text: /*
   * OpenSimplex (Simplectic) Noise in C.
   * Ported by Stephen M. Cameron from Kurt Spencer's java implementation
   * 
   * v1.1 (October 5, 2014)
   * - Added 2D and 4D implementations.
   * - Proper gradient sets for all dimensions, from a
   *   dimensionally-generalizable scheme with an actual
   *   rhyme and reason behind it.
   * - Removed default permutation array in favor of
   *   default seed.
   * - Changed seed-based constructor to be independent
   *   of any particular randomization library, so results
   *   will be the same when ported to other languages.
   */
  
  // -- GODOT start --
  // Modified to work without allocating memory, also removed some unused function. 
  // -- GODOT end --
  
  #include <math.h>
  #include <stdlib.h>
  #include <stdint.h>
  #include <string.h>
  #include <errno.h>
  
  #include "open-simplex-noise.h"
  
  #define STRETCH_CONSTANT_2D (-0.211324865405187)    /* (1 / sqrt(2 + 1) - 1 ) / 2; */
  #define SQUISH_CONSTANT_2D  (0.366025403784439)     /* (sqrt(2 + 1) -1) / 2; */
  #define STRETCH_CONSTANT_3D (-1.0 / 6.0)            /* (1 / sqrt(3 + 1) - 1) / 3; */
  #define SQUISH_CONSTANT_3D  (1.0 / 3.0)             /* (sqrt(3+1)-1)/3; */
  #define STRETCH_CONSTANT_4D (-0.138196601125011)    /* (1 / sqrt(4 + 1) - 1) / 4; */
  #define SQUISH_CONSTANT_4D  (0.309016994374947)     /* (sqrt(4 + 1) - 1) / 4; */
  	
  #define NORM_CONSTANT_2D (47.0)
  #define NORM_CONSTANT_3D (103.0)
  #define NORM_CONSTANT_4D (30.0)
  	
  #define DEFAULT_SEED (0LL)
  
  // -- GODOT start --
  /*struct osn_context {
  	int16_t *perm;
  	int16_t *permGradIndex3D;
  };*/
  // -- GODOT end --
  #define ARRAYSIZE(x) (sizeof((x)) / sizeof((x)[0]))
  
  /* 
   * Gradients for 2D. They approximate the directions to the
   * vertices of an octagon from the center.
   */
  static const int8_t gradients2D[] = {
  	 5,  2,    2,  5,
  	-5,  2,   -2,  5,
  	 5, -2,    2, -5,
  	-5, -2,   -2, -5,
  };
  
  /*	
   * Gradients for 3D. They approximate the directions to the
   * vertices of a rhombicuboctahedron from the center, skewed so
   * that the triangular and square facets can be inscribed inside
   * circles of the same radius.
   */
  static const signed char gradients3D[] = {
  	-11,  4,  4,     -4,  11,  4,    -4,  4,  11,
  	 11,  4,  4,      4,  11,  4,     4,  4,  11,
  	-11, -4,  4,     -4, -11,  4,    -4, -4,  11,
  	 11, -4,  4,      4, -11,  4,     4, -4,  11,
  	-11,  4, -4,     -4,  11, -4,    -4,  4, -11,
  	 11,  4, -4,      4,  11, -4,     4,  4, -11,
  	-11, -4, -4,     -4, -11, -4,    -4, -4, -11,
  	 11, -4, -4,      4, -11, -4,     4, -4, -11,
  };
  
  /*	
   * Gradients for 4D. They approximate the directions to the
   * vertices of a disprismatotesseractihexadecachoron from the center,
   * skewed so that the tetrahedral and cubic facets can be inscribed inside
   * spheres of the same radius.
   */
  static const signed char gradients4D[] = {
  	 3,  1,  1,  1,      1,  3,  1,  1,      1,  1,  3,  1,      1,  1,  1,  3,
  	-3,  1,  1,  1,     -1,  3,  1,  1,     -1,  1,  3,  1,     -1,  1,  1,  3,
  	 3, -1,  1,  1,      1, -3,  1,  1,      1, -1,  3,  1,      1, -1,  1,  3,
  	-3, -1,  1,  1,     -1, -3,  1,  1,     -1, -1,  3,  1,     -1, -1,  1,  3,
  	 3,  1, -1,  1,      1,  3, -1,  1,      1,  1, -3,  1,      1,  1, -1,  3,
  	-3,  1, -1,  1,     -1,  3, -1,  1,     -1,  1, -3,  1,     -1,  1, -1,  3,
  	 3, -1, -1,  1,      1, -3, -1,  1,      1, -1, -3,  1,      1, -1, -1,  3,
  	-3, -1, -1,  1,     -1, -3, -1,  1,     -1, -1, -3,  1,     -1, -1, -1,  3,
  	 3,  1,  1, -1,      1,  3,  1, -1,      1,  1,  3, -1,      1,  1,  1, -3,
  	-3,  1,  1, -1,     -1,  3,  1, -1,     -1,  1,  3, -1,     -1,  1,  1, -3,
  	 3, -1,  1, -1,      1, -3,  1, -1,      1, -1,  3, -1,      1, -1,  1, -3,
  	-3, -1,  1, -1,     -1, -3,  1, -1,     -1, -1,  3, -1,     -1, -1,  1, -3,
  	 3,  1, -1, -1,      1,  3, -1, -1,      1,  1, -3, -1,      1,  1, -1, -3,
  	-3,  1, -1, -1,     -1,  3, -1, -1,     -1,  1, -3, -1,     -1,  1, -1, -3,
  	 3, -1, -1, -1,      1, -3, -1, -1,      1, -1, -3, -1,      1, -1, -1, -3,
  	-3, -1, -1, -1,     -1, -3, -1, -1,     -1, -1, -3, -1,     -1, -1, -1, -3,
  };
  
  static double extrapolate2(const struct osn_context *ctx, int xsb, int ysb, double dx, double dy)
  {
  	const int16_t *perm = ctx->perm;
  	int index = perm[(perm[xsb & 0xFF] + ysb) & 0xFF] & 0x0E;
  	return gradients2D[index] * dx
  		+ gradients2D[index + 1] * dy;
  }
  	
  static double extrapolate3(const struct osn_context *ctx, int xsb, int ysb, int zsb, double dx, double dy, double dz)
  {
  	const int16_t *perm = ctx->perm;
  	const int16_t *permGradIndex3D = ctx->permGradIndex3D;
  	int index = permGradIndex3D[(perm[(perm[xsb & 0xFF] + ysb) & 0xFF] + zsb) & 0xFF];
  	return gradients3D[index] * dx
  		+ gradients3D[index + 1] * dy
  		+ gradients3D[index + 2] * dz;
  }
  	
  static double extrapolate4(const struct osn_context *ctx, int xsb, int ysb, int zsb, int wsb, double dx, double dy, double dz, double dw)
  {
  	const int16_t *perm = ctx->perm;
  	int index = perm[(perm[(perm[(perm[xsb & 0xFF] + ysb) & 0xFF] + zsb) & 0xFF] + wsb) & 0xFF] & 0xFC;
  	return gradients4D[index] * dx
  		+ gradients4D[index + 1] * dy
  		+ gradients4D[index + 2] * dz
  		+ gradients4D[index + 3] * dw;
  }
  	
  static INLINE int fastFloor(double x) {
  	int xi = (int) x;
  	return x < xi ? xi - 1 : xi;
  }
  
  // -- GODOT start --
  /*
  static int allocate_perm(struct osn_context *ctx, int nperm, int ngrad)
  {
  	if (ctx->perm)
  		free(ctx->perm);
  	if (ctx->permGradIndex3D)
  		free(ctx->permGradIndex3D);
  	ctx->perm = (int16_t *) malloc(sizeof(*ctx->perm) * nperm); 
  	if (!ctx->perm)
  		return -ENOMEM;
  	ctx->permGradIndex3D = (int16_t *) malloc(sizeof(*ctx->permGradIndex3D) * ngrad);
  	if (!ctx->permGradIndex3D) {
  		free(ctx->perm);
  		return -ENOMEM;
  	}
  	return 0;
  }
  	
  int open_simplex_noise_init_perm(struct osn_context *ctx, int16_t p[], int nelements)
  {
  	int i, rc;
  
  	rc = allocate_perm(ctx, nelements, 256);
  	if (rc)
  		return rc;
  	memcpy(ctx->perm, p, sizeof(*ctx->perm) * nelements);
  		
  	for (i = 0; i < 256; i++) {
  		// Since 3D has 24 gradients, simple bitmask won't work, so precompute modulo array.
  		ctx->permGradIndex3D[i] = (int16_t)((ctx->perm[i] % (ARRAYSIZE(gradients3D) / 3)) * 3);
  	}
  	return 0;
  }
  */
  // -- GODOT end --
  
  /*	
   * Initializes using a permutation array generated from a 64-bit seed.
   * Generates a proper permutation (i.e. doesn't merely perform N successive pair
   * swaps on a base array).  Uses a simple 64-bit LCG.
   */
  // -- GODOT start --
  int open_simplex_noise(int64_t seed, struct osn_context *ctx)
  {
  	int rc;
  	int16_t source[256];
  	int i;
  	int16_t *perm;
  	int16_t *permGradIndex3D;
  	int r;
  
  	perm = ctx->perm;
  	permGradIndex3D = ctx->permGradIndex3D;
  // -- GODOT end --
  
  	uint64_t seedU = seed;
  	for (i = 0; i < 256; i++)
  		source[i] = (int16_t) i;
  	seedU = seedU * 6364136223846793005ULL + 1442695040888963407ULL;
  	seedU = seedU * 6364136223846793005ULL + 1442695040888963407ULL;
  	seedU = seedU * 6364136223846793005ULL + 1442695040888963407ULL;
  	for (i = 255; i >= 0; i--) {
  		seedU = seedU * 6364136223846793005ULL + 1442695040888963407ULL;
  		r = (int)((seedU + 31) % (i + 1));
  		if (r < 0)
  			r += (i + 1);
  		perm[i] = source[r];
  		permGradIndex3D[i] = (short)((perm[i] % (ARRAYSIZE(gradients3D) / 3)) * 3);
  		source[r] = source[i];
  	}
  	return 0;
  }
  
  // -- GODOT start --
  /*
  void open_simplex_noise_free(struct osn_context *ctx)
  {
  	if (!ctx)
  		return;
  	if (ctx->perm) {
  		free(ctx->perm);
  		ctx->perm = NULL;	
  	}
  	if (ctx->permGradIndex3D) {
  		free(ctx->permGradIndex3D);
  		ctx->permGradIndex3D = NULL;
  	}
  	free(ctx);
  }
  */
  // -- GODOT end --
  	
  /* 2D OpenSimplex (Simplectic) Noise. */
  double open_simplex_noise2(const struct osn_context *ctx, double x, double y)
  {
  	
  	/* Place input coordinates onto grid. */
  	double stretchOffset = (x + y) * STRETCH_CONSTANT_2D;
  	double xs = x + stretchOffset;
  	double ys = y + stretchOffset;
  		
  	/* Floor to get grid coordinates of rhombus (stretched square) super-cell origin. */
  	int xsb = fastFloor(xs);
  	int ysb = fastFloor(ys);
  		
  	/* Skew out to get actual coordinates of rhombus origin. We'll need these later. */
  	double squishOffset = (xsb + ysb) * SQUISH_CONSTANT_2D;
  	double xb = xsb + squishOffset;
  	double yb = ysb + squishOffset;
  		
  	/* Compute grid coordinates relative to rhombus origin. */
  	double xins = xs - xsb;
  	double yins = ys - ysb;
  		
  	/* Sum those together to get a value that determines which region we're in. */
  	double inSum = xins + yins;
  
  	/* Positions relative to origin point. */
  	double dx0 = x - xb;
  	double dy0 = y - yb;
  		
  	/* We'll be defining these inside the next block and using them afterwards. */
  	double dx_ext, dy_ext;
  	int xsv_ext, ysv_ext;
  
  	double dx1;
  	double dy1;
  	double attn1;
  	double dx2;
  	double dy2;
  	double attn2;
  	double zins;
  	double attn0;
  	double attn_ext;
  
  	double value = 0;
  
  	/* Contribution (1,0) */
  	dx1 = dx0 - 1 - SQUISH_CONSTANT_2D;
  	dy1 = dy0 - 0 - SQUISH_CONSTANT_2D;
  	attn1 = 2 - dx1 * dx1 - dy1 * dy1;
  	if (attn1 > 0) {
  		attn1 *= attn1;
  		value += attn1 * attn1 * extrapolate2(ctx, xsb + 1, ysb + 0, dx1, dy1);
  	}
  
