Noise in Cairo

2D Perlin Noise - How To Use

Add perlin2D.cairo and its dependency Math64x61.cairo to your project folder, and import noise2D_custom into your project as follows

from perlin2D import noise2D_custom

Then define a new function with your desired parameters:

func my_noise{pedersen_ptr : HashBuiltin*, bitwise_ptr : BitwiseBuiltin*, range_check_ptr}(x, y) -> (noise):
    let (noise) = noise2D_custom((x, y), 100, 69)
    return (noise)
end

About noise2D_custom

• noise2D_custom takes 3 parameters: point, scale, and seed.

• seed can be any felt, and is used to randomize the noise function.

• point is a tuple of two felts: (felt, felt), and should NOT be in 64.61 format. Note that both point[0] and point[1] should be less than 2^64, as they are converted to 64.61 values and may overflow otherwise.

• scale should be a regular (i.e., not in 64.61 format) unsigned felt. scale determines the side lengths of the squares of the grid used to in the noise function. Practically speaking, the larger scale is, the more 'slowly' the noise function varies, and the smaller it is, the faster the noise function varies. So if scale is very large, the difference between noise(x,y) and noise(x, y+1) would very small, and if scale is very small the difference between them would be larger.

• This noise function currently outputs values approximately in the range [-0.707106, 0.707106]. This can easily be normalized to a range of [-1, 1] by multiplying the final output by sqrt(2), or ~1.41421, but this is not done in the function itself for efficiency.

---

3D Simplex Noise - How to use

Add simplex3D.cairo and its dependency Math64x61.cairo to your project folder, and import noise3D_custom into your project as follows:

from simplex3D import noise3D_custom

Then define a new function with your desired parameters:

func my_noise{range_check_ptr}(x, y, z) -> (noise):
    let (noise) = noise3D_custom(x,y,z, 100, 69)
    return (noise)
end

About noise3D_custom

• noise3D_custom takes 5 parameters: the coordinate of a point – x, y, z, a scale factor scale, and a seed seed

• x, y and z should all be less than 2^64, as they are converted to 64.61 bit values and may overflow otherwise. Their upper bound may need to be even less than 2^64, depending on the scale factor you choose. They can be signed (and should be greater than -2^64 in this case).

• scale behaves exactly the same as in noise2D_custom.

• seed behaves exactly the same as in noise2D_custom

• noise3D_custom outputs values between -1 and 1, in 64.61 format.