VRML - createVrmlFromString

Author

createVrmlFromString

Junaid

2004-01-25, 6:30 pm

Hi, In my recent post, I was advised to use the createVrmlFromString
function to make multiple copies of an atom(sphere). The problem I have is
that the VRML code which I use to create an atom involves a PROTO as below.
As far as I understand from what I've read on tutorials you cannot have
PROTOs in the createVrmlFromString function.

Component{
myRadius 0.1 0.1 0.1
myColor 1 1 0
}
My task is to make copies of this PROTO using some sort of Script rather
than copy and pasting the above code 50 or more times. I also have to keep
this Component PROTO because I have another PROTO called Environment which
stores all these atoms(PROTO Components) in a list and then uses a Script
written in java to access the radius and color.

I would be grateful if anyone could help. thnx.

Bill Angel

2004-01-25, 9:30 pm

Hi:

I prefer utilizing the Browser.createVRMLFromURL function to do
what you are suggesting. The following code shows how
to dynamically create a Node called NewObject from within
a Script utilizing the Browser.createVrmlFromURL function.
The code in the Script node then initializes some of the values
associated with the newly created Node. You will also note that
a dynamically created Node is being accessed in the function "objectAdded"
in Script Node OBJECT-SCRIPT as if it were stored in a list or in an array.

Here's the code:

Suppose the file "Object.wrl" contains the following code

#VRML V2.0 utf8

PROTO NewObject [
exposedField SFFloat transparency 0
exposedField SFBool initialized FALSE
]
{
Shape {
appearance Appearance {
material Material {
diffuseColor 0.58 0.79 1.00
shininess 0.5
transparency IS transparency
}
}

geometry Sphere {}
}
}
NewObject {}

#### End of file "Object.wrl" ###
##################################

The following code creates and adds an instance of the
node "NewObject" to the scene. The code then performs
some initializatiion to this newly created node.

#VRML V2.0 utf8

DEF OBJECT-GROUP Group {}

DEF OBJECT-SCRIPT Script {
field SFNode objectGroup USE OBJECT-GROUP
field MFString objectURL ["Object.wrl"]
eventIn MFNode objectAdded
directOutput TRUE
url [ "java script:
function initialize() {
Browser.createVrmlFromURL(objectURL,objectGroup,'addChildren');
}
function objectAdded(nodes) {
for (var i = 0; i < nodes.length; i++) {
if (nodes[i].getType() == 'NewObject' && nodes[i].initialized == false) {
print(' node ' + i + ' NOT initialized');
// Initialize the Node here
nodes[i].set_transparency = .5;
nodes[i].set_initialized = true;
break;
}
}
}
" ]
}
ROUTE OBJECT-GROUP.children_changed TO OBJECT-SCRIPT.objectAdded

##### End of initialization code ####
#####################################

Regards,

Bill Angel
Computer Scientist
Silver Spring, Maryland

"Junaid" <ug36jxh@cs.bham.ac.uk> wrote in message news:bv1dba$lud$1@soapbox.cs.bham.ac.uk...

quote:

> Hi, In my recent post, I was advised to use the createVrmlFromString
> function to make multiple copies of an atom(sphere). The problem I have is
> that the VRML code which I use to create an atom involves a PROTO as below.
> As far as I understand from what I've read on tutorials you cannot have
> PROTOs in the createVrmlFromString function.
>
> Component{
> myRadius 0.1 0.1 0.1
> myColor 1 1 0
> }
> My task is to make copies of this PROTO using some sort of Script rather
> than copy and pasting the above code 50 or more times. I also have to keep
> this Component PROTO because I have another PROTO called Environment which
> stores all these atoms(PROTO Components) in a list and then uses a Script
> written in java to access the radius and color.
>
> I would be grateful if anyone could help. thnx.
>
>

Muaddib

2004-01-25, 9:30 pm

Junaid,
To create a protoed node using createVrmlFromString, you have to
include an EXTERNPROTO for it in the creation string. This might look
something like the following:

ProtoedNode.wrl:
PROTO ProtoedNode [
....
] { .... }

test.wrl:
..... Browser.createVrmlFromString(
" EXTERNPROTO ProtoedNode [ " +
" .... " +
" ] \"ProtoedNode.wrl\" " +
" ProtoedNode {} "
);
.....

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