  	/* Contribution (0,1) */
  	dx2 = dx0 - 0 - SQUISH_CONSTANT_2D;
  	dy2 = dy0 - 1 - SQUISH_CONSTANT_2D;
  	attn2 = 2 - dx2 * dx2 - dy2 * dy2;
  	if (attn2 > 0) {
  		attn2 *= attn2;
  		value += attn2 * attn2 * extrapolate2(ctx, xsb + 0, ysb + 1, dx2, dy2);
  	}
  		
  	if (inSum <= 1) { /* We're inside the triangle (2-Simplex) at (0,0) */
  		zins = 1 - inSum;
  		if (zins > xins || zins > yins) { /* (0,0) is one of the closest two triangular vertices */
  			if (xins > yins) {
  				xsv_ext = xsb + 1;
  				ysv_ext = ysb - 1;
  				dx_ext = dx0 - 1;
  				dy_ext = dy0 + 1;
  			} else {
  				xsv_ext = xsb - 1;
  				ysv_ext = ysb + 1;
  				dx_ext = dx0 + 1;
  				dy_ext = dy0 - 1;
  			}
  		} else { /* (1,0) and (0,1) are the closest two vertices. */
  			xsv_ext = xsb + 1;
  			ysv_ext = ysb + 1;
  			dx_ext = dx0 - 1 - 2 * SQUISH_CONSTANT_2D;
  			dy_ext = dy0 - 1 - 2 * SQUISH_CONSTANT_2D;
  		}
  	} else { /* We're inside the triangle (2-Simplex) at (1,1) */
  		zins = 2 - inSum;
  		if (zins < xins || zins < yins) { /* (0,0) is one of the closest two triangular vertices */
  			if (xins > yins) {
  				xsv_ext = xsb + 2;
  				ysv_ext = ysb + 0;
  				dx_ext = dx0 - 2 - 2 * SQUISH_CONSTANT_2D;
  				dy_ext = dy0 + 0 - 2 * SQUISH_CONSTANT_2D;
  			} else {
  				xsv_ext = xsb + 0;
  				ysv_ext = ysb + 2;
  				dx_ext = dx0 + 0 - 2 * SQUISH_CONSTANT_2D;
  				dy_ext = dy0 - 2 - 2 * SQUISH_CONSTANT_2D;
  			}
  		} else { /* (1,0) and (0,1) are the closest two vertices. */
  			dx_ext = dx0;
  			dy_ext = dy0;
  			xsv_ext = xsb;
  			ysv_ext = ysb;
  		}
  		xsb += 1;
  		ysb += 1;
  		dx0 = dx0 - 1 - 2 * SQUISH_CONSTANT_2D;
  		dy0 = dy0 - 1 - 2 * SQUISH_CONSTANT_2D;
  	}
  		
  	/* Contribution (0,0) or (1,1) */
  	attn0 = 2 - dx0 * dx0 - dy0 * dy0;
  	if (attn0 > 0) {
  		attn0 *= attn0;
  		value += attn0 * attn0 * extrapolate2(ctx, xsb, ysb, dx0, dy0);
  	}
  	
  	/* Extra Vertex */
  	attn_ext = 2 - dx_ext * dx_ext - dy_ext * dy_ext;
  	if (attn_ext > 0) {
  		attn_ext *= attn_ext;
  		value += attn_ext * attn_ext * extrapolate2(ctx, xsv_ext, ysv_ext, dx_ext, dy_ext);
  	}
  	
  	return value / NORM_CONSTANT_2D;
  }
  	
  /*
   * 3D OpenSimplex (Simplectic) Noise
   */
  double open_simplex_noise3(const struct osn_context *ctx, double x, double y, double z)
  {
  
  	/* Place input coordinates on simplectic honeycomb. */
  	double stretchOffset = (x + y + z) * STRETCH_CONSTANT_3D;
  	double xs = x + stretchOffset;
  	double ys = y + stretchOffset;
  	double zs = z + stretchOffset;
  	
  	/* Floor to get simplectic honeycomb coordinates of rhombohedron (stretched cube) super-cell origin. */
  	int xsb = fastFloor(xs);
  	int ysb = fastFloor(ys);
  	int zsb = fastFloor(zs);
  	
  	/* Skew out to get actual coordinates of rhombohedron origin. We'll need these later. */
  	double squishOffset = (xsb + ysb + zsb) * SQUISH_CONSTANT_3D;
  	double xb = xsb + squishOffset;
  	double yb = ysb + squishOffset;
  	double zb = zsb + squishOffset;
  	
  	/* Compute simplectic honeycomb coordinates relative to rhombohedral origin. */
  	double xins = xs - xsb;
  	double yins = ys - ysb;
  	double zins = zs - zsb;
  	
  	/* Sum those together to get a value that determines which region we're in. */
  	double inSum = xins + yins + zins;
  
  	/* Positions relative to origin point. */
  	double dx0 = x - xb;
  	double dy0 = y - yb;
  	double dz0 = z - zb;
  	
  	/* We'll be defining these inside the next block and using them afterwards. */
  	double dx_ext0, dy_ext0, dz_ext0;
  	double dx_ext1, dy_ext1, dz_ext1;
  	int xsv_ext0, ysv_ext0, zsv_ext0;
  	int xsv_ext1, ysv_ext1, zsv_ext1;
  
  	double wins;
  	int8_t c, c1, c2;
  	int8_t aPoint, bPoint;
  	double aScore, bScore;
  	int aIsFurtherSide;
  	int bIsFurtherSide;
  	double p1, p2, p3;
  	double score;
  	double attn0, attn1, attn2, attn3, attn4, attn5, attn6;
  	double dx1, dy1, dz1;
  	double dx2, dy2, dz2;
  	double dx3, dy3, dz3;
  	double dx4, dy4, dz4;
  	double dx5, dy5, dz5;
  	double dx6, dy6, dz6;
  	double attn_ext0, attn_ext1;
  	
  	double value = 0;
  	if (inSum <= 1) { /* We're inside the tetrahedron (3-Simplex) at (0,0,0) */
  		
  		/* Determine which two of (0,0,1), (0,1,0), (1,0,0) are closest. */
  		aPoint = 0x01;
  		aScore = xins;
  		bPoint = 0x02;
  		bScore = yins;
  		if (aScore >= bScore && zins > bScore) {
  			bScore = zins;
  			bPoint = 0x04;
  		} else if (aScore < bScore && zins > aScore) {
  			aScore = zins;
  			aPoint = 0x04;
  		}
  		
  		/* Now we determine the two lattice points not part of the tetrahedron that may contribute.
  		   This depends on the closest two tetrahedral vertices, including (0,0,0) */
  		wins = 1 - inSum;
  		if (wins > aScore || wins > bScore) { /* (0,0,0) is one of the closest two tetrahedral vertices. */
  			c = (bScore > aScore ? bPoint : aPoint); /* Our other closest vertex is the closest out of a and b. */
  			
  			if ((c & 0x01) == 0) {
  				xsv_ext0 = xsb - 1;
  				xsv_ext1 = xsb;
  				dx_ext0 = dx0 + 1;
  				dx_ext1 = dx0;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsb + 1;
  				dx_ext0 = dx_ext1 = dx0 - 1;
  			}
  
  			if ((c & 0x02) == 0) {
  				ysv_ext0 = ysv_ext1 = ysb;
  				dy_ext0 = dy_ext1 = dy0;
  				if ((c & 0x01) == 0) {
  					ysv_ext1 -= 1;
  					dy_ext1 += 1;
  				} else {
  					ysv_ext0 -= 1;
  					dy_ext0 += 1;
  				}
  			} else {
  				ysv_ext0 = ysv_ext1 = ysb + 1;
  				dy_ext0 = dy_ext1 = dy0 - 1;
  			}
  
  			if ((c & 0x04) == 0) {
  				zsv_ext0 = zsb;
  				zsv_ext1 = zsb - 1;
  				dz_ext0 = dz0;
  				dz_ext1 = dz0 + 1;
  			} else {
  				zsv_ext0 = zsv_ext1 = zsb + 1;
  				dz_ext0 = dz_ext1 = dz0 - 1;
  			}
  		} else { /* (0,0,0) is not one of the closest two tetrahedral vertices. */
  			c = (int8_t)(aPoint | bPoint); /* Our two extra vertices are determined by the closest two. */
  			
  			if ((c & 0x01) == 0) {
  				xsv_ext0 = xsb;
  				xsv_ext1 = xsb - 1;
  				dx_ext0 = dx0 - 2 * SQUISH_CONSTANT_3D;
  				dx_ext1 = dx0 + 1 - SQUISH_CONSTANT_3D;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsb + 1;
  				dx_ext0 = dx0 - 1 - 2 * SQUISH_CONSTANT_3D;
  				dx_ext1 = dx0 - 1 - SQUISH_CONSTANT_3D;
  			}
  
  			if ((c & 0x02) == 0) {
  				ysv_ext0 = ysb;
  				ysv_ext1 = ysb - 1;
  				dy_ext0 = dy0 - 2 * SQUISH_CONSTANT_3D;
  				dy_ext1 = dy0 + 1 - SQUISH_CONSTANT_3D;
  			} else {
  				ysv_ext0 = ysv_ext1 = ysb + 1;
  				dy_ext0 = dy0 - 1 - 2 * SQUISH_CONSTANT_3D;
  				dy_ext1 = dy0 - 1 - SQUISH_CONSTANT_3D;
  			}
  
  			if ((c & 0x04) == 0) {
  				zsv_ext0 = zsb;
  				zsv_ext1 = zsb - 1;
  				dz_ext0 = dz0 - 2 * SQUISH_CONSTANT_3D;
  				dz_ext1 = dz0 + 1 - SQUISH_CONSTANT_3D;
  			} else {
  				zsv_ext0 = zsv_ext1 = zsb + 1;
  				dz_ext0 = dz0 - 1 - 2 * SQUISH_CONSTANT_3D;
  				dz_ext1 = dz0 - 1 - SQUISH_CONSTANT_3D;
  			}
  		}
  
  		/* Contribution (0,0,0) */
  		attn0 = 2 - dx0 * dx0 - dy0 * dy0 - dz0 * dz0;
  		if (attn0 > 0) {
  			attn0 *= attn0;
  			value += attn0 * attn0 * extrapolate3(ctx, xsb + 0, ysb + 0, zsb + 0, dx0, dy0, dz0);
  		}
  
  		/* Contribution (1,0,0) */
  		dx1 = dx0 - 1 - SQUISH_CONSTANT_3D;
  		dy1 = dy0 - 0 - SQUISH_CONSTANT_3D;
  		dz1 = dz0 - 0 - SQUISH_CONSTANT_3D;
  		attn1 = 2 - dx1 * dx1 - dy1 * dy1 - dz1 * dz1;
  		if (attn1 > 0) {
  			attn1 *= attn1;
  			value += attn1 * attn1 * extrapolate3(ctx, xsb + 1, ysb + 0, zsb + 0, dx1, dy1, dz1);
  		}
  
  		/* Contribution (0,1,0) */
  		dx2 = dx0 - 0 - SQUISH_CONSTANT_3D;
  		dy2 = dy0 - 1 - SQUISH_CONSTANT_3D;
  		dz2 = dz1;
  		attn2 = 2 - dx2 * dx2 - dy2 * dy2 - dz2 * dz2;
  		if (attn2 > 0) {
  			attn2 *= attn2;
  			value += attn2 * attn2 * extrapolate3(ctx, xsb + 0, ysb + 1, zsb + 0, dx2, dy2, dz2);
  		}
  
  		/* Contribution (0,0,1) */
  		dx3 = dx2;
  		dy3 = dy1;
  		dz3 = dz0 - 1 - SQUISH_CONSTANT_3D;
  		attn3 = 2 - dx3 * dx3 - dy3 * dy3 - dz3 * dz3;
  		if (attn3 > 0) {
  			attn3 *= attn3;
  			value += attn3 * attn3 * extrapolate3(ctx, xsb + 0, ysb + 0, zsb + 1, dx3, dy3, dz3);
  		}
  	} else if (inSum >= 2) { /* We're inside the tetrahedron (3-Simplex) at (1,1,1) */
  	
  		/* Determine which two tetrahedral vertices are the closest, out of (1,1,0), (1,0,1), (0,1,1) but not (1,1,1). */
  		aPoint = 0x06;
  		aScore = xins;
  		bPoint = 0x05;
  		bScore = yins;
  		if (aScore <= bScore && zins < bScore) {
  			bScore = zins;
  			bPoint = 0x03;
  		} else if (aScore > bScore && zins < aScore) {
  			aScore = zins;
  			aPoint = 0x03;
  		}
  		
