1/// @ref gtc_noise
2/// @file glm/gtc/noise.inl
3///
4// Based on the work of Stefan Gustavson and Ashima Arts on "webgl-noise":
5// https://github.com/ashima/webgl-noise
6// Following Stefan Gustavson's paper "Simplex noise demystified":
7// http://www.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
8
9namespace glm{
10namespace gtc
11{
12	template<typename T, qualifier Q>
13	GLM_FUNC_QUALIFIER vec<4, T, Q> grad4(T const& j, vec<4, T, Q> const& ip)
14	{
15		vec<3, T, Q> pXYZ = floor(fract(vec<3, T, Q>(j) * vec<3, T, Q>(ip)) * T(7)) * ip[2] - T(1);
16		T pW = static_cast<T>(1.5) - dot(abs(pXYZ), vec<3, T, Q>(1));
17		vec<4, T, Q> s = vec<4, T, Q>(lessThan(vec<4, T, Q>(pXYZ, pW), vec<4, T, Q>(0.0)));
18		pXYZ = pXYZ + (vec<3, T, Q>(s) * T(2) - T(1)) * s.w;
19		return vec<4, T, Q>(pXYZ, pW);
20	}
21}//namespace gtc
22
23	// Classic Perlin noise
24	template<typename T, qualifier Q>
25	GLM_FUNC_QUALIFIER T perlin(vec<2, T, Q> const& Position)
26	{
27		vec<4, T, Q> Pi = glm::floor(vec<4, T, Q>(Position.x, Position.y, Position.x, Position.y)) + vec<4, T, Q>(0.0, 0.0, 1.0, 1.0);
28		vec<4, T, Q> Pf = glm::fract(vec<4, T, Q>(Position.x, Position.y, Position.x, Position.y)) - vec<4, T, Q>(0.0, 0.0, 1.0, 1.0);
29		Pi = mod(Pi, vec<4, T, Q>(289)); // To avoid truncation effects in permutation
30		vec<4, T, Q> ix(Pi.x, Pi.z, Pi.x, Pi.z);
31		vec<4, T, Q> iy(Pi.y, Pi.y, Pi.w, Pi.w);
32		vec<4, T, Q> fx(Pf.x, Pf.z, Pf.x, Pf.z);
33		vec<4, T, Q> fy(Pf.y, Pf.y, Pf.w, Pf.w);
34
35		vec<4, T, Q> i = detail::permute(detail::permute(ix) + iy);
36
37		vec<4, T, Q> gx = static_cast<T>(2) * glm::fract(i / T(41)) - T(1);
38		vec<4, T, Q> gy = glm::abs(gx) - T(0.5);
39		vec<4, T, Q> tx = glm::floor(gx + T(0.5));
40		gx = gx - tx;
41
42		vec<2, T, Q> g00(gx.x, gy.x);
43		vec<2, T, Q> g10(gx.y, gy.y);
44		vec<2, T, Q> g01(gx.z, gy.z);
45		vec<2, T, Q> g11(gx.w, gy.w);
46
47		vec<4, T, Q> norm = detail::taylorInvSqrt(vec<4, T, Q>(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
48		g00 *= norm.x;
49		g01 *= norm.y;
50		g10 *= norm.z;
51		g11 *= norm.w;
52
53		T n00 = dot(g00, vec<2, T, Q>(fx.x, fy.x));
54		T n10 = dot(g10, vec<2, T, Q>(fx.y, fy.y));
55		T n01 = dot(g01, vec<2, T, Q>(fx.z, fy.z));
56		T n11 = dot(g11, vec<2, T, Q>(fx.w, fy.w));
57
58		vec<2, T, Q> fade_xy = detail::fade(vec<2, T, Q>(Pf.x, Pf.y));
59		vec<2, T, Q> n_x = mix(vec<2, T, Q>(n00, n01), vec<2, T, Q>(n10, n11), fade_xy.x);
60		T n_xy = mix(n_x.x, n_x.y, fade_xy.y);
61		return T(2.3) * n_xy;
62	}
63
64	// Classic Perlin noise
65	template<typename T, qualifier Q>
66	GLM_FUNC_QUALIFIER T perlin(vec<3, T, Q> const& Position)
67	{
68		vec<3, T, Q> Pi0 = floor(Position); // Integer part for indexing
69		vec<3, T, Q> Pi1 = Pi0 + T(1); // Integer part + 1
70		Pi0 = detail::mod289(Pi0);
71		Pi1 = detail::mod289(Pi1);
72		vec<3, T, Q> Pf0 = fract(Position); // Fractional part for interpolation
73		vec<3, T, Q> Pf1 = Pf0 - T(1); // Fractional part - 1.0
74		vec<4, T, Q> ix(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
75		vec<4, T, Q> iy = vec<4, T, Q>(vec<2, T, Q>(Pi0.y), vec<2, T, Q>(Pi1.y));
76		vec<4, T, Q> iz0(Pi0.z);
77		vec<4, T, Q> iz1(Pi1.z);
78
79		vec<4, T, Q> ixy = detail::permute(detail::permute(ix) + iy);
80		vec<4, T, Q> ixy0 = detail::permute(ixy + iz0);
81		vec<4, T, Q> ixy1 = detail::permute(ixy + iz1);
82
83		vec<4, T, Q> gx0 = ixy0 * T(1.0 / 7.0);
84		vec<4, T, Q> gy0 = fract(floor(gx0) * T(1.0 / 7.0)) - T(0.5);
85		gx0 = fract(gx0);
86		vec<4, T, Q> gz0 = vec<4, T, Q>(0.5) - abs(gx0) - abs(gy0);
87		vec<4, T, Q> sz0 = step(gz0, vec<4, T, Q>(0.0));
88		gx0 -= sz0 * (step(T(0), gx0) - T(0.5));
89		gy0 -= sz0 * (step(T(0), gy0) - T(0.5));
90
91		vec<4, T, Q> gx1 = ixy1 * T(1.0 / 7.0);
92		vec<4, T, Q> gy1 = fract(floor(gx1) * T(1.0 / 7.0)) - T(0.5);
93		gx1 = fract(gx1);
94		vec<4, T, Q> gz1 = vec<4, T, Q>(0.5) - abs(gx1) - abs(gy1);
95		vec<4, T, Q> sz1 = step(gz1, vec<4, T, Q>(0.0));
96		gx1 -= sz1 * (step(T(0), gx1) - T(0.5));
97		gy1 -= sz1 * (step(T(0), gy1) - T(0.5));
98
99		vec<3, T, Q> g000(gx0.x, gy0.x, gz0.x);
100		vec<3, T, Q> g100(gx0.y, gy0.y, gz0.y);
101		vec<3, T, Q> g010(gx0.z, gy0.z, gz0.z);
102		vec<3, T, Q> g110(gx0.w, gy0.w, gz0.w);
103		vec<3, T, Q> g001(gx1.x, gy1.x, gz1.x);
104		vec<3, T, Q> g101(gx1.y, gy1.y, gz1.y);
