source-engine/public/mathlib/compressed_vector.h

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose: 
//
// $NoKeywords: $
//
//=============================================================================//

#ifndef COMPRESSED_VECTOR_H
#define COMPRESSED_VECTOR_H

#ifdef _WIN32
#pragma once
#endif

#include <math.h>
#include <float.h>

// For vec_t, put this somewhere else?
#include "basetypes.h"

// For rand(). We really need a library!
#include <stdlib.h>

#include "tier0/dbg.h"
#include "mathlib/vector.h"

#include "mathlib/mathlib.h"

#if defined( _X360 )
#pragma bitfield_order( push, lsb_to_msb )
#endif
//=========================================================
// fit a 3D vector into 32 bits
//=========================================================

class Vector32
{
public:
	// Construction/destruction:
	Vector32(void); 
	Vector32(vec_t X, vec_t Y, vec_t Z);

	// assignment
	Vector32& operator=(const Vector &vOther);
	operator Vector ();

private:
	unsigned short x:10;
	unsigned short y:10;
	unsigned short z:10;
	unsigned short exp:2;
};

inline Vector32& Vector32::operator=(const Vector &vOther)	
{
	CHECK_VALID(vOther);

	static float expScale[4] = { 4.0f, 16.0f, 32.f, 64.f };

	float fmax = Max( fabs( vOther.x ), fabs( vOther.y ) );
	fmax = Max( fmax, (float)fabs( vOther.z ) );

	for (exp = 0; exp < 3; exp++)
	{
		if (fmax < expScale[exp])
			break;
	}
	Assert( fmax < expScale[exp] );

	float fexp = 512.0f / expScale[exp];

	x = Clamp( (int)(vOther.x * fexp) + 512, 0, 1023 );
	y = Clamp( (int)(vOther.y * fexp) + 512, 0, 1023 );
	z = Clamp( (int)(vOther.z * fexp) + 512, 0, 1023 );
	return *this; 
}


inline Vector32::operator Vector ()
{
	Vector tmp;

	static float expScale[4] = { 4.0f, 16.0f, 32.f, 64.f };

	float fexp = expScale[exp] / 512.0f;

	tmp.x = (((int)x) - 512) * fexp;
	tmp.y = (((int)y) - 512) * fexp;
	tmp.z = (((int)z) - 512) * fexp; 
	return tmp; 
}


//=========================================================
// Fit a unit vector into 32 bits
//=========================================================

class Normal32
{
public:
	// Construction/destruction:
	Normal32(void); 
	Normal32(vec_t X, vec_t Y, vec_t Z);

	// assignment
	Normal32& operator=(const Vector &vOther);
	operator Vector ();

private:
	unsigned short x:15;
	unsigned short y:15;
	unsigned short zneg:1;
};


inline Normal32& Normal32::operator=(const Vector &vOther)	
{
	CHECK_VALID(vOther);

	x = Clamp( (int)(vOther.x * 16384) + 16384, 0, 32767 );
	y = Clamp( (int)(vOther.y * 16384) + 16384, 0, 32767 );
	zneg = (vOther.z < 0);
	//x = vOther.x; 
	//y = vOther.y; 
	//z = vOther.z; 
	return *this; 
}


inline Normal32::operator Vector ()
{
	Vector tmp;

	tmp.x = ((int)x - 16384) * (1 / 16384.0);
	tmp.y = ((int)y - 16384) * (1 / 16384.0);
	tmp.z = sqrt( 1 - tmp.x * tmp.x - tmp.y * tmp.y );
	if (zneg)
		tmp.z = -tmp.z;
	return tmp; 
}


//=========================================================
// 64 bit Quaternion
//=========================================================

class Quaternion64
{
public:
	// Construction/destruction:
	Quaternion64(void) = default;
	Quaternion64(vec_t X, vec_t Y, vec_t Z);

	// assignment
	// Quaternion& operator=(const Quaternion64 &vOther);
	Quaternion64& operator=(const Quaternion &vOther);
	operator Quaternion ();
private:
	uint64 x:21;
	uint64 y:21;
	uint64 z:21;
	uint64 wneg:1;
};


inline Quaternion64::operator Quaternion ()	
{
	Quaternion tmp;