  		/* Now we determine the two lattice points not part of the tetrahedron that may contribute.
  		   This depends on the closest two tetrahedral vertices, including (1,1,1) */
  		wins = 3 - inSum;
  		if (wins < aScore || wins < bScore) { /* (1,1,1) is one of the closest two tetrahedral vertices. */
  			c = (bScore < aScore ? bPoint : aPoint); /* Our other closest vertex is the closest out of a and b. */
  			
  			if ((c & 0x01) != 0) {
  				xsv_ext0 = xsb + 2;
  				xsv_ext1 = xsb + 1;
  				dx_ext0 = dx0 - 2 - 3 * SQUISH_CONSTANT_3D;
  				dx_ext1 = dx0 - 1 - 3 * SQUISH_CONSTANT_3D;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsb;
  				dx_ext0 = dx_ext1 = dx0 - 3 * SQUISH_CONSTANT_3D;
  			}
  
  			if ((c & 0x02) != 0) {
  				ysv_ext0 = ysv_ext1 = ysb + 1;
  				dy_ext0 = dy_ext1 = dy0 - 1 - 3 * SQUISH_CONSTANT_3D;
  				if ((c & 0x01) != 0) {
  					ysv_ext1 += 1;
  					dy_ext1 -= 1;
  				} else {
  					ysv_ext0 += 1;
  					dy_ext0 -= 1;
  				}
  			} else {
  				ysv_ext0 = ysv_ext1 = ysb;
  				dy_ext0 = dy_ext1 = dy0 - 3 * SQUISH_CONSTANT_3D;
  			}
  
  			if ((c & 0x04) != 0) {
  				zsv_ext0 = zsb + 1;
  				zsv_ext1 = zsb + 2;
  				dz_ext0 = dz0 - 1 - 3 * SQUISH_CONSTANT_3D;
  				dz_ext1 = dz0 - 2 - 3 * SQUISH_CONSTANT_3D;
  			} else {
  				zsv_ext0 = zsv_ext1 = zsb;
  				dz_ext0 = dz_ext1 = dz0 - 3 * SQUISH_CONSTANT_3D;
  			}
  		} else { /* (1,1,1) is not one of the closest two tetrahedral vertices. */
  			c = (int8_t)(aPoint & bPoint); /* Our two extra vertices are determined by the closest two. */
  			
  			if ((c & 0x01) != 0) {
  				xsv_ext0 = xsb + 1;
  				xsv_ext1 = xsb + 2;
  				dx_ext0 = dx0 - 1 - SQUISH_CONSTANT_3D;
  				dx_ext1 = dx0 - 2 - 2 * SQUISH_CONSTANT_3D;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsb;
  				dx_ext0 = dx0 - SQUISH_CONSTANT_3D;
  				dx_ext1 = dx0 - 2 * SQUISH_CONSTANT_3D;
  			}
  
  			if ((c & 0x02) != 0) {
  				ysv_ext0 = ysb + 1;
  				ysv_ext1 = ysb + 2;
  				dy_ext0 = dy0 - 1 - SQUISH_CONSTANT_3D;
  				dy_ext1 = dy0 - 2 - 2 * SQUISH_CONSTANT_3D;
  			} else {
  				ysv_ext0 = ysv_ext1 = ysb;
  				dy_ext0 = dy0 - SQUISH_CONSTANT_3D;
  				dy_ext1 = dy0 - 2 * SQUISH_CONSTANT_3D;
  			}
  
  			if ((c & 0x04) != 0) {
  				zsv_ext0 = zsb + 1;
  				zsv_ext1 = zsb + 2;
  				dz_ext0 = dz0 - 1 - SQUISH_CONSTANT_3D;
  				dz_ext1 = dz0 - 2 - 2 * SQUISH_CONSTANT_3D;
  			} else {
  				zsv_ext0 = zsv_ext1 = zsb;
  				dz_ext0 = dz0 - SQUISH_CONSTANT_3D;
  				dz_ext1 = dz0 - 2 * SQUISH_CONSTANT_3D;
  			}
  		}
  		
  		/* Contribution (1,1,0) */
  		dx3 = dx0 - 1 - 2 * SQUISH_CONSTANT_3D;
  		dy3 = dy0 - 1 - 2 * SQUISH_CONSTANT_3D;
  		dz3 = dz0 - 0 - 2 * SQUISH_CONSTANT_3D;
  		attn3 = 2 - dx3 * dx3 - dy3 * dy3 - dz3 * dz3;
  		if (attn3 > 0) {
  			attn3 *= attn3;
  			value += attn3 * attn3 * extrapolate3(ctx, xsb + 1, ysb + 1, zsb + 0, dx3, dy3, dz3);
  		}
  
  		/* Contribution (1,0,1) */
  		dx2 = dx3;
  		dy2 = dy0 - 0 - 2 * SQUISH_CONSTANT_3D;
  		dz2 = dz0 - 1 - 2 * SQUISH_CONSTANT_3D;
  		attn2 = 2 - dx2 * dx2 - dy2 * dy2 - dz2 * dz2;
  		if (attn2 > 0) {
  			attn2 *= attn2;
  			value += attn2 * attn2 * extrapolate3(ctx, xsb + 1, ysb + 0, zsb + 1, dx2, dy2, dz2);
  		}
  
  		/* Contribution (0,1,1) */
  		dx1 = dx0 - 0 - 2 * SQUISH_CONSTANT_3D;
  		dy1 = dy3;
  		dz1 = dz2;
  		attn1 = 2 - dx1 * dx1 - dy1 * dy1 - dz1 * dz1;
  		if (attn1 > 0) {
  			attn1 *= attn1;
  			value += attn1 * attn1 * extrapolate3(ctx, xsb + 0, ysb + 1, zsb + 1, dx1, dy1, dz1);
  		}
  
  		/* Contribution (1,1,1) */
  		dx0 = dx0 - 1 - 3 * SQUISH_CONSTANT_3D;
  		dy0 = dy0 - 1 - 3 * SQUISH_CONSTANT_3D;
  		dz0 = dz0 - 1 - 3 * SQUISH_CONSTANT_3D;
  		attn0 = 2 - dx0 * dx0 - dy0 * dy0 - dz0 * dz0;
  		if (attn0 > 0) {
  			attn0 *= attn0;
  			value += attn0 * attn0 * extrapolate3(ctx, xsb + 1, ysb + 1, zsb + 1, dx0, dy0, dz0);
  		}
  	} else { /* We're inside the octahedron (Rectified 3-Simplex) in between.
  		        Decide between point (0,0,1) and (1,1,0) as closest */
  		p1 = xins + yins;
  		if (p1 > 1) {
  			aScore = p1 - 1;
  			aPoint = 0x03;
  			aIsFurtherSide = 1;
  		} else {
  			aScore = 1 - p1;
  			aPoint = 0x04;
  			aIsFurtherSide = 0;
  		}
  
  		/* Decide between point (0,1,0) and (1,0,1) as closest */
  		p2 = xins + zins;
  		if (p2 > 1) {
  			bScore = p2 - 1;
  			bPoint = 0x05;
  			bIsFurtherSide = 1;
  		} else {
  			bScore = 1 - p2;
  			bPoint = 0x02;
  			bIsFurtherSide = 0;
  		}
  		
  		/* The closest out of the two (1,0,0) and (0,1,1) will replace the furthest out of the two decided above, if closer. */
  		p3 = yins + zins;
  		if (p3 > 1) {
  			score = p3 - 1;
  			if (aScore <= bScore && aScore < score) {
  				aScore = score;
  				aPoint = 0x06;
  				aIsFurtherSide = 1;
  			} else if (aScore > bScore && bScore < score) {
  				bScore = score;
  				bPoint = 0x06;
  				bIsFurtherSide = 1;
  			}
  		} else {
  			score = 1 - p3;
  			if (aScore <= bScore && aScore < score) {
  				aScore = score;
  				aPoint = 0x01;
  				aIsFurtherSide = 0;
  			} else if (aScore > bScore && bScore < score) {
  				bScore = score;
  				bPoint = 0x01;
  				bIsFurtherSide = 0;
  			}
  		}
  		
  		/* Where each of the two closest points are determines how the extra two vertices are calculated. */
  		if (aIsFurtherSide == bIsFurtherSide) {
  			if (aIsFurtherSide) { /* Both closest points on (1,1,1) side */
  
  				/* One of the two extra points is (1,1,1) */
  				dx_ext0 = dx0 - 1 - 3 * SQUISH_CONSTANT_3D;
  				dy_ext0 = dy0 - 1 - 3 * SQUISH_CONSTANT_3D;
  				dz_ext0 = dz0 - 1 - 3 * SQUISH_CONSTANT_3D;
  				xsv_ext0 = xsb + 1;
  				ysv_ext0 = ysb + 1;
  				zsv_ext0 = zsb + 1;
  
  				/* Other extra point is based on the shared axis. */
  				c = (int8_t)(aPoint & bPoint);
  				if ((c & 0x01) != 0) {
  					dx_ext1 = dx0 - 2 - 2 * SQUISH_CONSTANT_3D;
  					dy_ext1 = dy0 - 2 * SQUISH_CONSTANT_3D;
  					dz_ext1 = dz0 - 2 * SQUISH_CONSTANT_3D;
  					xsv_ext1 = xsb + 2;
  					ysv_ext1 = ysb;
  					zsv_ext1 = zsb;
  				} else if ((c & 0x02) != 0) {
  					dx_ext1 = dx0 - 2 * SQUISH_CONSTANT_3D;
  					dy_ext1 = dy0 - 2 - 2 * SQUISH_CONSTANT_3D;
  					dz_ext1 = dz0 - 2 * SQUISH_CONSTANT_3D;
  					xsv_ext1 = xsb;
  					ysv_ext1 = ysb + 2;
  					zsv_ext1 = zsb;
  				} else {
  					dx_ext1 = dx0 - 2 * SQUISH_CONSTANT_3D;
  					dy_ext1 = dy0 - 2 * SQUISH_CONSTANT_3D;
  					dz_ext1 = dz0 - 2 - 2 * SQUISH_CONSTANT_3D;
  					xsv_ext1 = xsb;
  					ysv_ext1 = ysb;
  					zsv_ext1 = zsb + 2;
  				}
  			} else { /* Both closest points on (0,0,0) side */
  
  				/* One of the two extra points is (0,0,0) */
  				dx_ext0 = dx0;
  				dy_ext0 = dy0;
  				dz_ext0 = dz0;
  				xsv_ext0 = xsb;
  				ysv_ext0 = ysb;
  				zsv_ext0 = zsb;
  
  				/* Other extra point is based on the omitted axis. */
  				c = (int8_t)(aPoint | bPoint);
  				if ((c & 0x01) == 0) {
  					dx_ext1 = dx0 + 1 - SQUISH_CONSTANT_3D;
  					dy_ext1 = dy0 - 1 - SQUISH_CONSTANT_3D;
  					dz_ext1 = dz0 - 1 - SQUISH_CONSTANT_3D;
  					xsv_ext1 = xsb - 1;
  					ysv_ext1 = ysb + 1;
  					zsv_ext1 = zsb + 1;
  				} else if ((c & 0x02) == 0) {
  					dx_ext1 = dx0 - 1 - SQUISH_CONSTANT_3D;
  					dy_ext1 = dy0 + 1 - SQUISH_CONSTANT_3D;
  					dz_ext1 = dz0 - 1 - SQUISH_CONSTANT_3D;
  					xsv_ext1 = xsb + 1;
  					ysv_ext1 = ysb - 1;
  					zsv_ext1 = zsb + 1;
  				} else {
  					dx_ext1 = dx0 - 1 - SQUISH_CONSTANT_3D;
  					dy_ext1 = dy0 - 1 - SQUISH_CONSTANT_3D;
  					dz_ext1 = dz0 + 1 - SQUISH_CONSTANT_3D;
  					xsv_ext1 = xsb + 1;
  					ysv_ext1 = ysb + 1;
  					zsv_ext1 = zsb - 1;
  				}
  			}
  		} else { /* One point on (0,0,0) side, one point on (1,1,1) side */
  			if (aIsFurtherSide) {
  				c1 = aPoint;
  				c2 = bPoint;
  			} else {
  				c1 = bPoint;
  				c2 = aPoint;
  			}
  
  			/* One contribution is a permutation of (1,1,-1) */
  			if ((c1 & 0x01) == 0) {
  				dx_ext0 = dx0 + 1 - SQUISH_CONSTANT_3D;
  				dy_ext0 = dy0 - 1 - SQUISH_CONSTANT_3D;
  				dz_ext0 = dz0 - 1 - SQUISH_CONSTANT_3D;
  				xsv_ext0 = xsb - 1;
  				ysv_ext0 = ysb + 1;
  				zsv_ext0 = zsb + 1;
  			} else if ((c1 & 0x02) == 0) {
  				dx_ext0 = dx0 - 1 - SQUISH_CONSTANT_3D;
  				dy_ext0 = dy0 + 1 - SQUISH_CONSTANT_3D;
  				dz_ext0 = dz0 - 1 - SQUISH_CONSTANT_3D;
  				xsv_ext0 = xsb + 1;
  				ysv_ext0 = ysb - 1;
  				zsv_ext0 = zsb + 1;
  			} else {
  				dx_ext0 = dx0 - 1 - SQUISH_CONSTANT_3D;
  				dy_ext0 = dy0 - 1 - SQUISH_CONSTANT_3D;
  				dz_ext0 = dz0 + 1 - SQUISH_CONSTANT_3D;
  				xsv_ext0 = xsb + 1;
  				ysv_ext0 = ysb + 1;
  				zsv_ext0 = zsb - 1;
  			}
  
  			/* One contribution is a permutation of (0,0,2) */
  			dx_ext1 = dx0 - 2 * SQUISH_CONSTANT_3D;
  			dy_ext1 = dy0 - 2 * SQUISH_CONSTANT_3D;
  			dz_ext1 = dz0 - 2 * SQUISH_CONSTANT_3D;
  			xsv_ext1 = xsb;
  			ysv_ext1 = ysb;
  			zsv_ext1 = zsb;
  			if ((c2 & 0x01) != 0) {
  				dx_ext1 -= 2;
  				xsv_ext1 += 2;
  			} else if ((c2 & 0x02) != 0) {
  				dy_ext1 -= 2;
  				ysv_ext1 += 2;
  			} else {
  				dz_ext1 -= 2;
  				zsv_ext1 += 2;
  			}
  		}
  
