lib.rs.html -- source
Description: Source to the Rust file `src\lib.rs`.
Keywords: rust, rustlang, rust-lang

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    //!
    //! Fuss - Small, lightweight simplex noise generator for Rust
    //!
    //! Ported from http://staffwww.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
    //! originally in Java.
    //!

    #![crate_type = "lib"]
    #![crate_name = "fuss"]

    mod test;

    extern crate rand;
    use rand::{thread_rng, SeedableRng, Rng, StdRng};

    // Constants

    // Skew 2D
    const F2 : f32 = 0.366025403;
    // Unskew 2D
    const G2 : f32 = 0.211324865;

    // Skew 3D
    const F3 : f32 = 1.0/3.0;
    // Unskew 3D
    const G3 : f32 = 1.0/6.0;

    const GRAD3: [(i8, i8, i8); 12] = [
      (1, 1, 0), (-1, 1, 0), (1, -1, 0), (-1, -1, 0),
      (1, 0, 1), (-1, 0, 1), (1, 0, -1), (-1, 0, -1),
      (0, 1, 1), (0, -1, 1), (0, 1, -1), (0, -1, -1),
    ];

    // Generate a seed
    #[inline]
    fn generate_seed() -> Vec<usize> {
      thread_rng().gen_iter::<usize>().take(256).collect::<Vec<usize>>()
    }

    ///
    /// Hold the proper permutation tables and methods for generating 2D and 3D noise.
    ///
    /// It is intended for you to get a `Simplex` through `Simplex::new()` since that
    /// creates the necessary permutation tables needed to generate noise.
    ///
    /// Noise generated by `Simplex` is random every time.
    ///
    /// * `seed` - Seed that will be used by `Simplex` to generate it's permutation table
    ///
    pub struct Simplex {

      pub seed: Vec<usize>,

      perm: Vec<u8>,

    }

    impl Simplex {

      ///
      /// Return a new `Simplex` with a new random permutation table
      ///
      /// Necessary to generate the proper permutation tables (GRAD3)
      /// used by `noise_2d()` and `noise_3d`.
      ///
      /// # Examples
      ///
      /// ```
      /// use fuss::Simplex;
      ///
      /// let sn = Simplex::new();
      /// ```
      ///
      pub fn new() -> Simplex {

        return Simplex::from_seed(generate_seed());

      }

      ///
      /// Seed the random number generator with a specific
      /// seed
      ///
      /// A seed is just a vector of usizes that will be passed into
      /// `StdRng::from_seed` as a slice.
      ///
      /// # Examples
      ///
      /// ```
      /// use fuss::Simplex;
      ///
      /// let mut sn = Simplex::from_seed(vec![1, 2, 3]);
      /// let mut other_sn = Simplex::from_seed(vec![1, 2, 3]);
      ///
      /// assert_eq!(other_sn.noise_2d(1.0, 14.2), sn.noise_2d(1.0, 14.2));
      /// assert_eq!(other_sn.noise_3d(1.0, 14.2, -5.4), sn.noise_3d(1.0, 14.2, -5.4));
      ///
      /// sn = Simplex::from_seed(vec![4, 5, 6]);
      /// let mut other_sn = Simplex::from_seed(vec![1, 2, 3]);
      /// assert!(other_sn.noise_2d(1.0, 14.2) != sn.noise_2d(1.0, 14.2));
      /// assert!(other_sn.noise_3d(1.0, 14.2, -5.4) != sn.noise_3d(1.0, 14.2, -5.4));
      /// ```
      ///
      pub fn from_seed(seed: Vec<usize>) -> Simplex {
        let mut sn = Simplex {
          seed: seed,
          perm: Vec::new() // Gets overwritten
        };
        sn.generate_perms();
        return sn;
      }

      ///
      /// Generate the permutation table
      ///
      /// This method will overwrite the `Simplex`'s current `perm` vector
      /// with another random permutation table used by `noise_2d()` and
      /// `noise_3d`
      ///
      fn generate_perms(&mut self) {
        let p : Vec<u8> = StdRng::from_seed(&self.seed).gen_iter().take(256).collect::<Vec<u8>>();
        self.perm = Vec::<u8>::new();
        for i in 0..512 {
          self.perm.push(p[(i & 255) as usize]);
        }
      }

