 			}
 		}
 	}
-	if (tid == 0 && _i == 0)
+	if (tid == 0 && _i == 1)
 	{
 		test_polygon[3] = current_seed_pos.x;
 		test_polygon[4] = current_seed_pos.y;

			pong[pong_nb * 4 + 2] = vertex.z;
			pong[pong_nb * 4 + 3] = vertex.w;
			pong_nb++;
		}
	}
	return;
}

output: polygon pong and its number
*/
__device__
void clip_by_plane(double* ping, int& ping_nb, double* pong, int& pong_nb, int seed_i, int seed_j, double* seeds_pointer, int seeds_nb, double* test_double, int _tid)
{
	//test 
	int index = 150;
	//reset the pong
	pong_nb = 0;

