How To Make It Better?

Avoid using persistent global variables

A good idea gone bad.

Initially added to support scripted controllers and xrefs.

Problems:

Solutions:

Using scripted CAs for persistent data storage

Scripted Custom Attributes can be used instead of persistent global variables to store data with the scene file, avoiding the problems mentioned above.

A scripted CA can be placed on the scene root:

``` sceneDataCADef =attributes sceneDataCADef version:1 attribID:#(0x61e9ff5f, 0x63784819) ( parameters main rollout:params ( note type:#string ui:et_note default:"") rollout params "Scene Data Parameters" ( edittext et_note "Note: ") )

thescene = (refs.dependents rootnode)[1] rootNodeDataCA = undefined if (custattributes.add rootnode sceneDataCADef) do rootNodeDataCA = rootnode.custAttributes[rootnode.custAttributes.count] sceneDataCA = undefined if (custattributes.add thescene sceneDataCADef) do sceneDataCA = thescene.custAttributes[thescene.custAttributes.count] rootNodeDataCA.note sceneDataCA.note rootNodeDataCA.note = "rootnode" sceneDataCA.note = "thescene"

```

If the file is saved and reloaded, you can access the CAs:

``` rootNodeDataCA = undefined if(rootnode.custAttributes.count != 0) do rootNodeDataCA = rootnode.custAttributes[rootnode.custAttributes.count] sceneDataCA = undefined if(thescene.custAttributes.count != 0) do sceneDataCA = thescene.custAttributes[thescene.custAttributes.count]

```

If the file is brought in as an XRef scene, you can still access the CAs:

``` xr = xrefs.getXRefFile 1 xr_root = xr.tree xr_rootNodeDataCA = undefined if (xr_root.custAttributes.count != 0) do xr_rootNodeDataCA = xr_root.custAttributes[xr_root.custAttributes.count]

```

Building UI on Script/Expression Controller

By placing a scripted Custom Attributes definition on a script or expression controller, you can provide a custom UI for the controller.

EXAMPLE

``` floatDataCADef = attributes floatDataCADef version:1 ( parameters main rollout:params ( prop1 type:#float ui:s_prop1 ) rollout params "Parameters" ( spinner s_prop1 "Prop1: ") fn getRollout = params )

sc = float_Script() custattributes.add sc floatDataCADef floatCA = sc.custattributes[1] sc.addTarget "prop1" floatCA[#prop1]

displayControlDialog sc ""

mscas =for ca in sc.custattributes where isMSCustAttrib ca collect ca rollouts =for ca in mscas where isproperty ca #getrollout collect ca.getrollout() if rollouts.count == 1 then createdialog rollouts[1] else if rollouts.count > 1 do ( width = rollouts[1].width for ro in rollouts do width = amax width ro.width rof = newrolloutfloater "" (width+13) 0 0 0 for ro in rollouts do addrollout ro rof height = 6 for ro in rollouts do height += ro.height + 24 rof.size = [rof.size.x,height] )

```