/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "node_hash.h"
#include "stdcycles.h"
#include "vector2.h"
#include "vector4.h"

#define vector3 point

/* **** Distance Functions **** */

float distance(float a, float b)
{
  return abs(a - b);
}

float distance(vector2 a, vector2 b)
{
  return length(a - b);
}

float distance(vector4 a, vector4 b)
{
  return length(a - b);
}

/* **** Safe Division **** */

vector2 safe_divide(vector2 a, float b)
{
  return vector2((b != 0.0) ? a.x / b : 0.0, (b != 0.0) ? a.y / b : 0.0);
}

vector4 safe_divide(vector4 a, float b)
{
  return vector4((b != 0.0) ? a.x / b : 0.0,
                 (b != 0.0) ? a.y / b : 0.0,
                 (b != 0.0) ? a.z / b : 0.0,
                 (b != 0.0) ? a.w / b : 0.0);
}

/*
 * Original code is under the MIT License, Copyright (c) 2013 Inigo Quilez.
 *
 * Smooth Voronoi:
 * - https://wiki.blender.org/wiki/User:OmarSquircleArt/GSoC2019/Documentation/Smooth_Voronoi
 *
 * Distance To Edge based on:
 *
 * - https://www.iquilezles.org/www/articles/voronoilines/voronoilines.htm
 * - https://www.shadertoy.com/view/ldl3W8
 *
 * With optimization to change -2..2 scan window to -1..1 for better performance,
 * as explained in https://www.shadertoy.com/view/llG3zy.
 */

/* **** 1D Voronoi **** */

float voronoi_distance(float a, float b, string metric, float exponent)
{
  return abs(a - b);
}

void voronoi_f1_1d(float w,
                   float exponent,
                   float randomness,
                   string metric,
                   output float outDistance,
                   output color outColor,
                   output float outW)
{
  float cellPosition = floor(w);
  float localPosition = w - cellPosition;

  float minDistance = 8.0;
  float targetOffset, targetPosition;
  for (int i = -1; i <= 1; i++) {
    float cellOffset = float(i);
    float pointPosition = cellOffset + hash_float_to_float(cellPosition + cellOffset) * randomness;
    float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
    if (distanceToPoint < minDistance) {
      targetOffset = cellOffset;
      minDistance = distanceToPoint;
      targetPosition = pointPosition;
    }
  }
  outDistance = minDistance;
  outColor = hash_float_to_color(cellPosition + targetOffset);
  outW = targetPosition + cellPosition;
}

void voronoi_smooth_f1_1d(float w,
                          float smoothness,
                          float exponent,
                          float randomness,
                          string metric,
                          output float outDistance,
                          output color outColor,
                          output float outW)
{
  float cellPosition = floor(w);
  float localPosition = w - cellPosition;

  float smoothDistance = 8.0;
  float smoothPosition = 0.0;
  color smoothColor = color(0.0);
  for (int i = -2; i <= 2; i++) {
    float cellOffset = float(i);
    float pointPosition = cellOffset + hash_float_to_float(cellPosition + cellOffset) * randomness;
    float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
    float h = smoothstep(0.0, 1.0, 0.5 + 0.5 * (smoothDistance - distanceToPoint) / smoothness);
    float correctionFactor = smoothness * h * (1.0 - h);
    smoothDistance = mix(smoothDistance, distanceToPoint, h) - correctionFactor;
    correctionFactor /= 1.0 + 3.0 * smoothness;
    color cellColor = hash_float_to_color(cellPosition + cellOffset);
    smoothColor = mix(smoothColor, cellColor, h) - correctionFactor;
    smoothPosition = mix(smoothPosition, pointPosition, h) - correctionFactor;
  }
  outDistance = smoothDistance;
  outColor = smoothColor;
  outW = cellPosition + smoothPosition;
}

void voronoi_f2_1d(float w,
                   float exponent,
                   float randomness,
                   string metric,
                   output float outDistance,
                   output color outColor,
                   output float outW)
{
  float cellPosition = floor(w);
  float localPosition = w - cellPosition;

  float distanceF1 = 8.0;
  float distanceF2 = 8.0;
  float offsetF1 = 0.0;
  float positionF1 = 0.0;
  float offsetF2, positionF2;
  for (int i = -1; i <= 1; i++) {
    float cellOffset = float(i);
    float pointPosition = cellOffset + hash_float_to_float(cellPosition + cellOffset) * randomness;
    float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
    if (distanceToPoint < distanceF1) {
      distanceF2 = distanceF1;
      distanceF1 = distanceToPoint;
      offsetF2 = offsetF1;
      offsetF1 = cellOffset;
      positionF2 = positionF1;
      positionF1 = pointPosition;
    }
    else if (distanceToPoint < distanceF2) {
      distanceF2 = distanceToPoint;
      offsetF2 = cellOffset;
      positionF2 = pointPosition;
    }
  }
  outDistance = distanceF2;
  outColor = hash_float_to_color(cellPosition + offsetF2);
  outW = positionF2 + cellPosition;
}

