trig_lut.h File Reference

Fixed point trig functions. Angle can be in the range of -32768 to. More...

#include <nds/ndstypes.h>

Macros
#define	angleToDegrees(angle)   ((angle) * 360 / DEGREES_IN_CIRCLE)
	Converts an angle in the format used by libnds in the 360 degree format.
#define	DEGREES_IN_CIRCLE   (1 << 15)
	Number of degrees in a circle.
#define	degreesToAngle(degrees)   ((degrees) * DEGREES_IN_CIRCLE / 360)
	Convert an angle in 360 degree format to the format used by libnds.
#define	fixedToFloat(n, bits)   (((float)(n)) / (float)(1 << (bits)))
	Converts a fixed point number to a floating point number. More...
#define	fixedToInt(n, bits)   ((int)((n) >> (bits)))
	Convert a fixed point number to an integer. More...
#define	floatToFixed(n, bits)   ((int)((n) * (float)(1 << (bits))))
	Converts a floating point number to a fixed point number. More...
#define	floorFixed(n, bits)   ((int)((n) & ~(((1 << (bits)) - 1))))
	Removes the decimal part of a fixed point number. More...
#define	intToFixed(n, bits)   ((int)((n) << (bits)))
	Converts an integer to a fixed point number. More...

Functions
s16	acosLerp (s16 par)
	Fixed point arccos. More...
s16	asinLerp (s16 par)
	Fixed point arcsin. More...
s16	cosLerp (s16 angle)
	Fixed point cosine. More...
s16	sinLerp (s16 angle)
	Fixed point sine. More...
s32	tanLerp (s16 angle)
	Fixed point tangent. More...

Detailed Description

Fixed point trig functions. Angle can be in the range of -32768 to.

1. There are 32768 degrees in the unit circle used by nds. To convert between standard degrees (360 per circle):

angle = degreesToAngle(angleInDegrees);

or

angle = angleInDegrees * 32768 / 360;

This unit of measure is sometimes refered to as a binary radian (brad) or binary degree. It allows for more precise representation of angle and faster calculation as the DS has no floating point processor.

Macro Definition Documentation

fixedToFloat

#define fixedToFloat	(		n,
			bits
	)		(((float)(n)) / (float)(1 << (bits)))

Converts a fixed point number to a floating point number.

Parameters

n	The fixed point number to convert.
bits	The number of bits used for the decimal part.

Returns

The floating point number.

fixedToInt

#define fixedToInt	(		n,
			bits
	)		((int)((n) >> (bits)))

Convert a fixed point number to an integer.

Parameters

n	The number the number to convert.
bits	The number of bits used for the decimal part.

Returns

The integer part.

floatToFixed

#define floatToFixed	(		n,
			bits
	)		((int)((n) * (float)(1 << (bits))))

Converts a floating point number to a fixed point number.

Parameters

n	The floating point number to convert.
bits	The number of bits used for the decimal part.

Returns

The fixed point number.

floorFixed

#define floorFixed	(		n,
			bits
	)		((int)((n) & ~(((1 << (bits)) - 1))))

Removes the decimal part of a fixed point number.

Parameters

n	The fixed point number.
bits	The number of bits used for the decimal part.

Returns

A fixed point number with 0 as a decimal part.

intToFixed

#define intToFixed	(		n,
			bits
	)		((int)((n) << (bits)))

Converts an integer to a fixed point number.

Parameters

n	The integer to convert.
bits	The number of bits used for the decimal part.

Returns

The fixed point number.

Function Documentation

acosLerp()

s16 acosLerp

(

s16

par

)

Fixed point arccos.

Parameters

par	4.12 fixed point number with the range [-1, 1].

Returns

s16 Angle (-32768 to 32767).

asinLerp()

s16 asinLerp

(

s16

par

)

Fixed point arcsin.

Parameters

par	4.12 fixed point number with the range [-1, 1].

Returns

s16 Angle (-32768 to 32767).

cosLerp()

s16 cosLerp

(

s16

angle

)

Fixed point cosine.

Parameters

angle

Angle (-32768 to 32767).

Returns

4.12 fixed point number with the range [-1, 1].

sinLerp()

s16 sinLerp

(

s16

angle

)

Fixed point sine.

Parameters

angle

Angle (-32768 to 32767).

Returns

4.12 fixed point number with the range [-1, 1].

tanLerp()

s32 tanLerp

(

s16

angle

)

Fixed point tangent.

Parameters

angle

Angle (-32768 to 32767).

Returns

20.12 fixed point number with the range [-81.483, 524287.999].