105		vec<3, T, Q> g011(gx1.z, gy1.z, gz1.z);
106		vec<3, T, Q> g111(gx1.w, gy1.w, gz1.w);
107
108		vec<4, T, Q> norm0 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
109		g000 *= norm0.x;
110		g010 *= norm0.y;
111		g100 *= norm0.z;
112		g110 *= norm0.w;
113		vec<4, T, Q> norm1 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
114		g001 *= norm1.x;
115		g011 *= norm1.y;
116		g101 *= norm1.z;
117		g111 *= norm1.w;
118
119		T n000 = dot(g000, Pf0);
120		T n100 = dot(g100, vec<3, T, Q>(Pf1.x, Pf0.y, Pf0.z));
121		T n010 = dot(g010, vec<3, T, Q>(Pf0.x, Pf1.y, Pf0.z));
122		T n110 = dot(g110, vec<3, T, Q>(Pf1.x, Pf1.y, Pf0.z));
123		T n001 = dot(g001, vec<3, T, Q>(Pf0.x, Pf0.y, Pf1.z));
124		T n101 = dot(g101, vec<3, T, Q>(Pf1.x, Pf0.y, Pf1.z));
125		T n011 = dot(g011, vec<3, T, Q>(Pf0.x, Pf1.y, Pf1.z));
126		T n111 = dot(g111, Pf1);
127
128		vec<3, T, Q> fade_xyz = detail::fade(Pf0);
129		vec<4, T, Q> n_z = mix(vec<4, T, Q>(n000, n100, n010, n110), vec<4, T, Q>(n001, n101, n011, n111), fade_xyz.z);
130		vec<2, T, Q> n_yz = mix(vec<2, T, Q>(n_z.x, n_z.y), vec<2, T, Q>(n_z.z, n_z.w), fade_xyz.y);
131		T n_xyz = mix(n_yz.x, n_yz.y, fade_xyz.x);
132		return T(2.2) * n_xyz;
133	}
134	/*
135	// Classic Perlin noise
136	template<typename T, qualifier Q>
137	GLM_FUNC_QUALIFIER T perlin(vec<3, T, Q> const& P)
138	{
139		vec<3, T, Q> Pi0 = floor(P); // Integer part for indexing
140		vec<3, T, Q> Pi1 = Pi0 + T(1); // Integer part + 1
141		Pi0 = mod(Pi0, T(289));
142		Pi1 = mod(Pi1, T(289));
143		vec<3, T, Q> Pf0 = fract(P); // Fractional part for interpolation
144		vec<3, T, Q> Pf1 = Pf0 - T(1); // Fractional part - 1.0
145		vec<4, T, Q> ix(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
146		vec<4, T, Q> iy(Pi0.y, Pi0.y, Pi1.y, Pi1.y);
147		vec<4, T, Q> iz0(Pi0.z);
148		vec<4, T, Q> iz1(Pi1.z);
149
150		vec<4, T, Q> ixy = permute(permute(ix) + iy);
151		vec<4, T, Q> ixy0 = permute(ixy + iz0);
152		vec<4, T, Q> ixy1 = permute(ixy + iz1);
153
154		vec<4, T, Q> gx0 = ixy0 / T(7);
155		vec<4, T, Q> gy0 = fract(floor(gx0) / T(7)) - T(0.5);
156		gx0 = fract(gx0);
157		vec<4, T, Q> gz0 = vec<4, T, Q>(0.5) - abs(gx0) - abs(gy0);
158		vec<4, T, Q> sz0 = step(gz0, vec<4, T, Q>(0.0));
159		gx0 -= sz0 * (step(0.0, gx0) - T(0.5));
160		gy0 -= sz0 * (step(0.0, gy0) - T(0.5));
161
162		vec<4, T, Q> gx1 = ixy1 / T(7);
163		vec<4, T, Q> gy1 = fract(floor(gx1) / T(7)) - T(0.5);
164		gx1 = fract(gx1);
165		vec<4, T, Q> gz1 = vec<4, T, Q>(0.5) - abs(gx1) - abs(gy1);
166		vec<4, T, Q> sz1 = step(gz1, vec<4, T, Q>(0.0));
167		gx1 -= sz1 * (step(T(0), gx1) - T(0.5));
168		gy1 -= sz1 * (step(T(0), gy1) - T(0.5));
169
170		vec<3, T, Q> g000(gx0.x, gy0.x, gz0.x);
171		vec<3, T, Q> g100(gx0.y, gy0.y, gz0.y);
172		vec<3, T, Q> g010(gx0.z, gy0.z, gz0.z);
173		vec<3, T, Q> g110(gx0.w, gy0.w, gz0.w);
174		vec<3, T, Q> g001(gx1.x, gy1.x, gz1.x);
175		vec<3, T, Q> g101(gx1.y, gy1.y, gz1.y);
176		vec<3, T, Q> g011(gx1.z, gy1.z, gz1.z);
177		vec<3, T, Q> g111(gx1.w, gy1.w, gz1.w);
178
179		vec<4, T, Q> norm0 = taylorInvSqrt(vec<4, T, Q>(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
180		g000 *= norm0.x;
181		g010 *= norm0.y;
182		g100 *= norm0.z;
183		g110 *= norm0.w;
184		vec<4, T, Q> norm1 = taylorInvSqrt(vec<4, T, Q>(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
185		g001 *= norm1.x;
186		g011 *= norm1.y;
187		g101 *= norm1.z;
188		g111 *= norm1.w;
189
190		T n000 = dot(g000, Pf0);
191		T n100 = dot(g100, vec<3, T, Q>(Pf1.x, Pf0.y, Pf0.z));
192		T n010 = dot(g010, vec<3, T, Q>(Pf0.x, Pf1.y, Pf0.z));
193		T n110 = dot(g110, vec<3, T, Q>(Pf1.x, Pf1.y, Pf0.z));
194		T n001 = dot(g001, vec<3, T, Q>(Pf0.x, Pf0.y, Pf1.z));
195		T n101 = dot(g101, vec<3, T, Q>(Pf1.x, Pf0.y, Pf1.z));
196		T n011 = dot(g011, vec<3, T, Q>(Pf0.x, Pf1.y, Pf1.z));
197		T n111 = dot(g111, Pf1);
198
199		vec<3, T, Q> fade_xyz = fade(Pf0);
200		vec<4, T, Q> n_z = mix(vec<4, T, Q>(n000, n100, n010, n110), vec<4, T, Q>(n001, n101, n011, n111), fade_xyz.z);
201		vec<2, T, Q> n_yz = mix(
202			vec<2, T, Q>(n_z.x, n_z.y),
203			vec<2, T, Q>(n_z.z, n_z.w), fade_xyz.y);
204		T n_xyz = mix(n_yz.x, n_yz.y, fade_xyz.x);
205		return T(2.2) * n_xyz;
206	}
207	*/
208	// Classic Perlin noise
209	template<typename T, qualifier Q>
210	GLM_FUNC_QUALIFIER T perlin(vec<4, T, Q> const& Position)
211	{
