simplex-noise-demo

A web app for trying out texture generation using simplex-noise. Thanks to jwagner/simplex-noise.js ❤️

What's simplex-noise?

Simplex noise is the result of an n-dimensional noise function comparable to Perlin noise ("classic" noise) but with fewer directional artifacts and, in higher dimensions, a lower computational overhead.

https://en.wikipedia.org/wiki/Simplex_noise

Perlin noise is a procedural texture primitive, a type of gradient noise used by visual effects artists to increase the appearance of realism in computer graphics. The function has a pseudo-random appearance, yet all of its visual details are the same size. This property allows it to be readily controllable; multiple scaled copies of Perlin noise can be inserted into mathematical expressions to create a great variety of procedural textures. Synthetic textures using Perlin noise are often used in CGI to make computer-generated visual elements – such as object surfaces, fire, smoke, or clouds – appear more natural, by imitating the controlled random appearance of textures in nature.

https://en.wikipedia.org/wiki/Perlin_noise

Web app

https://gh.s7a.dev/simplex-noise-demo

It uses Math.random, so you'll see a similar but different texture each time you load the page. You can also regenerate it with the reload icon.

Press the gear icon to open the settings screen.

Behavior overview

Several files are in the src folder, but you can understand simplex-noise texture generation by reading NoisePreview.tsx.

export type NoisePreviewProps = {
  width: number
  height: number
  stepX: number
  stepY: number
  cellWidth: number
  cellHeight: number
  simplex: SimplexNoise
}

const NoisePreview: FC<NoisePreviewProps> = ({ width, height, stepX, stepY, cellWidth, cellHeight, simplex }) => {
  return (
    <Box maxW="full">
      {Array.from({ length: height }, (_y, y) => (
        <Flex key={y}>
          {Array.from({ length: width }, (_x, x) => {
            // Convert a value from -1 to 1 to 0 to 1.
            // After that, multiply 0 to 1 by 100 and convert to a percentage.
            const noise = simplex.noise2D(x * stepX, y * stepY)
            return (
              <Tooltip key={x} label={`(${x}, ${y}): ${noise}`} hasArrow placement="top">
                <Box w={cellWidth} h={cellHeight} bg={`hsl(0, 0%, ${(100 * (noise + 1)) / 2.0}%)`} flexShrink={0} />
              </Tooltip>
            )
          })}
        </Flex>
      ))}
    </Box>
  )
}

1. Generate a two-dimensional array by width and height.
2. Run simplex.noise2D(x * stepX, y * stepY) with indexes x and y.
3. simplex#noise2D returns one of the value -1 to 1.
4. Convert the value from 0 to 1 with (noise + 1) / 2.0.
5. hsl needs a percentage, so multiply by 100.

License

This web app is released under the MIT License, see LICENSE.