456 lines
18 KiB
C++
456 lines
18 KiB
C++
// SimplexNoise1234
|
||
// Copyright © 2003-2005, Stefan Gustavson
|
||
//
|
||
// Contact: stegu@itn.liu.se
|
||
//
|
||
// This library is free software; you can redistribute it and/or
|
||
// modify it under the terms of the GNU General Public
|
||
// License as published by the Free Software Foundation; either
|
||
// version 2 of the License, or (at your option) any later version.
|
||
//
|
||
// This library is distributed in the hope that it will be useful,
|
||
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
// General Public License for more details.
|
||
//
|
||
// You should have received a copy of the GNU General Public
|
||
// License along with this library; if not, write to the Free Software
|
||
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||
|
||
#include "simplexnoise1234.h"
|
||
|
||
#define FASTFLOOR(x) ( ((x)>0) ? ((int)x) : (((int)x)-1) )
|
||
|
||
//---------------------------------------------------------------------
|
||
// Static data
|
||
|
||
/*
|
||
* Permutation table. This is just a random jumble of all numbers 0-255,
|
||
* repeated twice to avoid wrapping the index at 255 for each lookup.
|
||
* This needs to be exactly the same for all instances on all platforms,
|
||
* so it's easiest to just keep it as static explicit data.
|
||
* This also removes the need for any initialisation of this class.
|
||
*
|
||
* Note that making this an int[] instead of a char[] might make the
|
||
* code run faster on platforms with a high penalty for unaligned single
|
||
* byte addressing. Intel x86 is generally single-byte-friendly, but
|
||
* some other CPUs are faster with 4-aligned reads.
|
||
* However, a char[] is smaller, which avoids cache trashing, and that
|
||
* is probably the most important aspect on most architectures.
|
||
* This array is accessed a *lot* by the noise functions.
|
||
* A vector-valued noise over 3D accesses it 96 times, and a
|
||
* float-valued 4D noise 64 times. We want this to fit in the cache!
|
||
*/
|
||
unsigned char perm[512] = {151,160,137,91,90,15,
|
||
131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
|
||
190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
|
||
88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
|
||
77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
|
||
102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
|
||
135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
|
||
5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
|
||
223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
|
||
129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
|
||
251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
|
||
49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
|
||
138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
|
||
151,160,137,91,90,15,
|
||
131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
|
||
190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
|
||
88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
|
||
77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
|
||
102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
|
||
135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
|
||
5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
|
||
223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
|
||
129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
|
||
251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
|
||
49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
|
||
138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
|
||
};
|
||
|
||
//---------------------------------------------------------------------
|
||
|
||
/*
|
||
* Helper functions to compute gradients-dot-residualvectors (1D to 4D)
|
||
* Note that these generate gradients of more than unit length. To make
|
||
* a close match with the value range of classic Perlin noise, the final
|
||
* noise values need to be rescaled to fit nicely within [-1,1].
|
||
* (The simplex noise functions as such also have different scaling.)
|
||
* Note also that these noise functions are the most practical and useful
|
||
* signed version of Perlin noise. To return values according to the
|
||
* RenderMan specification from the SL noise() and pnoise() functions,
|
||
* the noise values need to be scaled and offset to [0,1], like this:
|
||
* float SLnoise = (SimplexNoise1234::noise(x,y,z) + 1.0) * 0.5;
|
||
*/
|
||
|
||
float grad1( int hash, float x ) {
|
||
int h = hash & 15;
|
||
float grad = 1.0f + (h & 7); // Gradient value 1.0, 2.0, ..., 8.0
|
||
if (h&8) grad = -grad; // Set a random sign for the gradient
|
||
return ( grad * x ); // Multiply the gradient with the distance
|
||
}
|
||
|
||
float grad2( int hash, float x, float y ) {
|
||
int h = hash & 7; // Convert low 3 bits of hash code
|
||
float u = h<4 ? x : y; // into 8 simple gradient directions,
|
||
float v = h<4 ? y : x; // and compute the dot product with (x,y).
