GLU Tesselator returns always null data

[elvencode]

Hello,
i'm trying to use the tesselation of GLU but the callback functions are all correct but the vertex one that returns always null. I've tried to debug gluTessVertex and data seems to be loaded, if i change setting (one rettangle, than a rectangle with a hole) it gives different numbers of vertices and primitives. The code is this

GLUtessellatorImpl tess = new GLUtessellatorImpl();
TesselatorCallback callback = new TesselatorCallback();

tess.gluTessCallback(GLU.GLU_TESS_VERTEX, callback);       
tess.gluTessCallback(GLU.GLU_TESS_BEGIN, callback);
tess.gluTessCallback(GLU.GLU_TESS_END, 
tess.gluTessCallback(GLU.GLU_TESS_ERROR, callback);

tess.gluTessBeginPolygon(null);

tess.gluTessBeginContour();

double[] data = new double[4*3];
// p1
data[0] = 0;
data[1] = 0;
data[2] = 0;
// p2
data[3] = 0;
data[4] = 0;
data[5] = 100;        
// p3
data[6] = 100;
data[7] = 0;
data[8] = 100;
// p4
data[9] = 100;
data[10] = 0;
data[11] = 0;
        
for(int i=0;i<4;i++)
{
    tess.gluTessVertex(data, i*3, null);
}
        
tess.gluTessEndContour();

tess.gluTessEndPolygon();
                
tess.gluDeleteTess();

the callback class is this

    public class TesselatorCallback implements GLUtessellatorCallback
    {        
        @Override
        public void begin(int type)
        {
            if(type == GL11.GL_TRIANGLES)
                System.out.println("Tesselator: triangle");
            else if(type == GL11.GL_TRIANGLE_FAN)
                System.out.println("Tesselator: triangle fan");
            else if(type == GL11.GL_TRIANGLE_STRIP)
                System.out.println("Tesselator: triangle strip");
            else
                System.out.println("Tesselator: not handled primitive");
        }

        @Override
        public void beginData(int type, Object polygonData)
        {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void edgeFlag(boolean boundaryEdge)
        {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void edgeFlagData(boolean boundaryEdge, Object polygonData)
        {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void vertex(Object vertexData)
        {
            System.out.println(vertexData);
        }

        @Override
        public void vertexData(Object vertexData, Object polygonData)
        {
            System.out.println(vertexData);
        }

        @Override
        public void end()
        {
            System.out.println("Tesselation: end primitive");
        }

        @Override
        public void endData(Object polygonData)
        {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void combine(double[] coords, Object[] data, float[] weight, Object[] outData)
        {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void combineData(double[] coords, Object[] data, float[] weight, Object[] outData, Object polygonData)
        {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void error(int errnum)
        {
            System.out.println(System.out.format("Tesselation error: %d\n", errnum));
        }

        @Override
        public void errorData(int errnum, Object polygonData)
        {
            throw new UnsupportedOperationException("Not supported yet.");
        }
    
        
    }

I've tried to use GLUtessellatorCallbackAdapter but there's no difference, same as with the winding order (anyway something is returned with or without it).

[broumbroum]

hello, at a first glance your callbacks are incomplete. Callbacks are methods that encapsulate "low-end" functions, like GL11.glBegin(), GL11.glVertex() etc. so that your TesselatorCallback is working.

cu