void voronoi_distance_to_edge_1d(float w, float randomness, output float outDistance)
{
  float cellPosition = floor(w);
  float localPosition = w - cellPosition;

  float midPointPosition = hash_float_to_float(cellPosition) * randomness;
  float leftPointPosition = -1.0 + hash_float_to_float(cellPosition - 1.0) * randomness;
  float rightPointPosition = 1.0 + hash_float_to_float(cellPosition + 1.0) * randomness;
  float distanceToMidLeft = distance((midPointPosition + leftPointPosition) / 2.0, localPosition);
  float distanceToMidRight = distance((midPointPosition + rightPointPosition) / 2.0,
                                      localPosition);

  outDistance = min(distanceToMidLeft, distanceToMidRight);
}

void voronoi_n_sphere_radius_1d(float w, float randomness, output float outRadius)
{
  float cellPosition = floor(w);
  float localPosition = w - cellPosition;

  float closestPoint;
  float closestPointOffset;
  float minDistance = 8.0;
  for (int i = -1; i <= 1; i++) {
    float cellOffset = float(i);
    float pointPosition = cellOffset + hash_float_to_float(cellPosition + cellOffset) * randomness;
    float distanceToPoint = distance(pointPosition, localPosition);
    if (distanceToPoint < minDistance) {
      minDistance = distanceToPoint;
      closestPoint = pointPosition;
      closestPointOffset = cellOffset;
    }
  }

  minDistance = 8.0;
  float closestPointToClosestPoint;
  for (int i = -1; i <= 1; i++) {
    if (i == 0) {
      continue;
    }
    float cellOffset = float(i) + closestPointOffset;
    float pointPosition = cellOffset + hash_float_to_float(cellPosition + cellOffset) * randomness;
    float distanceToPoint = distance(closestPoint, pointPosition);
    if (distanceToPoint < minDistance) {
      minDistance = distanceToPoint;
      closestPointToClosestPoint = pointPosition;
    }
  }
  outRadius = distance(closestPointToClosestPoint, closestPoint) / 2.0;
}

/* **** 2D Voronoi **** */

float voronoi_distance(vector2 a, vector2 b, string metric, float exponent)
{
  if (metric == "euclidean") {
    return distance(a, b);
  }
  else if (metric == "manhattan") {
    return abs(a.x - b.x) + abs(a.y - b.y);
  }
  else if (metric == "chebychev") {
    return max(abs(a.x - b.x), abs(a.y - b.y));
  }
  else if (metric == "minkowski") {
    return pow(pow(abs(a.x - b.x), exponent) + pow(abs(a.y - b.y), exponent), 1.0 / exponent);
  }
  else {
    return 0.0;
  }
}

void voronoi_f1_2d(vector2 coord,
                   float exponent,
                   float randomness,
                   string metric,
                   output float outDistance,
                   output color outColor,
                   output vector2 outPosition)
{
  vector2 cellPosition = floor(coord);
  vector2 localPosition = coord - cellPosition;

  float minDistance = 8.0;
  vector2 targetOffset, targetPosition;
  for (int j = -1; j <= 1; j++) {
    for (int i = -1; i <= 1; i++) {
      vector2 cellOffset = vector2(i, j);
      vector2 pointPosition = cellOffset +
                              hash_vector2_to_vector2(cellPosition + cellOffset) * randomness;
      float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
      if (distanceToPoint < minDistance) {
        targetOffset = cellOffset;
        minDistance = distanceToPoint;
        targetPosition = pointPosition;
      }
    }
  }
  outDistance = minDistance;
  outColor = hash_vector2_to_color(cellPosition + targetOffset);
  outPosition = targetPosition + cellPosition;
}

void voronoi_smooth_f1_2d(vector2 coord,
                          float smoothness,
                          float exponent,
                          float randomness,
                          string metric,
                          output float outDistance,
                          output color outColor,
                          output vector2 outPosition)
{
  vector2 cellPosition = floor(coord);
  vector2 localPosition = coord - cellPosition;