|
||
return ((h&1)? -u : u) + ((h&2)? -2.0f*v : 2.0f*v);
|
||
}
|
||
|
||
float grad3( int hash, float x, float y , float z ) {
|
||
int h = hash & 15; // Convert low 4 bits of hash code into 12 simple
|
||
float u = h<8 ? x : y; // gradient directions, and compute dot product.
|
||
float v = h<4 ? y : h==12||h==14 ? x : z; // Fix repeats at h = 12 to 15
|
||
return ((h&1)? -u : u) + ((h&2)? -v : v);
|
||
}
|
||
|
||
float grad4( int hash, float x, float y, float z, float t ) {
|
||
int h = hash & 31; // Convert low 5 bits of hash code into 32 simple
|
||
float u = h<24 ? x : y; // gradient directions, and compute dot product.
|
||
float v = h<16 ? y : z;
|
||
float w = h<8 ? z : t;
|
||
return ((h&1)? -u : u) + ((h&2)? -v : v) + ((h&4)? -w : w);
|
||
}
|
||
|
||
// A lookup table to traverse the simplex around a given point in 4D.
|
||
// Details can be found where this table is used, in the 4D noise method.
|
||
/* TODO: This should not be required, backport it from Bill's GLSL code! */
|
||
static unsigned char simplex[64][4] = {
|
||
{0,1,2,3},{0,1,3,2},{0,0,0,0},{0,2,3,1},{0,0,0,0},{0,0,0,0},{0,0,0,0},{1,2,3,0},
|
||
{0,2,1,3},{0,0,0,0},{0,3,1,2},{0,3,2,1},{0,0,0,0},{0,0,0,0},{0,0,0,0},{1,3,2,0},
|
||
{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},
|
||
{1,2,0,3},{0,0,0,0},{1,3,0,2},{0,0,0,0},{0,0,0,0},{0,0,0,0},{2,3,0,1},{2,3,1,0},
|
||
{1,0,2,3},{1,0,3,2},{0,0,0,0},{0,0,0,0},{0,0,0,0},{2,0,3,1},{0,0,0,0},{2,1,3,0},
|
||
{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},
|
||
{2,0,1,3},{0,0,0,0},{0,0,0,0},{0,0,0,0},{3,0,1,2},{3,0,2,1},{0,0,0,0},{3,1,2,0},
|
||
{2,1,0,3},{0,0,0,0},{0,0,0,0},{0,0,0,0},{3,1,0,2},{0,0,0,0},{3,2,0,1},{3,2,1,0}};
|
||
|
||
// 1D simplex noise
|
||
float snoise1(float x) {
|
||
|
||
int i0 = FASTFLOOR(x);
|
||
int i1 = i0 + 1;
|
||
float x0 = x - i0;
|
||
float x1 = x0 - 1.0f;
|
||
|
||
float n0, n1;
|
||
|
||
float t0 = 1.0f - x0*x0;
|
||
// if(t0 < 0.0f) t0 = 0.0f; // this never happens for the 1D case
|
||
t0 *= t0;
|
||
n0 = t0 * t0 * grad1(perm[i0 & 0xff], x0);
|
||
|
||
float t1 = 1.0f - x1*x1;
|
||
// if(t1 < 0.0f) t1 = 0.0f; // this never happens for the 1D case
|
||
t1 *= t1;
|
||
n1 = t1 * t1 * grad1(perm[i1 & 0xff], x1);
|
||
// The maximum value of this noise is 8*(3/4)^4 = 2.53125
|
||
// A factor of 0.395 would scale to fit exactly within [-1,1], but
|
||
// we want to match PRMan's 1D noise, so we scale it down some more.
