Function noise

tutorials/common/tutorial/noise.cpp:74–83

  }
  
  float noise(float x) 
  {
    float fx = floorf(x);
    int X = (int)fx & 255;
    x -= fx;
    float u = fade(x);
    float g00 = grad(p[X  ],x  );
    float g10 = grad(p[X+1],x-1);
    return mylerp(u,g00,g10);
  }
  
  float noise(float x, float y) 
  {