Look-up tables

Tonc's internal look-up tables and related routines. More...

Macros
#define	SIN_LUT_SIZE   514
#define	DIV_LUT_SIZE   257

Functions
INLINE s32	lu_sin (uint theta)
	Look-up a sine value (2π = 0x10000)
INLINE s32	lu_cos (uint theta)
	Look-up a cosine value (2π = 0x10000)
INLINE uint	lu_div (uint x)
	Look-up a division value between 0 and 255.
INLINE int	lu_lerp32 (const s32 lut[], uint x, const uint shift)
	Linear interpolator for 32bit LUTs.
INLINE int	lu_lerp16 (const s16 lut[], uint x, const uint shift)
	As lu_lerp32, but for 16bit LUTs.

Variables
s32	div_lut [257]
s16	sin_lut [514]

Detailed Description

Tonc's internal look-up tables and related routines.

Function Documentation

lu_cos()

INLINE s32 lu_cos

(

uint

theta

)

Look-up a cosine value (2π = 0x10000)

Parameters

theta

Angle in [0,FFFFh] range

Returns

.12f cosine value

Referenced by bg_aff_rotate(), bg_aff_rotscale(), bg_aff_rotscale2(), bg_rotscale_ex(), obj_aff_rotate(), obj_aff_rotscale(), obj_aff_rotscale2(), and obj_rotscale_ex().

lu_div()

INLINE uint lu_div

(

uint

x

)

Look-up a division value between 0 and 255.

Parameters

x	reciprocal to look up.

Returns

1/x (.16f)

Referenced by clr_rgbscale().

lu_lerp32()

INLINE int lu_lerp32	(	const s32	lut[],
		uint	x,
		const uint	shift
	)

Linear interpolator for 32bit LUTs.

A lut is essentially the discrete form of a function, f(x). You can get values for non-integer x via (linear) interpolation between f(x) and f(x+1).

Parameters

lut	The LUT to interpolate from.
x	Fixed point number to interpolate at.
shift	Number of fixed-point bits of x.

lu_sin()

INLINE s32 lu_sin

(

uint

theta

)

Look-up a sine value (2π = 0x10000)

Parameters

theta

Angle in [0,FFFFh] range

Returns

.12f sine value

Referenced by bg_aff_rotate(), bg_aff_rotscale(), bg_aff_rotscale2(), bg_rotscale_ex(), obj_aff_rotate(), obj_aff_rotscale(), obj_aff_rotscale2(), and obj_rotscale_ex().