  		/* Contribution (1,0,0) */
  		dx1 = dx0 - 1 - SQUISH_CONSTANT_3D;
  		dy1 = dy0 - 0 - SQUISH_CONSTANT_3D;
  		dz1 = dz0 - 0 - SQUISH_CONSTANT_3D;
  		attn1 = 2 - dx1 * dx1 - dy1 * dy1 - dz1 * dz1;
  		if (attn1 > 0) {
  			attn1 *= attn1;
  			value += attn1 * attn1 * extrapolate3(ctx, xsb + 1, ysb + 0, zsb + 0, dx1, dy1, dz1);
  		}
  
  		/* Contribution (0,1,0) */
  		dx2 = dx0 - 0 - SQUISH_CONSTANT_3D;
  		dy2 = dy0 - 1 - SQUISH_CONSTANT_3D;
  		dz2 = dz1;
  		attn2 = 2 - dx2 * dx2 - dy2 * dy2 - dz2 * dz2;
  		if (attn2 > 0) {
  			attn2 *= attn2;
  			value += attn2 * attn2 * extrapolate3(ctx, xsb + 0, ysb + 1, zsb + 0, dx2, dy2, dz2);
  		}
  
  		/* Contribution (0,0,1) */
  		dx3 = dx2;
  		dy3 = dy1;
  		dz3 = dz0 - 1 - SQUISH_CONSTANT_3D;
  		attn3 = 2 - dx3 * dx3 - dy3 * dy3 - dz3 * dz3;
  		if (attn3 > 0) {
  			attn3 *= attn3;
  			value += attn3 * attn3 * extrapolate3(ctx, xsb + 0, ysb + 0, zsb + 1, dx3, dy3, dz3);
  		}
  
  		/* Contribution (1,1,0) */
  		dx4 = dx0 - 1 - 2 * SQUISH_CONSTANT_3D;
  		dy4 = dy0 - 1 - 2 * SQUISH_CONSTANT_3D;
  		dz4 = dz0 - 0 - 2 * SQUISH_CONSTANT_3D;
  		attn4 = 2 - dx4 * dx4 - dy4 * dy4 - dz4 * dz4;
  		if (attn4 > 0) {
  			attn4 *= attn4;
  			value += attn4 * attn4 * extrapolate3(ctx, xsb + 1, ysb + 1, zsb + 0, dx4, dy4, dz4);
  		}
  
  		/* Contribution (1,0,1) */
  		dx5 = dx4;
  		dy5 = dy0 - 0 - 2 * SQUISH_CONSTANT_3D;
  		dz5 = dz0 - 1 - 2 * SQUISH_CONSTANT_3D;
  		attn5 = 2 - dx5 * dx5 - dy5 * dy5 - dz5 * dz5;
  		if (attn5 > 0) {
  			attn5 *= attn5;
  			value += attn5 * attn5 * extrapolate3(ctx, xsb + 1, ysb + 0, zsb + 1, dx5, dy5, dz5);
  		}
  
  		/* Contribution (0,1,1) */
  		dx6 = dx0 - 0 - 2 * SQUISH_CONSTANT_3D;
  		dy6 = dy4;
  		dz6 = dz5;
  		attn6 = 2 - dx6 * dx6 - dy6 * dy6 - dz6 * dz6;
  		if (attn6 > 0) {
  			attn6 *= attn6;
  			value += attn6 * attn6 * extrapolate3(ctx, xsb + 0, ysb + 1, zsb + 1, dx6, dy6, dz6);
  		}
  	}
  
  	/* First extra vertex */
  	attn_ext0 = 2 - dx_ext0 * dx_ext0 - dy_ext0 * dy_ext0 - dz_ext0 * dz_ext0;
  	if (attn_ext0 > 0)
  	{
  		attn_ext0 *= attn_ext0;
  		value += attn_ext0 * attn_ext0 * extrapolate3(ctx, xsv_ext0, ysv_ext0, zsv_ext0, dx_ext0, dy_ext0, dz_ext0);
  	}
  
  	/* Second extra vertex */
  	attn_ext1 = 2 - dx_ext1 * dx_ext1 - dy_ext1 * dy_ext1 - dz_ext1 * dz_ext1;
  	if (attn_ext1 > 0)
  	{
  		attn_ext1 *= attn_ext1;
  		value += attn_ext1 * attn_ext1 * extrapolate3(ctx, xsv_ext1, ysv_ext1, zsv_ext1, dx_ext1, dy_ext1, dz_ext1);
  	}
  	
  	return value / NORM_CONSTANT_3D;
  }
  	
  /* 
   * 4D OpenSimplex (Simplectic) Noise.
   */
  double open_simplex_noise4(const struct osn_context *ctx, double x, double y, double z, double w)
  {
  	double uins;
  	double dx1, dy1, dz1, dw1;
  	double dx2, dy2, dz2, dw2;
  	double dx3, dy3, dz3, dw3;
  	double dx4, dy4, dz4, dw4;
  	double dx5, dy5, dz5, dw5;
  	double dx6, dy6, dz6, dw6;
  	double dx7, dy7, dz7, dw7;
  	double dx8, dy8, dz8, dw8;
  	double dx9, dy9, dz9, dw9;
  	double dx10, dy10, dz10, dw10;
  	double attn0, attn1, attn2, attn3, attn4;
  	double attn5, attn6, attn7, attn8, attn9, attn10;
  	double attn_ext0, attn_ext1, attn_ext2;
  	int8_t c, c1, c2;
  	int8_t aPoint, bPoint;
  	double aScore, bScore;
  	int aIsBiggerSide;
  	int bIsBiggerSide;
  	double p1, p2, p3, p4;
  	double score;
  
  	/* Place input coordinates on simplectic honeycomb. */
  	double stretchOffset = (x + y + z + w) * STRETCH_CONSTANT_4D;
  	double xs = x + stretchOffset;
  	double ys = y + stretchOffset;
  	double zs = z + stretchOffset;
  	double ws = w + stretchOffset;
  	
  	/* Floor to get simplectic honeycomb coordinates of rhombo-hypercube super-cell origin. */
  	int xsb = fastFloor(xs);
  	int ysb = fastFloor(ys);
  	int zsb = fastFloor(zs);
  	int wsb = fastFloor(ws);
  	
  	/* Skew out to get actual coordinates of stretched rhombo-hypercube origin. We'll need these later. */
  	double squishOffset = (xsb + ysb + zsb + wsb) * SQUISH_CONSTANT_4D;
  	double xb = xsb + squishOffset;
  	double yb = ysb + squishOffset;
  	double zb = zsb + squishOffset;
  	double wb = wsb + squishOffset;
  	
  	/* Compute simplectic honeycomb coordinates relative to rhombo-hypercube origin. */
  	double xins = xs - xsb;
  	double yins = ys - ysb;
  	double zins = zs - zsb;
  	double wins = ws - wsb;
  	
  	/* Sum those together to get a value that determines which region we're in. */
  	double inSum = xins + yins + zins + wins;
  
  	/* Positions relative to origin point. */
  	double dx0 = x - xb;
  	double dy0 = y - yb;
  	double dz0 = z - zb;
  	double dw0 = w - wb;
  	
  	/* We'll be defining these inside the next block and using them afterwards. */
  	double dx_ext0, dy_ext0, dz_ext0, dw_ext0;
  	double dx_ext1, dy_ext1, dz_ext1, dw_ext1;
  	double dx_ext2, dy_ext2, dz_ext2, dw_ext2;
  	int xsv_ext0, ysv_ext0, zsv_ext0, wsv_ext0;
  	int xsv_ext1, ysv_ext1, zsv_ext1, wsv_ext1;
  	int xsv_ext2, ysv_ext2, zsv_ext2, wsv_ext2;
  	
  	double value = 0;
  	if (inSum <= 1) { /* We're inside the pentachoron (4-Simplex) at (0,0,0,0) */
  
  		/* Determine which two of (0,0,0,1), (0,0,1,0), (0,1,0,0), (1,0,0,0) are closest. */
  		aPoint = 0x01;
  		aScore = xins;
  		bPoint = 0x02;
  		bScore = yins;
  		if (aScore >= bScore && zins > bScore) {
  			bScore = zins;
  			bPoint = 0x04;
  		} else if (aScore < bScore && zins > aScore) {
  			aScore = zins;
  			aPoint = 0x04;
  		}
  		if (aScore >= bScore && wins > bScore) {
  			bScore = wins;
  			bPoint = 0x08;
  		} else if (aScore < bScore && wins > aScore) {
  			aScore = wins;
  			aPoint = 0x08;
  		}
  		
  		/* Now we determine the three lattice points not part of the pentachoron that may contribute.
  		   This depends on the closest two pentachoron vertices, including (0,0,0,0) */
  		uins = 1 - inSum;
  		if (uins > aScore || uins > bScore) { /* (0,0,0,0) is one of the closest two pentachoron vertices. */
  			c = (bScore > aScore ? bPoint : aPoint); /* Our other closest vertex is the closest out of a and b. */
  			if ((c & 0x01) == 0) {
  				xsv_ext0 = xsb - 1;
  				xsv_ext1 = xsv_ext2 = xsb;
  				dx_ext0 = dx0 + 1;
  				dx_ext1 = dx_ext2 = dx0;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsv_ext2 = xsb + 1;
  				dx_ext0 = dx_ext1 = dx_ext2 = dx0 - 1;
  			}
  
  			if ((c & 0x02) == 0) {
  				ysv_ext0 = ysv_ext1 = ysv_ext2 = ysb;
  				dy_ext0 = dy_ext1 = dy_ext2 = dy0;
  				if ((c & 0x01) == 0x01) {
  					ysv_ext0 -= 1;
  					dy_ext0 += 1;
  				} else {
  					ysv_ext1 -= 1;
  					dy_ext1 += 1;
  				}
  			} else {
  				ysv_ext0 = ysv_ext1 = ysv_ext2 = ysb + 1;
  				dy_ext0 = dy_ext1 = dy_ext2 = dy0 - 1;
  			}
  			
  			if ((c & 0x04) == 0) {
  				zsv_ext0 = zsv_ext1 = zsv_ext2 = zsb;
  				dz_ext0 = dz_ext1 = dz_ext2 = dz0;
  				if ((c & 0x03) != 0) {
  					if ((c & 0x03) == 0x03) {
  						zsv_ext0 -= 1;
  						dz_ext0 += 1;
  					} else {
  						zsv_ext1 -= 1;
  						dz_ext1 += 1;
  					}
  				} else {
  					zsv_ext2 -= 1;
  					dz_ext2 += 1;
  				}
  			} else {
  				zsv_ext0 = zsv_ext1 = zsv_ext2 = zsb + 1;
  				dz_ext0 = dz_ext1 = dz_ext2 = dz0 - 1;
  			}
  			
  			if ((c & 0x08) == 0) {
  				wsv_ext0 = wsv_ext1 = wsb;
  				wsv_ext2 = wsb - 1;
  				dw_ext0 = dw_ext1 = dw0;
  				dw_ext2 = dw0 + 1;
  			} else {
  				wsv_ext0 = wsv_ext1 = wsv_ext2 = wsb + 1;
  				dw_ext0 = dw_ext1 = dw_ext2 = dw0 - 1;
  			}
  		} else { /* (0,0,0,0) is not one of the closest two pentachoron vertices. */
  			c = (int8_t)(aPoint | bPoint); /* Our three extra vertices are determined by the closest two. */
  			
  			if ((c & 0x01) == 0) {
  				xsv_ext0 = xsv_ext2 = xsb;
  				xsv_ext1 = xsb - 1;
  				dx_ext0 = dx0 - 2 * SQUISH_CONSTANT_4D;
  				dx_ext1 = dx0 + 1 - SQUISH_CONSTANT_4D;
  				dx_ext2 = dx0 - SQUISH_CONSTANT_4D;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsv_ext2 = xsb + 1;
  				dx_ext0 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dx_ext1 = dx_ext2 = dx0 - 1 - SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c & 0x02) == 0) {
  				ysv_ext0 = ysv_ext1 = ysv_ext2 = ysb;
  				dy_ext0 = dy0 - 2 * SQUISH_CONSTANT_4D;
  				dy_ext1 = dy_ext2 = dy0 - SQUISH_CONSTANT_4D;
  				if ((c & 0x01) == 0x01) {
  					ysv_ext1 -= 1;
  					dy_ext1 += 1;
  				} else {
  					ysv_ext2 -= 1;
  					dy_ext2 += 1;
  				}
  			} else {
  				ysv_ext0 = ysv_ext1 = ysv_ext2 = ysb + 1;
  				dy_ext0 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dy_ext1 = dy_ext2 = dy0 - 1 - SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c & 0x04) == 0) {
  				zsv_ext0 = zsv_ext1 = zsv_ext2 = zsb;
  				dz_ext0 = dz0 - 2 * SQUISH_CONSTANT_4D;
  				dz_ext1 = dz_ext2 = dz0 - SQUISH_CONSTANT_4D;
  				if ((c & 0x03) == 0x03) {
  					zsv_ext1 -= 1;
  					dz_ext1 += 1;
  				} else {
  					zsv_ext2 -= 1;
  					dz_ext2 += 1;
  				}
  			} else {
  				zsv_ext0 = zsv_ext1 = zsv_ext2 = zsb + 1;
  				dz_ext0 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dz_ext1 = dz_ext2 = dz0 - 1 - SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c & 0x08) == 0) {
  				wsv_ext0 = wsv_ext1 = wsb;
  				wsv_ext2 = wsb - 1;
  				dw_ext0 = dw0 - 2 * SQUISH_CONSTANT_4D;
  				dw_ext1 = dw0 - SQUISH_CONSTANT_4D;
  				dw_ext2 = dw0 + 1 - SQUISH_CONSTANT_4D;
  			} else {
  				wsv_ext0 = wsv_ext1 = wsv_ext2 = wsb + 1;
  				dw_ext0 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dw_ext1 = dw_ext2 = dw0 - 1 - SQUISH_CONSTANT_4D;
  			}
  		}
  