  float smoothDistance = 8.0;
  color smoothColor = color(0.0);
  vector2 smoothPosition = vector2(0.0, 0.0);
  for (int j = -2; j <= 2; j++) {
    for (int i = -2; i <= 2; i++) {
      vector2 cellOffset = vector2(i, j);
      vector2 pointPosition = cellOffset +
                              hash_vector2_to_vector2(cellPosition + cellOffset) * randomness;
      float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
      float h = smoothstep(0.0, 1.0, 0.5 + 0.5 * (smoothDistance - distanceToPoint) / smoothness);
      float correctionFactor = smoothness * h * (1.0 - h);
      smoothDistance = mix(smoothDistance, distanceToPoint, h) - correctionFactor;
      correctionFactor /= 1.0 + 3.0 * smoothness;
      color cellColor = hash_vector2_to_color(cellPosition + cellOffset);
      smoothColor = mix(smoothColor, cellColor, h) - correctionFactor;
      smoothPosition = mix(smoothPosition, pointPosition, h) - correctionFactor;
    }
  }
  outDistance = smoothDistance;
  outColor = smoothColor;
  outPosition = cellPosition + smoothPosition;
}

void voronoi_f2_2d(vector2 coord,
                   float exponent,
                   float randomness,
                   string metric,
                   output float outDistance,
                   output color outColor,
                   output vector2 outPosition)
{
  vector2 cellPosition = floor(coord);
  vector2 localPosition = coord - cellPosition;

  float distanceF1 = 8.0;
  float distanceF2 = 8.0;
  vector2 offsetF1 = vector2(0.0, 0.0);
  vector2 positionF1 = vector2(0.0, 0.0);
  vector2 offsetF2, positionF2;
  for (int j = -1; j <= 1; j++) {
    for (int i = -1; i <= 1; i++) {
      vector2 cellOffset = vector2(i, j);
      vector2 pointPosition = cellOffset +
                              hash_vector2_to_vector2(cellPosition + cellOffset) * randomness;
      float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
      if (distanceToPoint < distanceF1) {
        distanceF2 = distanceF1;
        distanceF1 = distanceToPoint;
        offsetF2 = offsetF1;
        offsetF1 = cellOffset;
        positionF2 = positionF1;
        positionF1 = pointPosition;
      }
      else if (distanceToPoint < distanceF2) {
        distanceF2 = distanceToPoint;
        offsetF2 = cellOffset;
        positionF2 = pointPosition;
      }
    }
  }
  outDistance = distanceF2;
  outColor = hash_vector2_to_color(cellPosition + offsetF2);
  outPosition = positionF2 + cellPosition;
}

void voronoi_distance_to_edge_2d(vector2 coord, float randomness, output float outDistance)
{
  vector2 cellPosition = floor(coord);
  vector2 localPosition = coord - cellPosition;

  vector2 vectorToClosest;
  float minDistance = 8.0;
  for (int j = -1; j <= 1; j++) {
    for (int i = -1; i <= 1; i++) {
      vector2 cellOffset = vector2(i, j);
      vector2 vectorToPoint = cellOffset +
                              hash_vector2_to_vector2(cellPosition + cellOffset) * randomness -
                              localPosition;
      float distanceToPoint = dot(vectorToPoint, vectorToPoint);
      if (distanceToPoint < minDistance) {
        minDistance = distanceToPoint;
        vectorToClosest = vectorToPoint;
      }
    }
  }

  minDistance = 8.0;
  for (int j = -1; j <= 1; j++) {
    for (int i = -1; i <= 1; i++) {
      vector2 cellOffset = vector2(i, j);
      vector2 vectorToPoint = cellOffset +
                              hash_vector2_to_vector2(cellPosition + cellOffset) * randomness -
                              localPosition;
      vector2 perpendicularToEdge = vectorToPoint - vectorToClosest;
      if (dot(perpendicularToEdge, perpendicularToEdge) > 0.0001) {
        float distanceToEdge = dot((vectorToClosest + vectorToPoint) / 2.0,
                                   normalize(perpendicularToEdge));
        minDistance = min(minDistance, distanceToEdge);
      }
    }
  }
  outDistance = minDistance;
}

void voronoi_n_sphere_radius_2d(vector2 coord, float randomness, output float outRadius)
{
  vector2 cellPosition = floor(coord);
  vector2 localPosition = coord - cellPosition;

  vector2 closestPoint;
  vector2 closestPointOffset;
  float minDistance = 8.0;
  for (int j = -1; j <= 1; j++) {
    for (int i = -1; i <= 1; i++) {
      vector2 cellOffset = vector2(i, j);
      vector2 pointPosition = cellOffset +
                              hash_vector2_to_vector2(cellPosition + cellOffset) * randomness;
      float distanceToPoint = distance(pointPosition, localPosition);
      if (distanceToPoint < minDistance) {
        minDistance = distanceToPoint;
        closestPoint = pointPosition;
        closestPointOffset = cellOffset;
      }
    }
  }

