/******************************************************************************/
/*
  Project   - MudBun
  Publisher - Long Bunny Labs
              http://LongBunnyLabs.com
  Author    - Ming-Lun "Allen" Chou
              http://AllenChou.net

  Based on project "webgl-noise" by Ashima Arts.
  Description : Array and textureless GLSL 2D simplex noise function.
      Author  : Ian McEwan, Ashima Arts.
  Maintainer  : ijm
      Lastmod : 20110822 (ijm)
      License : Copyright (C) 2011 Ashima Arts. All rights reserved.
                Distributed under the MIT License. See LICENSE file.
                https://github.com/ashima/webgl-noise
*/
/******************************************************************************/

#ifndef MUDBUN_CLASSIC_NOISE_3D
#define MUDBUN_CLASSIC_NOISE_3D

#include "NoiseCommon.cginc"
#include "../Math/MathConst.cginc"

// classic Perlin noise
// single octave
float mbn_cnoise(float3 P)
{
  float3 Pi0 = floor(P); // Integer part for indexing
  float3 Pi1 = Pi0 + (float3)1.0; // Integer part + 1
  Pi0 = mbn_mod289(Pi0);
  Pi1 = mbn_mod289(Pi1);
  float3 Pf0 = frac(P); // Fractional part for interpolation
  float3 Pf1 = Pf0 - (float3)1.0; // Fractional part - 1.0
  float4 ix = float4(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
  float4 iy = float4(Pi0.y, Pi0.y, Pi1.y, Pi1.y);
  float4 iz0 = (float4)Pi0.z;
  float4 iz1 = (float4)Pi1.z;

  float4 ixy = mbn_permute(mbn_permute(ix) + iy);
  float4 ixy0 = mbn_permute(ixy + iz0);
  float4 ixy1 = mbn_permute(ixy + iz1);

  float4 gx0 = ixy0 / 7.0;
  float4 gy0 = frac(floor(gx0) / 7.0) - 0.5;
  gx0 = frac(gx0);
  float4 gz0 = (float4)0.5 - abs(gx0) - abs(gy0);
  float4 sz0 = step(gz0, (float4)0.0);
  gx0 -= sz0 * (step((float4)0.0, gx0) - 0.5);
  gy0 -= sz0 * (step((float4)0.0, gy0) - 0.5);

  float4 gx1 = ixy1 / 7.0;
  float4 gy1 = frac(floor(gx1) / 7.0) - 0.5;
  gx1 = frac(gx1);
  float4 gz1 = (float4)0.5 - abs(gx1) - abs(gy1);
  float4 sz1 = step(gz1, (float4)0.0);
  gx1 -= sz1 * (step((float4)0.0, gx1) - 0.5);
  gy1 -= sz1 * (step((float4)0.0, gy1) - 0.5);

  float3 g000 = float3(gx0.x,gy0.x,gz0.x);
  float3 g100 = float3(gx0.y,gy0.y,gz0.y);
  float3 g010 = float3(gx0.z,gy0.z,gz0.z);
  float3 g110 = float3(gx0.w,gy0.w,gz0.w);
  float3 g001 = float3(gx1.x,gy1.x,gz1.x);
  float3 g101 = float3(gx1.y,gy1.y,gz1.y);
  float3 g011 = float3(gx1.z,gy1.z,gz1.z);
  float3 g111 = float3(gx1.w,gy1.w,gz1.w);

  float4 norm0 = mbn_taylorInvSqrt(float4(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
  g000 *= norm0.x;
  g010 *= norm0.y;
  g100 *= norm0.z;
  g110 *= norm0.w;

  float4 norm1 = mbn_taylorInvSqrt(float4(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
  g001 *= norm1.x;
  g011 *= norm1.y;
  g101 *= norm1.z;
  g111 *= norm1.w;

  float n000 = dot(g000, Pf0);
  float n100 = dot(g100, float3(Pf1.x, Pf0.y, Pf0.z));
  float n010 = dot(g010, float3(Pf0.x, Pf1.y, Pf0.z));
  float n110 = dot(g110, float3(Pf1.x, Pf1.y, Pf0.z));
  float n001 = dot(g001, float3(Pf0.x, Pf0.y, Pf1.z));
  float n101 = dot(g101, float3(Pf1.x, Pf0.y, Pf1.z));
  float n011 = dot(g011, float3(Pf0.x, Pf1.y, Pf1.z));
  float n111 = dot(g111, Pf1);

  float3 fade_xyz = mbn_fade(Pf0);
  float4 n_z = lerp(float4(n000, n100, n010, n110), float4(n001, n101, n011, n111), fade_xyz.z);
  float2 n_yz = lerp(n_z.xy, n_z.zw, fade_xyz.y);
  float n_xyz = lerp(n_yz.x, n_yz.y, fade_xyz.x);
  return 2.2 * n_xyz;
}