      ///
      /// Find dot product of a vector in 2 dimensions
      ///
      #[inline]
      fn dot2(&self, g: (i8, i8, i8), x: f32, y: f32) -> f32 {
        g.0 as f32 * x + g.1 as f32 * y
      }

      ///
      /// Find dot product of a vector in 3 dimensions
      ///
      #[inline]
      fn dot3(&self, g: (i8, i8, i8), x: f32, y: f32, z: f32) -> f32 {
        g.0 as f32 * x + g.1 as f32 * y + g.2 as f32 * z
      }

      ///
      /// Smooth the output from `noise_2d` based on fractal Brownian motion.
      ///
      /// Returns an f32 in [-1, 1]
      ///
      /// # Examples
      ///
      /// ```
      /// use fuss::Simplex;
      ///
      /// let sn = Simplex::new();
      ///
      /// let mut luminance = Vec::<Vec<f32>>::new();
      /// for x in 0..100 {
      ///   luminance.push(Vec::<f32>::new());
      ///   for y in 0..100 {
      ///     luminance[x as usize].push(sn.sum_octave_2d(16, x as f32, y as f32, 0.5, 0.008));
      ///   }
      /// }
      /// ```
      ///
      pub fn sum_octave_2d(&self, num_iterations: i32, xin: f32, yin: f32, persistence : f32, scale : f32) -> f32 {

        let mut max_amp = 0.0;
        let mut amp = 1.0;
        let mut freq = scale;
        let mut noise = 0.0;

        // Add successively smaller, higher-frequency terms
        for _ in 0..num_iterations {
          noise += self.noise_2d(xin * freq, yin * freq) * amp;
          max_amp += amp;
          amp *= persistence;
          freq *= 2.0;
        }

        // Take the average value of the iterations
        return noise / max_amp;

      }

      ///
      /// Smooth the output from `noise_3d` based on fractal Brownian motion.
      ///
      /// Returns an f32 in [-1, 1]
      ///
      /// # Examples
      ///
      /// ```
      /// use fuss::Simplex;
      ///
      /// let sn = Simplex::new();
      ///
      /// let mut luminance = Vec::<Vec<Vec<f32>>>::new();
      /// for x in 0..10 {
      ///   luminance.push(Vec::<Vec<f32>>::new());
      ///   for y in 0..10 {
      ///     luminance[x as usize].push(Vec::<f32>::new());
      ///     for z in 0..10 {
      ///       luminance[x as usize][y as usize].push(sn.sum_octave_3d(16, x as f32, y as f32, z as f32, 0.5, 0.008));
      ///     }
      ///   }
      /// }
      /// ```
      ///
      pub fn sum_octave_3d(&self, num_iterations: i32, xin: f32, yin: f32, zin: f32, persistence : f32, scale : f32) -> f32 {

        let mut max_amp = 0.0;
        let mut amp = 1.0;
        let mut freq = scale;
        let mut noise = 0.0;

        // Add successively smaller, higher-frequency terms
        for _ in 0..num_iterations {
          noise += self.noise_3d(xin * freq, yin * freq, zin * freq) * amp;
          max_amp += amp;
          amp *= persistence;
          freq *= 2.0;
        }

        // Take the average value of the iterations
        return noise / max_amp;

      }

      ///
      /// Generate 2D simplex noise for a specific point
      ///
      /// Returns an f32 in [-1, 1].
      ///
      /// # Examples
      ///
      /// ```
      /// use fuss::Simplex;
      ///
      /// let sn = Simplex::from_seed(vec![5, 3, 2, 1, 1]);
      /// println!("{}", sn.noise_2d(50.1912, 30.50102));
      ///
      /// // Simplex will return the same thing for the same points
      /// assert_eq!(sn.noise_2d(1.5, -0.5), sn.noise_2d(1.5, -0.5));
      ///
      /// let other_sn = Simplex::from_seed(vec![0, 1, 2, 3, 4, 5]);
      ///
      /// // However each `Simplex` has it's own set of permutations, therefore
      /// // each one is different. If you want consistency, try the `from_seed()` method.
      /// assert!(sn.noise_2d(1.5, -0.5) != other_sn.noise_2d(1.5, -0.5));
      /// ```
      ///
      pub fn noise_2d(&self, xin: f32, yin: f32) -> f32 {

        // Noise contributions from the three corners
        let n0 : f32;
        let n1 : f32;
        let n2 : f32;

        // Hairy factor for 2D
        let s = (xin + yin) * F2;
        let i = (xin + s).floor() as i32;
        let j = (yin + s).floor() as i32;

        let t = (i + j) as f32 * G2;

        // Unskew the cell origin back to (x,y) space
        // and get he x,y distances from the cell origin
        let x0 = xin - (i as f32 - t);
        let y0 = yin - (j as f32 - t);

        // For the 2D case, the simplex shape is an equilateral triangle.
        // Determine which simplex we are in.