  minDistance = 8.0;
  vector2 closestPointToClosestPoint;
  for (int j = -1; j <= 1; j++) {
    for (int i = -1; i <= 1; i++) {
      if (i == 0 && j == 0) {
        continue;
      }
      vector2 cellOffset = vector2(i, j) + closestPointOffset;
      vector2 pointPosition = cellOffset +
                              hash_vector2_to_vector2(cellPosition + cellOffset) * randomness;
      float distanceToPoint = distance(closestPoint, pointPosition);
      if (distanceToPoint < minDistance) {
        minDistance = distanceToPoint;
        closestPointToClosestPoint = pointPosition;
      }
    }
  }
  outRadius = distance(closestPointToClosestPoint, closestPoint) / 2.0;
}

/* **** 3D Voronoi **** */

float voronoi_distance(vector3 a, vector3 b, string metric, float exponent)
{
  if (metric == "euclidean") {
    return distance(a, b);
  }
  else if (metric == "manhattan") {
    return abs(a[0] - b[0]) + abs(a[1] - b[1]) + abs(a[2] - b[2]);
  }
  else if (metric == "chebychev") {
    return max(abs(a[0] - b[0]), max(abs(a[1] - b[1]), abs(a[2] - b[2])));
  }
  else if (metric == "minkowski") {
    return pow(pow(abs(a[0] - b[0]), exponent) + pow(abs(a[1] - b[1]), exponent) +
                   pow(abs(a[2] - b[2]), exponent),
               1.0 / exponent);
  }
  else {
    return 0.0;
  }
}

void voronoi_f1_3d(vector3 coord,
                   float exponent,
                   float randomness,
                   string metric,
                   output float outDistance,
                   output color outColor,
                   output vector3 outPosition)
{
  vector3 cellPosition = floor(coord);
  vector3 localPosition = coord - cellPosition;

  float minDistance = 8.0;
  vector3 targetOffset, targetPosition;
  for (int k = -1; k <= 1; k++) {
    for (int j = -1; j <= 1; j++) {
      for (int i = -1; i <= 1; i++) {
        vector3 cellOffset = vector3(i, j, k);
        vector3 pointPosition = cellOffset +
                                hash_vector3_to_vector3(cellPosition + cellOffset) * randomness;
        float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
        if (distanceToPoint < minDistance) {
          targetOffset = cellOffset;
          minDistance = distanceToPoint;
          targetPosition = pointPosition;
        }
      }
    }
  }
  outDistance = minDistance;
  outColor = hash_vector3_to_color(cellPosition + targetOffset);
  outPosition = targetPosition + cellPosition;
}

void voronoi_smooth_f1_3d(vector3 coord,
                          float smoothness,
                          float exponent,
                          float randomness,
                          string metric,
                          output float outDistance,
                          output color outColor,
                          output vector3 outPosition)
{
  vector3 cellPosition = floor(coord);
  vector3 localPosition = coord - cellPosition;

  float smoothDistance = 8.0;
  color smoothColor = color(0.0);
  vector3 smoothPosition = vector3(0.0);
  for (int k = -2; k <= 2; k++) {
    for (int j = -2; j <= 2; j++) {
      for (int i = -2; i <= 2; i++) {
        vector3 cellOffset = vector3(i, j, k);
        vector3 pointPosition = cellOffset +
                                hash_vector3_to_vector3(cellPosition + cellOffset) * randomness;
        float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
        float h = smoothstep(
            0.0, 1.0, 0.5 + 0.5 * (smoothDistance - distanceToPoint) / smoothness);
        float correctionFactor = smoothness * h * (1.0 - h);
        smoothDistance = mix(smoothDistance, distanceToPoint, h) - correctionFactor;
        correctionFactor /= 1.0 + 3.0 * smoothness;
        color cellColor = hash_vector3_to_color(cellPosition + cellOffset);
        smoothColor = mix(smoothColor, cellColor, h) - correctionFactor;
        smoothPosition = mix(smoothPosition, pointPosition, h) - correctionFactor;
      }
    }
  }
  outDistance = smoothDistance;
  outColor = smoothColor;
  outPosition = cellPosition + smoothPosition;
}

void voronoi_f2_3d(vector3 coord,
                   float exponent,
                   float randomness,
                   string metric,
                   output float outDistance,
                   output color outColor,
                   output vector3 outPosition)
{
  vector3 cellPosition = floor(coord);
  vector3 localPosition = coord - cellPosition;