  		/* Contribution (0,0,0,0) */
  		attn0 = 2 - dx0 * dx0 - dy0 * dy0 - dz0 * dz0 - dw0 * dw0;
  		if (attn0 > 0) {
  			attn0 *= attn0;
  			value += attn0 * attn0 * extrapolate4(ctx, xsb + 0, ysb + 0, zsb + 0, wsb + 0, dx0, dy0, dz0, dw0);
  		}
  
  		/* Contribution (1,0,0,0) */
  		dx1 = dx0 - 1 - SQUISH_CONSTANT_4D;
  		dy1 = dy0 - 0 - SQUISH_CONSTANT_4D;
  		dz1 = dz0 - 0 - SQUISH_CONSTANT_4D;
  		dw1 = dw0 - 0 - SQUISH_CONSTANT_4D;
  		attn1 = 2 - dx1 * dx1 - dy1 * dy1 - dz1 * dz1 - dw1 * dw1;
  		if (attn1 > 0) {
  			attn1 *= attn1;
  			value += attn1 * attn1 * extrapolate4(ctx, xsb + 1, ysb + 0, zsb + 0, wsb + 0, dx1, dy1, dz1, dw1);
  		}
  
  		/* Contribution (0,1,0,0) */
  		dx2 = dx0 - 0 - SQUISH_CONSTANT_4D;
  		dy2 = dy0 - 1 - SQUISH_CONSTANT_4D;
  		dz2 = dz1;
  		dw2 = dw1;
  		attn2 = 2 - dx2 * dx2 - dy2 * dy2 - dz2 * dz2 - dw2 * dw2;
  		if (attn2 > 0) {
  			attn2 *= attn2;
  			value += attn2 * attn2 * extrapolate4(ctx, xsb + 0, ysb + 1, zsb + 0, wsb + 0, dx2, dy2, dz2, dw2);
  		}
  
  		/* Contribution (0,0,1,0) */
  		dx3 = dx2;
  		dy3 = dy1;
  		dz3 = dz0 - 1 - SQUISH_CONSTANT_4D;
  		dw3 = dw1;
  		attn3 = 2 - dx3 * dx3 - dy3 * dy3 - dz3 * dz3 - dw3 * dw3;
  		if (attn3 > 0) {
  			attn3 *= attn3;
  			value += attn3 * attn3 * extrapolate4(ctx, xsb + 0, ysb + 0, zsb + 1, wsb + 0, dx3, dy3, dz3, dw3);
  		}
  
  		/* Contribution (0,0,0,1) */
  		dx4 = dx2;
  		dy4 = dy1;
  		dz4 = dz1;
  		dw4 = dw0 - 1 - SQUISH_CONSTANT_4D;
  		attn4 = 2 - dx4 * dx4 - dy4 * dy4 - dz4 * dz4 - dw4 * dw4;
  		if (attn4 > 0) {
  			attn4 *= attn4;
  			value += attn4 * attn4 * extrapolate4(ctx, xsb + 0, ysb + 0, zsb + 0, wsb + 1, dx4, dy4, dz4, dw4);
  		}
  	} else if (inSum >= 3) { /* We're inside the pentachoron (4-Simplex) at (1,1,1,1)
  		Determine which two of (1,1,1,0), (1,1,0,1), (1,0,1,1), (0,1,1,1) are closest. */
  		aPoint = 0x0E;
  		aScore = xins;
  		bPoint = 0x0D;
  		bScore = yins;
  		if (aScore <= bScore && zins < bScore) {
  			bScore = zins;
  			bPoint = 0x0B;
  		} else if (aScore > bScore && zins < aScore) {
  			aScore = zins;
  			aPoint = 0x0B;
  		}
  		if (aScore <= bScore && wins < bScore) {
  			bScore = wins;
  			bPoint = 0x07;
  		} else if (aScore > bScore && wins < aScore) {
  			aScore = wins;
  			aPoint = 0x07;
  		}
  		
  		/* Now we determine the three lattice points not part of the pentachoron that may contribute.
  		   This depends on the closest two pentachoron vertices, including (0,0,0,0) */
  		uins = 4 - inSum;
  		if (uins < aScore || uins < bScore) { /* (1,1,1,1) is one of the closest two pentachoron vertices. */
  			c = (bScore < aScore ? bPoint : aPoint); /* Our other closest vertex is the closest out of a and b. */
  			
  			if ((c & 0x01) != 0) {
  				xsv_ext0 = xsb + 2;
  				xsv_ext1 = xsv_ext2 = xsb + 1;
  				dx_ext0 = dx0 - 2 - 4 * SQUISH_CONSTANT_4D;
  				dx_ext1 = dx_ext2 = dx0 - 1 - 4 * SQUISH_CONSTANT_4D;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsv_ext2 = xsb;
  				dx_ext0 = dx_ext1 = dx_ext2 = dx0 - 4 * SQUISH_CONSTANT_4D;
  			}
  
  			if ((c & 0x02) != 0) {
  				ysv_ext0 = ysv_ext1 = ysv_ext2 = ysb + 1;
  				dy_ext0 = dy_ext1 = dy_ext2 = dy0 - 1 - 4 * SQUISH_CONSTANT_4D;
  				if ((c & 0x01) != 0) {
  					ysv_ext1 += 1;
  					dy_ext1 -= 1;
  				} else {
  					ysv_ext0 += 1;
  					dy_ext0 -= 1;
  				}
  			} else {
  				ysv_ext0 = ysv_ext1 = ysv_ext2 = ysb;
  				dy_ext0 = dy_ext1 = dy_ext2 = dy0 - 4 * SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c & 0x04) != 0) {
  				zsv_ext0 = zsv_ext1 = zsv_ext2 = zsb + 1;
  				dz_ext0 = dz_ext1 = dz_ext2 = dz0 - 1 - 4 * SQUISH_CONSTANT_4D;
  				if ((c & 0x03) != 0x03) {
  					if ((c & 0x03) == 0) {
  						zsv_ext0 += 1;
  						dz_ext0 -= 1;
  					} else {
  						zsv_ext1 += 1;
  						dz_ext1 -= 1;
  					}
  				} else {
  					zsv_ext2 += 1;
  					dz_ext2 -= 1;
  				}
  			} else {
  				zsv_ext0 = zsv_ext1 = zsv_ext2 = zsb;
  				dz_ext0 = dz_ext1 = dz_ext2 = dz0 - 4 * SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c & 0x08) != 0) {
  				wsv_ext0 = wsv_ext1 = wsb + 1;
  				wsv_ext2 = wsb + 2;
  				dw_ext0 = dw_ext1 = dw0 - 1 - 4 * SQUISH_CONSTANT_4D;
  				dw_ext2 = dw0 - 2 - 4 * SQUISH_CONSTANT_4D;
  			} else {
  				wsv_ext0 = wsv_ext1 = wsv_ext2 = wsb;
  				dw_ext0 = dw_ext1 = dw_ext2 = dw0 - 4 * SQUISH_CONSTANT_4D;
  			}
  		} else { /* (1,1,1,1) is not one of the closest two pentachoron vertices. */
  			c = (int8_t)(aPoint & bPoint); /* Our three extra vertices are determined by the closest two. */
  			
  			if ((c & 0x01) != 0) {
  				xsv_ext0 = xsv_ext2 = xsb + 1;
  				xsv_ext1 = xsb + 2;
  				dx_ext0 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dx_ext1 = dx0 - 2 - 3 * SQUISH_CONSTANT_4D;
  				dx_ext2 = dx0 - 1 - 3 * SQUISH_CONSTANT_4D;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsv_ext2 = xsb;
  				dx_ext0 = dx0 - 2 * SQUISH_CONSTANT_4D;
  				dx_ext1 = dx_ext2 = dx0 - 3 * SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c & 0x02) != 0) {
  				ysv_ext0 = ysv_ext1 = ysv_ext2 = ysb + 1;
  				dy_ext0 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dy_ext1 = dy_ext2 = dy0 - 1 - 3 * SQUISH_CONSTANT_4D;
  				if ((c & 0x01) != 0) {
  					ysv_ext2 += 1;
  					dy_ext2 -= 1;
  				} else {
  					ysv_ext1 += 1;
  					dy_ext1 -= 1;
  				}
  			} else {
  				ysv_ext0 = ysv_ext1 = ysv_ext2 = ysb;
  				dy_ext0 = dy0 - 2 * SQUISH_CONSTANT_4D;
  				dy_ext1 = dy_ext2 = dy0 - 3 * SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c & 0x04) != 0) {
  				zsv_ext0 = zsv_ext1 = zsv_ext2 = zsb + 1;
  				dz_ext0 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dz_ext1 = dz_ext2 = dz0 - 1 - 3 * SQUISH_CONSTANT_4D;
  				if ((c & 0x03) != 0) {
  					zsv_ext2 += 1;
  					dz_ext2 -= 1;
  				} else {
  					zsv_ext1 += 1;
  					dz_ext1 -= 1;
  				}
  			} else {
  				zsv_ext0 = zsv_ext1 = zsv_ext2 = zsb;
  				dz_ext0 = dz0 - 2 * SQUISH_CONSTANT_4D;
  				dz_ext1 = dz_ext2 = dz0 - 3 * SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c & 0x08) != 0) {
  				wsv_ext0 = wsv_ext1 = wsb + 1;
  				wsv_ext2 = wsb + 2;
  				dw_ext0 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dw_ext1 = dw0 - 1 - 3 * SQUISH_CONSTANT_4D;
  				dw_ext2 = dw0 - 2 - 3 * SQUISH_CONSTANT_4D;
  			} else {
  				wsv_ext0 = wsv_ext1 = wsv_ext2 = wsb;
  				dw_ext0 = dw0 - 2 * SQUISH_CONSTANT_4D;
  				dw_ext1 = dw_ext2 = dw0 - 3 * SQUISH_CONSTANT_4D;
  			}
  		}
  
  		/* Contribution (1,1,1,0) */
  		dx4 = dx0 - 1 - 3 * SQUISH_CONSTANT_4D;
  		dy4 = dy0 - 1 - 3 * SQUISH_CONSTANT_4D;
  		dz4 = dz0 - 1 - 3 * SQUISH_CONSTANT_4D;
  		dw4 = dw0 - 3 * SQUISH_CONSTANT_4D;
  		attn4 = 2 - dx4 * dx4 - dy4 * dy4 - dz4 * dz4 - dw4 * dw4;
  		if (attn4 > 0) {
  			attn4 *= attn4;
  			value += attn4 * attn4 * extrapolate4(ctx, xsb + 1, ysb + 1, zsb + 1, wsb + 0, dx4, dy4, dz4, dw4);
  		}
  
  		/* Contribution (1,1,0,1) */
  		dx3 = dx4;
  		dy3 = dy4;
  		dz3 = dz0 - 3 * SQUISH_CONSTANT_4D;
  		dw3 = dw0 - 1 - 3 * SQUISH_CONSTANT_4D;
  		attn3 = 2 - dx3 * dx3 - dy3 * dy3 - dz3 * dz3 - dw3 * dw3;
  		if (attn3 > 0) {
  			attn3 *= attn3;
  			value += attn3 * attn3 * extrapolate4(ctx, xsb + 1, ysb + 1, zsb + 0, wsb + 1, dx3, dy3, dz3, dw3);
  		}
  
  		/* Contribution (1,0,1,1) */
  		dx2 = dx4;
  		dy2 = dy0 - 3 * SQUISH_CONSTANT_4D;
  		dz2 = dz4;
  		dw2 = dw3;
  		attn2 = 2 - dx2 * dx2 - dy2 * dy2 - dz2 * dz2 - dw2 * dw2;
  		if (attn2 > 0) {
  			attn2 *= attn2;
  			value += attn2 * attn2 * extrapolate4(ctx, xsb + 1, ysb + 0, zsb + 1, wsb + 1, dx2, dy2, dz2, dw2);
  		}
  