212		vec<4, T, Q> Pi0 = floor(Position);	// Integer part for indexing
213		vec<4, T, Q> Pi1 = Pi0 + T(1);		// Integer part + 1
214		Pi0 = mod(Pi0, vec<4, T, Q>(289));
215		Pi1 = mod(Pi1, vec<4, T, Q>(289));
216		vec<4, T, Q> Pf0 = fract(Position);	// Fractional part for interpolation
217		vec<4, T, Q> Pf1 = Pf0 - T(1);		// Fractional part - 1.0
218		vec<4, T, Q> ix(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
219		vec<4, T, Q> iy(Pi0.y, Pi0.y, Pi1.y, Pi1.y);
220		vec<4, T, Q> iz0(Pi0.z);
221		vec<4, T, Q> iz1(Pi1.z);
222		vec<4, T, Q> iw0(Pi0.w);
223		vec<4, T, Q> iw1(Pi1.w);
224
225		vec<4, T, Q> ixy = detail::permute(detail::permute(ix) + iy);
226		vec<4, T, Q> ixy0 = detail::permute(ixy + iz0);
227		vec<4, T, Q> ixy1 = detail::permute(ixy + iz1);
228		vec<4, T, Q> ixy00 = detail::permute(ixy0 + iw0);
229		vec<4, T, Q> ixy01 = detail::permute(ixy0 + iw1);
230		vec<4, T, Q> ixy10 = detail::permute(ixy1 + iw0);
231		vec<4, T, Q> ixy11 = detail::permute(ixy1 + iw1);
232
233		vec<4, T, Q> gx00 = ixy00 / T(7);
234		vec<4, T, Q> gy00 = floor(gx00) / T(7);
235		vec<4, T, Q> gz00 = floor(gy00) / T(6);
236		gx00 = fract(gx00) - T(0.5);
237		gy00 = fract(gy00) - T(0.5);
238		gz00 = fract(gz00) - T(0.5);
239		vec<4, T, Q> gw00 = vec<4, T, Q>(0.75) - abs(gx00) - abs(gy00) - abs(gz00);
240		vec<4, T, Q> sw00 = step(gw00, vec<4, T, Q>(0.0));
241		gx00 -= sw00 * (step(T(0), gx00) - T(0.5));
242		gy00 -= sw00 * (step(T(0), gy00) - T(0.5));
243
244		vec<4, T, Q> gx01 = ixy01 / T(7);
245		vec<4, T, Q> gy01 = floor(gx01) / T(7);
246		vec<4, T, Q> gz01 = floor(gy01) / T(6);
247		gx01 = fract(gx01) - T(0.5);
248		gy01 = fract(gy01) - T(0.5);
249		gz01 = fract(gz01) - T(0.5);
250		vec<4, T, Q> gw01 = vec<4, T, Q>(0.75) - abs(gx01) - abs(gy01) - abs(gz01);
251		vec<4, T, Q> sw01 = step(gw01, vec<4, T, Q>(0.0));
252		gx01 -= sw01 * (step(T(0), gx01) - T(0.5));
253		gy01 -= sw01 * (step(T(0), gy01) - T(0.5));
254
255		vec<4, T, Q> gx10 = ixy10 / T(7);
256		vec<4, T, Q> gy10 = floor(gx10) / T(7);
257		vec<4, T, Q> gz10 = floor(gy10) / T(6);
258		gx10 = fract(gx10) - T(0.5);
259		gy10 = fract(gy10) - T(0.5);
260		gz10 = fract(gz10) - T(0.5);
261		vec<4, T, Q> gw10 = vec<4, T, Q>(0.75) - abs(gx10) - abs(gy10) - abs(gz10);
262		vec<4, T, Q> sw10 = step(gw10, vec<4, T, Q>(0));
263		gx10 -= sw10 * (step(T(0), gx10) - T(0.5));
264		gy10 -= sw10 * (step(T(0), gy10) - T(0.5));
265
266		vec<4, T, Q> gx11 = ixy11 / T(7);
267		vec<4, T, Q> gy11 = floor(gx11) / T(7);
268		vec<4, T, Q> gz11 = floor(gy11) / T(6);
269		gx11 = fract(gx11) - T(0.5);
270		gy11 = fract(gy11) - T(0.5);
271		gz11 = fract(gz11) - T(0.5);
272		vec<4, T, Q> gw11 = vec<4, T, Q>(0.75) - abs(gx11) - abs(gy11) - abs(gz11);
273		vec<4, T, Q> sw11 = step(gw11, vec<4, T, Q>(0.0));
274		gx11 -= sw11 * (step(T(0), gx11) - T(0.5));
275		gy11 -= sw11 * (step(T(0), gy11) - T(0.5));
276
277		vec<4, T, Q> g0000(gx00.x, gy00.x, gz00.x, gw00.x);
278		vec<4, T, Q> g1000(gx00.y, gy00.y, gz00.y, gw00.y);
279		vec<4, T, Q> g0100(gx00.z, gy00.z, gz00.z, gw00.z);
280		vec<4, T, Q> g1100(gx00.w, gy00.w, gz00.w, gw00.w);
281		vec<4, T, Q> g0010(gx10.x, gy10.x, gz10.x, gw10.x);
282		vec<4, T, Q> g1010(gx10.y, gy10.y, gz10.y, gw10.y);
283		vec<4, T, Q> g0110(gx10.z, gy10.z, gz10.z, gw10.z);
284		vec<4, T, Q> g1110(gx10.w, gy10.w, gz10.w, gw10.w);
285		vec<4, T, Q> g0001(gx01.x, gy01.x, gz01.x, gw01.x);
286		vec<4, T, Q> g1001(gx01.y, gy01.y, gz01.y, gw01.y);
287		vec<4, T, Q> g0101(gx01.z, gy01.z, gz01.z, gw01.z);
288		vec<4, T, Q> g1101(gx01.w, gy01.w, gz01.w, gw01.w);
289		vec<4, T, Q> g0011(gx11.x, gy11.x, gz11.x, gw11.x);
290		vec<4, T, Q> g1011(gx11.y, gy11.y, gz11.y, gw11.y);
291		vec<4, T, Q> g0111(gx11.z, gy11.z, gz11.z, gw11.z);
292		vec<4, T, Q> g1111(gx11.w, gy11.w, gz11.w, gw11.w);
293
294		vec<4, T, Q> norm00 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g0000, g0000), dot(g0100, g0100), dot(g1000, g1000), dot(g1100, g1100)));
295		g0000 *= norm00.x;
296		g0100 *= norm00.y;
297		g1000 *= norm00.z;
298		g1100 *= norm00.w;
299
300		vec<4, T, Q> norm01 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g0001, g0001), dot(g0101, g0101), dot(g1001, g1001), dot(g1101, g1101)));
301		g0001 *= norm01.x;
302		g0101 *= norm01.y;
303		g1001 *= norm01.z;
304		g1101 *= norm01.w;
305