  float distanceF1 = 8.0;
  float distanceF2 = 8.0;
  vector3 offsetF1 = vector3(0.0);
  vector3 positionF1 = vector3(0.0);
  vector3 offsetF2, positionF2;
  for (int k = -1; k <= 1; k++) {
    for (int j = -1; j <= 1; j++) {
      for (int i = -1; i <= 1; i++) {
        vector3 cellOffset = vector3(i, j, k);
        vector3 pointPosition = cellOffset +
                                hash_vector3_to_vector3(cellPosition + cellOffset) * randomness;
        float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
        if (distanceToPoint < distanceF1) {
          distanceF2 = distanceF1;
          distanceF1 = distanceToPoint;
          offsetF2 = offsetF1;
          offsetF1 = cellOffset;
          positionF2 = positionF1;
          positionF1 = pointPosition;
        }
        else if (distanceToPoint < distanceF2) {
          distanceF2 = distanceToPoint;
          offsetF2 = cellOffset;
          positionF2 = pointPosition;
        }
      }
    }
  }
  outDistance = distanceF2;
  outColor = hash_vector3_to_color(cellPosition + offsetF2);
  outPosition = positionF2 + cellPosition;
}

void voronoi_distance_to_edge_3d(vector3 coord, float randomness, output float outDistance)
{
  vector3 cellPosition = floor(coord);
  vector3 localPosition = coord - cellPosition;

  vector3 vectorToClosest;
  float minDistance = 8.0;
  for (int k = -1; k <= 1; k++) {
    for (int j = -1; j <= 1; j++) {
      for (int i = -1; i <= 1; i++) {
        vector3 cellOffset = vector3(i, j, k);
        vector3 vectorToPoint = cellOffset +
                                hash_vector3_to_vector3(cellPosition + cellOffset) * randomness -
                                localPosition;
        float distanceToPoint = dot(vectorToPoint, vectorToPoint);
        if (distanceToPoint < minDistance) {
          minDistance = distanceToPoint;
          vectorToClosest = vectorToPoint;
        }
      }
    }
  }

  minDistance = 8.0;
  for (int k = -1; k <= 1; k++) {
    for (int j = -1; j <= 1; j++) {
      for (int i = -1; i <= 1; i++) {
        vector3 cellOffset = vector3(i, j, k);
        vector3 vectorToPoint = cellOffset +
                                hash_vector3_to_vector3(cellPosition + cellOffset) * randomness -
                                localPosition;
        vector3 perpendicularToEdge = vectorToPoint - vectorToClosest;
        if (dot(perpendicularToEdge, perpendicularToEdge) > 0.0001) {
          float distanceToEdge = dot((vectorToClosest + vectorToPoint) / 2.0,
                                     normalize((vector)perpendicularToEdge));
          minDistance = min(minDistance, distanceToEdge);
        }
      }
    }
  }
  outDistance = minDistance;
}

void voronoi_n_sphere_radius_3d(vector3 coord, float randomness, output float outRadius)
{
  vector3 cellPosition = floor(coord);
  vector3 localPosition = coord - cellPosition;

  vector3 closestPoint;
  vector3 closestPointOffset;
  float minDistance = 8.0;
  for (int k = -1; k <= 1; k++) {
    for (int j = -1; j <= 1; j++) {
      for (int i = -1; i <= 1; i++) {
        vector3 cellOffset = vector3(i, j, k);
        vector3 pointPosition = cellOffset +
                                hash_vector3_to_vector3(cellPosition + cellOffset) * randomness;
        float distanceToPoint = distance(pointPosition, localPosition);
        if (distanceToPoint < minDistance) {
          minDistance = distanceToPoint;
          closestPoint = pointPosition;
          closestPointOffset = cellOffset;
        }
      }
    }
  }

  minDistance = 8.0;
  vector3 closestPointToClosestPoint;
  for (int k = -1; k <= 1; k++) {
    for (int j = -1; j <= 1; j++) {
      for (int i = -1; i <= 1; i++) {
        if (i == 0 && j == 0 && k == 0) {
          continue;
        }
        vector3 cellOffset = vector3(i, j, k) + closestPointOffset;
        vector3 pointPosition = cellOffset +
                                hash_vector3_to_vector3(cellPosition + cellOffset) * randomness;
        float distanceToPoint = distance(closestPoint, pointPosition);
        if (distanceToPoint < minDistance) {
          minDistance = distanceToPoint;
          closestPointToClosestPoint = pointPosition;
        }
      }
    }
  }
  outRadius = distance(closestPointToClosestPoint, closestPoint) / 2.0;
}

