How to draw solid polygon (newbie)

[rhhaney145]

Please Help,

I am very new at Java3D and trying to draw a solid polygon based on a set of Points (X, Y, and Z Coordinates). I was using JOGL but like the purely Object-oriented paradigm provided by Java3D. Anyway, I have a series of Points stored in a Vector and need to draw them as a Polygon that is solid. In JOGL I used the following code:

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Vector pts = getPoints(); gl.glBegin(GL.GL_POLYGON); for (int i = 0; i < pts.size(); i++)  {     PointData p = (PointData)pts.get(i);     gl.glVertex3f(p.x, p.y, p.z); } gl.glEnd();

The problem is that when I have tried it with Java3D using the GeometryInfo Class I sometimes get strange triangulation renderings.  Can anyone out there help a newbie out?

Thanks in advance.

[Conzar]

You need to use a QuadArray.

So something like this

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Point3f point0 = new Point3f(0,0,0); Point3f point1 = new Point3f(1,0,0); Point3f point2 = new Point3f(1,1,0); Point3f point3 = new Point3f(0,1,0); QuadArray quadArray = new QuadArray(4,QuadArray.COORDINATES | QuadArray.NORMALS); quadArray.setCoordinates(0,point0); quadArray.setCoordinates(1,point1); quadArray.setCoordinates(2,point2); quadArray.setCoordinates(3,point3); Vector3f norm = new Vector3f(0f,0f,1f); quadArray.setNormal(0,norm); quadArray.setNormal(1,norm); quadArray.setNormal(2,norm); quadArray.setNormal(3,norm);

Now just add the QuadArray to the scene graph and your all set.

[rhhaney145]

Thank you very much for the reply Conzar. 

However, I probably should clarify the issue a little more.  The Model I am rendering is made up of a series of potentially complex (contain "holes") polygons that may or may not fall on a total vertex number that is a factor of 4.  Each polygon being rendered could have any number of vertices.  When this is the situation what is the best idea to do with Java3D ?

Once again, thank you for the response.

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[rhhaney145]

All right,

I think I am begining to understand enough about Java3D to properly ask the question that I have regarding rendering Polygons.  I have a set of Polygons that I would like to render together to form a single Object.  I believe the problem is occurring when I try to append multiple Geometries, the following snippet of code shows what I am trying to do (this Class extends the Shape3D Class):

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public void setGeometry() {         // The outers Vector contains a Collection of Polygon Objects (each of which is       // composed of a series of Point3d Objects)  ...        //        for (int i = 0; i < this.outers.size(); i++) {             this.gInf = new GeometryInfo(GeometryInfo.POLYGON_ARRAY);             Polygon poly = (Polygon)this.outers.get(i);             Point3d[] outerPts = poly.outerToArray();             int[] stripCounts = {outerPts.length};             int[] contourCount = {1};             this.gInf.setCoordinates(outerPts);             this.gInf.setStripCounts(stripCounts);             Triangulator tr = new Triangulator();             tr.triangulate(this.gInf);             this.gInf.recomputeIndices();             NormalGenerator ng = new NormalGenerator();             ng.generateNormals(this.gInf);             this.gInf.recomputeIndices();             Stripifier st = new Stripifier();             st.stripify(this.gInf);             this.gInf.recomputeIndices();            //this.setGeometry(this.gInf.getGeometryArray());           this.addGeometry(this.gInf.getGeometryArray());         }// End of FOR-LOOP }// End of setGeometry()

When I uncomment the setGeometry(this.gInf.getGeometryArray()) and comment-out the addGeometry(this.gInf.getGeometryArray()) methods I get a correct Polygon rendering (although only the LAST polygon in the series represented by the "outers" Vector is rendered.  I am hoping that this is a SIMPLE fix.  Can anyone out there PLEASE help a newbie out?

Thanks in advance.

[rhhaney145]

Fixed the problem!!

It had nothing to do with the GeometryInfo Class. I had forgot to check the direction of the Point3d Objects to be rendered, thus the points sometimes yielded malformed triangle divisions.

Thanks everybody for all the help/hints.  It really helps a newbie like myself.

[Conzar]

Glad you got it working man!