Opengl Winding Not Working?

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C++

OpenGL

Hello Everyone,

I have been trying to clip polygons. The basic process works, but I am not able to get the desired result. I want to get the result of subtraction of polygon B from A.

links for images to help understand desired result:
1)
http://i48.tinypic.com/14m8hls.jpg[^]

2)

http://i45.tinypic.com/apllh.jpg[^]

Also, below is the code(I have tried all the Winding rules!!!):

GLUtesselator *tess = gluNewTess(); // create a tessellator
    if(!tess) return 0;         // failed to create tessellation object, return 0


	GLdouble quad2[8][3] = { {0,0,0}, {3,0,0}, {3,4,0}, { 0,4,0},
                             {1,1,0}, {4,1,0}, {4,2,0}, { 1,2,0} };

    // register callback functions
    gluTessCallback(tess, GLU_TESS_BEGIN, (void (__stdcall*)(void))tessBeginCB);
    gluTessCallback(tess, GLU_TESS_END, (void (__stdcall*)(void))tessEndCB);
    gluTessCallback(tess, GLU_TESS_ERROR, (void (__stdcall*)(void))tessErrorCB);
    gluTessCallback(tess, GLU_TESS_VERTEX, (void (__stdcall*)())tessVertexCB);
	gluTessCallback(tess, GLU_TESS_COMBINE, (void (__stdcall*)(void))tessCombineCB);


	//reference : http://www.glprogramming.com/red/chapter11.html
	//gluTessProperty(tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_ABS_GEQ_TWO);
		//gluTessProperty(tess, GLU_TESS_BOUNDARY_ONLY, GL_TRUE);
	gluTessProperty(tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_POSITIVE);


    // tessellate and compile a concave quad into display list
    glNewList(id, GL_COMPILE);
    glColor3f(1,1,1);
    gluTessBeginPolygon(tess, 0);                       // with NULL data
	
        gluTessBeginContour(tess);                      // outer quad
            gluTessVertex(tess, quad2[0], quad2[0]);
            gluTessVertex(tess, quad2[1], quad2[1]);
            gluTessVertex(tess, quad2[2], quad2[2]);
            gluTessVertex(tess, quad2[3], quad2[3]);
        gluTessEndContour(tess);
        gluTessBeginContour(tess);                      // inner quad (hole)
            gluTessVertex(tess, quad2[4], quad2[4]);
            gluTessVertex(tess, quad2[5], quad2[5]);
            gluTessVertex(tess, quad2[6], quad2[6]);
            gluTessVertex(tess, quad2[7], quad2[7]);
        gluTessEndContour(tess);
    gluTessEndPolygon(tess);
    glEndList();

    gluDeleteTess(tess);        // delete after tessellation

Thanks In Advance