	// shift to -1048576, + 1048575, then round down slightly to -1.0 < x < 1.0
	tmp.x = ((int)x - 1048576) * (1 / 1048576.5f);
	tmp.y = ((int)y - 1048576) * (1 / 1048576.5f);
	tmp.z = ((int)z - 1048576) * (1 / 1048576.5f);
	tmp.w = sqrt( 1 - tmp.x * tmp.x - tmp.y * tmp.y - tmp.z * tmp.z );
	if (wneg)
		tmp.w = -tmp.w;
	return tmp; 
}

inline Quaternion64& Quaternion64::operator=(const Quaternion &vOther)	
{
	CHECK_VALID(vOther);

	x = Clamp( (int)(vOther.x * 1048576) + 1048576, 0, 2097151 );
	y = Clamp( (int)(vOther.y * 1048576) + 1048576, 0, 2097151 );
	z = Clamp( (int)(vOther.z * 1048576) + 1048576, 0, 2097151 );
	wneg = (vOther.w < 0);
	return *this; 
}

//=========================================================
// 48 bit Quaternion
//=========================================================

class Quaternion48
{
public:
	// Construction/destruction:
	Quaternion48(void) = default;
	Quaternion48(vec_t X, vec_t Y, vec_t Z);

	// assignment
	// Quaternion& operator=(const Quaternion48 &vOther);
	Quaternion48& operator=(const Quaternion &vOther);
	operator Quaternion ();
private:
	unsigned short x:16;
	unsigned short y:16;
	unsigned short z:15;
	unsigned short wneg:1;
};


inline Quaternion48::operator Quaternion ()	
{
	Quaternion tmp;

	tmp.x = ((int)x - 32768) * (1 / 32768.0);
	tmp.y = ((int)y - 32768) * (1 / 32768.0);
	tmp.z = ((int)z - 16384) * (1 / 16384.0);
	tmp.w = sqrt( 1 - tmp.x * tmp.x - tmp.y * tmp.y - tmp.z * tmp.z );
	if (wneg)
		tmp.w = -tmp.w;
	return tmp; 
}

inline Quaternion48& Quaternion48::operator=(const Quaternion &vOther)	
{
	CHECK_VALID(vOther);

	x = Clamp( (int)(vOther.x * 32768) + 32768, 0, 65535 );
	y = Clamp( (int)(vOther.y * 32768) + 32768, 0, 65535 );
	z = Clamp( (int)(vOther.z * 16384) + 16384, 0, 32767 );
	wneg = (vOther.w < 0);
	return *this; 
}

//=========================================================
// 32 bit Quaternion
//=========================================================

class Quaternion32
{
public:
	// Construction/destruction:
	Quaternion32(void); 
	Quaternion32(vec_t X, vec_t Y, vec_t Z);

	// assignment
	// Quaternion& operator=(const Quaternion48 &vOther);
	Quaternion32& operator=(const Quaternion &vOther);
	operator Quaternion ();
private:
	unsigned int x:11;
	unsigned int y:10;
	unsigned int z:10;
	unsigned int wneg:1;
};


inline Quaternion32::operator Quaternion ()	
{
	Quaternion tmp;

	tmp.x = ((int)x - 1024) * (1 / 1024.0);
	tmp.y = ((int)y - 512) * (1 / 512.0);
	tmp.z = ((int)z - 512) * (1 / 512.0);
	tmp.w = sqrt( 1 - tmp.x * tmp.x - tmp.y * tmp.y - tmp.z * tmp.z );
	if (wneg)
		tmp.w = -tmp.w;
	return tmp; 
}

inline Quaternion32& Quaternion32::operator=(const Quaternion &vOther)	
{
	CHECK_VALID(vOther);

	x = Clamp( (int)(vOther.x * 1024) + 1024, 0, 2047 );
	y = Clamp( (int)(vOther.y * 512) + 512, 0, 1023 );
	z = Clamp( (int)(vOther.z * 512) + 512, 0, 1023 );
	wneg = (vOther.w < 0);
	return *this; 
}

