Shader generating random placed fur strands for displacement

shader_toon_fur.osl

//#define DEBUG 1

void _show_1cell(float z, float x, output float r) {
  float b = 0.01;
  if ((x < b || z < b)) {
    r = 1;
  }
}

float _strand_curve(float x) {
  return pow(abs(x - 0.5) * 2, 1.2);
}

float _cnoise(float z, float x, int i) {
  return noise("cell", point(z, x, i));
}

float _calc_strand(
    float dz, float dx,
    float z, float x, 
    int scale, int i, 
    float slope, int count
) {
  float sdz = dz / scale;
  float sdx = dx / scale;
  float nx = dx * _cnoise(z/dz, x/dx, i) / scale;
  float nz = dz * _cnoise(z/dz, x/dx, i + count) / scale;
  float fz = fmod(z - nz, dz) / sdz; 
  float fx = fmod(x - nx, dx) / sdx;
  if( fz >= 1 || fz < 0 || fx < 0 || fx >= 1) {
    // we must calc only one strand in [0, 1)
    return 0;
  }
  float sc = _strand_curve(fx);
  float f = sin((fz - sc) * M_PI_2) * slope;
  float n = _cnoise(z / dz, x / dx, i + count * 2);
  f *= n;
  f = min(max(f, 0), 1);
  f = f * pow(1 - fz, 2);
  #ifdef DEBUG
  if( abs(fz - sc) <= 0.001) {
    f = 1;
  }
  _show_1cell(fz, fx, f);
  #endif
  return f;
}

shader toon_fur_shader(
    float z = 0 [[
      string label = "Z"
    ]],
    float x = 0 [[
      string label = "X"
    ]],
    float scale = 1 [[
      string label = "Scale"
    ]],
    float slope = 10 [[
      string label = "Slope"
    ]],
    int count = 1 [[
      string label = "Count"
    ]],
    output float out = 0 [[
      string label = "Factor"
    ]]
)
{   
  float dz = scale;
  float dx = scale;
  int cellScale = 2;
  for (int m = 0; m < 2; ++m) {
    for (int n = 0; n < 2; ++n) {
      for (int i = 0; i < count; ++i) {
        out = max(_calc_strand(
          dz, dx, 
          z + m * dz / 2, 
          x + n * dx / 2, 
          cellScale, 
          i + count * n + count * 2 * m, 
          slope,
          count
        ), out);
      }
    }
  }
  #ifdef DEBUG
  _show_1cell(fmod(z, dz), fmod(x, dx), out);
  #endif
}