Unigine.WorldTrigger Class
| Inherits from: | Node |
World triggers fire callbacks when any nodes (colliders or not) get inside or outside of them. The trigger can detect a node of any type by its bounding box. The trigger reacts to all nodes (default behavior).
The callback function of World Trigger is actually executed only when the next engine function is called: that is, before UpdatePhysics() (in the current frame) or before Update() (in the next frame) — whatever comes first.
Notice
If you have moved some nodes and want to get callbacks based on changed positions in the same frame, you need to call UpdateSpatial() first.
Example#
The example below allows creating a line of boxes moving in and out of the World Trigger area and triggering the callbacks. Getting inside the World Trigger enables emission for the boxes, and getting out of it disables the emission.
Source code (C#)
private static void set_state(Node n, string name, int val)
{
Unigine.Object node = n as Unigine.Object;
if (node == null)
return;
for (int i = 0; i < node.NumSurfaces; i++)
{
Material material = node.GetMaterialInherit(i);
if (material == null)
continue;
int id = material.FindState(name);
if (id != -1)
material.SetState(id, val);
}
}
private static void trigger_enter(Node node)
{
set_state(node, "emission", 1);
}
private static void trigger_leave(Node node)
{
set_state(node, "emission", 0);
}
private const int MAX_OBJECTS = 10;
private List<ObjectMeshStatic> objects = new List<ObjectMeshStatic>();
WorldTrigger trigger;
private void Init()
{
// create trigger
trigger = new WorldTrigger(new vec3(3.0f));
trigger.AddEnterCallback(trigger_enter);
trigger.AddLeaveCallback(trigger_leave);
// create objects
for (int i = 0; i < MAX_OBJECTS; i++)
{
ObjectMeshStatic mesh = new ObjectMeshStatic("cbox.mesh");
mesh.TriggerInteractionEnabled = true;
mesh.SetMaterialParameterFloat4("albedo_color", new vec4(1.0f, 0.0f, 0.0f, 1.0f), 0);
objects.Add(mesh);
}
// enable the visualizer
Visualizer.Enabled = true;
}
private void Update()
{
trigger.RenderVisualizer();
float time = Game.Time;
float hsize = objects.Count / 2.0f;
for (int i = 0; i < objects.Count; i++)
{
float x = (float)Math.Sin(time) * hsize - hsize + i;
objects[i].WorldTransform = MathLib.Translate(new Vec3(x, -x, 0.0f));
}
}See Also#
- A video tutorial on How To Use World Triggers to Detect Nodes by Their Bounds
- An article on Event Handling Callbacks
- A C++ API sample located in the <UnigineSDK>/source/samples/Api/Nodes/WorldTrigger folder
- A C# API sample located in the <UnigineSDK>/source/csharp/samples/Api/Nodes/WorldTrigger folder
- A set of UnigineScript API samples located in the <UnigineSDK>/data/samples/worlds/ folder:
- trigger_00
- trigger_01
- trigger_02
WorldTrigger Class
Properties
string LeaveCallbackName#
The name of the callback function name to be fired on leaving the world trigger. this callback function is set via setLeaveCallbackName().
string EnterCallbackName#
The name of callback function to be fired on entering the world trigger. this callback function is set via setEnterCallbackName().
int NumNodes#
The number of nodes contained in the world trigger.
vec3 Size#
The current dimensions of the world trigger.
bool Touch#
The A value indicating if a touch mode is enabled for the trigger. with this mode on, the trigger will react to the node by partial contact. when set to off, the trigger reacts only if the whole bounding sphere/box gets inside or outside of it.
Members
WorldTrigger ( vec3 size ) #
Constructor. Creates a new world trigger with given dimensions.Arguments
- vec3 size - Dimensions of the new world trigger. If negative values are provided, 0 will be used instead of them.
IntPtr AddEnterCallback ( EnterDelegate func ) #
Adds a callback function to be fired when a node enters the world trigger. The callback function must receive a Node as its first argument. In addition, it can also take 2 arguments of any type.Source code (C#)
// implement the enter callback
void enter_callback(Node node)
{
Log.Message("\nA node named {0} has entered the trigger\n", node.Name);
}
WorldTrigger trigger;
private void Init()
{
// create a world trigger
trigger = new WorldTrigger(new vec3(3.0f));
// add the enter callback to be fired when a node enters the world trigger
trigger.AddEnterCallback(enter_callback);
}Arguments
- EnterDelegate func - Callback function with the following signature: void EnterDelegate(Node node)
Return value
ID of the last added enter callback, if the callback was added successfully; otherwise, nullptr. This ID can be used to remove this callback when necessary.bool RemoveEnterCallback ( IntPtr id ) #
Removes the specified callback from the list of enter callbacks.Arguments
- IntPtr id - Enter callback ID obtained when adding it.
Return value
True if the enter callback with the given ID was removed successfully; otherwise false.void ClearEnterCallbacks ( ) #
Clears all added enter callbacks.IntPtr AddLeaveCallback ( LeaveDelegate func ) #
Adds a callback function to be fired when a node leaves the world trigger. The callback function must receive a Node as its first argument. In addition, it can also take 2 arguments of any type.Source code (C#)
// implement the leave callback
void leave_callback(Node node)
{
Log.Message("\nA node named {0} has left the trigger\n", node.Name);
}
WorldTrigger trigger;
private void Init()
{
// create a world trigger
trigger = new WorldTrigger(new vec3(3.0f));
// add the leave callback to be fired when a node leaves the world trigger
trigger.AddLeaveCallback(leave_callback);
}Arguments
- LeaveDelegate func - Callback function with the following signature: void LeaveDelegate(Node node)
Return value
ID of the last added leave callback, if the callback was added successfully; otherwise, nullptr. This ID can be used to remove this callback when necessary.bool RemoveLeaveCallback ( IntPtr id ) #
Removes the specified callback from the list of leave callbacks.Arguments
- IntPtr id - Leave callback ID obtained when adding it.
Return value
True if the leave callback with the given ID was removed successfully; otherwise false.void ClearLeaveCallbacks ( ) #
Clears all added leave callbacks.Node GetNode ( int num ) #
Returns a specified node contained in the world trigger.Source code (C#)
WorldTrigger trigger;
private void Init()
{
// create a world trigger
trigger = new WorldTrigger(new vec3(3.0f));
}
private void Update()
{
// press the i key to get the info about nodes inside the trigger
if (trigger != null && Input.IsKeyDown(Input.KEY.I))
{
//get the number of nodes inside the trigger
int numNodes = trigger.NumNodes;
Unigine.Log.Message("The number of nodes inside the trigger is " + numNodes + "\n");
//loop through all nodes to print their names and types
for (int i = 0; i < numNodes; i++)
{
Node node = trigger.GetNode(i);
Unigine.Log.Message("The type of the " + node.Name + " node is " + node.Type + "\n");
}
}
}Arguments
- int num - Node number in range from 0 to the total number of nodes.
Return value
Node pointer.Node[] GetNodes ( ) #
Gets nodes contained in the trigger.Arguments
static int type ( ) #
Returns the type of the node.Return value
World type identifier.Last update:
2022-12-14
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