"Head Nod" - Trigger action for face

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Gio Magneto

Snap Lens Network Member Lens Studio Team

• April 30, 2018 08:24

Hi Guys, Just started using lens studio, have zero programming skills.. So bear with me. Trying to setup an animation to run, when the user "nods" their head. Any way to do this?..

Thanks for any advice.

1

• 

  Travis Chen

  Snap Lens Network Member Lens Studio Team

  • April 30, 2018 22:32

  Hi Gio! Great question. I've created a script that checks to see if the user has nodded their head. Follow these steps to get it working. 

  • Create a New Project
  • Add a Head Binding object (Objects Panel -> Add New -> Head Binding)
  • Add a new empty object (Objects Panel -> Add New -> Empty Object)
  • Create a new script (Resources Panel -> Add New -> Script)
  • Attach this new script to the new empty object. One easy way to do this is to select the empty object and drag and drop the script onto it in the inspector panel
  • Add the below code to the new script
  • Then, in the inspector, set the Head Binding Object property to the Head Binding you created
  • You'll now notice anytime you nod that "User Nodded" is printed out to the Logger
  • Now, add any logic you want to have happen into the nodded() function

  // -----JS CODE-----
  // @input SceneObject headBindingObject
  // @input int numNodSamples = 10
  // @input float nodThreshold = 0.15
  
  var nodSamples = [];
  
  function update (eventData)
  {
      var headTransform = script.headBindingObject.getTransform();
      var headForward = headTransform.forward;
      var headForwardNoY = new vec3( headTransform.forward.x, 0.0, headTransform.forward.z )
      var dot = headForwardNoY.dot( headForward );
  
      if( nodSamples.length >= script.numNodSamples )
      {
          nodSamples.shift();
      }
      nodSamples.push( dot );
  
      checkForNod();
  }
  var event = script.createEvent("UpdateEvent");
  event.bind( update );
  
  function checkForNod()
  {
      var latestNodIndex = nodSamples.length - 1;
      var latestNod = nodSamples[latestNodIndex];
      for( var i = latestNodIndex - 1; i > 0; i-- )
      {
          var diff = latestNod - nodSamples[i];
          if( diff < -script.nodThreshold )
          {
              nodded();
              nodSamples = [];
              break;
          }
      }
  }
  
  function nodded()
  {
      print( "User Nodded" );
  }

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• 

  Gio Magneto

  Snap Lens Network Member Lens Studio Team

  • May 04, 2018 12:06

  Hi Travis!... Thank you so much!.. Much appreciated!.. :)

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• 

  Code I

  Snap Lens Network Member Lens Studio Team

  • May 16, 2021 11:48

  why is this function only triggered by head up?And head down didn't?

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