2basis[0 * 3 + 0] = (1.0 - tt) * (1.0 - ss);
3basis[0 * 3 + 1] = rr * (1.0 - tt);
6basis[1 * 3 + 0] = ss * (tt - 1.0);
7basis[1 * 3 + 1] = rr * (1.0 - tt);
10basis[2 * 3 + 0] = ss * (tt - 1.0);
11basis[2 * 3 + 1] = (1.0 - rr) * (tt - 1.0);
12basis[2 * 3 + 2] = 0.0;
14basis[3 * 3 + 0] = (1.0 - ss) * (1.0 + tt);
15basis[3 * 3 + 1] = rr * (1.0 + tt);
16basis[3 * 3 + 2] = 0.0;
18basis[4 * 3 + 0] = -ss * (1.0 + tt);
19basis[4 * 3 + 1] = rr * (1.0 + tt);
20basis[4 * 3 + 2] = 0.0;
22basis[5 * 3 + 0] = -ss * (1.0 + tt);
23basis[5 * 3 + 1] = (rr - 1.0) * (1.0 + tt);
24basis[5 * 3 + 2] = 0.0;
26basis[6 * 3 + 0] = 0.0;
27basis[6 * 3 + 1] = 0.0;
28basis[6 * 3 + 2] = (1.0 - rr - ss);
30basis[7 * 3 + 0] = 0.0;
31basis[7 * 3 + 1] = 0.0;
34basis[8 * 3 + 0] = 0.0;
35basis[8 * 3 + 1] = 0.0;