  		/* Contribution (0,1,1,1) */
  		dx1 = dx0 - 3 * SQUISH_CONSTANT_4D;
  		dz1 = dz4;
  		dy1 = dy4;
  		dw1 = dw3;
  		attn1 = 2 - dx1 * dx1 - dy1 * dy1 - dz1 * dz1 - dw1 * dw1;
  		if (attn1 > 0) {
  			attn1 *= attn1;
  			value += attn1 * attn1 * extrapolate4(ctx, xsb + 0, ysb + 1, zsb + 1, wsb + 1, dx1, dy1, dz1, dw1);
  		}
  
  		/* Contribution (1,1,1,1) */
  		dx0 = dx0 - 1 - 4 * SQUISH_CONSTANT_4D;
  		dy0 = dy0 - 1 - 4 * SQUISH_CONSTANT_4D;
  		dz0 = dz0 - 1 - 4 * SQUISH_CONSTANT_4D;
  		dw0 = dw0 - 1 - 4 * SQUISH_CONSTANT_4D;
  		attn0 = 2 - dx0 * dx0 - dy0 * dy0 - dz0 * dz0 - dw0 * dw0;
  		if (attn0 > 0) {
  			attn0 *= attn0;
  			value += attn0 * attn0 * extrapolate4(ctx, xsb + 1, ysb + 1, zsb + 1, wsb + 1, dx0, dy0, dz0, dw0);
  		}
  	} else if (inSum <= 2) { /* We're inside the first dispentachoron (Rectified 4-Simplex) */
  		aIsBiggerSide = 1;
  		bIsBiggerSide = 1;
  		
  		/* Decide between (1,1,0,0) and (0,0,1,1) */
  		if (xins + yins > zins + wins) {
  			aScore = xins + yins;
  			aPoint = 0x03;
  		} else {
  			aScore = zins + wins;
  			aPoint = 0x0C;
  		}
  		
  		/* Decide between (1,0,1,0) and (0,1,0,1) */
  		if (xins + zins > yins + wins) {
  			bScore = xins + zins;
  			bPoint = 0x05;
  		} else {
  			bScore = yins + wins;
  			bPoint = 0x0A;
  		}
  		
  		/* Closer between (1,0,0,1) and (0,1,1,0) will replace the further of a and b, if closer. */
  		if (xins + wins > yins + zins) {
  			score = xins + wins;
  			if (aScore >= bScore && score > bScore) {
  				bScore = score;
  				bPoint = 0x09;
  			} else if (aScore < bScore && score > aScore) {
  				aScore = score;
  				aPoint = 0x09;
  			}
  		} else {
  			score = yins + zins;
  			if (aScore >= bScore && score > bScore) {
  				bScore = score;
  				bPoint = 0x06;
  			} else if (aScore < bScore && score > aScore) {
  				aScore = score;
  				aPoint = 0x06;
  			}
  		}
  		
  		/* Decide if (1,0,0,0) is closer. */
  		p1 = 2 - inSum + xins;
  		if (aScore >= bScore && p1 > bScore) {
  			bScore = p1;
  			bPoint = 0x01;
  			bIsBiggerSide = 0;
  		} else if (aScore < bScore && p1 > aScore) {
  			aScore = p1;
  			aPoint = 0x01;
  			aIsBiggerSide = 0;
  		}
  		
  		/* Decide if (0,1,0,0) is closer. */
  		p2 = 2 - inSum + yins;
  		if (aScore >= bScore && p2 > bScore) {
  			bScore = p2;
  			bPoint = 0x02;
  			bIsBiggerSide = 0;
  		} else if (aScore < bScore && p2 > aScore) {
  			aScore = p2;
  			aPoint = 0x02;
  			aIsBiggerSide = 0;
  		}
  		
  		/* Decide if (0,0,1,0) is closer. */
  		p3 = 2 - inSum + zins;
  		if (aScore >= bScore && p3 > bScore) {
  			bScore = p3;
  			bPoint = 0x04;
  			bIsBiggerSide = 0;
  		} else if (aScore < bScore && p3 > aScore) {
  			aScore = p3;
  			aPoint = 0x04;
  			aIsBiggerSide = 0;
  		}
  		
  		/* Decide if (0,0,0,1) is closer. */
  		p4 = 2 - inSum + wins;
  		if (aScore >= bScore && p4 > bScore) {
  			bScore = p4;
  			bPoint = 0x08;
  			bIsBiggerSide = 0;
  		} else if (aScore < bScore && p4 > aScore) {
  			aScore = p4;
  			aPoint = 0x08;
  			aIsBiggerSide = 0;
  		}
  		
  		/* Where each of the two closest points are determines how the extra three vertices are calculated. */
  		if (aIsBiggerSide == bIsBiggerSide) {
  			if (aIsBiggerSide) { /* Both closest points on the bigger side */
  				c1 = (int8_t)(aPoint | bPoint);
  				c2 = (int8_t)(aPoint & bPoint);
  				if ((c1 & 0x01) == 0) {
  					xsv_ext0 = xsb;
  					xsv_ext1 = xsb - 1;
  					dx_ext0 = dx0 - 3 * SQUISH_CONSTANT_4D;
  					dx_ext1 = dx0 + 1 - 2 * SQUISH_CONSTANT_4D;
  				} else {
  					xsv_ext0 = xsv_ext1 = xsb + 1;
  					dx_ext0 = dx0 - 1 - 3 * SQUISH_CONSTANT_4D;
  					dx_ext1 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c1 & 0x02) == 0) {
  					ysv_ext0 = ysb;
  					ysv_ext1 = ysb - 1;
  					dy_ext0 = dy0 - 3 * SQUISH_CONSTANT_4D;
  					dy_ext1 = dy0 + 1 - 2 * SQUISH_CONSTANT_4D;
  				} else {
  					ysv_ext0 = ysv_ext1 = ysb + 1;
  					dy_ext0 = dy0 - 1 - 3 * SQUISH_CONSTANT_4D;
  					dy_ext1 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c1 & 0x04) == 0) {
  					zsv_ext0 = zsb;
  					zsv_ext1 = zsb - 1;
  					dz_ext0 = dz0 - 3 * SQUISH_CONSTANT_4D;
  					dz_ext1 = dz0 + 1 - 2 * SQUISH_CONSTANT_4D;
  				} else {
  					zsv_ext0 = zsv_ext1 = zsb + 1;
  					dz_ext0 = dz0 - 1 - 3 * SQUISH_CONSTANT_4D;
  					dz_ext1 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c1 & 0x08) == 0) {
  					wsv_ext0 = wsb;
  					wsv_ext1 = wsb - 1;
  					dw_ext0 = dw0 - 3 * SQUISH_CONSTANT_4D;
  					dw_ext1 = dw0 + 1 - 2 * SQUISH_CONSTANT_4D;
  				} else {
  					wsv_ext0 = wsv_ext1 = wsb + 1;
  					dw_ext0 = dw0 - 1 - 3 * SQUISH_CONSTANT_4D;
  					dw_ext1 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				}
  				
  				/* One combination is a permutation of (0,0,0,2) based on c2 */
  				xsv_ext2 = xsb;
  				ysv_ext2 = ysb;
  				zsv_ext2 = zsb;
  				wsv_ext2 = wsb;
  				dx_ext2 = dx0 - 2 * SQUISH_CONSTANT_4D;
  				dy_ext2 = dy0 - 2 * SQUISH_CONSTANT_4D;
  				dz_ext2 = dz0 - 2 * SQUISH_CONSTANT_4D;
  				dw_ext2 = dw0 - 2 * SQUISH_CONSTANT_4D;
  				if ((c2 & 0x01) != 0) {
  					xsv_ext2 += 2;
  					dx_ext2 -= 2;
  				} else if ((c2 & 0x02) != 0) {
  					ysv_ext2 += 2;
  					dy_ext2 -= 2;
  				} else if ((c2 & 0x04) != 0) {
  					zsv_ext2 += 2;
  					dz_ext2 -= 2;
  				} else {
  					wsv_ext2 += 2;
  					dw_ext2 -= 2;
  				}
  				
  			} else { /* Both closest points on the smaller side */
  				/* One of the two extra points is (0,0,0,0) */
  				xsv_ext2 = xsb;
  				ysv_ext2 = ysb;
  				zsv_ext2 = zsb;
  				wsv_ext2 = wsb;
  				dx_ext2 = dx0;
  				dy_ext2 = dy0;
  				dz_ext2 = dz0;
  				dw_ext2 = dw0;
  				
  				/* Other two points are based on the omitted axes. */
  				c = (int8_t)(aPoint | bPoint);
  				
  				if ((c & 0x01) == 0) {
  					xsv_ext0 = xsb - 1;
  					xsv_ext1 = xsb;
  					dx_ext0 = dx0 + 1 - SQUISH_CONSTANT_4D;
  					dx_ext1 = dx0 - SQUISH_CONSTANT_4D;
  				} else {
  					xsv_ext0 = xsv_ext1 = xsb + 1;
  					dx_ext0 = dx_ext1 = dx0 - 1 - SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c & 0x02) == 0) {
  					ysv_ext0 = ysv_ext1 = ysb;
  					dy_ext0 = dy_ext1 = dy0 - SQUISH_CONSTANT_4D;
  					if ((c & 0x01) == 0x01)
  					{
  						ysv_ext0 -= 1;
  						dy_ext0 += 1;
  					} else {
  						ysv_ext1 -= 1;
  						dy_ext1 += 1;
  					}
  				} else {
  					ysv_ext0 = ysv_ext1 = ysb + 1;
  					dy_ext0 = dy_ext1 = dy0 - 1 - SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c & 0x04) == 0) {
  					zsv_ext0 = zsv_ext1 = zsb;
  					dz_ext0 = dz_ext1 = dz0 - SQUISH_CONSTANT_4D;
  					if ((c & 0x03) == 0x03)
  					{
  						zsv_ext0 -= 1;
  						dz_ext0 += 1;
  					} else {
  						zsv_ext1 -= 1;
  						dz_ext1 += 1;
  					}
  				} else {
  					zsv_ext0 = zsv_ext1 = zsb + 1;
  					dz_ext0 = dz_ext1 = dz0 - 1 - SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c & 0x08) == 0)
  				{
  					wsv_ext0 = wsb;
  					wsv_ext1 = wsb - 1;
  					dw_ext0 = dw0 - SQUISH_CONSTANT_4D;
  					dw_ext1 = dw0 + 1 - SQUISH_CONSTANT_4D;
  				} else {
  					wsv_ext0 = wsv_ext1 = wsb + 1;
  					dw_ext0 = dw_ext1 = dw0 - 1 - SQUISH_CONSTANT_4D;
  				}
  				
  			}
  		} else { /* One point on each "side" */
  			if (aIsBiggerSide) {
  				c1 = aPoint;
  				c2 = bPoint;
  			} else {
  				c1 = bPoint;
  				c2 = aPoint;
  			}
  			
  			/* Two contributions are the bigger-sided point with each 0 replaced with -1. */
  			if ((c1 & 0x01) == 0) {
  				xsv_ext0 = xsb - 1;
  				xsv_ext1 = xsb;
  				dx_ext0 = dx0 + 1 - SQUISH_CONSTANT_4D;
  				dx_ext1 = dx0 - SQUISH_CONSTANT_4D;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsb + 1;
  				dx_ext0 = dx_ext1 = dx0 - 1 - SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c1 & 0x02) == 0) {
  				ysv_ext0 = ysv_ext1 = ysb;
  				dy_ext0 = dy_ext1 = dy0 - SQUISH_CONSTANT_4D;
  				if ((c1 & 0x01) == 0x01) {
  					ysv_ext0 -= 1;
  					dy_ext0 += 1;
  				} else {
  					ysv_ext1 -= 1;
  					dy_ext1 += 1;
  				}
  			} else {
  				ysv_ext0 = ysv_ext1 = ysb + 1;
  				dy_ext0 = dy_ext1 = dy0 - 1 - SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c1 & 0x04) == 0) {
  				zsv_ext0 = zsv_ext1 = zsb;
  				dz_ext0 = dz_ext1 = dz0 - SQUISH_CONSTANT_4D;
  				if ((c1 & 0x03) == 0x03) {
  					zsv_ext0 -= 1;
  					dz_ext0 += 1;
  				} else {
  					zsv_ext1 -= 1;
  					dz_ext1 += 1;
  				}
  			} else {
  				zsv_ext0 = zsv_ext1 = zsb + 1;
  				dz_ext0 = dz_ext1 = dz0 - 1 - SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c1 & 0x08) == 0) {
  				wsv_ext0 = wsb;
  				wsv_ext1 = wsb - 1;
  				dw_ext0 = dw0 - SQUISH_CONSTANT_4D;
  				dw_ext1 = dw0 + 1 - SQUISH_CONSTANT_4D;
  			} else {
  				wsv_ext0 = wsv_ext1 = wsb + 1;
  				dw_ext0 = dw_ext1 = dw0 - 1 - SQUISH_CONSTANT_4D;
  			}
  
