danger.util
Class Fixed

java.lang.Object
  danger.util.Fixed

public class Fixed
extends Object

Fixed point math library. Precision is 16 bits whole, 16 bits fractional. Uses 32 bit values to represent the Fixed number.

Field Summary

static int	FIXED_ONE Positive one as a fixed point value.
static int	FIXED_ONE_HALF Positive .5 as a fixed point value.
static int	FIXED_PI Pi as a fixed point value.
static int	FIXED_TWO Positive two as a fixed point value.
static int	MAX_VALUE The largest fixed point value.

Constructor Summary

Fixed()

Method Summary

static int	abs(int value) Returns the absolute value of a fixed point number.
static int	acosf(int cosf) Returns the arccosine of a fixed point value.
static int	add(int fvalue1, int fvalue2) Returns the sum of two fixed point values.
static int	asinf(int sinf) Returns the arcsine of a fixed point value.
static int	atanf(int tanf) Returns the arctangent of a fixed point value.
static int	cos(int angle) Returns the cosine of a whole number.
static int	cosf(int fAngle) Returns the cosine of a fixed point value.
static int	divide(int dividend, int divisor) Divides a fixed point value by another fixed point value.
static int	floor(int fValue) Returns the nearest whole number less than or equal to the specified fixed point value.
static int	fromInt(int value) Given an integer value, return a fixed point value.
static int	fromReal(int whole, int dividend, int divisor) Create a fixed point value from a real expression.
static int	getFraction(int fValue) Given a fixed point value, return the fraction.
static int	hypot(int x, int y) Returns the hypotenuse of a right-angled triangle with sides of length x and y.
static int	multiply(int factor1, int factor2) Performs signed multiplication of two fixed point values.
static int	round(int fValue) Returns the whole number nearest to the specified fixed point value.
static int	sin(int angle) Returns the sine of a whole number.
static int	sinf(int fAngle) Returns the sine of a fixed point value.
static int	sqrt(int fValue) Returns the square root of a fixed point value.
static int	subtract(int fvalue1, int fvalue2) Returns the difference of two fixed point values.
static int	tan(int angle) Returns the tangent of a whole number.
static int	tanf(int fAngle) Returns the tangent of a fixed point value.
static int	toInt(int fvalue) Given a fixed point value, return an integer.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FIXED_ONE

public static final int FIXED_ONE

Positive one as a fixed point value.

See Also:

Constant Field Values

FIXED_TWO

public static final int FIXED_TWO

Positive two as a fixed point value.

See Also:

Constant Field Values

FIXED_PI

public static final int FIXED_PI

Pi as a fixed point value.

See Also:

Constant Field Values

MAX_VALUE

public static final int MAX_VALUE

The largest fixed point value.

See Also:

Constant Field Values

FIXED_ONE_HALF

public static final int FIXED_ONE_HALF

Positive .5 as a fixed point value.

See Also:

Constant Field Values

Constructor Detail

Fixed

public Fixed()

Method Detail

fromInt

public static int fromInt(int value)

Given an integer value, return a fixed point value. The value is shifted up 16 bits.

Parameters:

value - the whole number to convert

Returns:

the fixed point value

toInt

public static int toInt(int fvalue)

Given a fixed point value, return an integer. The value is shifted down 16 bits.

Parameters:

fvalue - the fixed point value to convert

Returns:

the whole number

getFraction

public static int getFraction(int fValue)

Given a fixed point value, return the fraction. The high 16 bits of the value are cleared.

Parameters:

fValue - the fixed point value

Returns:

the fraction

fromReal

public static int fromReal(int whole,
                           int dividend,
                           int divisor)

Create a fixed point value from a real expression.

• 5 3/4 would be 5, 3, 4
• -5 3/4 would be -5, 3, 4
• pi 3.14 would be 0, 22, 7
• -pi -3.14 would be 0, -22, 7

Parameters:

whole - the whole number

dividend - the top of the fraction

divisor - the bottom of the fraction

Returns:

the fixed point value

Throws:

IllegalArgumentException - if either dividend or divisor is negative and whole is non-zero

abs

public static int abs(int value)

Returns the absolute value of a fixed point number.

Parameters:

value - the fixed point value

Returns:

the absolute value of value

divide

public static int divide(int dividend,
                         int divisor)

Divides a fixed point value by another fixed point value.

Parameters:

dividend - value divided into

divisor - value divided by

Returns:

the divided, fixed point value

Throws:

ArithmeticException - if divisor is zero

add

public static int add(int fvalue1,
                      int fvalue2)

Returns the sum of two fixed point values.

