NodeTrigger Class
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.
#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);
// change material albedo color
object.setMaterialParameterFloat4("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);
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 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.
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:
#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));
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:
#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");
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;
}
See Also#
- 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 NodeTrigger ( ) #
Constructor. Creates a new trigger node.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.// implement the enabled callback
void enabled_callback(Node node) {
log.message("The enabled flag is %d\n", node.isEnabled());
}
NodeTrigger trigger;
int init() {
// create a trigger node
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.// implement the enabled callback
void enabled_callback(Node node) {
log.message("The enabled flag is %d\n", node.isEnabled());
}
NodeTrigger trigger;
int init() {
// create a trigger node
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.// implement the position callback
void position_callback(Node node) {
log.message("A new position of the node is %s\n", typeinfo(node.getWorldPosition()));
}
NodeTrigger trigger;
int init() {
// create a trigger node
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.// implement the position callback
void position_callback(Node node) {
log.message("A new position of the node is %s\n", typeinfo(node.getWorldPosition()));
}
NodeTrigger trigger;
int init() {
// create a trigger node
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).