server/common/noise.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2010 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * 
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program 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 Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

#include "noise.h"

/////////////////////////////////////////////////////////////////////////////

noise2d::noise2d (uint32_t seed)
{
  seedable_rand_gen rng (seed);

  for (int i = 0; i < 256; ++i)
    {
      vec2d rv;
      rv[0] = rng () - 0.5f;
      rv[1] = rng () - 0.5f;

      // normalise
      float mag = 1.f / sqrtf (rv[0] * rv[0] + rv[1] * rv[1]);

      rv[0] *= mag;
      rv[1] *= mag;

      rvec[i][0] = rv[0];
      rvec[i][1] = rv[1];
    }

  rvmap[0].seed (rng);
  rvmap[1].seed (rng);
}

float
noise2d::noise (float x, float y)
{
  int ix = floorf (x); float fx = x - ix;
  int iy = floorf (y); float fy = y - iy;

  float v = 0;

  for (int j = -1; j <= 2; ++j)
    for (int i = -1; i <= 2; ++i)
      {
        float Ax = fx - i;
        float Ay = fy - j;

        float d = Ax * Ax + Ay * Ay;

        if (d < 4)
          {
            float t1 = 1 - d / 4;
            float t2 = t1 * t1;
            float t4 = t2 * t2;

            float p = (4 * t1 - 3) * t4;

            int h = rvmap[0](ix + i) ^ rvmap[1](iy + j);
            float G0 = rvec[h & 0xff][0];
            float G1 = rvec[h & 0xff][1];
            //vec2d G = rvec[h & 0xff];

            v += (Ax * G0 + Ay * G1) * p;
          }
      }

  return clamp (v * 2, -.9999999f, .9999999f);
}

#if 0||ABSTRACTION_PENALTY_IS_GONE
float
noise2d::noise (float x, float y)
{
  vec2d X = vec2d (x, y);
  gen_vec<2,int> I = floor (X);
  vec2d F = X - I;

  float v = 0;

  for (int j = -1; j <= 2; ++j)
    for (int i = -1; i <= 2; ++i)
      {
        vec2d A = F - vec2d (i, j);

        float d = A * A;
  
        if (d < 4)
          {
            int h = rvmap [0](I[0] + i) ^ rvmap [1](I[1] + j);
            float *G = rvec [h & 0xff];
  
            float t1 = 1 - d / 4;
            float t2 = t1 * t1;
            float t4 = t2 * t2;

            float p = (4 * t1 - 3) * t4;
            v += A * vec2d (G[0], G[1]) * p;
          }
      }
    
  return clamp (v * 2, -.9999999f, .9999999f);
} 
#endif

/////////////////////////////////////////////////////////////////////////////

noise3d::noise3d (uint32_t seed)
{
  seedable_rand_gen rng (seed);

  for (int i = 0; i < 256; ++i)
    {
      for (int j = 0; j < 3; ++j)
        rvec [i][j] = rng () - 0.5f;

      // normalise
      float mag = 1.f / sqrtf (rvec [i][0] * rvec [i][0]
                             + rvec [i][1] * rvec [i][1]
                             + rvec [i][2] * rvec [i][2]);

      rvec [i][0] *= mag;
      rvec [i][1] *= mag;
      rvec [i][2] *= mag;
    }

  rvmap [0].seed (rng);
  rvmap [1].seed (rng);
  rvmap [2].seed (rng);
}

float
noise3d::noise (float x, float y, float z)
{
  int ix = floorf (x); float fx = x - ix;
  int iy = floorf (y); float fy = y - iy;
  int iz = floorf (z); float fz = z - iz;

  float v = 0;

  for (int j = -1; j <= 2; ++j)
    for (int i = -1; i <= 2; ++i)
      for (int k = -1; k <= 2; ++k)
        {
          float Ax = fx - i;
          float Ay = fy - j;
          float Az = fz - k;

          float d = Ax * Ax + Ay * Ay + Az * Az;

          if (d < 4)
            {
              int h = rvmap [0](ix + i) ^ rvmap [1](iy + j) ^ rvmap [2](iz + k);
              float *G = rvec [h & 0xff];

              float t1 = 1 - d / 4;
              float t2 = t1 * t1;
              float t4 = t2 * t2;