/* **** 4D Voronoi **** */

float voronoi_distance(vector4 a, vector4 b, string metric, float exponent)
{
  if (metric == "euclidean") {
    return distance(a, b);
  }
  else if (metric == "manhattan") {
    return abs(a.x - b.x) + abs(a.y - b.y) + abs(a.z - b.z) + abs(a.w - b.w);
  }
  else if (metric == "chebychev") {
    return max(abs(a.x - b.x), max(abs(a.y - b.y), max(abs(a.z - b.z), abs(a.w - b.w))));
  }
  else if (metric == "minkowski") {
    return pow(pow(abs(a.x - b.x), exponent) + pow(abs(a.y - b.y), exponent) +
                   pow(abs(a.z - b.z), exponent) + pow(abs(a.w - b.w), exponent),
               1.0 / exponent);
  }
  else {
    return 0.0;
  }
}

void voronoi_f1_4d(vector4 coord,
                   float exponent,
                   float randomness,
                   string metric,
                   output float outDistance,
                   output color outColor,
                   output vector4 outPosition)
{
  vector4 cellPosition = floor(coord);
  vector4 localPosition = coord - cellPosition;

  float minDistance = 8.0;
  vector4 targetOffset, targetPosition;
  for (int u = -1; u <= 1; u++) {
    for (int k = -1; k <= 1; k++) {
      for (int j = -1; j <= 1; j++) {
        for (int i = -1; i <= 1; i++) {
          vector4 cellOffset = vector4(i, j, k, u);
          vector4 pointPosition = cellOffset +
                                  hash_vector4_to_vector4(cellPosition + cellOffset) * randomness;
          float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
          if (distanceToPoint < minDistance) {
            targetOffset = cellOffset;
            minDistance = distanceToPoint;
            targetPosition = pointPosition;
          }
        }
      }
    }
  }
  outDistance = minDistance;
  outColor = hash_vector4_to_color(cellPosition + targetOffset);
  outPosition = targetPosition + cellPosition;
}

void voronoi_smooth_f1_4d(vector4 coord,
                          float smoothness,
                          float exponent,
                          float randomness,
                          string metric,
                          output float outDistance,
                          output color outColor,
                          output vector4 outPosition)
{
  vector4 cellPosition = floor(coord);
  vector4 localPosition = coord - cellPosition;

  float smoothDistance = 8.0;
  color smoothColor = color(0.0);
  vector4 smoothPosition = vector4(0.0, 0.0, 0.0, 0.0);
  for (int u = -2; u <= 2; u++) {
    for (int k = -2; k <= 2; k++) {
      for (int j = -2; j <= 2; j++) {
        for (int i = -2; i <= 2; i++) {
          vector4 cellOffset = vector4(i, j, k, u);
          vector4 pointPosition = cellOffset +
                                  hash_vector4_to_vector4(cellPosition + cellOffset) * randomness;
          float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
          float h = smoothstep(
              0.0, 1.0, 0.5 + 0.5 * (smoothDistance - distanceToPoint) / smoothness);
          float correctionFactor = smoothness * h * (1.0 - h);
          smoothDistance = mix(smoothDistance, distanceToPoint, h) - correctionFactor;
          correctionFactor /= 1.0 + 3.0 * smoothness;
          color cellColor = hash_vector4_to_color(cellPosition + cellOffset);
          smoothColor = mix(smoothColor, cellColor, h) - correctionFactor;
          smoothPosition = mix(smoothPosition, pointPosition, h) - correctionFactor;
        }
      }
    }
  }
  outDistance = smoothDistance;
  outColor = smoothColor;
  outPosition = cellPosition + smoothPosition;
}

void voronoi_f2_4d(vector4 coord,
                   float exponent,
                   float randomness,
                   string metric,
                   output float outDistance,
                   output color outColor,
                   output vector4 outPosition)
{
  vector4 cellPosition = floor(coord);
  vector4 localPosition = coord - cellPosition;

  float distanceF1 = 8.0;
  float distanceF2 = 8.0;
  vector4 offsetF1 = vector4(0.0, 0.0, 0.0, 0.0);
  vector4 positionF1 = vector4(0.0, 0.0, 0.0, 0.0);
  vector4 offsetF2, positionF2;
  for (int u = -1; u <= 1; u++) {
    for (int k = -1; k <= 1; k++) {
      for (int j = -1; j <= 1; j++) {
        for (int i = -1; i <= 1; i++) {
          vector4 cellOffset = vector4(i, j, k, u);
          vector4 pointPosition = cellOffset +
                                  hash_vector4_to_vector4(cellPosition + cellOffset) * randomness;
          float distanceToPoint = voronoi_distance(pointPosition, localPosition, metric, exponent);
          if (distanceToPoint < distanceF1) {
            distanceF2 = distanceF1;
            distanceF1 = distanceToPoint;
            offsetF2 = offsetF1;
            offsetF1 = cellOffset;
            positionF2 = positionF1;
            positionF1 = pointPosition;
          }
          else if (distanceToPoint < distanceF2) {
            distanceF2 = distanceToPoint;
            offsetF2 = cellOffset;
            positionF2 = pointPosition;
          }
        }
      }
    }
  }
  outDistance = distanceF2;
  outColor = hash_vector4_to_color(cellPosition + offsetF2);
  outPosition = positionF2 + cellPosition;
}