        // Offsets for second (middle) corner of simplex in (i,j) coords
        let i1 : i32;
        let j1 : i32;

        // lower triangle, XY order: (0,0)->(1,0)->(1,1)
        if x0 > y0 {
          i1 = 1;
          j1 = 0;
        }
        // upper triangle, YX order: (0,0)->(0,1)->(1,1)
        else {
          i1 = 0;
          j1 = 1;
        }

        // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
        // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
        // c = (3-sqrt(3))/6

        // Offsets for middle corner in (x,y) unskewed coords
        let x1 = x0 - i1 as f32 + G2;
        let y1 = y0 - j1 as f32 + G2;

        // Offsets for last corner in (x,y) unskewed coords
        let x2 = x0 - 1.0 + 2.0 * G2;
        let y2 = y0 - 1.0 + 2.0 * G2;

        // Work out the hashed gradient indices of the three simplex corners
        let ii = i & 255;
        let jj = j & 255;
        let gi0 = self.perm[(ii +    self.perm[jj as usize] as i32) as usize ] % 12;
        let gi1 = self.perm[(ii + i1 + self.perm[(jj + j1) as usize] as i32) as usize ] % 12;
        let gi2 = self.perm[(ii + 1 + self.perm[ (jj + 1) as usize] as i32) as usize] % 12;

        let mut t0 = 0.5 - x0*x0-y0*y0;
        if t0 < 0.0 {
          n0 = 0.0;
        } else {
          t0 *= t0;
          n0 = t0 * t0 * self.dot2(GRAD3[gi0 as usize], x0, y0);
        }

        let mut t1 = 0.5 - x1*x1-y1*y1;
        if t1 < 0. {
          n1 = 0.0;
        } else {
          t1 *= t1;
          n1 = t1 * t1 * self.dot2(GRAD3[gi1 as usize], x1, y1);
        }

        let mut t2 = 0.5 - x2*x2-y2*y2;
        if t2 < 0.0 {
          n2 = 0.0;
        }
        else {
          t2 *= t2;
          n2 = t2 * t2 * self.dot2(GRAD3[gi2 as usize], x2, y2);
        }

        // Add contributions from each corner to get the final noise value.
        // The result is scaled to return values in the interval [-1,1].
        return 70.0 * (n0 + n1 + n2);

      }

      ///
      /// Generate 3D simplex noise for a specific point
      ///
      /// Returns an f32 in [-1, 1].
      ///
      /// # Examples
      ///
      /// ```
      /// use fuss::Simplex;
      ///
      /// let sn = Simplex::new();
      /// println!("{}", sn.noise_2d(50.1912, 30.50102));
      ///
      /// // Simplex will return the same thing for the same points
      /// assert_eq!(sn.noise_3d(1.5, -0.5, 2.1), sn.noise_3d(1.5, -0.5, 2.1));
      ///
      /// let other_sn = Simplex::new();
      ///
      /// // However each `Simplex` has it's own set of permutations, therefore
      /// // each one is different. If you want consistency, try the `from_seed()` method.
      /// assert!(sn.noise_3d(1.5, -0.5, 2.1) != other_sn.noise_3d(1.5, -0.5, 2.1));
      /// ```
      ///
      pub fn noise_3d(&self, xin: f32, yin: f32, zin: f32) -> f32 {

        // Noise contributions from the four corners
        let n0 : f32;
        let n1 : f32;
        let n2 : f32;
        let n3 : f32;

        // Very nice and simple skew factor for 3D
        let s = (xin + yin + zin) * F3;
        let i = (xin + s).floor();
        let j = (yin + s).floor();
        let k = (zin + s).floor();

        // Unskew the cell origin back to (x,y,z) space
        let t = (i + j + k) * G3;

        // The x,y,z distances from the cell origin
        let x0 = xin - (i - t);
        let y0 = yin - (j - t);
        let z0 = zin - (k - t);

        // For the 3D case, the simplex shape is a slightly
        // irregular tetrahedron.

        // Determine which simplex we are in.