              // (4t⁵ - 3t⁴)
              float p = (4 * t1 - 3) * t4;
              v += (Ax * G[0] + Ay * G[1] + Az * G[2]) * p;
            }
        }

  return clamp (v * 2, -.9999999f, .9999999f);
}

float
noise3d::noise (float x, float y, float z, float nx, float ny, float nz)
{
  int ix = floorf (x); float fx = x - ix;
  int iy = floorf (y); float fy = y - iy;
  int iz = floorf (z); float fz = z - iz;

  float v = 0;

  for (int j = -1; j <= 2; ++j)
    for (int i = -1; i <= 2; ++i)
      for (int k = -1; k <= 2; ++k)
        {
          float Dx = fx - i;
          float Dy = fy - j;
          float Dz = fz - k;

          float e = Dx * nx + Dy * ny + Dz * nz;

          float o = 1 - abs (e);

          if (o > 0)
            {
              float Ax = Dx - e * nx;
              float Ay = Dy - e * ny;
              float Az = Dz - e * nz;

              float d = Ax * Ax + Ay * Ay + Az * Az;

              if (d < 4)
                {
                  int h = rvmap [0](ix + i) ^ rvmap [1](iy + j) ^ rvmap [2](iz + k);
                  float *G = rvec [h & 0xff];

                  float t1 = 1 - d / 4;
                  float t2 = t1 * t1;
                  float t4 = t2 * t2;

                  float o2 = o * o;

                  // (4t⁵ - 3t⁴) * (3o³ - 2o²)
                  float p = (4 * t1 - 3) * t4 * (3 * o2 - 2 * o2 * o);
                  v += (Ax * G[0] + Ay * G[1] + Az * G[2]) * p;
                }
            }
        }

  return clamp (v * 2, -.9999999f, .9999999f);
}

frac_gen::frac_gen (float hurst_expo, float lacunarity)
: h (hurst_expo), lac (lacunarity), noise2d (0)
{
  float exsum = 0;

  for (int i = 0; i < MAX_OCTAVES; ++i)
    {
      ex [i] = powf (lac, -h * i);
      exsum += ex [i];
      fbm_mul [i] = 0.5f / (exsum * 0.75f); // .75f is a heuristic
      rot [i].set (0.4488f * i);
    }
}

float
frac_gen::fBm (float x, float y, int octaves)
{
  float v = 0.f;

  for (int i = 0; i < octaves; ++i)
    {
      rot [i](x, y);
      
      v += noise (x + i, y) * ex [i];

      x *= lac;
      y *= lac;
    }

  return clamp (v * fbm_mul [octaves - 1] + 0.5f, 0.f, .9999999f);
}

float
frac_gen::turbulence (float x, float y, int octaves)
{
  float v = 0.f;

  for (int i = 0; i < octaves; ++i)
    {
      rot [i](x, y);

      v += fabsf (noise (x + i, y)) * ex [i];

      x *= lac;
      y *= lac;
    }

  return clamp (v * fbm_mul [octaves - 1] * 2.f, 0.f, .9999999f);
}

float
frac_gen::multifractal (float x, float y, int octaves, float offset)
{
  float v = 1.f;

  for (int i = 0; i < octaves; ++i)
    {
      rot [i](x, y);

      v *= noise (x, y) * ex [i] + offset;

      x *= lac;
      y *= lac;
    }

  return clamp (v * 0.5f, 0.f, .9999999f);
}

float
frac_gen::heterofractal (float x, float y, int octaves, float offset)
{
  float v = noise (x, y) + offset;
  int i;

  for (i = 1; i < octaves; ++i)
    {
      rot [i](x, y);

      x *= lac;
      y *= lac;

      v += v * (noise (x, y) * ex [i] + offset);
    }

  return v / powf (2., octaves);
}

float
frac_gen::hybridfractal (float x, float y, int octaves, float offset, float gain)
{
  float v = (noise (x, y) + offset) * ex [0];
  float weight = v;
  int i;

  for (i = 1; i < octaves; ++i)
    {
      rot [i](x, y);

      x *= lac;
      y *= lac;

      min_it (weight, 1.f);

      float sig = (noise (x, y) + offset) * ex [i];
      v += weight * sig;
      weight *= gain * sig;
    }

  return clamp (v * 0.5f + 0.5f, 0.f, .9999999f);
}

// http://www.gamasutra.com/view/feature/3098/a_realtime_procedural_universe_.php?page=2
float
frac_gen::terrain (float x, float y, int octaves)
{
  float v = 0.f;