Parameters:

fvalue1 - the first fixed point value

fvalue2 - the second fixed point value

Returns:

the sum of fvalue1 and fvalue2, as a fixed point value

subtract

public static int subtract(int fvalue1,
                           int fvalue2)

Returns the difference of two fixed point values.

Parameters:

fvalue1 - the first fixed point value

fvalue2 - the second fixed point value

Returns:

the difference of fvalue1 and fvalue2, as a fixed point value

multiply

public static int multiply(int factor1,
                           int factor2)

Performs signed multiplication of two fixed point values.

Parameters:

factor1 - the first fixed point value

factor2 - the second fixed point value

Returns:

the multiplied, fixed point value

sinf

public static int sinf(int fAngle)

Returns the sine of a fixed point value.

Parameters:

fAngle - the fixed point angle in degrees

Returns:

the sine of fAngle as a fixed point value

cosf

public static int cosf(int fAngle)

Returns the cosine of a fixed point value.

Parameters:

fAngle - the fixed point angle in degrees

Returns:

the cosine of fAngle as a fixed point value

tanf

public static int tanf(int fAngle)

Returns the tangent of a fixed point value. The tangent is equal to the sine divided by the cosine.

Parameters:

fAngle - the fixed point angle in degrees

Returns:

the tangent of fAngle as a fixed point value

Throws:

ArithmeticException - if the cosine of fAngle is zero

Since:

4.0

asinf

public static int asinf(int sinf)

Returns the arcsine of a fixed point value. Arcsine converts a sine back to its original value. Therefore, arcsine is defined only for the range of the sine fuction (i.e., -1 to 1, inclusive).

Parameters:

sinf - the fixed point sine value

Returns:

the arcsine of sinf as a fixed point value

Throws:

ArithmeticException - if arcsine is undefined for sinf

Since:

4.0

acosf

public static int acosf(int cosf)

Returns the arccosine of a fixed point value. Arccosine converts a cosine back to its original value. Therefore, arccosine is defined only for the range of the cosine fuction (i.e., -1 to 1, inclusive).

Parameters:

cosf - the fixed point cosine value

Returns:

the arccosine of cosf as a fixed point value

Throws:

ArithmeticException - if arccosine is undefined for cosf

Since:

4.0

atanf

public static int atanf(int tanf)

Returns the arctangent of a fixed point value. Arctangent converts a tangent back to its original value.

Parameters:

tanf - the fixed point tangent value

Returns:

the arctangent of tanf as a fixed point value

Since:

4.0

sin

public static int sin(int angle)

Returns the sine of a whole number.

Parameters:

angle - the angle in degrees

Returns:

the sine of angle as a fixed point value

cos

public static int cos(int angle)

Returns the cosine of a whole number.

Parameters:

angle - the angle in degrees

Returns:

the cosine of angle as a fixed point value

tan

public static int tan(int angle)

Returns the tangent of a whole number. The tangent is equal to the sine divided by the cosine.

Parameters:

angle - the angle in degrees

Returns:

the tangent of angle as a fixed point value

Throws:

ArithmeticException - if the cosine of angle is zero

Since:

4.0

floor

public static int floor(int fValue)

Returns the nearest whole number less than or equal to the specified fixed point value.

Parameters:

fValue - the fixed point value

Returns:

the nearest whole number less than or equal to fValue, as a whole number

round

public static int round(int fValue)

Returns the whole number nearest to the specified fixed point value.

Parameters:

fValue - the fixed point value

Returns:

the nearest whole number to fValue, as a fixed point value

hypot

public static int hypot(int x,
                        int y)

Returns the hypotenuse of a right-angled triangle with sides of length x and y. By the Pythagorean theorem, this is equal to sqrt(x**2 + y**2).

Parameters:

x - length of side x, as a fixed point value

y - length of side y, as a fixed point value

Returns:

the hypotenuse, as a fixed point value

Throws:

IllegalArgumentException - if ((x|y) < 0) || (x > 0x800000) || (y > 0x800000)

sqrt

public static int sqrt(int fValue)

Returns the square root of a fixed point value. The algorithm is less accurate, but faster, than Math.sqrt().

Parameters:

fValue - the fixed point value

Returns:

the square root of fValue, as a fixed point value

Throws:

ArithmeticException - if fValue is less than zero

See Also:

Math.sqrt(double)