306		vec<4, T, Q> norm10 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g0010, g0010), dot(g0110, g0110), dot(g1010, g1010), dot(g1110, g1110)));
307		g0010 *= norm10.x;
308		g0110 *= norm10.y;
309		g1010 *= norm10.z;
310		g1110 *= norm10.w;
311
312		vec<4, T, Q> norm11 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g0011, g0011), dot(g0111, g0111), dot(g1011, g1011), dot(g1111, g1111)));
313		g0011 *= norm11.x;
314		g0111 *= norm11.y;
315		g1011 *= norm11.z;
316		g1111 *= norm11.w;
317
318		T n0000 = dot(g0000, Pf0);
319		T n1000 = dot(g1000, vec<4, T, Q>(Pf1.x, Pf0.y, Pf0.z, Pf0.w));
320		T n0100 = dot(g0100, vec<4, T, Q>(Pf0.x, Pf1.y, Pf0.z, Pf0.w));
321		T n1100 = dot(g1100, vec<4, T, Q>(Pf1.x, Pf1.y, Pf0.z, Pf0.w));
322		T n0010 = dot(g0010, vec<4, T, Q>(Pf0.x, Pf0.y, Pf1.z, Pf0.w));
323		T n1010 = dot(g1010, vec<4, T, Q>(Pf1.x, Pf0.y, Pf1.z, Pf0.w));
324		T n0110 = dot(g0110, vec<4, T, Q>(Pf0.x, Pf1.y, Pf1.z, Pf0.w));
325		T n1110 = dot(g1110, vec<4, T, Q>(Pf1.x, Pf1.y, Pf1.z, Pf0.w));
326		T n0001 = dot(g0001, vec<4, T, Q>(Pf0.x, Pf0.y, Pf0.z, Pf1.w));
327		T n1001 = dot(g1001, vec<4, T, Q>(Pf1.x, Pf0.y, Pf0.z, Pf1.w));
328		T n0101 = dot(g0101, vec<4, T, Q>(Pf0.x, Pf1.y, Pf0.z, Pf1.w));
329		T n1101 = dot(g1101, vec<4, T, Q>(Pf1.x, Pf1.y, Pf0.z, Pf1.w));
330		T n0011 = dot(g0011, vec<4, T, Q>(Pf0.x, Pf0.y, Pf1.z, Pf1.w));
331		T n1011 = dot(g1011, vec<4, T, Q>(Pf1.x, Pf0.y, Pf1.z, Pf1.w));
332		T n0111 = dot(g0111, vec<4, T, Q>(Pf0.x, Pf1.y, Pf1.z, Pf1.w));
333		T n1111 = dot(g1111, Pf1);
334
335		vec<4, T, Q> fade_xyzw = detail::fade(Pf0);
336		vec<4, T, Q> n_0w = mix(vec<4, T, Q>(n0000, n1000, n0100, n1100), vec<4, T, Q>(n0001, n1001, n0101, n1101), fade_xyzw.w);
337		vec<4, T, Q> n_1w = mix(vec<4, T, Q>(n0010, n1010, n0110, n1110), vec<4, T, Q>(n0011, n1011, n0111, n1111), fade_xyzw.w);
338		vec<4, T, Q> n_zw = mix(n_0w, n_1w, fade_xyzw.z);
339		vec<2, T, Q> n_yzw = mix(vec<2, T, Q>(n_zw.x, n_zw.y), vec<2, T, Q>(n_zw.z, n_zw.w), fade_xyzw.y);
340		T n_xyzw = mix(n_yzw.x, n_yzw.y, fade_xyzw.x);
341		return T(2.2) * n_xyzw;
342	}
343
344	// Classic Perlin noise, periodic variant
345	template<typename T, qualifier Q>
346	GLM_FUNC_QUALIFIER T perlin(vec<2, T, Q> const& Position, vec<2, T, Q> const& rep)
347	{
348		vec<4, T, Q> Pi = floor(vec<4, T, Q>(Position.x, Position.y, Position.x, Position.y)) + vec<4, T, Q>(0.0, 0.0, 1.0, 1.0);
349		vec<4, T, Q> Pf = fract(vec<4, T, Q>(Position.x, Position.y, Position.x, Position.y)) - vec<4, T, Q>(0.0, 0.0, 1.0, 1.0);
350		Pi = mod(Pi, vec<4, T, Q>(rep.x, rep.y, rep.x, rep.y)); // To create noise with explicit period
351		Pi = mod(Pi, vec<4, T, Q>(289)); // To avoid truncation effects in permutation
352		vec<4, T, Q> ix(Pi.x, Pi.z, Pi.x, Pi.z);
353		vec<4, T, Q> iy(Pi.y, Pi.y, Pi.w, Pi.w);
354		vec<4, T, Q> fx(Pf.x, Pf.z, Pf.x, Pf.z);
355		vec<4, T, Q> fy(Pf.y, Pf.y, Pf.w, Pf.w);
356
357		vec<4, T, Q> i = detail::permute(detail::permute(ix) + iy);
358
359		vec<4, T, Q> gx = static_cast<T>(2) * fract(i / T(41)) - T(1);
360		vec<4, T, Q> gy = abs(gx) - T(0.5);
361		vec<4, T, Q> tx = floor(gx + T(0.5));
362		gx = gx - tx;
363
364		vec<2, T, Q> g00(gx.x, gy.x);
365		vec<2, T, Q> g10(gx.y, gy.y);
366		vec<2, T, Q> g01(gx.z, gy.z);
367		vec<2, T, Q> g11(gx.w, gy.w);
368
369		vec<4, T, Q> norm = detail::taylorInvSqrt(vec<4, T, Q>(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
370		g00 *= norm.x;
371		g01 *= norm.y;
372		g10 *= norm.z;
373		g11 *= norm.w;
374
375		T n00 = dot(g00, vec<2, T, Q>(fx.x, fy.x));
376		T n10 = dot(g10, vec<2, T, Q>(fx.y, fy.y));
377		T n01 = dot(g01, vec<2, T, Q>(fx.z, fy.z));
378		T n11 = dot(g11, vec<2, T, Q>(fx.w, fy.w));
379
380		vec<2, T, Q> fade_xy = detail::fade(vec<2, T, Q>(Pf.x, Pf.y));
381		vec<2, T, Q> n_x = mix(vec<2, T, Q>(n00, n01), vec<2, T, Q>(n10, n11), fade_xy.x);
382		T n_xy = mix(n_x.x, n_x.y, fade_xy.y);
383		return T(2.3) * n_xy;
384	}
385
386	// Classic Perlin noise, periodic variant
387	template<typename T, qualifier Q>
388	GLM_FUNC_QUALIFIER T perlin(vec<3, T, Q> const& Position, vec<3, T, Q> const& rep)
389	{
390		vec<3, T, Q> Pi0 = mod(floor(Position), rep); // Integer part, modulo period
391		vec<3, T, Q> Pi1 = mod(Pi0 + vec<3, T, Q>(T(1)), rep); // Integer part + 1, mod period
392		Pi0 = mod(Pi0, vec<3, T, Q>(289));