  			/* One contribution is a permutation of (0,0,0,2) based on the smaller-sided point */
  			xsv_ext2 = xsb;
  			ysv_ext2 = ysb;
  			zsv_ext2 = zsb;
  			wsv_ext2 = wsb;
  			dx_ext2 = dx0 - 2 * SQUISH_CONSTANT_4D;
  			dy_ext2 = dy0 - 2 * SQUISH_CONSTANT_4D;
  			dz_ext2 = dz0 - 2 * SQUISH_CONSTANT_4D;
  			dw_ext2 = dw0 - 2 * SQUISH_CONSTANT_4D;
  			if ((c2 & 0x01) != 0) {
  				xsv_ext2 += 2;
  				dx_ext2 -= 2;
  			} else if ((c2 & 0x02) != 0) {
  				ysv_ext2 += 2;
  				dy_ext2 -= 2;
  			} else if ((c2 & 0x04) != 0) {
  				zsv_ext2 += 2;
  				dz_ext2 -= 2;
  			} else {
  				wsv_ext2 += 2;
  				dw_ext2 -= 2;
  			}
  		}
  		
  		/* Contribution (1,0,0,0) */
  		dx1 = dx0 - 1 - SQUISH_CONSTANT_4D;
  		dy1 = dy0 - 0 - SQUISH_CONSTANT_4D;
  		dz1 = dz0 - 0 - SQUISH_CONSTANT_4D;
  		dw1 = dw0 - 0 - SQUISH_CONSTANT_4D;
  		attn1 = 2 - dx1 * dx1 - dy1 * dy1 - dz1 * dz1 - dw1 * dw1;
  		if (attn1 > 0) {
  			attn1 *= attn1;
  			value += attn1 * attn1 * extrapolate4(ctx, xsb + 1, ysb + 0, zsb + 0, wsb + 0, dx1, dy1, dz1, dw1);
  		}
  
  		/* Contribution (0,1,0,0) */
  		dx2 = dx0 - 0 - SQUISH_CONSTANT_4D;
  		dy2 = dy0 - 1 - SQUISH_CONSTANT_4D;
  		dz2 = dz1;
  		dw2 = dw1;
  		attn2 = 2 - dx2 * dx2 - dy2 * dy2 - dz2 * dz2 - dw2 * dw2;
  		if (attn2 > 0) {
  			attn2 *= attn2;
  			value += attn2 * attn2 * extrapolate4(ctx, xsb + 0, ysb + 1, zsb + 0, wsb + 0, dx2, dy2, dz2, dw2);
  		}
  
  		/* Contribution (0,0,1,0) */
  		dx3 = dx2;
  		dy3 = dy1;
  		dz3 = dz0 - 1 - SQUISH_CONSTANT_4D;
  		dw3 = dw1;
  		attn3 = 2 - dx3 * dx3 - dy3 * dy3 - dz3 * dz3 - dw3 * dw3;
  		if (attn3 > 0) {
  			attn3 *= attn3;
  			value += attn3 * attn3 * extrapolate4(ctx, xsb + 0, ysb + 0, zsb + 1, wsb + 0, dx3, dy3, dz3, dw3);
  		}
  
  		/* Contribution (0,0,0,1) */
  		dx4 = dx2;
  		dy4 = dy1;
  		dz4 = dz1;
  		dw4 = dw0 - 1 - SQUISH_CONSTANT_4D;
  		attn4 = 2 - dx4 * dx4 - dy4 * dy4 - dz4 * dz4 - dw4 * dw4;
  		if (attn4 > 0) {
  			attn4 *= attn4;
  			value += attn4 * attn4 * extrapolate4(ctx, xsb + 0, ysb + 0, zsb + 0, wsb + 1, dx4, dy4, dz4, dw4);
  		}
  		
  		/* Contribution (1,1,0,0) */
  		dx5 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dy5 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dz5 = dz0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dw5 = dw0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		attn5 = 2 - dx5 * dx5 - dy5 * dy5 - dz5 * dz5 - dw5 * dw5;
  		if (attn5 > 0) {
  			attn5 *= attn5;
  			value += attn5 * attn5 * extrapolate4(ctx, xsb + 1, ysb + 1, zsb + 0, wsb + 0, dx5, dy5, dz5, dw5);
  		}
  		
  		/* Contribution (1,0,1,0) */
  		dx6 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dy6 = dy0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dz6 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dw6 = dw0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		attn6 = 2 - dx6 * dx6 - dy6 * dy6 - dz6 * dz6 - dw6 * dw6;
  		if (attn6 > 0) {
  			attn6 *= attn6;
  			value += attn6 * attn6 * extrapolate4(ctx, xsb + 1, ysb + 0, zsb + 1, wsb + 0, dx6, dy6, dz6, dw6);
  		}
  
  		/* Contribution (1,0,0,1) */
  		dx7 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dy7 = dy0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dz7 = dz0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dw7 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		attn7 = 2 - dx7 * dx7 - dy7 * dy7 - dz7 * dz7 - dw7 * dw7;
  		if (attn7 > 0) {
  			attn7 *= attn7;
  			value += attn7 * attn7 * extrapolate4(ctx, xsb + 1, ysb + 0, zsb + 0, wsb + 1, dx7, dy7, dz7, dw7);
  		}
  		
  		/* Contribution (0,1,1,0) */
  		dx8 = dx0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dy8 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dz8 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dw8 = dw0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		attn8 = 2 - dx8 * dx8 - dy8 * dy8 - dz8 * dz8 - dw8 * dw8;
  		if (attn8 > 0) {
  			attn8 *= attn8;
  			value += attn8 * attn8 * extrapolate4(ctx, xsb + 0, ysb + 1, zsb + 1, wsb + 0, dx8, dy8, dz8, dw8);
  		}
  		
  		/* Contribution (0,1,0,1) */
  		dx9 = dx0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dy9 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dz9 = dz0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dw9 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		attn9 = 2 - dx9 * dx9 - dy9 * dy9 - dz9 * dz9 - dw9 * dw9;
  		if (attn9 > 0) {
  			attn9 *= attn9;
  			value += attn9 * attn9 * extrapolate4(ctx, xsb + 0, ysb + 1, zsb + 0, wsb + 1, dx9, dy9, dz9, dw9);
  		}
  		
  		/* Contribution (0,0,1,1) */
  		dx10 = dx0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dy10 = dy0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dz10 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dw10 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		attn10 = 2 - dx10 * dx10 - dy10 * dy10 - dz10 * dz10 - dw10 * dw10;
  		if (attn10 > 0) {
  			attn10 *= attn10;
  			value += attn10 * attn10 * extrapolate4(ctx, xsb + 0, ysb + 0, zsb + 1, wsb + 1, dx10, dy10, dz10, dw10);
  		}
  	} else { /* We're inside the second dispentachoron (Rectified 4-Simplex) */
  		aIsBiggerSide = 1;
  		bIsBiggerSide = 1;
  		
  		/* Decide between (0,0,1,1) and (1,1,0,0) */
  		if (xins + yins < zins + wins) {
  			aScore = xins + yins;
  			aPoint = 0x0C;
  		} else {
  			aScore = zins + wins;
  			aPoint = 0x03;
  		}
  		
  		/* Decide between (0,1,0,1) and (1,0,1,0) */
  		if (xins + zins < yins + wins) {
  			bScore = xins + zins;
  			bPoint = 0x0A;
  		} else {
  			bScore = yins + wins;
  			bPoint = 0x05;
  		}
  		
  		/* Closer between (0,1,1,0) and (1,0,0,1) will replace the further of a and b, if closer. */
  		if (xins + wins < yins + zins) {
  			score = xins + wins;
  			if (aScore <= bScore && score < bScore) {
  				bScore = score;
  				bPoint = 0x06;
  			} else if (aScore > bScore && score < aScore) {
  				aScore = score;
  				aPoint = 0x06;
  			}
  		} else {
  			score = yins + zins;
  			if (aScore <= bScore && score < bScore) {
  				bScore = score;
  				bPoint = 0x09;
  			} else if (aScore > bScore && score < aScore) {
  				aScore = score;
  				aPoint = 0x09;
  			}
  		}
  		
  		/* Decide if (0,1,1,1) is closer. */
  		p1 = 3 - inSum + xins;
  		if (aScore <= bScore && p1 < bScore) {
  			bScore = p1;
  			bPoint = 0x0E;
  			bIsBiggerSide = 0;
  		} else if (aScore > bScore && p1 < aScore) {
  			aScore = p1;
  			aPoint = 0x0E;
  			aIsBiggerSide = 0;
  		}
  		
  		/* Decide if (1,0,1,1) is closer. */
  		p2 = 3 - inSum + yins;
  		if (aScore <= bScore && p2 < bScore) {
  			bScore = p2;
  			bPoint = 0x0D;
  			bIsBiggerSide = 0;
  		} else if (aScore > bScore && p2 < aScore) {
  			aScore = p2;
  			aPoint = 0x0D;
  			aIsBiggerSide = 0;
  		}
  		
  		/* Decide if (1,1,0,1) is closer. */
  		p3 = 3 - inSum + zins;
  		if (aScore <= bScore && p3 < bScore) {
  			bScore = p3;
  			bPoint = 0x0B;
  			bIsBiggerSide = 0;
  		} else if (aScore > bScore && p3 < aScore) {
  			aScore = p3;
  			aPoint = 0x0B;
  			aIsBiggerSide = 0;
  		}
  		
  		/* Decide if (1,1,1,0) is closer. */
  		p4 = 3 - inSum + wins;
  		if (aScore <= bScore && p4 < bScore) {
  			bScore = p4;
  			bPoint = 0x07;
  			bIsBiggerSide = 0;
  		} else if (aScore > bScore && p4 < aScore) {
  			aScore = p4;
  			aPoint = 0x07;
  			aIsBiggerSide = 0;
  		}
  		
  		/* Where each of the two closest points are determines how the extra three vertices are calculated. */
  		if (aIsBiggerSide == bIsBiggerSide) {
  			if (aIsBiggerSide) { /* Both closest points on the bigger side */
  				c1 = (int8_t)(aPoint & bPoint);
  				c2 = (int8_t)(aPoint | bPoint);
  				
  				/* Two contributions are permutations of (0,0,0,1) and (0,0,0,2) based on c1 */
  				xsv_ext0 = xsv_ext1 = xsb;
  				ysv_ext0 = ysv_ext1 = ysb;
  				zsv_ext0 = zsv_ext1 = zsb;
  				wsv_ext0 = wsv_ext1 = wsb;
  				dx_ext0 = dx0 - SQUISH_CONSTANT_4D;
  				dy_ext0 = dy0 - SQUISH_CONSTANT_4D;
  				dz_ext0 = dz0 - SQUISH_CONSTANT_4D;
  				dw_ext0 = dw0 - SQUISH_CONSTANT_4D;
  				dx_ext1 = dx0 - 2 * SQUISH_CONSTANT_4D;
  				dy_ext1 = dy0 - 2 * SQUISH_CONSTANT_4D;
  				dz_ext1 = dz0 - 2 * SQUISH_CONSTANT_4D;
  				dw_ext1 = dw0 - 2 * SQUISH_CONSTANT_4D;
  				if ((c1 & 0x01) != 0) {
  					xsv_ext0 += 1;
  					dx_ext0 -= 1;
  					xsv_ext1 += 2;
  					dx_ext1 -= 2;
  				} else if ((c1 & 0x02) != 0) {
  					ysv_ext0 += 1;
  					dy_ext0 -= 1;
  					ysv_ext1 += 2;
  					dy_ext1 -= 2;
  				} else if ((c1 & 0x04) != 0) {
  					zsv_ext0 += 1;
  					dz_ext0 -= 1;
  					zsv_ext1 += 2;
  					dz_ext1 -= 2;
  				} else {
  					wsv_ext0 += 1;
  					dw_ext0 -= 1;
  					wsv_ext1 += 2;
  					dw_ext1 -= 2;
  				}
  				
  				/* One contribution is a permutation of (1,1,1,-1) based on c2 */
  				xsv_ext2 = xsb + 1;
  				ysv_ext2 = ysb + 1;
  				zsv_ext2 = zsb + 1;
  				wsv_ext2 = wsb + 1;
  				dx_ext2 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dy_ext2 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dz_ext2 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				dw_ext2 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  				if ((c2 & 0x01) == 0) {
  					xsv_ext2 -= 2;
  					dx_ext2 += 2;
  				} else if ((c2 & 0x02) == 0) {
  					ysv_ext2 -= 2;
  					dy_ext2 += 2;
  				} else if ((c2 & 0x04) == 0) {
  					zsv_ext2 -= 2;
  					dz_ext2 += 2;
  				} else {
  					wsv_ext2 -= 2;
  					dw_ext2 += 2;
  				}
  			} else { /* Both closest points on the smaller side */
  				/* One of the two extra points is (1,1,1,1) */
  				xsv_ext2 = xsb + 1;
  				ysv_ext2 = ysb + 1;
  				zsv_ext2 = zsb + 1;
  				wsv_ext2 = wsb + 1;
  				dx_ext2 = dx0 - 1 - 4 * SQUISH_CONSTANT_4D;
  				dy_ext2 = dy0 - 1 - 4 * SQUISH_CONSTANT_4D;
  				dz_ext2 = dz0 - 1 - 4 * SQUISH_CONSTANT_4D;
  				dw_ext2 = dw0 - 1 - 4 * SQUISH_CONSTANT_4D;
  				