        // Offsets for second corner of simplex in (i,j,k) coords
        let i1 : i32;
        let j1 : i32;
        let k1 : i32;

        // Offsets for third corner of simplex in (i,j,k) coords
        let i2 : i32;
        let j2 : i32;
        let k2 : i32;

        if x0 >= y0 {
          if y0 >= z0 {
            // X Y Z order
            i1 = 1;
            j1 = 0;
            k1 = 0;
            i2 = 1;
            j2 = 1;
            k2 = 0;
          } else if x0 >= z0 {
            // X Z Y order
            i1=1;
            j1=0;
            k1=0;
            i2=1;
            j2=0;
            k2=1;
          } else {
            // Z X Y order
            i1=0;
            j1=0;
            k1=1;
            i2=1;
            j2=0;
            k2=1;
          }
        }
        // x0 < y0
        else {
          if y0 < z0 {
            // Z Y X order
            i1=0;
            j1=0;
            k1=1;
            i2=0;
            j2=1;
            k2=1;
          } else if x0 < z0 {
            // Y Z X order
            i1=0;
            j1=1;
            k1=0;
            i2=0;
            j2=1;
            k2=1;
          } else {
            // Y X Z order
            i1=0;
            j1=1;
            k1=0;
            i2=1;
            j2=1;
            k2=0;
          }
        }

        // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
        // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
        // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
        // c = 1/6.

        // Offsets for second corner in (x,y,z) coords
        let x1 = x0 - i1 as f32 + G3;
        let y1 = y0 - j1 as f32 + G3;
        let z1 = z0 - k1 as f32 + G3;

        // Offsets for third corner in (x,y,z) coords
        let x2 = x0 - i2 as f32 + 2.0*G3;
        let y2 = y0 - j2 as f32 + 2.0*G3;
        let z2 = z0 - k2 as f32 + 2.0*G3;

        // Offsets for last corner in (x,y,z) coords
        let x3 = x0 - 1.0 + 3.0*G3;
        let y3 = y0 - 1.0 + 3.0*G3;
        let z3 = z0 - 1.0 + 3.0*G3;

        // Work out the hashed gradient indices of the four simplex corners
        let ii = i as i32 & 255;
        let jj = j as i32 & 255;
        let kk = k as i32 & 255;

        let gi0 = self.perm[(ii + self.perm[(jj + self.perm[kk as usize] as i32) as usize] as i32) as usize] % 12;
        let gi1 = self.perm[(ii + i1 + self.perm[(jj + j1 + self.perm[(kk + k1) as usize] as i32) as usize] as i32) as usize] % 12;
        let gi2 = self.perm[(ii + i2 + self.perm[(jj + j2 + self.perm[(kk + k2) as usize] as i32) as usize] as i32) as usize] % 12;
        let gi3 = self.perm[(ii + 1 + self.perm [(jj + 1 + self.perm[kk as usize + 1] as i32) as usize] as i32) as usize] % 12;

        // Calculate the contribution from the four corners
        let mut t0 = 0.6 - x0*x0 - y0*y0 - z0*z0;
        if t0 < 0.0 {
          n0 = 0.0;
        }
        else {
          t0 *= t0;
          n0 = t0 * t0 * self.dot3(GRAD3[gi0 as usize], x0, y0, z0);
        }
        let mut t1 = 0.6 - x1*x1 - y1*y1 - z1*z1;
        if t1 < 0.0 {
          n1 = 0.0;
        } else {
          t1 *= t1;
          n1 = t1 * t1 * self.dot3(GRAD3[gi1 as usize], x1, y1, z1);
        }

        let mut t2 = 0.6 - x2*x2 - y2*y2 - z2*z2;
        if t2 < 0.0 {
          n2 = 0.0;
        }
        else {
          t2 *= t2;
          n2 = t2 * t2 * self.dot3(GRAD3[gi2 as usize], x2, y2, z2);
        }

        let mut t3 = 0.6 - x3*x3 - y3*y3 - z3*z3;
        if t3 < 0.0 {
          n3 = 0.0;
        } else {
          t3 *= t3;
          n3 = t3 * t3 * self.dot3(GRAD3[gi3 as usize], x3, y3, z3);
        }

        // Add contributions from each corner to get the final noise value.
        // The result is scaled to stay just inside [-1,1]
        return 32.0*(n0 + n1 + n2 + n3);

      }

    }

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