  for (int i = 0; i < octaves; ++i)
    {
      rot[i] (x, y);

      v += noise (x + i, y) * ex [i];

      x *= lac;
      y *= lac;
    }

  v *= fbm_mul [octaves - 1];

  return v <= 0.f ? - powf (-v, 0.7f) : powf (v, 1. + noise (x, y) * v);
}

float
frac_gen::terrain2 (float x, float y, int octaves)
{
  float a = fBm (x, y, octaves);
  float b = ridgedmultifractal (x, y, octaves, 1, 8);
  float fade = fBm (x + 10.3, y + 10.3, octaves);

  const float width = 0.05f;

  if (fade > 0.5f + width)
    return a;
  else if (fade < 0.5f - width)
    return b;

  fade = (fade - 0.5f + width) / (width * 2);

  // sigmoidal curve
  fade = fade * fade * 2 * (1.5f - fade);

  return a * fade + b * (1 - fade);
}

float
frac_gen::ridgedmultifractal (float x, float y, int octaves, float offset, float gain)
{
  float sig = offset - fabsf (noise (x, y));
  sig *= sig;
  float v = sig;

  for (int i = 1; i < octaves; ++i)
    {
      rot [i](x, y);

      x *= lac;
      y *= lac;

      float w = clamp (sig * gain, 0.f, 1.f);

      sig = offset - fabsf (noise (x, y));
      sig *= sig;
      sig *= w;

      v += sig * ex [i];
    }

  return clamp (v * 0.25f, 0.f, .9999999f);
}

#if 1
void hack()
{
  frac_gen gen (0.5, 2);
  noise3d n(0);

#if 1
  int N = 1024;

  printf ("P5 %d %d 255\n", N, N);
  // pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm
  for (int y = 0; y < N; ++y)
    {
      if (!(y&63))fprintf (stderr, "y %d\n", y);//D
    for (int x = 0; x < N; ++x)
      {
        putc (127 * gen.noise (x * 0.04, y * 0.04) + 128, stdout);
        //putc (256 * gen.terrain2 (x * 0.004, y * 0.004, 8), stdout);
        //putc (256 * gen.fBm (x * 0.01, y * 0.01, 7), stdout);
        //putc (256 * gen.turbulence (x * 0.004 - 1, y * 0.004 - 1, 8), stdout);
        //putc (256 * gen.heterofractal (x * 0.008, y * 0.008, 8, -1.1, 2.0), stdout);
        //putc (256 * gen.ridgedmultifractal (x * 0.001, y * 0.001, 32, 1.001, 32), stdout);
      }
    }
#else
  int N = 128;

  //printf ("P6 %d %d 255\n", N, N);
  // pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm
  for (int z = 0; z < N; ++z)
    {
      if (!(z&4))fprintf (stderr, "z %d\n", z);//D
  for (int y = 0; y < N; ++y)
    for (int x = 0; x < N; ++x)
      {
        float v = n.noise (x * 0.06 + 0.2, y * 0.06 + 0.2, z * 0.06 + 0.2) * 0.5 + 0.5;

        if (z < 64)
          v = v * (z * z) / (64 * 64);

        if (v <= 0.1)
          continue;

        float r[4];
        int i[4];

        r[0] = x;
        r[1] = y;
        r[2] = z;
        r[3] = v;

        memcpy (i, r, 16);

        i[0] = htonl (i[0]);
        i[1] = htonl (i[1]);
        i[2] = htonl (i[2]);
        i[3] = htonl (i[3]);