// multiple octave
DEFINE_NOISE_FUNC_MULTIPLE_OCTAVES(mbn_cnoise, float, float3, 0.5)

// classic Perlin noise, periodic variant
// single octave
float mbn_pnoise(float3 P, float3 rep)
{
  float3 Pi0 = mbn_mod(floor(P), max(kEpsilon, rep));
  float3 Pi1 = mbn_mod(Pi0 + (float3)1.0, max(kEpsilon, rep)); // Integer part + 1, mod period
  float3 Pf0 = frac(P); // Fractional part for interpolation
  float3 Pf1 = Pf0 - (float3)1.0; // Fractional part - 1.0
  float4 ix = float4(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
  float4 iy = float4(Pi0.y, Pi0.y, Pi1.y, Pi1.y);
  float4 iz0 = (float4)Pi0.z;
  float4 iz1 = (float4)Pi1.z;

  float4 ixy = mbn_permute(mbn_permute(ix) + iy);
  float4 ixy0 = mbn_permute(ixy + iz0);
  float4 ixy1 = mbn_permute(ixy + iz1);

  float4 gx0 = ixy0 / 7.0;
  float4 gy0 = frac(floor(gx0) / 7.0) - 0.5;
  gx0 = frac(gx0);
  float4 gz0 = (float4)0.5 - abs(gx0) - abs(gy0);
  float4 sz0 = step(gz0, (float4)0.0);
  gx0 -= sz0 * (step((float4)0.0, gx0) - 0.5);
  gy0 -= sz0 * (step((float4)0.0, gy0) - 0.5);

  float4 gx1 = ixy1 / 7.0;
  float4 gy1 = frac(floor(gx1) / 7.0) - 0.5;
  gx1 = frac(gx1);
  float4 gz1 = (float4)0.5 - abs(gx1) - abs(gy1);
  float4 sz1 = step(gz1, (float4)0.0);
  gx1 -= sz1 * (step((float4)0.0, gx1) - 0.5);
  gy1 -= sz1 * (step((float4)0.0, gy1) - 0.5);

  float3 g000 = float3(gx0.x,gy0.x,gz0.x);
  float3 g100 = float3(gx0.y,gy0.y,gz0.y);
  float3 g010 = float3(gx0.z,gy0.z,gz0.z);
  float3 g110 = float3(gx0.w,gy0.w,gz0.w);
  float3 g001 = float3(gx1.x,gy1.x,gz1.x);
  float3 g101 = float3(gx1.y,gy1.y,gz1.y);
  float3 g011 = float3(gx1.z,gy1.z,gz1.z);
  float3 g111 = float3(gx1.w,gy1.w,gz1.w);

  float4 norm0 = mbn_taylorInvSqrt(float4(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
  g000 *= norm0.x;
  g010 *= norm0.y;
  g100 *= norm0.z;
  g110 *= norm0.w;
  float4 norm1 = mbn_taylorInvSqrt(float4(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
  g001 *= norm1.x;
  g011 *= norm1.y;
  g101 *= norm1.z;
  g111 *= norm1.w;

  float n000 = dot(g000, Pf0);
  float n100 = dot(g100, float3(Pf1.x, Pf0.y, Pf0.z));
  float n010 = dot(g010, float3(Pf0.x, Pf1.y, Pf0.z));
  float n110 = dot(g110, float3(Pf1.x, Pf1.y, Pf0.z));
  float n001 = dot(g001, float3(Pf0.x, Pf0.y, Pf1.z));
  float n101 = dot(g101, float3(Pf1.x, Pf0.y, Pf1.z));
  float n011 = dot(g011, float3(Pf0.x, Pf1.y, Pf1.z));
  float n111 = dot(g111, Pf1);

  float3 fade_xyz = mbn_fade(Pf0);
  float4 n_z = lerp(float4(n000, n100, n010, n110), float4(n001, n101, n011, n111), fade_xyz.z);
  float2 n_yz = lerp(n_z.xy, n_z.zw, fade_xyz.y);
  float n_xyz = lerp(n_yz.x, n_yz.y, fade_xyz.x);
  return 2.2 * n_xyz;
}

// multiple octaves
DEFINE_PERIODIC_NOISE_FUNC_MULTIPLE_OCTAVES(mbn_pnoise, float, float3)

#endif