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dragengine:modules:dragonscript:behavior_vrhmd

ECBehaviorVRHMD

Behavior in action

Behavior element behavior adding VR HMD support to actor. This behavior tracks the HMD position and orientation and if it is attached or not.

Instance Counts

This behavior can be used only once on an element.

Element Class Properties

This behavior has no element class properties.

Events

hmdAttached

HMD attached and ready to use.

hmdDetached

HMD detached and no more usable.

Behavior Tree Actions

This behavior adds these behavior tree actions if behavior tree is present.

vrhmd.check

Check one or more VR HMD parameters. Action succeeds if all parameter value matches their respective VR HMD parameter otherwise action fails. This action is typically used as first action in a sequence to run the sequence only if a VR HMD parameter matches (or not).

ParameterValueDescription
attachedtrue, falseVR HMD is attached and usable
wait If present action returns BTResult.running instead of BTResult.failed to wait until the checks are all fulfilled

This is an example of using this action:

<sequence>
  <action name='vrhmd.check'>
    <parameter name='attached>true</parameter>
  </action>
  <!-- actions here run only if VR HMD is attached and usable -->
</sequence>

Behavior Tree Conditions

This behavior adds these behavior tree conditions if behavior tree is present.

vrhmd.check

Check one or more VR HMD parameters. Conditions returns true if all parameter value match their respective VR HMD parameter. This condition is typically used to run an action or sequence of actions as long as VR HMD conditions are true.

ParameterValueDescription
vrhmd.attachedtrue, falseVR HMD is attached and usable

This is an example of using this condition:

<action name='myAction' id='doing something'>
  <parameter name='vrhmd.attached'>true</parameter>
  <condition>vrhmd.check</condition>
</action>

State Machine Actions

State Machine Conditions

State Machine Events

This behavior sends no state machine events.

Required Behaviors

Optional Behaviors

Persistency

This behavior does not use persistency.

API Documentation

ECBehaviorVRHMD.

Since DragonScript Module Version 1.6

Use Cases

  • Attach in-game camera to HMD. Required to see rendered scene in the HMD.

Element Class Example

The following example creates an element class supporting HMD being driven by actor:

class MyElement extends BehaviorElementClass
  public func new()
    // Add VR Playspace behavior. Base behavior required by all VR behaviors
    var ECBehaviorVRPlayspace vrPlayspace = ECBehaviorVRPlayspace.new(this)
    
    // Add VR HMD behavior. With this behavior present VRPlayerControlledActorCameraDirector
    // can attach the HMD to the in-game camera
    ECBehaviorVRHMD.new(this, vrPlayspace)
  end
end

Behavior Factory

Using element class supporting adding behaviors the behavior can be added like this:

<?xml version='1.0' encoding='UTF-8'?>
<elementClass name='MyClass' class='GenericBehaviorElement'>
  <behavior type='ECBehaviorVRPlayspace'/>
 
  <behavior type='ECBehaviorVRHMD'>
    <!-- optional: use BaseGameApp binding manager. game can add more supported values -->
    <string name='bindingManager'>default</string>
 
    <!-- optional: add behavior trees. default adds all behavior trees. -->
    <list name='behaviorTrees'>
      <string/> <!-- add behavior with empty identifier -->
      <string>default</string> <!-- add behavior with 'default' identifier -->
    </list>
 
    <!-- optional: add state machines. default adds all state machines. -->
    <list name='stateMachines'>
      <string/> <!-- add behavior with empty identifier -->
      <string>default</string> <!-- add behavior with 'default' identifier -->
    </list>
  </behavior>
</elementClass>

Live Examples

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dragengine/modules/dragonscript/behavior_vrhmd.txt · Last modified: 2025/05/13 23:04 by dragonlord