393		Pi1 = mod(Pi1, vec<3, T, Q>(289));
394		vec<3, T, Q> Pf0 = fract(Position); // Fractional part for interpolation
395		vec<3, T, Q> Pf1 = Pf0 - vec<3, T, Q>(T(1)); // Fractional part - 1.0
396		vec<4, T, Q> ix = vec<4, T, Q>(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
397		vec<4, T, Q> iy = vec<4, T, Q>(Pi0.y, Pi0.y, Pi1.y, Pi1.y);
398		vec<4, T, Q> iz0(Pi0.z);
399		vec<4, T, Q> iz1(Pi1.z);
400
401		vec<4, T, Q> ixy = detail::permute(detail::permute(ix) + iy);
402		vec<4, T, Q> ixy0 = detail::permute(ixy + iz0);
403		vec<4, T, Q> ixy1 = detail::permute(ixy + iz1);
404
405		vec<4, T, Q> gx0 = ixy0 / T(7);
406		vec<4, T, Q> gy0 = fract(floor(gx0) / T(7)) - T(0.5);
407		gx0 = fract(gx0);
408		vec<4, T, Q> gz0 = vec<4, T, Q>(0.5) - abs(gx0) - abs(gy0);
409		vec<4, T, Q> sz0 = step(gz0, vec<4, T, Q>(0));
410		gx0 -= sz0 * (step(T(0), gx0) - T(0.5));
411		gy0 -= sz0 * (step(T(0), gy0) - T(0.5));
412
413		vec<4, T, Q> gx1 = ixy1 / T(7);
414		vec<4, T, Q> gy1 = fract(floor(gx1) / T(7)) - T(0.5);
415		gx1 = fract(gx1);
416		vec<4, T, Q> gz1 = vec<4, T, Q>(0.5) - abs(gx1) - abs(gy1);
417		vec<4, T, Q> sz1 = step(gz1, vec<4, T, Q>(T(0)));
418		gx1 -= sz1 * (step(T(0), gx1) - T(0.5));
419		gy1 -= sz1 * (step(T(0), gy1) - T(0.5));
420
421		vec<3, T, Q> g000 = vec<3, T, Q>(gx0.x, gy0.x, gz0.x);
422		vec<3, T, Q> g100 = vec<3, T, Q>(gx0.y, gy0.y, gz0.y);
423		vec<3, T, Q> g010 = vec<3, T, Q>(gx0.z, gy0.z, gz0.z);
424		vec<3, T, Q> g110 = vec<3, T, Q>(gx0.w, gy0.w, gz0.w);
425		vec<3, T, Q> g001 = vec<3, T, Q>(gx1.x, gy1.x, gz1.x);
426		vec<3, T, Q> g101 = vec<3, T, Q>(gx1.y, gy1.y, gz1.y);
427		vec<3, T, Q> g011 = vec<3, T, Q>(gx1.z, gy1.z, gz1.z);
428		vec<3, T, Q> g111 = vec<3, T, Q>(gx1.w, gy1.w, gz1.w);
429
430		vec<4, T, Q> norm0 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
431		g000 *= norm0.x;
432		g010 *= norm0.y;
433		g100 *= norm0.z;
434		g110 *= norm0.w;
435		vec<4, T, Q> norm1 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
436		g001 *= norm1.x;
437		g011 *= norm1.y;
438		g101 *= norm1.z;
439		g111 *= norm1.w;
440
441		T n000 = dot(g000, Pf0);
442		T n100 = dot(g100, vec<3, T, Q>(Pf1.x, Pf0.y, Pf0.z));
443		T n010 = dot(g010, vec<3, T, Q>(Pf0.x, Pf1.y, Pf0.z));
444		T n110 = dot(g110, vec<3, T, Q>(Pf1.x, Pf1.y, Pf0.z));
445		T n001 = dot(g001, vec<3, T, Q>(Pf0.x, Pf0.y, Pf1.z));
446		T n101 = dot(g101, vec<3, T, Q>(Pf1.x, Pf0.y, Pf1.z));
447		T n011 = dot(g011, vec<3, T, Q>(Pf0.x, Pf1.y, Pf1.z));
448		T n111 = dot(g111, Pf1);
449
450		vec<3, T, Q> fade_xyz = detail::fade(Pf0);
451		vec<4, T, Q> n_z = mix(vec<4, T, Q>(n000, n100, n010, n110), vec<4, T, Q>(n001, n101, n011, n111), fade_xyz.z);
452		vec<2, T, Q> n_yz = mix(vec<2, T, Q>(n_z.x, n_z.y), vec<2, T, Q>(n_z.z, n_z.w), fade_xyz.y);
453		T n_xyz = mix(n_yz.x, n_yz.y, fade_xyz.x);
454		return T(2.2) * n_xyz;
455	}
456
457	// Classic Perlin noise, periodic version
458	template<typename T, qualifier Q>
459	GLM_FUNC_QUALIFIER T perlin(vec<4, T, Q> const& Position, vec<4, T, Q> const& rep)
460	{
461		vec<4, T, Q> Pi0 = mod(floor(Position), rep); // Integer part modulo rep
462		vec<4, T, Q> Pi1 = mod(Pi0 + T(1), rep); // Integer part + 1 mod rep
463		vec<4, T, Q> Pf0 = fract(Position); // Fractional part for interpolation
464		vec<4, T, Q> Pf1 = Pf0 - T(1); // Fractional part - 1.0
465		vec<4, T, Q> ix = vec<4, T, Q>(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
466		vec<4, T, Q> iy = vec<4, T, Q>(Pi0.y, Pi0.y, Pi1.y, Pi1.y);
467		vec<4, T, Q> iz0(Pi0.z);
468		vec<4, T, Q> iz1(Pi1.z);
469		vec<4, T, Q> iw0(Pi0.w);
470		vec<4, T, Q> iw1(Pi1.w);
471
472		vec<4, T, Q> ixy = detail::permute(detail::permute(ix) + iy);
473		vec<4, T, Q> ixy0 = detail::permute(ixy + iz0);
474		vec<4, T, Q> ixy1 = detail::permute(ixy + iz1);
475		vec<4, T, Q> ixy00 = detail::permute(ixy0 + iw0);
476		vec<4, T, Q> ixy01 = detail::permute(ixy0 + iw1);
477		vec<4, T, Q> ixy10 = detail::permute(ixy1 + iw0);
478		vec<4, T, Q> ixy11 = detail::permute(ixy1 + iw1);
479
480		vec<4, T, Q> gx00 = ixy00 / T(7);
481		vec<4, T, Q> gy00 = floor(gx00) / T(7);
482		vec<4, T, Q> gz00 = floor(gy00) / T(6);
483		gx00 = fract(gx00) - T(0.5);
484		gy00 = fract(gy00) - T(0.5);
485		gz00 = fract(gz00) - T(0.5);
486		vec<4, T, Q> gw00 = vec<4, T, Q>(0.75) - abs(gx00) - abs(gy00) - abs(gz00);
