FindSeedCells

MIN_INSIDE_FACES = 4;
MIN_INSIDE_PERCENTAGE = 0.03f;
 
int cubemap_sides_seeing_inside = 0;
 
for (int i = 0; i < 6; i++)
{
    RenderCubeMapSide(i);
    float backfacePercentage = CalculateBackfacePercentage(i);
 
    if (backfacePercentage > MIN_INSIDE_PERCENTAGE)
        cubemap_sides_seeing_inside++;
}
 
if (cubemap_sides_seeing_inside >= MIN_INSIDE_FACES || cubemap_sides_seeing_inside == 0)
{
    if (cubemap_sides_seeing_inside >= MIN_INSIDE_FACES)
        cell.Status = CellStatus.Inside;
    else // cubemap_sides_seeing_inside == 0
        cell.Status = CellStatus.Outside;
 
    // Propagate cell status...
}
else
{
    // Unable to solve status exactly.
}