opengl - Draw disk using Triangle Fan mode -

I am trying to attract the disk using triangle_fan mode, but my disk disappears near its end Drag with part is not fully attracted, something like 320 degree is visible).

What do I have here:

  int vertexCount = 40; // varteris float radius = 0.5 f; Posts. Push_back (vec3 (0, 0, 0)); For (int a = 0; a & lt; 360; a + = 360 / vertex count) {double top = one * M_PI / 180.f; Posts. Push_back (vec3 (cos (title) * radius, sin (title) * radius, 0)); } // Index Index Indic Data = Status. Shape (); (Int i = 0; i