opengl(代码都能运行,但不出图案,不知到是为什么)!!!!!!!!!!!!!!!!!!!!!!!!!!!(28分)

{
glubeginpolygon(tess);
glColor3f(1,0,0); glutessvertex(tess,listdot[0],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[1],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[2],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[3],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[4],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[5],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[6],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[7],nil);

gluendpolygon(tess); }

又或者代码如下代码都能运行,但不出图案,不知到是为什么)!!!!!!!!!!!!!!!!!!!!!!!!!!!
glutessbeginpolygon(tess,nil);
glutessbegincontour(tess);
glColor3f(1,0,0); glutessvertex(tess,listdot[0],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[1],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[2],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[3],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[4],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[5],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[6],nil);
glColor3f(1,0,0); glutessvertex(tess,listdot[7],nil);
glutessendcontour(tess);
gluendpolygon(tess);


急求各位大师!!!!!!!!!!!!!!!!!!

type
T3DArray = array [0..2] of double;


var

i : integer;
count :integer;

T: PGLUtesselator;
V: array of T3DArray;

begin

T := gluNewTess();

gluTessCallback(T, GLU_TESS_BEGIN, @glBegin);
gluTessCallback(T, GLU_TESS_VERTEX, @glVertex3dv);
gluTessCallback(T, GLU_TESS_END, @glEnd);

count := 10;
setlength(V,count);
//填充V数据，省略

gluBeginPolygon(T);
for i:= 0 to count - 1 do
gluTessVertex(T,V,@V);
gluEndPolygon(T);

gluDeleteTess(T);

end;