...
for (int x = 0; x < 3; ++x)
{
int x2 = x + 1;
// improvement 1
if (uv[x].x == uv[x2].x) continue;
for (int y = 0; y < 3; ++y)
{
if (!mFillCenter && x == 1 && y == 1) continue;
int y2 = y + 1;
// improvement 2
if (uv[y].y == uv[y2].y) continue;
...