Question

I want to round a float number to a given precision, for example :

0.051 i want to convert it to
0.1

0.049 i want to convert it to
0.0

0.56 i want to convert it to
0.6

0.54 i want to convert it to
0.5

I cant explain it better, but the reason for this is to translate a point location (like 0.131f, 0.432f) to the location of tile in a grid (like 0.1f, 0.4f).

Answer 1

As long as your grid is regular, just find a transformation from integers to this grid. So let’s say your grid is

0.2  0.4  0.6  ...

Then you round by

float round(float f)
{
    return floor(f * 5 + 0.5) / 5;
    // return std::round(f * 5) / 5; // C++11
}