|
||
return 0.25f * (n0 + n1);
|
||
|
||
}
|
||
|
||
// 2D simplex noise
|
||
float snoise2(float x, float y) {
|
||
|
||
#define F2 0.366025403 // F2 = 0.5*(sqrt(3.0)-1.0)
|
||
#define G2 0.211324865 // G2 = (3.0-Math.sqrt(3.0))/6.0
|
||
|
||
float n0, n1, n2; // Noise contributions from the three corners
|
||
|
||
// Skew the input space to determine which simplex cell we're in
|
||
float s = (x+y)*F2; // Hairy factor for 2D
|
||
float xs = x + s;
|
||
float ys = y + s;
|
||
int i = FASTFLOOR(xs);
|
||
int j = FASTFLOOR(ys);
|
||
|
||
float t = (float)(i+j)*G2;
|
||
float X0 = i-t; // Unskew the cell origin back to (x,y) space
|
||
float Y0 = j-t;
|
||
float x0 = x-X0; // The x,y distances from the cell origin
|
||
float y0 = y-Y0;
|
||
|
||
// For the 2D case, the simplex shape is an equilateral triangle.
|
||
// Determine which simplex we are in.
|
||
int i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords
|
||
if(x0>y0) {i1=1; j1=0;} // lower triangle, XY order: (0,0)->(1,0)->(1,1)
|
||
else {i1=0; j1=1;} // upper triangle, YX order: (0,0)->(0,1)->(1,1)
|
||
|
||
// A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
|
||
// a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
|
||
// c = (3-sqrt(3))/6
|
||
|
||
float x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
|
||
float y1 = y0 - j1 + G2;
|
||
float x2 = x0 - 1.0f + 2.0f * G2; // Offsets for last corner in (x,y) unskewed coords
|
||
float y2 = y0 - 1.0f + 2.0f * G2;
|
||
|
||
// Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
|
||
int ii = i % 256;
|
||
int jj = j % 256;
|
||
|
||
// Calculate the contribution from the three corners
|
||
float t0 = 0.5f - x0*x0-y0*y0;
|
||
if(t0 < 0.0f) n0 = 0.0f;
|
||
else {
|
||
t0 *= t0;
|
||
n0 = t0 * t0 * grad2(perm[ii+perm[jj]], x0, y0);
|
||
}
|
||
|
||
float t1 = 0.5f - x1*x1-y1*y1;
|
||
if(t1 < 0.0f) n1 = 0.0f;
|
||
else {
|
||
t1 *= t1;
|
||
n1 = t1 * t1 * grad2(perm[ii+i1+perm[jj+j1]], x1, y1);
|
||
}
|
||
|
||
float t2 = 0.5f - x2*x2-y2*y2;
|
||
if(t2 < 0.0f) n2 = 0.0f;
|
||
else {
|
||
t2 *= t2;
|
||
n2 = t2 * t2 * grad2(perm[ii+1+perm[jj+1]], x2, y2);
|
||
}
|
||
|
||
// Add contributions from each corner to get the final noise value.
|
||
// The result is scaled to return values in the interval [-1,1].
|
||
return 40.0f * (n0 + n1 + n2); // TODO: The scale factor is preliminary!
|
||
}
|
||
|
||
// 3D simplex noise
|
||
float snoise3(float x, float y, float z) {
|
||
|
||
// Simple skewing factors for the 3D case
|
||
#define F3 0.333333333
|
||
#define G3 0.166666667
|
||
|
||
float n0, n1, n2, n3; // Noise contributions from the four corners
|
||
|
||
// Skew the input space to determine which simplex cell we're in
|
||
float s = (x+y+z)*F3; // Very nice and simple skew factor for 3D
|
||
float xs = x+s;
|
||
float ys = y+s;
|
||
float zs = z+s;
|
||
int i = FASTFLOOR(xs);
|
||
int j = FASTFLOOR(ys);
|
||
int k = FASTFLOOR(zs);
|
||
|
||
float t = (float)(i+j+k)*G3;
|
||
float X0 = i-t; // Unskew the cell origin back to (x,y,z) space
|
||
float Y0 = j-t;
|
||
float Z0 = k-t;
|
||
float x0 = x-X0; // The x,y,z distances from the cell origin
|
||
float y0 = y-Y0;
|
||
float z0 = z-Z0;
|
||
|
||
// For the 3D case, the simplex shape is a slightly irregular tetrahedron.
