Minecraft as a side-effect

Thanks to our powerful voxel engine we can get sometimes quite unexpected results. While we were testing a new feature, we accidentally developed new Minecraft clone. And it was fun to play :)

Would you like MinerWars craft mode? :)

NextAfter in C# without allocations or unsafe code

In C99, there is a standard way to get the next larger or smaller float32: the function nextafterf. In C#, there’s no such function and I had to roll my own version.
There are three ugly possibilities.

1. use pointer aliasing,
2. BitConverter.GetBytes,
3. simulate an union.

The main update loop may not make any allocations, so BitConverter is out. Pointer aliasing is unsafe, so I couldn’t use it either. So the version I ended up with looks like this:

[StructLayout(LayoutKind.Explicit)]
struct FloatIntUnion
{
    [FieldOffset(0)]
    public int i;
    [FieldOffset(0)]
    public float f;
}

//  Returns the next float after x in the direction of y.
float NextAfter(float x, float y)
{
    if (float.IsNaN(x) || float.IsNaN(y)) return x + y;
    if (x == y) return y;  // nextafter(0, -0) = -0

    FloatIntUnion u;
    u.i = 0; u.f = x;  // shut up the compiler

    if (x == 0)
    {
        u.i = 1;
        return y > 0 ? u.f : -u.f;
    }

    if ((x > 0) == (y > x))
        u.i++;
    else
        u.i--;
    return u.f;
}