487		vec<4, T, Q> sw00 = step(gw00, vec<4, T, Q>(0));
488		gx00 -= sw00 * (step(T(0), gx00) - T(0.5));
489		gy00 -= sw00 * (step(T(0), gy00) - T(0.5));
490
491		vec<4, T, Q> gx01 = ixy01 / T(7);
492		vec<4, T, Q> gy01 = floor(gx01) / T(7);
493		vec<4, T, Q> gz01 = floor(gy01) / T(6);
494		gx01 = fract(gx01) - T(0.5);
495		gy01 = fract(gy01) - T(0.5);
496		gz01 = fract(gz01) - T(0.5);
497		vec<4, T, Q> gw01 = vec<4, T, Q>(0.75) - abs(gx01) - abs(gy01) - abs(gz01);
498		vec<4, T, Q> sw01 = step(gw01, vec<4, T, Q>(0.0));
499		gx01 -= sw01 * (step(T(0), gx01) - T(0.5));
500		gy01 -= sw01 * (step(T(0), gy01) - T(0.5));
501
502		vec<4, T, Q> gx10 = ixy10 / T(7);
503		vec<4, T, Q> gy10 = floor(gx10) / T(7);
504		vec<4, T, Q> gz10 = floor(gy10) / T(6);
505		gx10 = fract(gx10) - T(0.5);
506		gy10 = fract(gy10) - T(0.5);
507		gz10 = fract(gz10) - T(0.5);
508		vec<4, T, Q> gw10 = vec<4, T, Q>(0.75) - abs(gx10) - abs(gy10) - abs(gz10);
509		vec<4, T, Q> sw10 = step(gw10, vec<4, T, Q>(0.0));
510		gx10 -= sw10 * (step(T(0), gx10) - T(0.5));
511		gy10 -= sw10 * (step(T(0), gy10) - T(0.5));
512
513		vec<4, T, Q> gx11 = ixy11 / T(7);
514		vec<4, T, Q> gy11 = floor(gx11) / T(7);
515		vec<4, T, Q> gz11 = floor(gy11) / T(6);
516		gx11 = fract(gx11) - T(0.5);
517		gy11 = fract(gy11) - T(0.5);
518		gz11 = fract(gz11) - T(0.5);
519		vec<4, T, Q> gw11 = vec<4, T, Q>(0.75) - abs(gx11) - abs(gy11) - abs(gz11);
520		vec<4, T, Q> sw11 = step(gw11, vec<4, T, Q>(T(0)));
521		gx11 -= sw11 * (step(T(0), gx11) - T(0.5));
522		gy11 -= sw11 * (step(T(0), gy11) - T(0.5));
523
524		vec<4, T, Q> g0000(gx00.x, gy00.x, gz00.x, gw00.x);
525		vec<4, T, Q> g1000(gx00.y, gy00.y, gz00.y, gw00.y);
526		vec<4, T, Q> g0100(gx00.z, gy00.z, gz00.z, gw00.z);
527		vec<4, T, Q> g1100(gx00.w, gy00.w, gz00.w, gw00.w);
528		vec<4, T, Q> g0010(gx10.x, gy10.x, gz10.x, gw10.x);
529		vec<4, T, Q> g1010(gx10.y, gy10.y, gz10.y, gw10.y);
530		vec<4, T, Q> g0110(gx10.z, gy10.z, gz10.z, gw10.z);
531		vec<4, T, Q> g1110(gx10.w, gy10.w, gz10.w, gw10.w);
532		vec<4, T, Q> g0001(gx01.x, gy01.x, gz01.x, gw01.x);
533		vec<4, T, Q> g1001(gx01.y, gy01.y, gz01.y, gw01.y);
534		vec<4, T, Q> g0101(gx01.z, gy01.z, gz01.z, gw01.z);
535		vec<4, T, Q> g1101(gx01.w, gy01.w, gz01.w, gw01.w);
536		vec<4, T, Q> g0011(gx11.x, gy11.x, gz11.x, gw11.x);
537		vec<4, T, Q> g1011(gx11.y, gy11.y, gz11.y, gw11.y);
538		vec<4, T, Q> g0111(gx11.z, gy11.z, gz11.z, gw11.z);
539		vec<4, T, Q> g1111(gx11.w, gy11.w, gz11.w, gw11.w);
540
541		vec<4, T, Q> norm00 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g0000, g0000), dot(g0100, g0100), dot(g1000, g1000), dot(g1100, g1100)));
542		g0000 *= norm00.x;
543		g0100 *= norm00.y;
544		g1000 *= norm00.z;
545		g1100 *= norm00.w;
546
547		vec<4, T, Q> norm01 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g0001, g0001), dot(g0101, g0101), dot(g1001, g1001), dot(g1101, g1101)));
548		g0001 *= norm01.x;
549		g0101 *= norm01.y;
550		g1001 *= norm01.z;
551		g1101 *= norm01.w;
552
553		vec<4, T, Q> norm10 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g0010, g0010), dot(g0110, g0110), dot(g1010, g1010), dot(g1110, g1110)));
554		g0010 *= norm10.x;
555		g0110 *= norm10.y;
556		g1010 *= norm10.z;
557		g1110 *= norm10.w;
558
559		vec<4, T, Q> norm11 = detail::taylorInvSqrt(vec<4, T, Q>(dot(g0011, g0011), dot(g0111, g0111), dot(g1011, g1011), dot(g1111, g1111)));
560		g0011 *= norm11.x;
561		g0111 *= norm11.y;
562		g1011 *= norm11.z;
563		g1111 *= norm11.w;
564
565		T n0000 = dot(g0000, Pf0);
566		T n1000 = dot(g1000, vec<4, T, Q>(Pf1.x, Pf0.y, Pf0.z, Pf0.w));
567		T n0100 = dot(g0100, vec<4, T, Q>(Pf0.x, Pf1.y, Pf0.z, Pf0.w));
568		T n1100 = dot(g1100, vec<4, T, Q>(Pf1.x, Pf1.y, Pf0.z, Pf0.w));
569		T n0010 = dot(g0010, vec<4, T, Q>(Pf0.x, Pf0.y, Pf1.z, Pf0.w));
570		T n1010 = dot(g1010, vec<4, T, Q>(Pf1.x, Pf0.y, Pf1.z, Pf0.w));
571		T n0110 = dot(g0110, vec<4, T, Q>(Pf0.x, Pf1.y, Pf1.z, Pf0.w));
572		T n1110 = dot(g1110, vec<4, T, Q>(Pf1.x, Pf1.y, Pf1.z, Pf0.w));
573		T n0001 = dot(g0001, vec<4, T, Q>(Pf0.x, Pf0.y, Pf0.z, Pf1.w));
574		T n1001 = dot(g1001, vec<4, T, Q>(Pf1.x, Pf0.y, Pf0.z, Pf1.w));
575		T n0101 = dot(g0101, vec<4, T, Q>(Pf0.x, Pf1.y, Pf0.z, Pf1.w));
576		T n1101 = dot(g1101, vec<4, T, Q>(Pf1.x, Pf1.y, Pf0.z, Pf1.w));
577		T n0011 = dot(g0011, vec<4, T, Q>(Pf0.x, Pf0.y, Pf1.z, Pf1.w));