|
||
// Determine which simplex we are in.
|
||
int i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords
|
||
int i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords
|
||
|
||
/* This code would benefit from a backport from the GLSL version! */
|
||
if(x0>=y0) {
|
||
if(y0>=z0)
|
||
{ i1=1; j1=0; k1=0; i2=1; j2=1; k2=0; } // X Y Z order
|
||
else if(x0>=z0) { i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; } // X Z Y order
|
||
else { i1=0; j1=0; k1=1; i2=1; j2=0; k2=1; } // Z X Y order
|
||
}
|
||
else { // x0<y0
|
||
if(y0<z0) { i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; } // Z Y X order
|
||
else if(x0<z0) { i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; } // Y Z X order
|
||
else { i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; } // Y X Z order
|
||
}
|
||
|
||
// A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
|
||
// a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
|
||
// a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
|
||
// c = 1/6.
|
||
|
||
float x1 = x0 - i1 + G3; // Offsets for second corner in (x,y,z) coords
|
||
float y1 = y0 - j1 + G3;
|
||
float z1 = z0 - k1 + G3;
|
||
float x2 = x0 - i2 + 2.0f*G3; // Offsets for third corner in (x,y,z) coords
|
||
float y2 = y0 - j2 + 2.0f*G3;
|
||
float z2 = z0 - k2 + 2.0f*G3;
|
||
float x3 = x0 - 1.0f + 3.0f*G3; // Offsets for last corner in (x,y,z) coords
|
||
float y3 = y0 - 1.0f + 3.0f*G3;
|
||
float z3 = z0 - 1.0f + 3.0f*G3;
|
||
|
||
// Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
|
||
int ii = i % 256;
|
||
int jj = j % 256;
|
||
int kk = k % 256;
|
||
|
||
// Calculate the contribution from the four corners
|
||
float t0 = 0.6f - x0*x0 - y0*y0 - z0*z0;
|
||
if(t0 < 0.0f) n0 = 0.0f;
|
||
else {
|
||
t0 *= t0;
|
||
n0 = t0 * t0 * grad3(perm[ii+perm[jj+perm[kk]]], x0, y0, z0);
|
||
}
|
||
|
||
float t1 = 0.6f - x1*x1 - y1*y1 - z1*z1;
|
||
if(t1 < 0.0f) n1 = 0.0f;
|
||
else {
|
||
t1 *= t1;
|
||
n1 = t1 * t1 * grad3(perm[ii+i1+perm[jj+j1+perm[kk+k1]]], x1, y1, z1);
|
||
}
|
||
|
||
float t2 = 0.6f - x2*x2 - y2*y2 - z2*z2;
|
||
if(t2 < 0.0f) n2 = 0.0f;
|
||
else {
|
||
t2 *= t2;
|
||
n2 = t2 * t2 * grad3(perm[ii+i2+perm[jj+j2+perm[kk+k2]]], x2, y2, z2);
|
||
}
|
||
|
||
float t3 = 0.6f - x3*x3 - y3*y3 - z3*z3;
|
||
if(t3<0.0f) n3 = 0.0f;
|
||
else {
|
||
t3 *= t3;
|
||
n3 = t3 * t3 * grad3(perm[ii+1+perm[jj+1+perm[kk+1]]], x3, y3, z3);
|
||
}
|
||
|
||
// Add contributions from each corner to get the final noise value.
|
||
// The result is scaled to stay just inside [-1,1]
|
||
return 32.0f * (n0 + n1 + n2 + n3); // TODO: The scale factor is preliminary!
