Fixed.h File Reference

#include "lib/types.h"
#include "maths/Sqrt.h"

Go to the source code of this file.

Classes
class	CFixed< T, max_t, total_bits, int_bits, fract_bits_, fract_pow2 >
	A simple fixed-point number class. More...
struct	std::numeric_limits< CFixed< T, max_t, total_bits, int_bits, fract_bits_, fract_pow2 > >
	std::numeric_limits specialisation, currently just providing min and max More...

Namespaces
	std

Macros
#define	USE_FIXED_OVERFLOW_CHECKS
#define	FIXED_MUL_I64_I32_I32(a, b)   ((i64)(a) * (i64)(b))
#define	CheckSignedSubtractionOverflow(type, left, right, overflowWarning, underflowWarning)
#define	CheckSignedAdditionOverflow(type, left, right, overflowWarning, underflowWarning)
#define	CheckCastOverflow(var, targetType, overflowWarning, underflowWarning)
#define	CheckU32CastOverflow(var, targetType, overflowWarning)
#define	CheckUnsignedAdditionOverflow(result, operand, overflowWarning)
#define	CheckUnsignedSubtractionOverflow(result, left, overflowWarning)
#define	CheckNegationOverflow(var, type, overflowWarning)
#define	CheckMultiplicationOverflow(type, left, right, overflowWarning, underflowWarning)
#define	CheckDivisionOverflow(type, left, right, overflowWarning)   if(right == -1) { CheckNegationOverflow(left, type, overflowWarning) }

Typedefs
typedef CFixed< i32,(i32) 0x7fffffff, 32, 15, 16, 65536 >	CFixed_15_16
	A fixed-point number class with 1-bit sign, 15-bit integral part, 16-bit fractional part. More...
typedef CFixed_15_16	fixed
	Default fixed-point type used by the engine. More...

Functions
template<typename T >
T	round_away_from_zero (float value)
template<typename T >
T	round_away_from_zero (double value)
CFixed_15_16	atan2_approx (CFixed_15_16 y, CFixed_15_16 x)
	Inaccurate approximation of atan2 over fixed-point numbers. More...
void	sincos_approx (CFixed_15_16 a, CFixed_15_16 &sin_out, CFixed_15_16 &cos_out)
	Compute sin(a) and cos(a). More...

Macro Definition Documentation

#define CheckCastOverflow	(		var,
			targetType,
			overflowWarning,
			underflowWarning
	)

Value:

if(var > std::numeric_limits<targetType>::max()) \
		debug_warn(overflowWarning); \
    else if(var < std::numeric_limits<targetType>::min()) \
		debug_warn(underflowWarning);

Definition at line 66 of file Fixed.h.

#define CheckDivisionOverflow	(		type,
			left,
			right,
			overflowWarning
	)		if(right == -1) { CheckNegationOverflow(left, type, overflowWarning) }

Definition at line 92 of file Fixed.h.

#define CheckMultiplicationOverflow	(		type,
			left,
			right,
			overflowWarning,
			underflowWarning
	)

Value:

i64 res##left = (i64)left * (i64)right; \
	CheckCastOverflow(res##left, type, overflowWarning, underflowWarning)

Definition at line 88 of file Fixed.h.

#define CheckNegationOverflow	(		var,
			type,
			overflowWarning
	)

Value:

if(value == std::numeric_limits<type>::min()) \
		debug_warn(overflowWarning);

Definition at line 84 of file Fixed.h.

#define CheckSignedAdditionOverflow	(		type,
			left,
			right,
			overflowWarning,
			underflowWarning
	)

Value:

if(left > 0 && right > 0 && std::numeric_limits<type>::max() - left < right) \
		debug_warn(overflowWarning); \
    else if(left < 0 && right < 0 && std::numeric_limits<type>::min() - left > right) \
		debug_warn(underflowWarning);

Definition at line 60 of file Fixed.h.

#define CheckSignedSubtractionOverflow	(		type,
			left,
			right,
			overflowWarning,
			underflowWarning
	)

Value:

if(left > 0 && right < 0 && left > std::numeric_limits<type>::max() + right) \
		debug_warn(overflowWarning); \
    else if(left < 0 && right > 0 && left < std::numeric_limits<type>::min() + right) \
		debug_warn(underflowWarning);

Definition at line 54 of file Fixed.h.

#define CheckU32CastOverflow	(		var,
			targetType,
			overflowWarning
	)

Value:

if(var > (u32)std::numeric_limits<targetType>::max()) \
		debug_warn(overflowWarning);

Definition at line 72 of file Fixed.h.

#define CheckUnsignedAdditionOverflow	(		result,
			operand,
			overflowWarning
	)

Value:

if(result < operand) \
		debug_warn(overflowWarning);

Definition at line 76 of file Fixed.h.

#define CheckUnsignedSubtractionOverflow	(		result,
			left,
			overflowWarning
	)

Value:

if(result > left) \
		debug_warn(overflowWarning);

Definition at line 80 of file Fixed.h.

#define FIXED_MUL_I64_I32_I32	(		a,
			b
	)		((i64)(a) * (i64)(b))

Definition at line 36 of file Fixed.h.

#define USE_FIXED_OVERFLOW_CHECKS

Definition at line 28 of file Fixed.h.

Typedef Documentation

typedef CFixed<i32, (i32)0x7fffffff, 32, 15, 16, 65536> CFixed_15_16

A fixed-point number class with 1-bit sign, 15-bit integral part, 16-bit fractional part.

Definition at line 334 of file Fixed.h.

typedef CFixed_15_16 fixed

Default fixed-point type used by the engine.

Definition at line 339 of file Fixed.h.

Function Documentation

CFixed_15_16 atan2_approx	(	CFixed_15_16	y,
		CFixed_15_16	x
	)

Inaccurate approximation of atan2 over fixed-point numbers.

Maximum error is almost 0.08 radians (4.5 degrees).

Definition at line 147 of file Fixed.cpp.

template<typename T >

T round_away_from_zero ( float  value )

inline

Definition at line 98 of file Fixed.h.

template<typename T >

T round_away_from_zero ( double  value )

inline

Definition at line 104 of file Fixed.h.

void sincos_approx	(	CFixed_15_16	a,
		CFixed_15_16 &	sin_out,
		CFixed_15_16 &	cos_out
	)

Compute sin(a) and cos(a).

Maximum error for -2pi < a < 2pi is almost 0.0005.

Definition at line 187 of file Fixed.cpp.