struct CellNoise3D

Structure

CellNoise3D

A type of three-dimensional cellular noise (sometimes called Worley noise, or Voronoi noise), suitable for texturing arbitrary three-dimensional objects.

Unlike many other cell noise implementations, Noise-Swift’s implementation samples all relevant generating-points, preventing artifacts or discontinuities from ever appearing in the noise. Accordingly, Noise-Swift’s implementation is heavily optimized to prevent the additional edge cases from impacting the performance of the cell noise.

Three dimensional cell noise is approximately three to four times slower than its two-dimensional version, but has a vastly superior visual appearance, even when sampled in two dimensions.

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Symbols

Initializers

init(amplitude:Double, frequency:Double, seed:Int = 0)

Creates an instance with the given amplitude, frequency, and random seed values. Creating an instance generates a new pseudo-random permutation table for that instance, and a new instance does not need to be regenerated to sample the same procedural noise field.

The given amplitude is adjusted internally to produce output exactly within the range of 0 ... amplitude. However, in practice the cell noise rarely reaches the maximum threshold, as it is often useful to inflate the amplitude to get the desired appearance.

Instance methods

func closest_point(_ x:Double, _ y:Double, _ z:Double) -> (point:(Int, Int, Int), r2:Double)

Returns the index numbers of the closest feature point to the given coordinate, and the squared distance from the given coordinate to the feature point. These index numbers can be fed to a color hashing function to produce a Voronoi diagram.

func evaluate(_ x:Double, _ y:Double) -> Double

Evaluates the cell noise field at the given x, y coordinates, supplying 0 for the missing z coordinate.

func evaluate(_ x:Double, _ y:Double, _ z:Double) -> Double

Evaluates the cell noise field at the given coordinates.

func evaluate(_ x:Double, _ y:Double, _ z:Double, _:Double) -> Double

Evaluates the cell noise field at the given coordinates. The fourth coordinate is ignored.

func sample_area(width:Int, height:Int) -> [(Double, Double, Double)]

Evaluates the noise field over the given area, starting from the origin, and extending over the first quadrant, taking unit steps in both directions. Although the x and y coordinates are returned, the output vector is guaranteed to be in row-major order.

func sample_area_saturated_to_u8(width:Int, height:Int, offset:Double = 0.5) -> [UInt8]

Evaluates the noise field over the given area, starting from the origin, and extending over the first quadrant, storing the values in a row-major array of samples. The samples are clamped, but not scaled, to the range 0 ... 255.

Relationships

Conforms to

Noise