Observers

These functions allow callbacks to be performed in response to nodes being updated.

The defined callbacks will take place following the execution of the script, or during a vrYield.

vrAddPropertyObserver

Adds an observer to monitor and respond to value changes for a single property.

Script

local myNode = vrCreateNode("Assembly", "ObservedNode", vrScenesNode())
vrYield(0)

local myCallback = function(node, value)
  print(node:getName() .. " enabled: " .. tostring(value))
end

vrAddPropertyObserver(
  "enabledObserver",
  myCallback,
  "Assembly",
  "Enabled"
)

myNode.Enabled = false
vrYield(0)

myNode.Enabled = true
vrYield(0)

vrRemoveObserver("enabledObserver")
vrDeleteNode(myNode)

Output

Running...
ObservedNode enabled: false
ObservedNode enabled: true
Ended.

vrAddNodeObserver

Adds an observer to monitor and respond to changes on a Node.

The function takes a map of callback functions. These will be called in response to the appropriate changes.

Key	Callback	Callback Signature
valuesChanged	Called in response to a property's value being changed.	function(node)
addingToRecycleBin	Called in repsonse to the node being sent to the recycle bin.	function(node)
restoredFromRecycleBin	Called in repsonse to the node being returned from the recycle bin.	function(node)
nodeDestroyed	Called in response to the node being destroyed.	function(node)

Script

local myNode = vrCreateNode("Assembly", "ObservedNode", vrScenesNode())
vrYield(0)

local callbackMap = {
  valuesChanged = function(node)
    print(node:getName() .. " enabled: " .. tostring(node.Enabled))
  end,

  addingToRecycleBin = function(node)
    print(node:getName() .. " removed")
  end
}

vrAddNodeObserver(
  "nodeObserver",
  myNode,
  callbackMap
)

myNode.Enabled = false
vrYield(0)

myNode.Enabled = true
vrYield(0)

vrDeleteNode(myNode)
vrYield(0)

vrRemoveObserver("nodeObserver")

Output

Running...
ObservedNode enabled: false
ObservedNode enabled: true
ObservedNode removed
Ended.

vrAddMetaNodeObserver

Adds an observer to monitor and respond to changes on instances of a MetaNode.

The function takes a map of callback functions. These will be called in response to the appropriate changes.

Key	Callback	Callback Signature
nodeCreated	Called in response to a node being created.	function(meta, node)
nodeRenamed	Called in repsonse to a node being renamed.	function(meta, node)
nodeParentChanged	Called in response to a node being moved.	function(meta, node, oldParent, newParent)
nodeAddingToRecycleBin	Called in repsonse to a node being sent to the recycle bin.	function(meta, node)
nodeRestoredFromRecycleBin	Called in repsonse to a node being returned from the recycle bin.	function(meta, node)
nodeDestroying	Called in response to a node being destroyed.	function(meta, node)

Script

local callbackMap = {
  nodeCreated = function(meta, node)
    print(node:getName() .. " created")
  end,

  nodeRenamed = function(meta, node)
    print(node:getName() .. " renamed")
  end,

  nodeParentChanged = function(meta, node, old, new)
    if(old and new) then
      print(node:getName() .. " moved from " .. old:getName() .. " to " .. new:getName()) 
    end
  end,
  
  nodeAddingToRecycleBin = function(meta, node)
    print(node:getName() .. " removed")
  end
}

vrAddMetaNodeObserver(
  "nodeObserver",
  "Assembly",
  callbackMap
)

local myNode = vrCreateNode("Assembly", "ObservedNode", vrScenesNode())

myNode:setParent(vrLibrariesNode())
vrYield(0)

myNode:setName("NamedNode")
vrYield(0)

vrDeleteNode(myNode)
vrYield(0)

vrRemoveObserver("nodeObserver")

Output

Running...
ObservedNode created
ObservedNode moved from Scenes to Libraries
NamedNode renamed
NamedNode removed
NamedNode moved from Libraries to RecycleBin
Ended.

vrAddTransformNodeObserver

Adds an observer to monitor and respond to the transform related value changes of a Node.

Script

local myNode = vrCreateNode("Assembly", "ObservedNode", vrScenesNode())
vrYield(0)

local myTransformCallback = function(node, value)
  print(node:getName() .. " transformed:")
  print(tostring(value))
end

local myEnabledCallback = function(node, value)
  print(node:getName() .. " enabled: " .. tostring(value))
end

vrAddTransformNodeObserver(
  "transformObserver",
  myTransformCallback,
  myEnabledCallback,
  myNode
)

myNode.Enabled = false
vrYield(0)

myNode.Enabled = true
vrYield(0)

local transform = myNode.Transform
transform.position.x = transform.position.x + 1.0
vrYield(0)

vrRemoveObserver("transformObserver")

vrDeleteNode(myNode)
vrYield(0)

Output

Running...
ObservedNode enabled: false
ObservedNode enabled: true
ObservedNode transformed:
1 0 0 0
0 1 0 0
0 0 1 0
1 0 0 1
Ended.