//=========================================================
// 16 bit float
//=========================================================


const int float32bias = 127;
const int float16bias = 15;

const float maxfloat16bits = 65504.0f;

class float16
{
public:
	//float16() {}
	//float16( float f ) { m_storage.rawWord = ConvertFloatTo16bits(f); }

	void Init() { m_storage.rawWord = 0; }
//	float16& operator=(const float16 &other) { m_storage.rawWord = other.m_storage.rawWord; return *this; }
//	float16& operator=(const float &other) { m_storage.rawWord = ConvertFloatTo16bits(other); return *this; }
//	operator unsigned short () { return m_storage.rawWord; }
//	operator float () { return Convert16bitFloatTo32bits( m_storage.rawWord ); }
	unsigned short GetBits() const 
	{ 
		return m_storage.rawWord; 
	}
	float GetFloat() const 
	{ 
		return Convert16bitFloatTo32bits( m_storage.rawWord ); 
	}
	void SetFloat( float in ) 
	{ 
		m_storage.rawWord = ConvertFloatTo16bits( in ); 
	}

	bool IsInfinity() const
	{
		return m_storage.bits.biased_exponent == 31 && m_storage.bits.mantissa == 0;
	}
	bool IsNaN() const
	{
		return m_storage.bits.biased_exponent == 31 && m_storage.bits.mantissa != 0;
	}

	bool operator==(const float16 other) const { return m_storage.rawWord == other.m_storage.rawWord; }
	bool operator!=(const float16 other) const { return m_storage.rawWord != other.m_storage.rawWord; }
	
//	bool operator< (const float other) const	   { return GetFloat() < other; }
//	bool operator> (const float other) const	   { return GetFloat() > other; }

protected:
	union float32bits
	{
		float rawFloat;
		struct 
		{
			unsigned int mantissa : 23;
			unsigned int biased_exponent : 8;
			unsigned int sign : 1;
		} bits;
	};

	union float16bits
	{
		unsigned short rawWord;
		struct
		{
			unsigned short mantissa : 10;
			unsigned short biased_exponent : 5;
			unsigned short sign : 1;
		} bits;
	};

	static bool IsNaN( float16bits in )
	{
		return in.bits.biased_exponent == 31 && in.bits.mantissa != 0;
	}
	static bool IsInfinity( float16bits in )
	{
		return in.bits.biased_exponent == 31 && in.bits.mantissa == 0;
	}

	// 0x0001 - 0x03ff
	static unsigned short ConvertFloatTo16bits( float input )
	{
		if ( input > maxfloat16bits )
			input = maxfloat16bits;
		else if ( input < -maxfloat16bits )
			input = -maxfloat16bits;

		float16bits output;
		float32bits inFloat;

		inFloat.rawFloat = input;

		output.bits.sign = inFloat.bits.sign;

		if ( (inFloat.bits.biased_exponent==0) && (inFloat.bits.mantissa==0) ) 
		{ 
			// zero
			output.bits.mantissa = 0;
			output.bits.biased_exponent = 0;
		}
		else if ( (inFloat.bits.biased_exponent==0) && (inFloat.bits.mantissa!=0) ) 
		{  
			// denorm -- denorm float maps to 0 half
			output.bits.mantissa = 0;
			output.bits.biased_exponent = 0;
		}
		else if ( (inFloat.bits.biased_exponent==0xff) && (inFloat.bits.mantissa==0) ) 
		{ 
#if 0
			// infinity
			output.bits.mantissa = 0;
			output.bits.biased_exponent = 31;
#else
			// infinity maps to maxfloat
			output.bits.mantissa = 0x3ff;
			output.bits.biased_exponent = 0x1e;
#endif
		}
		else if ( (inFloat.bits.biased_exponent==0xff) && (inFloat.bits.mantissa!=0) ) 
		{ 
#if 0
			// NaN
			output.bits.mantissa = 1;
			output.bits.biased_exponent = 31;
#else
			// NaN maps to zero
			output.bits.mantissa = 0;
			output.bits.biased_exponent = 0;
#endif
		}
		else 
		{ 
			// regular number
			int new_exp = inFloat.bits.biased_exponent-127;

			if (new_exp<-24) 
			{ 
				// this maps to 0
				output.bits.mantissa = 0;
				output.bits.biased_exponent = 0;
			}

			if (new_exp<-14) 
			{
				// this maps to a denorm
				output.bits.biased_exponent = 0;
				unsigned int exp_val = ( unsigned int )( -14 - ( inFloat.bits.biased_exponent - float32bias ) );
				if( exp_val > 0 && exp_val < 11 )
				{
					output.bits.mantissa = ( 1 << ( 10 - exp_val ) ) + ( inFloat.bits.mantissa >> ( 13 + exp_val ) );
				}
			}
			else if (new_exp>15) 
			{ 
#if 0
				// map this value to infinity
				output.bits.mantissa = 0;
				output.bits.biased_exponent = 31;
#else
				// to big. . . maps to maxfloat
				output.bits.mantissa = 0x3ff;
				output.bits.biased_exponent = 0x1e;
#endif
			}
			else 
			{
				output.bits.biased_exponent = new_exp+15;
				output.bits.mantissa = (inFloat.bits.mantissa >> 13);
			}
		}
		return output.rawWord;
	}