|
||
}
|
||
|
||
|
||
// 4D simplex noise
|
||
float snoise4(float x, float y, float z, float w) {
|
||
|
||
// The skewing and unskewing factors are hairy again for the 4D case
|
||
#define F4 0.309016994 // F4 = (Math.sqrt(5.0)-1.0)/4.0
|
||
#define G4 0.138196601 // G4 = (5.0-Math.sqrt(5.0))/20.0
|
||
|
||
float n0, n1, n2, n3, n4; // Noise contributions from the five corners
|
||
|
||
// Skew the (x,y,z,w) space to determine which cell of 24 simplices we're in
|
||
float s = (x + y + z + w) * F4; // Factor for 4D skewing
|
||
float xs = x + s;
|
||
float ys = y + s;
|
||
float zs = z + s;
|
||
float ws = w + s;
|
||
int i = FASTFLOOR(xs);
|
||
int j = FASTFLOOR(ys);
|
||
int k = FASTFLOOR(zs);
|
||
int l = FASTFLOOR(ws);
|
||
|
||
float t = (i + j + k + l) * G4; // Factor for 4D unskewing
|
||
float X0 = i - t; // Unskew the cell origin back to (x,y,z,w) space
|
||
float Y0 = j - t;
|
||
float Z0 = k - t;
|
||
float W0 = l - t;
|
||
|
||
float x0 = x - X0; // The x,y,z,w distances from the cell origin
|
||
float y0 = y - Y0;
|
||
float z0 = z - Z0;
|
||
float w0 = w - W0;
|
||
|
||
// For the 4D case, the simplex is a 4D shape I won't even try to describe.
|
||
// To find out which of the 24 possible simplices we're in, we need to
|
||
// determine the magnitude ordering of x0, y0, z0 and w0.
|
||
// The method below is a good way of finding the ordering of x,y,z,w and
|
||
// then find the correct traversal order for the simplex we’re in.
|
||
// First, six pair-wise comparisons are performed between each possible pair
|
||
// of the four coordinates, and the results are used to add up binary bits
|
||
// for an integer index.
|
||
int c1 = (x0 > y0) ? 32 : 0;
|
||
int c2 = (x0 > z0) ? 16 : 0;
|
||
int c3 = (y0 > z0) ? 8 : 0;
|
||
int c4 = (x0 > w0) ? 4 : 0;
|
||
int c5 = (y0 > w0) ? 2 : 0;
|
||
int c6 = (z0 > w0) ? 1 : 0;
|
||
int c = c1 + c2 + c3 + c4 + c5 + c6;
|
||
|
||
int i1, j1, k1, l1; // The integer offsets for the second simplex corner
|
||
int i2, j2, k2, l2; // The integer offsets for the third simplex corner
|
||
int i3, j3, k3, l3; // The integer offsets for the fourth simplex corner
|
||
|
||
// simplex[c] is a 4-vector with the numbers 0, 1, 2 and 3 in some order.
|
||
// Many values of c will never occur, since e.g. x>y>z>w makes x<z, y<w and x<w
|
||
// impossible. Only the 24 indices which have non-zero entries make any sense.
|
||
// We use a thresholding to set the coordinates in turn from the largest magnitude.
|
||
// The number 3 in the "simplex" array is at the position of the largest coordinate.
|
||
i1 = simplex[c][0]>=3 ? 1 : 0;
|
||
j1 = simplex[c][1]>=3 ? 1 : 0;
|
||
k1 = simplex[c][2]>=3 ? 1 : 0;
|
||
l1 = simplex[c][3]>=3 ? 1 : 0;
|
||
// The number 2 in the "simplex" array is at the second largest coordinate.
|
||
i2 = simplex[c][0]>=2 ? 1 : 0;
|
||
j2 = simplex[c][1]>=2 ? 1 : 0;
|
||
k2 = simplex[c][2]>=2 ? 1 : 0;
|
||
l2 = simplex[c][3]>=2 ? 1 : 0;
|
||
// The number 1 in the "simplex" array is at the second smallest coordinate.
|
||
i3 = simplex[c][0]>=1 ? 1 : 0;
|
||
j3 = simplex[c][1]>=1 ? 1 : 0;
|
||
k3 = simplex[c][2]>=1 ? 1 : 0;
|
||
l3 = simplex[c][3]>=1 ? 1 : 0;
|
||
// The fifth corner has all coordinate offsets = 1, so no need to look that up.
