quote:

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> I am a beginner working with Ames _VRML 2.0 Sourcebook_, specifically
> example 31.8, a prototyped boolean filter. I have been trying
> unsuccessfully to use any script events from a prototyped objects and
> am looking for an example or guidance. As a consequence, I have been
> unable to reuse behaviors encapsulated in a script. Fields from an
> instance of a prototype I can handle fine.
>
> The specific context I am working with was a switch statement and a
> series of menu item controls. When the user clicks on the menu item
> button (a sphere), the number of the menu item is captured and sent to
> a switch statement. The objects and behaviors in each switch node
> differ on the selection. In psuedo-VRML-code, it looks like this:
>
> DEF Option_Group Switch
> whichChoice 0
> choice [ < some option groups > ]
> End Switch
>
> DEF Menu_Options
> Control_1 <-- Proto or ExternProto Menu_Item
> TouchSensor { Sphere }
> DEF Sphere_Click Script { <code> }
> Route
> < back to Option_Group.set_whichChoice
> by proto >
>
> Control_2 <-- Proto or ExternProto Menu_Item
> TouchSensor { Sphere }
> DEF Sphere_Click Script {<code> }
> Route < back to
> Option_Group.set_whichChoice >
>
> Try though I may, whenever I try to instance a Menu_Item prototype, as
> object Control_1, I cannot get an OnClick event on the Sphere to
> trigger whichChoice. I keep on getting a "bad node within node"
> syntax error, or thing just sits there and ignores the onclick event.
>
> Conversely, this works fine, but suffers from a excessive code-reuse
> by being able to abstract the Menu_Item behavior:
>
> DEF Option_Group Switch
> whichChoice 0
> choice [ < some option groups > ]
> End Switch
>
> DEF Menu_Options
> Control_1
> TouchSensor { Sphere }
> Sphere_Click Script { <code> }
> Route < back to Option_Group.set_whichChoice >
>
> Control_2
> TouchSensor { Sphere }
> Sphere_Click Script { <code> }
> Route < back to Option_Group.set_whichChoice >
>
> For example, on an 8 menu control panel, the repaste and repeated code
> works fine, but eats up a couple of hundred lines of code.
>
> I couldn't get other simplier variations to work, like:
>
> DEF Option_Group Switch
> whichChoice 0
> choice [ < some option groups > ]
> End Switch
>
> DEF Menu_Options
> Control_1
> TouchSensor { Sphere }
> Sphere_Click Script { <-- PROTO Boolean_Filter Script { <code>
> }
> }
> Route < back to Option_Group.set_whichChoice >
>
> Control_2
> TouchSensor { Sphere }
> DEF Sphere_Click Script { PROTO Boolean_Filter Script { <code>
> }
> }
> Route < back to Option_Group.set_whichChoice >
>
> At this point, I concluded there was something very basic that I'm
> just not "getting" about prototyping when proto'ing script events and
> reusing the script object. About the only thing I haven't tried is
> nesting prototypes.
>
> Some guidance or an example using the VRML 2.0 Handbook's Figure 31.8
> code as an external prototype - showing how to access the eventOut
> once the prototyped is instanced and routing it to a set_whichChoice
> or other event, would be greatly appreciated.
>
> - Kurt
>
> P.S. - Thank you for the help and code samples the group has provided
> over the last week. I have been able to get an initial working VRML
> application up with the desired features, but would still like to
> shrink some of those repeated code lines paired down (and get a handle
> on this basic script prototyping skill).

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quote:

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> The following code shows one way to define MenuItems as instances of
> a PROTO, and then route events generated by a Script withing the PROTO
> instances to another Script for the purpose of setting the whichChoice
> value of a Switch node.

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