com.flowpowered.noise

Class Utils

java.lang.Object

com.flowpowered.noise.Utils

public final class Utils
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
static double[]	RANDOM_VECTORS A table of 256 random normalized vectors.

Method Summary

Modifier and Type	Method and Description
static int	clamp(int value, int low, int high) Clamps the value between the low and high boundaries
static double	cubicInterp(double n0, double n1, double n2, double n3, double a) Performs cubic interpolation between two values bound between two other values
static int	floor(double x) Rounds x down to the closest integer
static double[]	latLonToXYZ(double latitude, double longitude)
static double	linearInterp(double n0, double n1, double a) Performs linear interpolation between two values
static double	makeInt32Range(double n) Modifies a floating-point value so that it can be stored in a noise::int32 variable.
static double	sCurve3(double a) Maps a value onto a cubic S-Curve
static double	sCurve5(double a) maps a value onto a quitnic S-Curve

Methods inherited from class java.lang.Object

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

Field Detail

RANDOM_VECTORS

public static final double[] RANDOM_VECTORS

A table of 256 random normalized vectors. Each row is an (x, y, z, 0) coordinate. The 0 is used as padding so we can use bit shifts to index any row in the table. These vectors have an even statistical distribution, which improves the quality of the coherent noise generated by these vectors. For more information, see "GPU Gems", Chapter 5 - Implementing Improved Perlin Noise by Ken Perlin, specifically page 76.

Method Detail

cubicInterp

public static double cubicInterp(double n0,
                                 double n1,
                                 double n2,
                                 double n3,
                                 double a)

Performs cubic interpolation between two values bound between two other values

Parameters:

n0 - the value before the first value

n1 - the first value

n2 - the second value

n3 - the value after the second value

a - the alpha value

Returns:

the interpolated value

linearInterp

public static double linearInterp(double n0,
                                  double n1,
                                  double a)

Performs linear interpolation between two values

Parameters:

n0 - first value

n1 - second value

a - the alpha value. Should be between 0 and 1.

Returns:

the interpolated value

sCurve3

public static double sCurve3(double a)

Maps a value onto a cubic S-Curve

Parameters:

a - the value to map onto a S-Curve

Returns:

the mapped value

sCurve5

public static double sCurve5(double a)

maps a value onto a quitnic S-Curve

Parameters:

a - the value to map onto a quitic S-curve

Returns:

the mapped value

latLonToXYZ

public static double[] latLonToXYZ(double latitude,
                                   double longitude)

makeInt32Range

public static double makeInt32Range(double n)

Modifies a floating-point value so that it can be stored in a noise::int32 variable.

Parameters:

n - A floating-point number.

Returns:

The modified floating-point number.

This function does not modify @a n.

In libnoise, the noise-generating algorithms are all integer-based; they use variables of type noise::int32. Before calling a noise function, pass the @a x, @a y, and @a z coordinates to this function to ensure that these coordinates can be cast to a noise::int32 value.

Although you could do a straight cast from double to noise::int32, the resulting value may differ between platforms. By using this function, you ensure that the resulting value is identical between platforms.

clamp

public static int clamp(int value,
                        int low,
                        int high)

Clamps the value between the low and high boundaries

Parameters:

value - The value to clamp

low - The low bound of the clamp

high - The high bound of the clamp

Returns:

the clamped value

floor

public static int floor(double x)

Rounds x down to the closest integer

Parameters:

x - The value to floor

Returns:

The closest integer