Camera Switching

Hi Anas!

Glad you're making your first Lens!

Take a look at BehaviorScript which allows you to do some certain action based on some events:  

https://lensstudio.snapchat.com/guides/scripting/behavior-script/

So let's say you have some scene like the following:

Then we can add a new object to control which object is visible depending on the camera. In the Object panel press Add New > Object. Then, in the Inspector panel, press Add Component > Script. Finally press the Add Script button and select the BehaviorScript you've imported from the page above. 

Now you should see some options. Select the Trigger drop down and choose "Front camera" Then select the Response Type "Set Enabled". Click the "Target" field and select the object that you want to show up in the Front Camera. 

Then we can similarly add another BehaviorScript to this controller object to disable the objects that should only appear in the rear camera. 

You can do the same for the Trigger "Back Camera". To enable objects that you want to be visible in the rear camera, and disable objects that you want to not be visible in the rear camera. 

Your final scene set up should looks something like this:

And that's it! Let me know if you need any clarification :)

Cheers,

Jon

Hi Anas! 

Ah I see. Thanks for sharing your scene, it's very helpful.

It is not possible to have the Lens switch which camera is active. However, you can show a hint to tell the user to switch camera. Take a look at this guide: https://lensstudio.snapchat.com/guides/scripting/scripting-hints/ 

Additionally, I've modified the WorldObjectController script to allow you to add a list of objects to enable only on the front side:

// ModifiedWorldObjectController.js
// Version: 0.0.3
// Event: Lens Initialized
// Description: Controls the touch, hiding, and showing functionality of the movable character

//@input bool useGroundGrid
//@input Asset.Material touchCollisionMaterial
//@input SceneObject groundGrid
//@input Component.WorldTracking worldTrackingComponent

//@input SceneObject[] frontOnlyObjects

// If an object with a touch component is defined then this will allow the user to double tap through them to 
// perform a camera swap from back to front cam
if(script.getSceneObject().getComponentCount("Component.TouchComponent") > 0)
{
script.getSceneObject().getFirstComponent("Component.TouchComponent").addTouchBlockingException("TouchTypeDoubleTap");
}

// Hides the ground grid if the option is chosen to do so
if(!script.useGroundGrid && script.groundGrid)
{ 
script.groundGrid.enabled = false; 
}

// Hides the touchCollision object when lens is running by setting the alpha on its material to 0
if(script.touchCollisionMaterial)
{
script.touchCollisionMaterial.mainPass.baseColor = new vec4(1,1,1,0);
}

// Event and callback setup 
function onSurfaceReset(eventData)
{
script.getSceneObject().getTransform().setLocalPosition(new vec3(0, 0, 0));
setTrackingTarget();
}
var worldTrackingResetEvent = script.createEvent("WorldTrackingResetEvent");
worldTrackingResetEvent.bind(onSurfaceReset);

function onFrontCamEvent(eventData)
{
for(var i = 0; i < script.getSceneObject().getChildrenCount(); i++)
{
var childObject = script.getSceneObject().getChild(i);
if(childObject)
{
childObject.enabled = false;
}
}

for(var j = 0; j < script.frontOnlyObjects.length; j++)
{
var object = script.frontOnlyObjects[j];
if(object)
{
object.enabled = true; 
}
} 
}
var cameraFrontEvent = script.createEvent("CameraFrontEvent");
cameraFrontEvent.bind(onFrontCamEvent);

function onBackCamEvent(eventData)
{
for(var i = 0; i < script.getSceneObject().getChildrenCount(); i++)
{
var childObject = script.getSceneObject().getChild(i);
if(childObject)
{
childObject.enabled = true; 
}
}
if(!script.useGroundGrid && script.groundGrid)
{
script.groundGrid.enabled = false;
}

for(var j = 0; j < script.frontOnlyObjects.length; j++)
{
var object = script.frontOnlyObjects[j];
if(object)
{
object.enabled = false; 
}
}
}
var cameraBackEvent = script.createEvent("CameraBackEvent");
cameraBackEvent.bind(onBackCamEvent);

function setTrackingTarget()
{
if(script.worldTrackingComponent)
{
script.worldTrackingComponent.surfaceTrackingTarget = script.getSceneObject();
}
}
setTrackingTarget();

To use it, in the Resources panel, open the Scripts folder and select WorldObjectController. Then in the Inspector panel, replace the script and press "Apply Changes."

Now, in the Objects panel, when you select FaceImagePickerController, in the Inspector panel you should see a new field called "Front Object Only". You can press the "Add Value" button to add objects you want to only show up in the front camera. 

For example, here I added the "2D Sprite 1" object so that the sprite will only show up when the front camera is active.

Can't wait to see what you come up with!

Cheers,

Jon