NodeTrigger Class

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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).

The trigger node is usually added as a child node to another node, so that the callbacks will be fired on the parent node enabling/disabling or transforming.

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 (UnigineScript)

#include <core/unigine.h>

int init() {
	
	NodeTrigger trigger;
	ObjectMeshStatic object;
	
	// create a mesh
	Mesh mesh = new Mesh();
	mesh.addBoxSurface("box_0", vec3(1.0f));
	// create a node (e.g. an instance of the ObjectMeshStatic class)
	object = new ObjectMeshStatic(mesh);
	// assign a material and a property to the node
	object.setMaterial("mesh_base", "*");
    object.setMaterialParameter("albedo_color", vec4(1.0f, 0.0f, 0.0f, 1.0f), 0);
	// release script ownership
	node_remove(object);
	
	// create a trigger node
	trigger = new NodeTrigger();
	node_remove(trigger);
	// add it as a child to the static mesh
	object.addWorldChild(trigger);

	// add nodes to UnigineEditor
	engine.editor.addNode(object);
	
	return 1;
}

Editing a Trigger Node

Editing a trigger node includes implementing and specifying the enabled and postion callbacks that are fired on enabling or positioning the trigger node correspondingly.

The callback functions can be set by identifiers of the callback functions or by their names:

setEnabledCallback() and setPositionCallback() receive identifiers of the callback functions. Wherein the callback function must receive at least 1 argument of the Node type. In addition, it can also take another 2 arguments of any type.
setEnabledCallbackName() and setPositionCallbackName() receive names of the callback functions implemented in the world script. In this case, the callback function can receive no arguments or 1 argument of the Node or NodeTrigger type.
Notice
These methods allow for setting callbacks with 0 or 1 argument only. To set callbacks with additional arguments, use setEnabledCallback()/setPositionCallback().

Setting the callback functions by their identifiers:

Source code (UnigineScript)

#include <core/unigine.h>

NodeTrigger trigger;

// the position callback
void position_callback(Node trigger) {
    log.message("Object position has been changed. New position is: %s\n", typeinfo(trigger.getWorldPosition()));
}
// the enabled callback
void enabled_callback(Node trigger) {
    log.message("The enabled flag is %d\n", trigger.isEnabled());
}

int init() {

	// create a trigger node
    trigger = new NodeTrigger();
    // set the enabled and position callbacks by their identifiers
	trigger.setEnabledCallback(functionid(enabled_callback));
	trigger.setPositionCallback(functionid(position_callback));
    // add nodes to UnigineEditor
    engine.editor.addNode(node_remove(trigger));
	
	return 1;
}

int update() {
	
	// change the enabled flag and the trigger position to fire callbacks
	float time = engine.game.getTime();
	Vec3 pos = Vec3(sin(time) * 2.0f, cos(time) * 2.0f, 0.0f);
	trigger.setEnabled(pos.x > 0.0f || pos.y > 0.0f ? 1 : 0);
	trigger.setWorldPosition(pos);
	
	return 1;
}

Setting the callback functions by their names:

Source code (UnigineScript)

#include <core/unigine.h>

NodeTrigger trigger;

// the position callback
void position_callback(NodeTrigger trigger) {
    log.message("Object position has been changed. New position is: %s\n", typeinfo(trigger.getWorldPosition()));
}
// the enabled callback
void enabled_callback(NodeTrigger trigger) {
    log.message("The enabled flag is %d\n", trigger.isEnabled());
}

int init() {

	// create a trigger node
    trigger = new NodeTrigger();
    // set the enabled and position callbacks by their names
	trigger.setEnabledCallbackName("enabled_callback");
	trigger.setPositionCallbackName("position_callback");
    // add nodes to UnigineEditor
    engine.editor.addNode(node_remove(trigger));
	
	return 1;
}

int update() {
	
	// change the enabled flag and the trigger position to fire callbacks
	float time = engine.game.getTime();
	Vec3 pos = Vec3(sin(time) * 2.0f, cos(time) * 2.0f, 0.0f);
	trigger.setEnabled(pos.x > 0.0f || pos.y > 0.0f ? 1 : 0);
	trigger.setWorldPosition(pos);
	
	return 1;
}

NodeTrigger Class

Members

static NodeTrigger()

Constructor. Creates a new trigger node.

NodeTrigger cast(Node node)

Casts a NodeTrigger out of the Node instance.

Arguments

Node node - Node instance.

Return value

NodeTrigger instance.

void setEnabledCallback(int func)

Sets a callback function to be fired when the trigger node is enabled. The callback function must receive a Node as its first argument. In addition, it can also take 2 arguments of any type.

Source code (UnigineScript)

// implement the enabled callback
void enabled_callback(Node node) {
	log.message("The enabled flag is %d\n", node.isEnabled());
}

int init() {

	// create a trigger node
	NodeTrigger trigger = new NodeTrigger();
	// set the enabled callback to be fired when the node is enabled/disabled
	trigger.setEnabledCallback(functionid(enabled_callback));
	
	return 1;
}

Arguments

int func - Callback function identifier.

void setEnabledCallbackName(string name)

Sets a callback function to be fired when the trigger node is enabled. The callback function can take no arguments, a Node or a NodeTrigger.

Notice

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)

// implement the enabled callback
void enabled_callback(Node node) {
	log.message("The enabled flag is %d\n", node.isEnabled());
}

int init() {

	// create a trigger node
	NodeTrigger trigger = new NodeTrigger();
	// set the enabled callback to be fired when the node is enabled/disabled
	trigger.setEnabledCallbackName("enabled_callback");
	
	return 1;
}

Arguments

string name - Name of the callback function implemented in the world script (UnigineScript side).

string 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 setPositionCallback(int func)

Sets a callback function to be fired when the trigger node position has changed. The callback function must receive a Node as its first argument. In addition, it can also take 2 arguments of any type.

Source code (UnigineScript)

// implement the position callback
void position_callback(Node node) {
	log.message("A new position of the node is %s\n", typeinfo(node.getWorldPosition()));
}

int init() {

	// create a trigger node
	NodeTrigger trigger = new NodeTrigger();
	// set the position callback to be fired when the node position is changed
	trigger.setPositionCallback(functionid(position_callback));
	
	return 1;
}

Arguments

int func - Callback function identifier.

void setPositionCallbackName(string name)

Sets a callback function to be fired when the trigger node position has changed. The callback function can take no arguments or a Node or a NodeTrigger as the first argument.

Notice

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)

// implement the position callback
void position_callback(Node node) {
	log.message("A new position of the node is %s\n", typeinfo(node.getWorldPosition()));
}

int init() {

	// create a trigger node
	NodeTrigger trigger = new NodeTrigger();
	// set the position callback to be fired when the node position is changed
	trigger.setPositionCallbackName("position_callback");
	
	return 1;
}

Arguments

string name - Name of the callback function implemented in the world script (UnigineScript side).

string 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).

Last update: 2018-08-10

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