void voronoi_distance_to_edge_4d(vector4 coord, float randomness, output float outDistance)
{
  vector4 cellPosition = floor(coord);
  vector4 localPosition = coord - cellPosition;

  vector4 vectorToClosest;
  float minDistance = 8.0;
  for (int u = -1; u <= 1; u++) {
    for (int k = -1; k <= 1; k++) {
      for (int j = -1; j <= 1; j++) {
        for (int i = -1; i <= 1; i++) {
          vector4 cellOffset = vector4(i, j, k, u);
          vector4 vectorToPoint = cellOffset +
                                  hash_vector4_to_vector4(cellPosition + cellOffset) * randomness -
                                  localPosition;
          float distanceToPoint = dot(vectorToPoint, vectorToPoint);
          if (distanceToPoint < minDistance) {
            minDistance = distanceToPoint;
            vectorToClosest = vectorToPoint;
          }
        }
      }
    }
  }

  minDistance = 8.0;
  for (int u = -1; u <= 1; u++) {
    for (int k = -1; k <= 1; k++) {
      for (int j = -1; j <= 1; j++) {
        for (int i = -1; i <= 1; i++) {
          vector4 cellOffset = vector4(i, j, k, u);
          vector4 vectorToPoint = cellOffset +
                                  hash_vector4_to_vector4(cellPosition + cellOffset) * randomness -
                                  localPosition;
          vector4 perpendicularToEdge = vectorToPoint - vectorToClosest;
          if (dot(perpendicularToEdge, perpendicularToEdge) > 0.0001) {
            float distanceToEdge = dot((vectorToClosest + vectorToPoint) / 2.0,
                                       normalize(perpendicularToEdge));
            minDistance = min(minDistance, distanceToEdge);
          }
        }
      }
    }
  }
  outDistance = minDistance;
}

void voronoi_n_sphere_radius_4d(vector4 coord, float randomness, output float outRadius)
{
  vector4 cellPosition = floor(coord);
  vector4 localPosition = coord - cellPosition;

  vector4 closestPoint;
  vector4 closestPointOffset;
  float minDistance = 8.0;
  for (int u = -1; u <= 1; u++) {
    for (int k = -1; k <= 1; k++) {
      for (int j = -1; j <= 1; j++) {
        for (int i = -1; i <= 1; i++) {
          vector4 cellOffset = vector4(i, j, k, u);
          vector4 pointPosition = cellOffset +
                                  hash_vector4_to_vector4(cellPosition + cellOffset) * randomness;
          float distanceToPoint = distance(pointPosition, localPosition);
          if (distanceToPoint < minDistance) {
            minDistance = distanceToPoint;
            closestPoint = pointPosition;
            closestPointOffset = cellOffset;
          }
        }
      }
    }
  }

  minDistance = 8.0;
  vector4 closestPointToClosestPoint;
  for (int u = -1; u <= 1; u++) {
    for (int k = -1; k <= 1; k++) {
      for (int j = -1; j <= 1; j++) {
        for (int i = -1; i <= 1; i++) {
          if (i == 0 && j == 0 && k == 0 && u == 0) {
            continue;
          }
          vector4 cellOffset = vector4(i, j, k, u) + closestPointOffset;
          vector4 pointPosition = cellOffset +
                                  hash_vector4_to_vector4(cellPosition + cellOffset) * randomness;
          float distanceToPoint = distance(closestPoint, pointPosition);
          if (distanceToPoint < minDistance) {
            minDistance = distanceToPoint;
            closestPointToClosestPoint = pointPosition;
          }
        }
      }
    }
  }
  outRadius = distance(closestPointToClosestPoint, closestPoint) / 2.0;
}

