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winia
03-17-2010, 07:44 AM
Hi Guys,

I am currentlly working on the managed c++(VS2008) and Opengl

one part of my code is using gluTessBeginPolygon to draw Polygons.

here is my function to draw polygon
----------------------------------------------------------
void Display1()
{
GLdouble rect[4][3] = {50.0, 50.0, 0.0,
200.0, 50.0, 0.0,
200.0, 200.0, 0.0,
50.0, 200.0, 0.0};


GLUtesselator* tobj = gluNewTess();
gluTessCallback(tobj, GLU_TESS_BEGIN,(void (CALLBACK*) ()) beginCallback);

gluTessCallback(tobj, GLU_TESS_VERTEX,(void (CALLBACK*) ()) glVertex3dv);
gluTessCallback(tobj, GLU_TESS_END,(void (CALLBACK*) ()) endCallback);


gluTessBeginPolygon(tobj, NULL);
gluTessBeginContour(tobj);
gluTessVertex(tobj, rect[0], rect[0]);
gluTessVertex(tobj, rect[1], rect[1]);
gluTessVertex(tobj, rect[2], rect[2]);
gluTessEndContour(tobj);
gluTessEndPolygon(tobj);

}
static void CALLBACK beginCallback(GLenum which)
{
glBegin(which);
}

static void CALLBACK errorCallback(GLenum errorCode)
{
const GLubyte *estring;

estring = gluErrorString(errorCode);
fprintf(stderr, "Tessellation Error: %s\n", estring);
exit(0);
}

static void CALLBACK endCallback(void)
{
glEnd();
}
---------------------------------------------------

But when I am debugging at line: gluTessEndPolygon(tobj);
I always get exception:

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.


does anybody have experience to deal with this problem?