#pragma once

#define KINDA_SMALL_NUMBER (1.e-4f)
#define BIG_NUMBER (3.4e+38f)

struct Math_KSH
{
	static inline float Square(float x)
	{
		return x * x;
	}

	static inline float Abs(float x)
	{
		return x >= 0.f ? x : -x;
	}

	static inline float Sqrt(float x)
	{
		int NUM_REAPEAT = 16;
		int k;
		float t;
		float buf = x;

		for (k = 0, t = buf; k < NUM_REAPEAT; k++)
		{
			if (t < 1.f)
				break;
			t = (t * t + buf) / (2.f * t);
		}

		return t;
	}

	static inline float InvSqrt(float x)
	{
		float FHalf = 0.5f * x;
		int i = *(int*)&x;
		i = 0x5f3759df - (i >> 1);
		x = *(float*)&i;
		x = x * (1.5f - (FHalf * x * x));

		return x;
	}
};