shader node_voronoi_texture(
    int use_mapping = 0,
    matrix mapping = matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
    string dimensions = "3D",
    string feature = "f1",
    string metric = "euclidean",
    vector3 Vector = P,
    float WIn = 0.0,
    float Scale = 5.0,
    float Smoothness = 5.0,
    float Exponent = 1.0,
    float Randomness = 1.0,
    output float Distance = 0.0,
    output color Color = 0.0,
    output vector3 Position = P,
    output float WOut = 0.0,
    output float Radius = 0.0)
{
  float randomness = clamp(Randomness, 0.0, 1.0);
  float smoothness = clamp(Smoothness / 2.0, 0.0, 0.5);

  vector3 coord = Vector;
  if (use_mapping)
    coord = transform(mapping, coord);

  float w = WIn * Scale;
  coord *= Scale;

  if (dimensions == "1D") {
    if (feature == "f1") {
      voronoi_f1_1d(w, Exponent, randomness, metric, Distance, Color, WOut);
    }
    else if (feature == "smooth_f1") {
      voronoi_smooth_f1_1d(w, smoothness, Exponent, randomness, metric, Distance, Color, WOut);
    }
    else if (feature == "f2") {
      voronoi_f2_1d(w, Exponent, randomness, metric, Distance, Color, WOut);
    }
    else if (feature == "distance_to_edge") {
      voronoi_distance_to_edge_1d(w, randomness, Distance);
    }
    else if (feature == "n_sphere_radius") {
      voronoi_n_sphere_radius_1d(w, randomness, Radius);
    }
    else {
      error("Unknown feature!");
    }
    WOut = (Scale != 0.0) ? WOut / Scale : 0.0;
  }
  else if (dimensions == "2D") {
    vector2 coord2D = vector2(coord[0], coord[1]);
    vector2 outPosition2D;
    if (feature == "f1") {
      voronoi_f1_2d(coord2D, Exponent, randomness, metric, Distance, Color, outPosition2D);
    }
    else if (feature == "smooth_f1") {
      voronoi_smooth_f1_2d(
          coord2D, smoothness, Exponent, randomness, metric, Distance, Color, outPosition2D);
    }
    else if (feature == "f2") {
      voronoi_f2_2d(coord2D, Exponent, randomness, metric, Distance, Color, outPosition2D);
    }
    else if (feature == "distance_to_edge") {
      voronoi_distance_to_edge_2d(coord2D, randomness, Distance);
    }
    else if (feature == "n_sphere_radius") {
      voronoi_n_sphere_radius_2d(coord2D, randomness, Radius);
    }
    else {
      error("Unknown feature!");
    }
    outPosition2D = safe_divide(outPosition2D, Scale);
    Position = vector3(outPosition2D.x, outPosition2D.y, 0.0);
  }
  else if (dimensions == "3D") {
    if (feature == "f1") {
      voronoi_f1_3d(coord, Exponent, randomness, metric, Distance, Color, Position);
    }
    else if (feature == "smooth_f1") {
      voronoi_smooth_f1_3d(
          coord, smoothness, Exponent, randomness, metric, Distance, Color, Position);
    }
    else if (feature == "f2") {
      voronoi_f2_3d(coord, Exponent, randomness, metric, Distance, Color, Position);
    }
    else if (feature == "distance_to_edge") {
      voronoi_distance_to_edge_3d(coord, randomness, Distance);
    }
    else if (feature == "n_sphere_radius") {
      voronoi_n_sphere_radius_3d(coord, randomness, Radius);
    }
    else {
      error("Unknown feature!");
    }
    Position = (Scale != 0.0) ? Position / Scale : vector3(0.0);
  }
  else if (dimensions == "4D") {
    vector4 coord4D = vector4(coord[0], coord[1], coord[2], w);
    vector4 outPosition4D;
    if (feature == "f1") {
      voronoi_f1_4d(coord4D, Exponent, randomness, metric, Distance, Color, outPosition4D);
    }
    else if (feature == "smooth_f1") {
      voronoi_smooth_f1_4d(
          coord4D, smoothness, Exponent, randomness, metric, Distance, Color, outPosition4D);
    }
    else if (feature == "f2") {
      voronoi_f2_4d(coord4D, Exponent, randomness, metric, Distance, Color, outPosition4D);
    }
    else if (feature == "distance_to_edge") {
      voronoi_distance_to_edge_4d(coord4D, randomness, Distance);
    }
    else if (feature == "n_sphere_radius") {
      voronoi_n_sphere_radius_4d(coord4D, randomness, Radius);
    }
    else {
      error("Unknown feature!");
    }
    outPosition4D = safe_divide(outPosition4D, Scale);
    Position = vector3(outPosition4D.x, outPosition4D.y, outPosition4D.z);
    WOut = outPosition4D.w;
  }
  else {
    error("Unknown dimension!");
  }
}