Types conversion in Unity3D

Hey there!
Recently I needed to store floats as integers and vice versa (used it to easily xor floats in my Anti-Cheat Toolkit) and I came across few ways of doing this.

Unsafe pointers – fastest one:

public unsafe int FloatToInt(float value)
{
	return *(int*)&value;
}

public unsafe float IntToFloat(int value)
{
	return *(float*)&value;
}

Easy, right?
Please, note, it requires /unsafe compiler option. To leverage unsafe operations in unity, you have two commonly used options to choose from:
1. Use it in a separate dll, compiled with /unsafe option.
2. Set /unsafe option right in your project using “Global Custom Defines”, putting it in .rsp file in your Assets/ root. See bottom of this page for details.
And keep in mind unsafe code is not supported in some build targets, like Web Player and Flash Player.

Unions (Explicitly layouted structs) – slower than pointers, but works in Web Player (not in Flash Player, d’oh!):

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

	[FieldOffset(0)]
	public int i;
}

public int FloatToInt(float value)
{
	var u = new FloatIntUnion();
	u.f = value;
	return u.i;
}

public float IntToFloat(int value)
{
	var u = new FloatIntUnion();
	u.i = value;
	return u.f;
}

Pretty easy to use, safe and works on more build targets comparing to pointers.
Note [StructLayout(LayoutKind.Explicit)] attribute is used here in conjunction with [FieldOffset(*)] attribute. It allows you to set each struct field position in memory explicitly and read data stored there.

BitConverter class – pretend to be slowest:

public int FloatToInt(float value)
{
	return BitConverter.ToInt32(BitConverter.GetBytes(value), 0);
}

public float IntToFloat(int value)
{
	return BitConverter.ToSingle(BitConverter.GetBytes(value), 0);
}

Safest one though (works even in Flash Player).

I should mention there are so-called “safe pointers” in C#, used through Marshal class, but they are pretty complicated, require unmanaged memory allocations and constant control on memory at all (C# developers are usually rely on GC and do not bother on allocations), so I’ll not post Marshal review here for now, these 3 methods I described are usually enough for the types conversion.
I hop I’ll have some time to make performance tests on these methods in latest Unity 4.3 later and post results with tests sourcers here (in another blog post).

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