  				/* Other two points are based on the shared axes. */
  				c = (int8_t)(aPoint & bPoint);
  				
  				if ((c & 0x01) != 0) {
  					xsv_ext0 = xsb + 2;
  					xsv_ext1 = xsb + 1;
  					dx_ext0 = dx0 - 2 - 3 * SQUISH_CONSTANT_4D;
  					dx_ext1 = dx0 - 1 - 3 * SQUISH_CONSTANT_4D;
  				} else {
  					xsv_ext0 = xsv_ext1 = xsb;
  					dx_ext0 = dx_ext1 = dx0 - 3 * SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c & 0x02) != 0) {
  					ysv_ext0 = ysv_ext1 = ysb + 1;
  					dy_ext0 = dy_ext1 = dy0 - 1 - 3 * SQUISH_CONSTANT_4D;
  					if ((c & 0x01) == 0)
  					{
  						ysv_ext0 += 1;
  						dy_ext0 -= 1;
  					} else {
  						ysv_ext1 += 1;
  						dy_ext1 -= 1;
  					}
  				} else {
  					ysv_ext0 = ysv_ext1 = ysb;
  					dy_ext0 = dy_ext1 = dy0 - 3 * SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c & 0x04) != 0) {
  					zsv_ext0 = zsv_ext1 = zsb + 1;
  					dz_ext0 = dz_ext1 = dz0 - 1 - 3 * SQUISH_CONSTANT_4D;
  					if ((c & 0x03) == 0)
  					{
  						zsv_ext0 += 1;
  						dz_ext0 -= 1;
  					} else {
  						zsv_ext1 += 1;
  						dz_ext1 -= 1;
  					}
  				} else {
  					zsv_ext0 = zsv_ext1 = zsb;
  					dz_ext0 = dz_ext1 = dz0 - 3 * SQUISH_CONSTANT_4D;
  				}
  				
  				if ((c & 0x08) != 0)
  				{
  					wsv_ext0 = wsb + 1;
  					wsv_ext1 = wsb + 2;
  					dw_ext0 = dw0 - 1 - 3 * SQUISH_CONSTANT_4D;
  					dw_ext1 = dw0 - 2 - 3 * SQUISH_CONSTANT_4D;
  				} else {
  					wsv_ext0 = wsv_ext1 = wsb;
  					dw_ext0 = dw_ext1 = dw0 - 3 * SQUISH_CONSTANT_4D;
  				}
  			}
  		} else { /* One point on each "side" */
  			if (aIsBiggerSide) {
  				c1 = aPoint;
  				c2 = bPoint;
  			} else {
  				c1 = bPoint;
  				c2 = aPoint;
  			}
  			
  			/* Two contributions are the bigger-sided point with each 1 replaced with 2. */
  			if ((c1 & 0x01) != 0) {
  				xsv_ext0 = xsb + 2;
  				xsv_ext1 = xsb + 1;
  				dx_ext0 = dx0 - 2 - 3 * SQUISH_CONSTANT_4D;
  				dx_ext1 = dx0 - 1 - 3 * SQUISH_CONSTANT_4D;
  			} else {
  				xsv_ext0 = xsv_ext1 = xsb;
  				dx_ext0 = dx_ext1 = dx0 - 3 * SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c1 & 0x02) != 0) {
  				ysv_ext0 = ysv_ext1 = ysb + 1;
  				dy_ext0 = dy_ext1 = dy0 - 1 - 3 * SQUISH_CONSTANT_4D;
  				if ((c1 & 0x01) == 0) {
  					ysv_ext0 += 1;
  					dy_ext0 -= 1;
  				} else {
  					ysv_ext1 += 1;
  					dy_ext1 -= 1;
  				}
  			} else {
  				ysv_ext0 = ysv_ext1 = ysb;
  				dy_ext0 = dy_ext1 = dy0 - 3 * SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c1 & 0x04) != 0) {
  				zsv_ext0 = zsv_ext1 = zsb + 1;
  				dz_ext0 = dz_ext1 = dz0 - 1 - 3 * SQUISH_CONSTANT_4D;
  				if ((c1 & 0x03) == 0) {
  					zsv_ext0 += 1;
  					dz_ext0 -= 1;
  				} else {
  					zsv_ext1 += 1;
  					dz_ext1 -= 1;
  				}
  			} else {
  				zsv_ext0 = zsv_ext1 = zsb;
  				dz_ext0 = dz_ext1 = dz0 - 3 * SQUISH_CONSTANT_4D;
  			}
  			
  			if ((c1 & 0x08) != 0) {
  				wsv_ext0 = wsb + 1;
  				wsv_ext1 = wsb + 2;
  				dw_ext0 = dw0 - 1 - 3 * SQUISH_CONSTANT_4D;
  				dw_ext1 = dw0 - 2 - 3 * SQUISH_CONSTANT_4D;
  			} else {
  				wsv_ext0 = wsv_ext1 = wsb;
  				dw_ext0 = dw_ext1 = dw0 - 3 * SQUISH_CONSTANT_4D;
  			}
  
  			/* One contribution is a permutation of (1,1,1,-1) based on the smaller-sided point */
  			xsv_ext2 = xsb + 1;
  			ysv_ext2 = ysb + 1;
  			zsv_ext2 = zsb + 1;
  			wsv_ext2 = wsb + 1;
  			dx_ext2 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  			dy_ext2 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  			dz_ext2 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  			dw_ext2 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  			if ((c2 & 0x01) == 0) {
  				xsv_ext2 -= 2;
  				dx_ext2 += 2;
  			} else if ((c2 & 0x02) == 0) {
  				ysv_ext2 -= 2;
  				dy_ext2 += 2;
  			} else if ((c2 & 0x04) == 0) {
  				zsv_ext2 -= 2;
  				dz_ext2 += 2;
  			} else {
  				wsv_ext2 -= 2;
  				dw_ext2 += 2;
  			}
  		}
  		
  		/* Contribution (1,1,1,0) */
  		dx4 = dx0 - 1 - 3 * SQUISH_CONSTANT_4D;
  		dy4 = dy0 - 1 - 3 * SQUISH_CONSTANT_4D;
  		dz4 = dz0 - 1 - 3 * SQUISH_CONSTANT_4D;
  		dw4 = dw0 - 3 * SQUISH_CONSTANT_4D;
  		attn4 = 2 - dx4 * dx4 - dy4 * dy4 - dz4 * dz4 - dw4 * dw4;
  		if (attn4 > 0) {
  			attn4 *= attn4;
  			value += attn4 * attn4 * extrapolate4(ctx, xsb + 1, ysb + 1, zsb + 1, wsb + 0, dx4, dy4, dz4, dw4);
  		}
  
  		/* Contribution (1,1,0,1) */
  		dx3 = dx4;
  		dy3 = dy4;
  		dz3 = dz0 - 3 * SQUISH_CONSTANT_4D;
  		dw3 = dw0 - 1 - 3 * SQUISH_CONSTANT_4D;
  		attn3 = 2 - dx3 * dx3 - dy3 * dy3 - dz3 * dz3 - dw3 * dw3;
  		if (attn3 > 0) {
  			attn3 *= attn3;
  			value += attn3 * attn3 * extrapolate4(ctx, xsb + 1, ysb + 1, zsb + 0, wsb + 1, dx3, dy3, dz3, dw3);
  		}
  
  		/* Contribution (1,0,1,1) */
  		dx2 = dx4;
  		dy2 = dy0 - 3 * SQUISH_CONSTANT_4D;
  		dz2 = dz4;
  		dw2 = dw3;
  		attn2 = 2 - dx2 * dx2 - dy2 * dy2 - dz2 * dz2 - dw2 * dw2;
  		if (attn2 > 0) {
  			attn2 *= attn2;
  			value += attn2 * attn2 * extrapolate4(ctx, xsb + 1, ysb + 0, zsb + 1, wsb + 1, dx2, dy2, dz2, dw2);
  		}
  
  		/* Contribution (0,1,1,1) */
  		dx1 = dx0 - 3 * SQUISH_CONSTANT_4D;
  		dz1 = dz4;
  		dy1 = dy4;
  		dw1 = dw3;
  		attn1 = 2 - dx1 * dx1 - dy1 * dy1 - dz1 * dz1 - dw1 * dw1;
  		if (attn1 > 0) {
  			attn1 *= attn1;
  			value += attn1 * attn1 * extrapolate4(ctx, xsb + 0, ysb + 1, zsb + 1, wsb + 1, dx1, dy1, dz1, dw1);
  		}
  		
  		/* Contribution (1,1,0,0) */
  		dx5 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dy5 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dz5 = dz0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dw5 = dw0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		attn5 = 2 - dx5 * dx5 - dy5 * dy5 - dz5 * dz5 - dw5 * dw5;
  		if (attn5 > 0) {
  			attn5 *= attn5;
  			value += attn5 * attn5 * extrapolate4(ctx, xsb + 1, ysb + 1, zsb + 0, wsb + 0, dx5, dy5, dz5, dw5);
  		}
  		
  		/* Contribution (1,0,1,0) */
  		dx6 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dy6 = dy0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dz6 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dw6 = dw0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		attn6 = 2 - dx6 * dx6 - dy6 * dy6 - dz6 * dz6 - dw6 * dw6;
  		if (attn6 > 0) {
  			attn6 *= attn6;
  			value += attn6 * attn6 * extrapolate4(ctx, xsb + 1, ysb + 0, zsb + 1, wsb + 0, dx6, dy6, dz6, dw6);
  		}
  
  		/* Contribution (1,0,0,1) */
  		dx7 = dx0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dy7 = dy0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dz7 = dz0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dw7 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		attn7 = 2 - dx7 * dx7 - dy7 * dy7 - dz7 * dz7 - dw7 * dw7;
  		if (attn7 > 0) {
  			attn7 *= attn7;
  			value += attn7 * attn7 * extrapolate4(ctx, xsb + 1, ysb + 0, zsb + 0, wsb + 1, dx7, dy7, dz7, dw7);
  		}
  		
  		/* Contribution (0,1,1,0) */
  		dx8 = dx0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dy8 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dz8 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dw8 = dw0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		attn8 = 2 - dx8 * dx8 - dy8 * dy8 - dz8 * dz8 - dw8 * dw8;
  		if (attn8 > 0) {
  			attn8 *= attn8;
  			value += attn8 * attn8 * extrapolate4(ctx, xsb + 0, ysb + 1, zsb + 1, wsb + 0, dx8, dy8, dz8, dw8);
  		}
  		
  		/* Contribution (0,1,0,1) */
  		dx9 = dx0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dy9 = dy0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dz9 = dz0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dw9 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		attn9 = 2 - dx9 * dx9 - dy9 * dy9 - dz9 * dz9 - dw9 * dw9;
  		if (attn9 > 0) {
  			attn9 *= attn9;
  			value += attn9 * attn9 * extrapolate4(ctx, xsb + 0, ysb + 1, zsb + 0, wsb + 1, dx9, dy9, dz9, dw9);
  		}
  		
  		/* Contribution (0,0,1,1) */
  		dx10 = dx0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dy10 = dy0 - 0 - 2 * SQUISH_CONSTANT_4D;
  		dz10 = dz0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		dw10 = dw0 - 1 - 2 * SQUISH_CONSTANT_4D;
  		attn10 = 2 - dx10 * dx10 - dy10 * dy10 - dz10 * dz10 - dw10 * dw10;
  		if (attn10 > 0) {
  			attn10 *= attn10;
  			value += attn10 * attn10 * extrapolate4(ctx, xsb + 0, ysb + 0, zsb + 1, wsb + 1, dx10, dy10, dz10, dw10);
  		}
  	}
  
  	/* First extra vertex */
  	attn_ext0 = 2 - dx_ext0 * dx_ext0 - dy_ext0 * dy_ext0 - dz_ext0 * dz_ext0 - dw_ext0 * dw_ext0;
  	if (attn_ext0 > 0)
  	{
  		attn_ext0 *= attn_ext0;
  		value += attn_ext0 * attn_ext0 * extrapolate4(ctx, xsv_ext0, ysv_ext0, zsv_ext0, wsv_ext0, dx_ext0, dy_ext0, dz_ext0, dw_ext0);
  	}
  
  	/* Second extra vertex */
  	attn_ext1 = 2 - dx_ext1 * dx_ext1 - dy_ext1 * dy_ext1 - dz_ext1 * dz_ext1 - dw_ext1 * dw_ext1;
  	if (attn_ext1 > 0)
  	{
  		attn_ext1 *= attn_ext1;
  		value += attn_ext1 * attn_ext1 * extrapolate4(ctx, xsv_ext1, ysv_ext1, zsv_ext1, wsv_ext1, dx_ext1, dy_ext1, dz_ext1, dw_ext1);
  	}
  
  	/* Third extra vertex */
  	attn_ext2 = 2 - dx_ext2 * dx_ext2 - dy_ext2 * dy_ext2 - dz_ext2 * dz_ext2 - dw_ext2 * dw_ext2;
  	if (attn_ext2 > 0)
  	{
  		attn_ext2 *= attn_ext2;
  		value += attn_ext2 * attn_ext2 * extrapolate4(ctx, xsv_ext2, ysv_ext2, zsv_ext2, wsv_ext2, dx_ext2, dy_ext2, dz_ext2, dw_ext2);
  	}
  
  	return value / NORM_CONSTANT_4D;
  }
  	
  