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A sampled scalar noise field

Source: R/noise_field.R
noise_field.Rd

noise_field bundles the settings needed to sample a scalar-valued noise field from ambient at arbitrary (x, y) positions: which base noise function and fractal combinator to use (ambient::fracture()'s noise/fractal arguments), how coarse or fine the field is (frequency), how many octaves of detail to layer (octaves), and which seed to draw from.

Usage

noise_field(
  noise = ambient::gen_simplex,
  fractal = ambient::fbm,
  frequency = 1,
  octaves = 2L,
  seed = 1L
)

Arguments

noise

A noise-generating function, passed to ambient::fracture()'s noise argument (e.g. ambient::gen_simplex(), ambient::gen_perlin(), ambient::gen_worley()). Default ambient::gen_simplex().

fractal

A fractal combinator function, passed to ambient::fracture()'s fractal argument (e.g. ambient::fbm(), ambient::billow()). Default ambient::fbm().

frequency

Noise frequency. Must be non-negative. Default 1.

octaves

Number of noise octaves. Must be a positive integer. Default 2L.

seed

Integer seed for the noise field. Default 1L.

Details

noise_sample() evaluates a noise_field at a set of positions and rescales the result into a target range – the operation shared by shape_blob()'s radius perturbation and shape_ribbon()/ shape_twist()'s width modulation, factored out here so it isn't duplicated across those three constructors, and so the noise/fractal functions themselves are configurable rather than hardcoded to ambient::gen_simplex()/ambient::fbm().

See also

Other noise helpers: noise_bridge(), noise_sample()

Examples

noise_field(frequency = 2, octaves = 3, seed = 4821)
#> <sketchpad::noise_field>
#>  @ noise    : function (x, y = NULL, z = NULL, t = NULL, frequency = 1, seed = NULL, 
#>     ...)  
#>  @ fractal  : function (base, new, strength, ...)  
#>  @ frequency: num 2
#>  @ octaves  : int 3
#>  @ seed     : int 4821

# a noise_field's effect is easiest to see through a drawable that
# samples it -- lower frequency gives broad, gentle undulation, higher
# frequency a bumpier, more textured one
draw(shape_blob(
  radius = 1,
  range = 0.4,
  distortion = noise_field(frequency = 0.5, seed = 4821)
))

draw(shape_blob(
  radius = 1,
  range = 0.4,
  distortion = noise_field(frequency = 6, seed = 4821)
))


# more octaves layer finer detail on top of the base frequency
draw(shape_blob(
  radius = 1,
  range = 0.4,
  distortion = noise_field(octaves = 6, seed = 4821)
))