	static float Convert16bitFloatTo32bits( unsigned short input )
	{
		float32bits output;
		const float16bits &inFloat = *((float16bits *)&input);

		if( IsInfinity( inFloat ) )
		{
			return maxfloat16bits * ( ( inFloat.bits.sign == 1 ) ? -1.0f : 1.0f );
		}
		if( IsNaN( inFloat ) )
		{
			return 0.0;
		}
		if( inFloat.bits.biased_exponent == 0 && inFloat.bits.mantissa != 0 )
		{
			// denorm
			const float half_denorm = (1.0f/16384.0f); // 2^-14
			float mantissa = ((float)(inFloat.bits.mantissa)) / 1024.0f;
			float sgn = (inFloat.bits.sign)? -1.0f :1.0f;
			output.rawFloat = sgn*mantissa*half_denorm;
		}
		else
		{
			// regular number
			unsigned mantissa = inFloat.bits.mantissa;
			unsigned biased_exponent = inFloat.bits.biased_exponent;
			unsigned sign = ((unsigned)inFloat.bits.sign) << 31;
			biased_exponent = ( (biased_exponent - float16bias + float32bias) * (biased_exponent != 0) ) << 23;
			mantissa <<= (23-10);

			*((unsigned *)&output) = ( mantissa | biased_exponent | sign );
		}
		
		return output.rawFloat;
	}


	float16bits m_storage;
};

class float16_with_assign : public float16
{
public:
	float16_with_assign() = default;
	float16_with_assign( float f ) { m_storage.rawWord = ConvertFloatTo16bits(f); }

	float16& operator=(const float16 &other) { m_storage.rawWord = ((float16_with_assign &)other).m_storage.rawWord; return *this; }
	float16& operator=(const float &other) { m_storage.rawWord = ConvertFloatTo16bits(other); return *this; }
//	operator unsigned short () const { return m_storage.rawWord; }
	operator float () const { return Convert16bitFloatTo32bits( m_storage.rawWord ); }
};

//=========================================================
// Fit a 3D vector in 48 bits
//=========================================================

class Vector48
{
public:
	// Construction/destruction:
	Vector48(void) = default;
	Vector48(vec_t X, vec_t Y, vec_t Z) { x.SetFloat( X ); y.SetFloat( Y ); z.SetFloat( Z ); }

	// assignment
	Vector48& operator=(const Vector &vOther);
	operator Vector ();

	const float operator[]( int i ) const { return (((float16 *)this)[i]).GetFloat(); }

	float16 x;
	float16 y;
	float16 z;
};

inline Vector48& Vector48::operator=(const Vector &vOther)	
{
	CHECK_VALID(vOther);

	x.SetFloat( vOther.x );
	y.SetFloat( vOther.y );
	z.SetFloat( vOther.z );
	return *this; 
}


inline Vector48::operator Vector ()
{
	Vector tmp;

	tmp.x = x.GetFloat();
	tmp.y = y.GetFloat();
	tmp.z = z.GetFloat(); 

	return tmp;
}

//=========================================================
// Fit a 2D vector in 32 bits
//=========================================================

class Vector2d32
{
public:
	// Construction/destruction:
	Vector2d32(void) = default;
	Vector2d32(vec_t X, vec_t Y) { x.SetFloat( X ); y.SetFloat( Y ); }

	// assignment
	Vector2d32& operator=(const Vector &vOther);
	Vector2d32& operator=(const Vector2D &vOther);

	operator Vector2D ();

	void Init( vec_t ix = 0.f, vec_t iy = 0.f);

	float16_with_assign x;
	float16_with_assign y;
};

inline Vector2d32& Vector2d32::operator=(const Vector2D &vOther)	
{
	x.SetFloat( vOther.x );
	y.SetFloat( vOther.y );
	return *this; 
}

inline Vector2d32::operator Vector2D ()
{
	Vector2D tmp;

	tmp.x = x.GetFloat();
	tmp.y = y.GetFloat();

	return tmp;
}

inline void Vector2d32::Init( vec_t ix, vec_t iy )
{
	x.SetFloat(ix);
	y.SetFloat(iy);
}

#if defined( _X360 )
#pragma bitfield_order( pop )
#endif

#endif