)
object = ObjectMeshStatic::create(mesh);
// change material albedo color
object->setMaterialParameterFloat4("albedo_color", vec4(1.0f, 0.0f, 0.0f, 1.0f), 0);
// create node trigger
trigger = NodeTrigger::create();
// add the trigger node to the static mesh as a child node
object->addWorldChild(trigger);
// add the enabled and position callbacks
trigger->addEnabledCallback(MakeCallback(this, &AppWorldLogic::enabled_callback));
trigger->addPositionCallback(MakeCallback(this, &AppWorldLogic::position_callback));
return 1;
}
int AppWorldLogic::update() {
float time = Game::getTime();
Vec3 pos = Vec3(Math::sin(time) * 2.0f, Math::cos(time) * 2.0f, 0.0f);
object->setEnabled(pos.x > 0.0f || pos.y > 0.0f);
object->setWorldPosition(pos);
return 1;
}Setting the callback functions by their names:
- Implement the callback functions in the world script (on the UnigineScript side).
- Set the callback functions for the trigger node by using their names on the C++ side (AppWorldLogic.cpp).
Source code (UnigineScript)
// unigine_project.cpp
#include <core/unigine.h>
// the enabled callback
void enabled_callback(NodeTrigger trigger) {
log.message("Enabled flag is %d\n", trigger.isEnabled());
}
// the position callback
void position_callback(NodeTrigger trigger) {
log.message("The node position is %s\n", typeinfo(trigger.getWorldPosition()));
}
int init() {
// some logic if required
return 1;
}Source code (C++)
#include <UnigineLogic.h>
#include <UnigineGame.h>
using namespace Unigine;
class AppWorldLogic : public Unigine::WorldLogic {
public:
virtual int init();
virtual int update();
private:
NodeTriggerPtr trigger;
};Source code (C++)
// AppWorldLogic.cpp
#include "AppWorldLogic.h"
#include <UnigineCallback.h>
#include <UnigineNodes.h>
using namespace Unigine;
NodeTriggerPtr trigger;
int AppWorldLogic::init() {
// create a trigger node
trigger = NodeTrigger::create();
// set the enabled and position callbacks
trigger->setEnabledCallbackName("enabled_callback");
trigger->setPositionCallbackName("position_callback");
return 1;
}
int AppWorldLogic::update() {
float time = Game::getTime();
Vec3 pos = Vec3(Math::sin(time) * 2.0f, Math::cos(time) * 2.0f, 0.0f);
trigger->setEnabled(pos.x > 0.0f || pos.y > 0.0f);
trigger->setWorldPosition(pos);
return 1;
}See Also#
- A video tutorial on How To Use Node Triggers to Detect Changes in Node States
- An article on Event Handling Callbacks
- A C++ API sample <UnigineSDK>/source/samples/Api/Nodes/NodeTrigger
- A C# API sample located in the <UnigineSDK>/source/csharp/samples/Api/Nodes/NodeTrigger folder
NodeTrigger Class
Members
static NodeTriggerPtr create ( ) #
Constructor. Creates a new trigger node.void * addEnabledCallback ( Unigine::CallbackBase1< Ptr<NodeTrigger> > * func ) #
Sets a pointer to a callback to be fired when the trigger node is enabled or disabled. The callback function must receive a NodeTrigger as its first argument. In addition, it can also take 2 arguments of any type.Source code (C++)
// implement the enabled callback
void AppWorldLogic::enabled_callback(NodeTriggerPtr trigger){
Log::message("The enabled flag is %d\n", trigger->isEnabled());
}
NodeTriggerPtr trigger;
int AppWorldLogic::init() {
// create a trigger node
trigger = NodeTrigger::create();
// add the enabled callback to be fired when the node is enabled/disabled
trigger->addEnabledCallback(MakeCallback(this, &AppWorldLogic::enabled_callback));
return 1;
}Arguments
- Unigine::CallbackBase1< Ptr<NodeTrigger> > * func - Callback pointer.
Return value
ID of the last added enabled callback, if the callback was added successfully; otherwise, nullptr. This ID can be used to remove this callback when necessary.bool removeEnabledCallback ( void * id ) #
Removes the specified callback from the list of enabled callbacks.Arguments
- void * id - Enabled callback ID obtained when adding it.
