> Date: Wed, 3 Jul 2002 13:45:33 +0200
> From: =?iso-8859-1?q?BEGHIN=20Matthieu?= <[EMAIL PROTECTED]>
>
> I had the same problem and posted it. My solution was to avoid getting
> vertex coordinates. I know this exception is only thrown with Java3D 1.3,
> not with previous realeases.
>
> The problem is that loaders we are using creates GeometryArray in
> BY_REFERENCE mode, which is a parameter of the constructor. I'd like to know
> another way to get vertex coordinates in a TriangleStrip array.
>
>> Olivier Tassy <[EMAIL PROTECTED]> a �crit : Hello,I am trying to get
>> the position of every vertex of a shape3d in a live scene.I use the
>> following code:
>>
>> Shape3D node1 = (Shape3D);
>> shapeTab.get(item1);
>> TriangleArray geom1 = (TriangleArray);
>> node1.getGeometry();
>> Point3d[] coordinates = new Point3d[geom1.getVertexCount()];
>>
>> for(int n = 0; n < geom1.getVertexCount(); n++)
>> coordinates[n] = new Point3d();
>>
>> geom1.getCoordinates(0, coordinates);
>>
>> java.lang.IllegalStateException:
>> GeometryArray: cannot directly access data in BY_REFERENCE mode
>> at javax.media.j3d.GeometryArray.getCoordinates(GeometryArray.java:2743)
You may be getting the geometry from ObjectFile, which for performance reasons
was revised in Java 3D 1.3 to use by-ref interleaved access semantics.
A quick fix is to modify ObjectFile.java at line 1230 from
shape.setGeometry(gi.getGeometryArray(true, true, false));
to
shape.setGeometry(gi.getGeometryArray(false, false, false));
Or you could create a new GeometryInfo with the constructor that takes a
GeometryArray as a parameter, and then use the getCoordinates() method of
GeometryInfo. This is probably the best way to get what you want.
Otherwise, you would need to extract the by-ref data yourself by inspecting the
vertex format flags to see how the data is formatted. Unfortunately, this is
can be quite complex -- see the source code for the private
processGeometryArray() method of GeometryInfoGenerator for hints. By-ref
geometry is easy to construct but wasn't intended to be easily taken apart by
anything other than the native graphics API.
Basically you have three bits to look at in the vertex format of the
GeometryArray:
boolean NIO = (vertexFormat & GeometryArray.USE_NIO_BUFFER) != 0 ;
boolean byRef = (vertexFormat & GeometryArray.BY_REFERENCE) != 0 ;
boolean interleaved = (vertexFormat & GeometryArray.INTERLEAVED) != 0 ;
If byRef is false, you have the normal by-copy access semantics of the Java 3D
1.2. Otherwise, you have all the boolean combinations of interleaved and NIO
to consider:
If both NIO and interleaved are false, then you access coordinates with
getCoordRefFloat() and gotCoordRefDouble() to get the references to the float
and double arrays containing the vertex coordinates. There isn't any way to
determine if it contains float or double arrays other than checking if the
returned reference is null.
If interleaved is true but NIO is false, then you get the interleaved float
array by calling getInterleavedVertices(). You have to examine the vertex
format to determine what's included in each vertex -- the texture data comes
first, followed by the color, then the normal, then the vertex coordinates.
If both interleaved and NIO are true, then you get the vertex data by calling
getInterleavedVertexBuffer() to get a reference to a J3DBuffer which wraps the
NIO contents. This will always be of type BufferWrapper.TYPE_FLOAT, so you
create a FloatBufferWrapper object from the J3DBuffer and then use the get()
method on that object to retrieve the data.
If only NIO is true, then you call getCoordRefBuffer() to get the J3DBuffer.
This buffer can be of two types -- BufferWrapper.TYPE_FLOAT or
BufferWrapper.TYPE_DOUBLE.
-- Mark Hood
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