|
||
|
||
float x1 = x0 - i1 + G4; // Offsets for second corner in (x,y,z,w) coords
|
||
float y1 = y0 - j1 + G4;
|
||
float z1 = z0 - k1 + G4;
|
||
float w1 = w0 - l1 + G4;
|
||
float x2 = x0 - i2 + 2.0f*G4; // Offsets for third corner in (x,y,z,w) coords
|
||
float y2 = y0 - j2 + 2.0f*G4;
|
||
float z2 = z0 - k2 + 2.0f*G4;
|
||
float w2 = w0 - l2 + 2.0f*G4;
|
||
float x3 = x0 - i3 + 3.0f*G4; // Offsets for fourth corner in (x,y,z,w) coords
|
||
float y3 = y0 - j3 + 3.0f*G4;
|
||
float z3 = z0 - k3 + 3.0f*G4;
|
||
float w3 = w0 - l3 + 3.0f*G4;
|
||
float x4 = x0 - 1.0f + 4.0f*G4; // Offsets for last corner in (x,y,z,w) coords
|
||
float y4 = y0 - 1.0f + 4.0f*G4;
|
||
float z4 = z0 - 1.0f + 4.0f*G4;
|
||
float w4 = w0 - 1.0f + 4.0f*G4;
|
||
|
||
// Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
|
||
int ii = i % 256;
|
||
int jj = j % 256;
|
||
int kk = k % 256;
|
||
int ll = l % 256;
|
||
|
||
// Calculate the contribution from the five corners
|
||
float t0 = 0.6f - x0*x0 - y0*y0 - z0*z0 - w0*w0;
|
||
if(t0 < 0.0f) n0 = 0.0f;
|
||
else {
|
||
t0 *= t0;
|
||
n0 = t0 * t0 * grad4(perm[ii+perm[jj+perm[kk+perm[ll]]]], x0, y0, z0, w0);
|
||
}
|
||
|
||
float t1 = 0.6f - x1*x1 - y1*y1 - z1*z1 - w1*w1;
|
||
if(t1 < 0.0f) n1 = 0.0f;
|
||
else {
|
||
t1 *= t1;
|
||
n1 = t1 * t1 * grad4(perm[ii+i1+perm[jj+j1+perm[kk+k1+perm[ll+l1]]]], x1, y1, z1, w1);
|
||
}
|
||
|
||
float t2 = 0.6f - x2*x2 - y2*y2 - z2*z2 - w2*w2;
|
||
if(t2 < 0.0f) n2 = 0.0f;
|
||
else {
|
||
t2 *= t2;
|
||
n2 = t2 * t2 * grad4(perm[ii+i2+perm[jj+j2+perm[kk+k2+perm[ll+l2]]]], x2, y2, z2, w2);
|
||
}
|
||
|
||
float t3 = 0.6f - x3*x3 - y3*y3 - z3*z3 - w3*w3;
|
||
if(t3 < 0.0f) n3 = 0.0f;
|
||
else {
|
||
t3 *= t3;
|
||
n3 = t3 * t3 * grad4(perm[ii+i3+perm[jj+j3+perm[kk+k3+perm[ll+l3]]]], x3, y3, z3, w3);
|
||
}
|
||
|
||
float t4 = 0.6f - x4*x4 - y4*y4 - z4*z4 - w4*w4;
|
||
if(t4 < 0.0f) n4 = 0.0f;
|
||
else {
|
||
t4 *= t4;
|
||
n4 = t4 * t4 * grad4(perm[ii+1+perm[jj+1+perm[kk+1+perm[ll+1]]]], x4, y4, z4, w4);
|
||
}
|
||
|
||
// Sum up and scale the result to cover the range [-1,1]
|
||
return 27.0f * (n0 + n1 + n2 + n3 + n4); // TODO: The scale factor is preliminary!
|
||
}
|
||
//---------------------------------------------------------------------
|