578		T n1011 = dot(g1011, vec<4, T, Q>(Pf1.x, Pf0.y, Pf1.z, Pf1.w));
579		T n0111 = dot(g0111, vec<4, T, Q>(Pf0.x, Pf1.y, Pf1.z, Pf1.w));
580		T n1111 = dot(g1111, Pf1);
581
582		vec<4, T, Q> fade_xyzw = detail::fade(Pf0);
583		vec<4, T, Q> n_0w = mix(vec<4, T, Q>(n0000, n1000, n0100, n1100), vec<4, T, Q>(n0001, n1001, n0101, n1101), fade_xyzw.w);
584		vec<4, T, Q> n_1w = mix(vec<4, T, Q>(n0010, n1010, n0110, n1110), vec<4, T, Q>(n0011, n1011, n0111, n1111), fade_xyzw.w);
585		vec<4, T, Q> n_zw = mix(n_0w, n_1w, fade_xyzw.z);
586		vec<2, T, Q> n_yzw = mix(vec<2, T, Q>(n_zw.x, n_zw.y), vec<2, T, Q>(n_zw.z, n_zw.w), fade_xyzw.y);
587		T n_xyzw = mix(n_yzw.x, n_yzw.y, fade_xyzw.x);
588		return T(2.2) * n_xyzw;
589	}
590
591	template<typename T, qualifier Q>
592	GLM_FUNC_QUALIFIER T simplex(glm::vec<2, T, Q> const& v)
593	{
594		vec<4, T, Q> const C = vec<4, T, Q>(
595			T( 0.211324865405187),  // (3.0 -  sqrt(3.0)) / 6.0
596			T( 0.366025403784439),  //  0.5 * (sqrt(3.0)  - 1.0)
597			T(-0.577350269189626),	// -1.0 + 2.0 * C.x
598			T( 0.024390243902439)); //  1.0 / 41.0
599
600		// First corner
601		vec<2, T, Q> i  = floor(v + dot(v, vec<2, T, Q>(C[1])));
602		vec<2, T, Q> x0 = v -   i + dot(i, vec<2, T, Q>(C[0]));
603
604		// Other corners
605		//i1.x = step( x0.y, x0.x ); // x0.x > x0.y ? 1.0 : 0.0
606		//i1.y = 1.0 - i1.x;
607		vec<2, T, Q> i1 = (x0.x > x0.y) ? vec<2, T, Q>(1, 0) : vec<2, T, Q>(0, 1);
608		// x0 = x0 - 0.0 + 0.0 * C.xx ;
609		// x1 = x0 - i1 + 1.0 * C.xx ;
610		// x2 = x0 - 1.0 + 2.0 * C.xx ;
611		vec<4, T, Q> x12 = vec<4, T, Q>(x0.x, x0.y, x0.x, x0.y) + vec<4, T, Q>(C.x, C.x, C.z, C.z);
612		x12 = vec<4, T, Q>(vec<2, T, Q>(x12) - i1, x12.z, x12.w);
613
614		// Permutations
615		i = mod(i, vec<2, T, Q>(289)); // Avoid truncation effects in permutation
616		vec<3, T, Q> p = detail::permute(
617			detail::permute(i.y + vec<3, T, Q>(T(0), i1.y, T(1)))
618			+ i.x + vec<3, T, Q>(T(0), i1.x, T(1)));
619
620		vec<3, T, Q> m = max(vec<3, T, Q>(0.5) - vec<3, T, Q>(
621			dot(x0, x0),
622			dot(vec<2, T, Q>(x12.x, x12.y), vec<2, T, Q>(x12.x, x12.y)),
623			dot(vec<2, T, Q>(x12.z, x12.w), vec<2, T, Q>(x12.z, x12.w))), vec<3, T, Q>(0));
624		m = m * m ;
625		m = m * m ;
626
627		// Gradients: 41 points uniformly over a line, mapped onto a diamond.
628		// The ring size 17*17 = 289 is close to a multiple of 41 (41*7 = 287)
629
630		vec<3, T, Q> x = static_cast<T>(2) * fract(p * C.w) - T(1);
631		vec<3, T, Q> h = abs(x) - T(0.5);
632		vec<3, T, Q> ox = floor(x + T(0.5));
633		vec<3, T, Q> a0 = x - ox;
634
635		// Normalise gradients implicitly by scaling m
636		// Inlined for speed: m *= taylorInvSqrt( a0*a0 + h*h );
637		m *= static_cast<T>(1.79284291400159) - T(0.85373472095314) * (a0 * a0 + h * h);
638
639		// Compute final noise value at P
640		vec<3, T, Q> g;
641		g.x  = a0.x  * x0.x  + h.x  * x0.y;
642		//g.yz = a0.yz * x12.xz + h.yz * x12.yw;
643		g.y = a0.y * x12.x + h.y * x12.y;
644		g.z = a0.z * x12.z + h.z * x12.w;
645		return T(130) * dot(m, g);
646	}
647
648	template<typename T, qualifier Q>
649	GLM_FUNC_QUALIFIER T simplex(vec<3, T, Q> const& v)
650	{
651		vec<2, T, Q> const C(1.0 / 6.0, 1.0 / 3.0);
652		vec<4, T, Q> const D(0.0, 0.5, 1.0, 2.0);
653
654		// First corner
655		vec<3, T, Q> i(floor(v + dot(v, vec<3, T, Q>(C.y))));
656		vec<3, T, Q> x0(v - i + dot(i, vec<3, T, Q>(C.x)));
657
658		// Other corners
659		vec<3, T, Q> g(step(vec<3, T, Q>(x0.y, x0.z, x0.x), x0));
660		vec<3, T, Q> l(T(1) - g);
661		vec<3, T, Q> i1(min(g, vec<3, T, Q>(l.z, l.x, l.y)));
662		vec<3, T, Q> i2(max(g, vec<3, T, Q>(l.z, l.x, l.y)));
663
664		//   x0 = x0 - 0.0 + 0.0 * C.xxx;
665		//   x1 = x0 - i1  + 1.0 * C.xxx;
666		//   x2 = x0 - i2  + 2.0 * C.xxx;
667		//   x3 = x0 - 1.0 + 3.0 * C.xxx;
668		vec<3, T, Q> x1(x0 - i1 + C.x);
669		vec<3, T, Q> x2(x0 - i2 + C.y); // 2.0*C.x = 1/3 = C.y
670		vec<3, T, Q> x3(x0 - D.y);      // -1.0+3.0*C.x = -0.5 = -D.y
671
672		// Permutations
673		i = detail::mod289(i);
674		vec<4, T, Q> p(detail::permute(detail::permute(detail::permute(
675			i.z + vec<4, T, Q>(T(0), i1.z, i2.z, T(1))) +
676			i.y + vec<4, T, Q>(T(0), i1.y, i2.y, T(1))) +
677			i.x + vec<4, T, Q>(T(0), i1.x, i2.x, T(1))));
678
679		// Gradients: 7x7 points over a square, mapped onto an octahedron.
