Burger::FracMath Class Reference

Functions to handle Frac point integer math. More...

#include <fxfixed.h>

List of all members.

Static Public Member Functions
static Frac32 BURGER_API	MultiplySaturate (Frac32 fInputMulA, Frac32 fInputMulB)
	Multiply two 2.30 fixed point numbers with saturation.
static Frac32 BURGER_API	DivideSaturate (Frac32 fInputNumerator, Frac32 fInputDenominator)
	Divide a 2.30 fixed point number with saturation.
static Frac32 BURGER_API	CosFromFixed (Fixed32 fRadians)
	Calculate a cosine from a Fixed32 radian value.
static Frac32 BURGER_API	SinFromFixed (Fixed32 fRadians)
	Calculate a sine from a Fixed32 radian value.

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Detailed Description

Functions to handle Frac point integer math.

Not all modern computers have floating point support in hardware, so to get hiogh precision fractional values, a 2.30 integer format is used.

How it works is simple. The upper 2 bits are treated as a 2 bit whole integer while the lower 30 bits represent the numerator of the fraction x/1073741824. Using this method, 1.5f is represented at 0x60000000.

These routines will make it easy to perform conversion of numbers to this numeric type and to handle the most common mathematical operations with 1/1073741824th precision.

Many of these functions are inline or written in assembly language for speed.

See also:

Fixed32, Frac32 or Int32

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Member Function Documentation

Frac32 BURGER_API Burger::FracMath::CosFromFixed

(

Fixed32

fRadians

)

[static]

Calculate a cosine from a Fixed32 radian value.

Given a radian value of Burger::PiFixed32 to - Burger::PiFixed32 return the cosine value as a Frac32 from -1 to 1

Parameters:

fRadians

A Fixed32 value in radians

Returns:

Cosine in Frac32 precision.

Frac32 BURGER_API Burger::FracMath::DivideSaturate	(	Frac32	fInputNumerator,
		Frac32	fInputDenominator
	)		[static]

Divide a 2.30 fixed point number with saturation.

Perform a signed division of two 32-bit fixed point numbers and return the Frac point result. If the answer exceeds the range allowable for a Frac32 value, it will be saturated to the minimum and maximum bounds. Division by zero will return positive or negative maximums.

Parameters:

fInputNumerator	Value to divide
fInputDenominator	Value to divide with

Returns:

Result of fInputNumerator / fInputDenominator with saturation.

See also:

Burger::FixedMath::Divide(Fixed32,Fixed32)

Frac32 BURGER_API Burger::FracMath::MultiplySaturate	(	Frac32	fInputMulA,
		Frac32	fInputMulB
	)		[static]

Multiply two 2.30 fixed point numbers with saturation.

Perform a signed multiplication of two 32-bit frac point numbers and return the frac point result. If the value exceeds the range allowable for a Frac32 value, it will be saturated to the minimum and maximum bounds.

Parameters:

fInputMulA	First signed value to multiply
fInputMulB	Second signed value to multiply

Returns:

Result of fInputMulA * fInputMulB with saturation.

Frac32 BURGER_API Burger::FracMath::SinFromFixed

(

Fixed32

fRadians

)

[static]

Calculate a sine from a Fixed32 radian value.

Given a radian value of Burger::PiFixed32 to - Burger::PiFixed32 return the sine value as a Frac32 from -1 to 1

Parameters:

fRadians

A Fixed32 value in radians

Returns:

Sine in Frac32 precision.