Return value
True if the enabled callback with the given ID was removed successfully; otherwise false.void clearEnabledCallbacks ( ) #
Clears all added enabled callbacks.void setEnabledCallbackName ( const char * name ) #
Sets a callback function to be fired when the trigger node is enabled. The callback function must be implemented in the world script (on the UnigineScript side). The callback function can take no arguments, a Node or a NodeTrigger.Notice
On UnigineScript side:
The method allows for setting a callback with 0 or 1 argument only. To set the callback with additional arguments, use setEnabledCallback().
Source code (UnigineScript)
On C++ side:
// implement the enabled callback
void enabled_callback(Node node) {
log.message("The enabled flag is %d\n", node.isEnabled());
}Source code (C++)
NodeTriggerPtr trigger;
int AppWorldLogic::init() {
// create a trigger node
trigger = NodeTrigger::create();
// set the enabled callback to be fired when the node is enabled/disabled
trigger->setEnabledCallbackName("enabled_callback");
return 1;
}Arguments
- const char * name - Name of the callback function implemented in the world script (UnigineScript side).
const char * getEnabledCallbackName ( ) #
Returns the name of callback function to be fired on enabling the trigger node. This callback function is set via setEnabledCallbackName().Return value
Name of the callback function implemented in the world script (UnigineScript side).void * addPositionCallback ( Unigine::CallbackBase1< Ptr<NodeTrigger> > * func ) #
Adds a pointer to a callback to be fired when the trigger node position has changed. The callback function must receive a NodeTrigger as its first argument. In addition, it can also take 2 arguments of any type.Source code (C++)
// implement the position callback
void AppWorldLogic::position_callback(NodeTriggerPtr trigger){
Log::message("A new position of the node is (%f %f %f)\n", trigger->getWorldPosition().x, trigger->getWorldPosition().y, trigger->getWorldPosition().z);
}
NodeTriggerPtr trigger;
int AppWorldLogic::init() {
// create a trigger node
trigger = NodeTrigger::create();
// add the position callback to be fired when the node position is changed
trigger->addPositionCallback(MakeCallback(this, &AppWorldLogic::position_callback));
return 1;
}Arguments
- Unigine::CallbackBase1< Ptr<NodeTrigger> > * func - Callback pointer.
Return value
ID of the last added position callback, if the callback was added successfully; otherwise, nullptr. This ID can be used to remove this callback when necessary.bool removePositionCallback ( void * id ) #
Removes the specified callback from the list of position callbacks.Arguments
- void * id - Position callback ID obtained when adding it.
Return value
True if the position callback with the given ID was removed successfully; otherwise false.void clearPositionCallbacks ( ) #
Clears all added position callbacks.void setPositionCallbackName ( const char * name ) #
Sets a callback function to be fired when the trigger node position has changed. The callback function must be implemented in the world script (on the UnigineScript side). The callback function can take no arguments, a Node or a NodeTrigger.Notice
On UnigineScript side:
The method allows for setting a callback with 0 or 1 argument only. To set the callback with additional arguments, use setPositionCallback().
Source code (UnigineScript)
On C++ side:
// implement the position callback
void position_callback(Node node) {
log.message("A new position of the node is %s\n", typeinfo(node.getWorldPosition()));
}Source code (C++)
NodeTriggerPtr trigger;
int AppWorldLogic::init() {
// create a trigger node
trigger = NodeTrigger::create();
// set the position callback to be fired when the node position is changed
trigger->setPositionCallbackName("position_callback");
return 1;
}Arguments
- const char * name - Name of the callback function implemented in the world script (UnigineScript side).
const char * getPositionCallbackName ( ) #
Returns the name of callback function to be fired on changing the trigger node position. This function is set by using the setPositionCallbackName() function.Return value
Name of the callback function implemented in the world script (UnigineScript side).static int type ( ) #
Returns the type of the node.Return value
NodeTrigger type identifier.Last update:
2022-10-10
Help improve this article
Was this article helpful?
(or select a word/phrase and press Ctrl+Enter)