680		// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
681		T n_ = static_cast<T>(0.142857142857); // 1.0/7.0
682		vec<3, T, Q> ns(n_ * vec<3, T, Q>(D.w, D.y, D.z) - vec<3, T, Q>(D.x, D.z, D.x));
683
684		vec<4, T, Q> j(p - T(49) * floor(p * ns.z * ns.z));  //  mod(p,7*7)
685
686		vec<4, T, Q> x_(floor(j * ns.z));
687		vec<4, T, Q> y_(floor(j - T(7) * x_));    // mod(j,N)
688
689		vec<4, T, Q> x(x_ * ns.x + ns.y);
690		vec<4, T, Q> y(y_ * ns.x + ns.y);
691		vec<4, T, Q> h(T(1) - abs(x) - abs(y));
692
693		vec<4, T, Q> b0(x.x, x.y, y.x, y.y);
694		vec<4, T, Q> b1(x.z, x.w, y.z, y.w);
695
696		// vec4 s0 = vec4(lessThan(b0,0.0))*2.0 - 1.0;
697		// vec4 s1 = vec4(lessThan(b1,0.0))*2.0 - 1.0;
698		vec<4, T, Q> s0(floor(b0) * T(2) + T(1));
699		vec<4, T, Q> s1(floor(b1) * T(2) + T(1));
700		vec<4, T, Q> sh(-step(h, vec<4, T, Q>(0.0)));
701
702		vec<4, T, Q> a0 = vec<4, T, Q>(b0.x, b0.z, b0.y, b0.w) + vec<4, T, Q>(s0.x, s0.z, s0.y, s0.w) * vec<4, T, Q>(sh.x, sh.x, sh.y, sh.y);
703		vec<4, T, Q> a1 = vec<4, T, Q>(b1.x, b1.z, b1.y, b1.w) + vec<4, T, Q>(s1.x, s1.z, s1.y, s1.w) * vec<4, T, Q>(sh.z, sh.z, sh.w, sh.w);
704
705		vec<3, T, Q> p0(a0.x, a0.y, h.x);
706		vec<3, T, Q> p1(a0.z, a0.w, h.y);
707		vec<3, T, Q> p2(a1.x, a1.y, h.z);
708		vec<3, T, Q> p3(a1.z, a1.w, h.w);
709
710		// Normalise gradients
711		vec<4, T, Q> norm = detail::taylorInvSqrt(vec<4, T, Q>(dot(p0, p0), dot(p1, p1), dot(p2, p2), dot(p3, p3)));
712		p0 *= norm.x;
713		p1 *= norm.y;
714		p2 *= norm.z;
715		p3 *= norm.w;
716
717		// Mix final noise value
718		vec<4, T, Q> m = max(T(0.6) - vec<4, T, Q>(dot(x0, x0), dot(x1, x1), dot(x2, x2), dot(x3, x3)), vec<4, T, Q>(0));
719		m = m * m;
720		return T(42) * dot(m * m, vec<4, T, Q>(dot(p0, x0), dot(p1, x1), dot(p2, x2), dot(p3, x3)));
721	}
722
723	template<typename T, qualifier Q>
724	GLM_FUNC_QUALIFIER T simplex(vec<4, T, Q> const& v)
725	{
726		vec<4, T, Q> const C(
727			0.138196601125011,  // (5 - sqrt(5))/20  G4
728			0.276393202250021,  // 2 * G4
729			0.414589803375032,  // 3 * G4
730			-0.447213595499958); // -1 + 4 * G4
731
732		// (sqrt(5) - 1)/4 = F4, used once below
733		T const F4 = static_cast<T>(0.309016994374947451);
734
735		// First corner
736		vec<4, T, Q> i  = floor(v + dot(v, vec4(F4)));
737		vec<4, T, Q> x0 = v -   i + dot(i, vec4(C.x));
738
739		// Other corners
740
741		// Rank sorting originally contributed by Bill Licea-Kane, AMD (formerly ATI)
742		vec<4, T, Q> i0;
743		vec<3, T, Q> isX = step(vec<3, T, Q>(x0.y, x0.z, x0.w), vec<3, T, Q>(x0.x));
744		vec<3, T, Q> isYZ = step(vec<3, T, Q>(x0.z, x0.w, x0.w), vec<3, T, Q>(x0.y, x0.y, x0.z));
745		//  i0.x = dot(isX, vec3(1.0));
746		//i0.x = isX.x + isX.y + isX.z;
747		//i0.yzw = static_cast<T>(1) - isX;
748		i0 = vec<4, T, Q>(isX.x + isX.y + isX.z, T(1) - isX);
749		//  i0.y += dot(isYZ.xy, vec2(1.0));
750		i0.y += isYZ.x + isYZ.y;
751		//i0.zw += 1.0 - vec<2, T, Q>(isYZ.x, isYZ.y);
752		i0.z += static_cast<T>(1) - isYZ.x;
753		i0.w += static_cast<T>(1) - isYZ.y;
754		i0.z += isYZ.z;
755		i0.w += static_cast<T>(1) - isYZ.z;
756
757		// i0 now contains the unique values 0,1,2,3 in each channel
758		vec<4, T, Q> i3 = clamp(i0, T(0), T(1));
759		vec<4, T, Q> i2 = clamp(i0 - T(1), T(0), T(1));
760		vec<4, T, Q> i1 = clamp(i0 - T(2), T(0), T(1));
761
762		//  x0 = x0 - 0.0 + 0.0 * C.xxxx
763		//  x1 = x0 - i1  + 0.0 * C.xxxx
764		//  x2 = x0 - i2  + 0.0 * C.xxxx
765		//  x3 = x0 - i3  + 0.0 * C.xxxx
766		//  x4 = x0 - 1.0 + 4.0 * C.xxxx
767		vec<4, T, Q> x1 = x0 - i1 + C.x;
768		vec<4, T, Q> x2 = x0 - i2 + C.y;
769		vec<4, T, Q> x3 = x0 - i3 + C.z;
770		vec<4, T, Q> x4 = x0 + C.w;
771
772		// Permutations
773		i = mod(i, vec<4, T, Q>(289));
774		T j0 = detail::permute(detail::permute(detail::permute(detail::permute(i.w) + i.z) + i.y) + i.x);
775		vec<4, T, Q> j1 = detail::permute(detail::permute(detail::permute(detail::permute(
776			i.w + vec<4, T, Q>(i1.w, i2.w, i3.w, T(1))) +
777			i.z + vec<4, T, Q>(i1.z, i2.z, i3.z, T(1))) +
778			i.y + vec<4, T, Q>(i1.y, i2.y, i3.y, T(1))) +
779			i.x + vec<4, T, Q>(i1.x, i2.x, i3.x, T(1)));
780
781		// Gradients: 7x7x6 points over a cube, mapped onto a 4-cross polytope
782		// 7*7*6 = 294, which is close to the ring size 17*17 = 289.
783		vec<4, T, Q> ip = vec<4, T, Q>(T(1) / T(294), T(1) / T(49), T(1) / T(7), T(0));
784
785		vec<4, T, Q> p0 = gtc::grad4(j0,   ip);
786		vec<4, T, Q> p1 = gtc::grad4(j1.x, ip);
787		vec<4, T, Q> p2 = gtc::grad4(j1.y, ip);
788		vec<4, T, Q> p3 = gtc::grad4(j1.z, ip);
789		vec<4, T, Q> p4 = gtc::grad4(j1.w, ip);
790
791		// Normalise gradients
792		vec<4, T, Q> norm = detail::taylorInvSqrt(vec<4, T, Q>(dot(p0, p0), dot(p1, p1), dot(p2, p2), dot(p3, p3)));
793		p0 *= norm.x;
794		p1 *= norm.y;
795		p2 *= norm.z;
796		p3 *= norm.w;
797		p4 *= detail::taylorInvSqrt(dot(p4, p4));
798
799		// Mix contributions from the five corners
800		vec<3, T, Q> m0 = max(T(0.6) - vec<3, T, Q>(dot(x0, x0), dot(x1, x1), dot(x2, x2)), vec<3, T, Q>(0));
801		vec<2, T, Q> m1 = max(T(0.6) - vec<2, T, Q>(dot(x3, x3), dot(x4, x4)             ), vec<2, T, Q>(0));
802		m0 = m0 * m0;
803		m1 = m1 * m1;
804		return T(49) *
805			(dot(m0 * m0, vec<3, T, Q>(dot(p0, x0), dot(p1, x1), dot(p2, x2))) +
806			dot(m1 * m1, vec<2, T, Q>(dot(p3, x3), dot(p4, x4))));
807	}
808}//namespace glm
809