        fwrite (i, 4*4, 1, stdout);
      }
    }
#endif

  exit (0);
}
#endif
Revision:	1.3
Committed:	Fri Apr 22 07:56:46 2011 UTC (13 years, 1 month ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+23 -18 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3	*
4	* Copyright (©) 2010 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	*
6	* Deliantra is free software: you can redistribute it and/or modify it under
7	* the terms of the Affero GNU General Public License as published by the
8	* Free Software Foundation, either version 3 of the License, or (at your
9	* option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the Affero GNU General Public License
17	* and the GNU General Public License along with this program. If not, see
18	* <http://www.gnu.org/licenses/>.
19	*
20	* The authors can be reached via e-mail to <support@deliantra.net>
21	*/
22
23	#include "noise.h"
24
25	/////////////////////////////////////////////////////////////////////////////
26
27	noise2d::noise2d (uint32_t seed)
28	{
29	seedable_rand_gen rng (seed);
30
31	for (int i = 0; i < 256; ++i)
32	{
33	vec2d rv;
34	rv[0] = rng () - 0.5f;
35	rv[1] = rng () - 0.5f;
36
37	// normalise
38	float mag = 1.f / sqrtf (rv[0] * rv[0] + rv[1] * rv[1]);
39
40	rv[0] *= mag;
41	rv[1] *= mag;
42
43	rvec[i][0] = rv[0];
44	rvec[i][1] = rv[1];
45	}
46
47	rvmap[0].seed (rng);
48	rvmap[1].seed (rng);
49	}
50
51	float
52	noise2d::noise (float x, float y)
53	{
54	int ix = floorf (x); float fx = x - ix;
55	int iy = floorf (y); float fy = y - iy;
56
57	float v = 0;
58
59	for (int j = -1; j <= 2; ++j)
60	for (int i = -1; i <= 2; ++i)
61	{
62	float Ax = fx - i;
63	float Ay = fy - j;
64
65	float d = Ax * Ax + Ay * Ay;
66
67	if (d < 4)
68	{
69	float t1 = 1 - d / 4;
70	float t2 = t1 * t1;
71	float t4 = t2 * t2;
72
73	float p = (4 * t1 - 3) * t4;
74
75	int h = rvmap[0](ix + i) ^ rvmap[1](iy + j);
76	float G0 = rvec[h & 0xff][0];
77	float G1 = rvec[h & 0xff][1];
78	//vec2d G = rvec[h & 0xff];
79
80	v += (Ax * G0 + Ay * G1) * p;
81	}
82	}
83
84	return clamp (v * 2, -.9999999f, .9999999f);
85	}
86
87	#if 0\|\|ABSTRACTION_PENALTY_IS_GONE
88	float
89	noise2d::noise (float x, float y)
90	{
91	vec2d X = vec2d (x, y);
92	gen_vec<2,int> I = floor (X);
93	vec2d F = X - I;
94
95	float v = 0;
96
97	for (int j = -1; j <= 2; ++j)
98	for (int i = -1; i <= 2; ++i)
99	{
100	vec2d A = F - vec2d (i, j);
101
102	float d = A * A;
103
104	if (d < 4)
105	{
106	int h = rvmap [0](I[0] + i) ^ rvmap [1](I[1] + j);
107	float *G = rvec [h & 0xff];
108
109	float t1 = 1 - d / 4;
110	float t2 = t1 * t1;
111	float t4 = t2 * t2;
112
113	float p = (4 * t1 - 3) * t4;
114	v += A * vec2d (G[0], G[1]) * p;
115	}
116	}
117
118	return clamp (v * 2, -.9999999f, .9999999f);
119	}
120	#endif
121
122	/////////////////////////////////////////////////////////////////////////////
123
124	noise3d::noise3d (uint32_t seed)
125	{
126	seedable_rand_gen rng (seed);
127
128	for (int i = 0; i < 256; ++i)
129	{
130	for (int j = 0; j < 3; ++j)
131	rvec [i][j] = rng () - 0.5f;
132
133	// normalise
134	float mag = 1.f / sqrtf (rvec [i][0] * rvec [i][0]
135	+ rvec [i][1] * rvec [i][1]
136	+ rvec [i][2] * rvec [i][2]);
137
138	rvec [i][0] *= mag;
139	rvec [i][1] *= mag;
140	rvec [i][2] *= mag;
141	}
142
143	rvmap [0].seed (rng);
144	rvmap [1].seed (rng);
145	rvmap [2].seed (rng);
146	}
147
148	float
149	noise3d::noise (float x, float y, float z)
150	{
151	int ix = floorf (x); float fx = x - ix;
152	int iy = floorf (y); float fy = y - iy;
153	int iz = floorf (z); float fz = z - iz;
154
155	float v = 0;
156
157	for (int j = -1; j <= 2; ++j)
158	for (int i = -1; i <= 2; ++i)
159	for (int k = -1; k <= 2; ++k)
160	{
161	float Ax = fx - i;
162	float Ay = fy - j;
163	float Az = fz - k;
164
165	float d = Ax * Ax + Ay * Ay + Az * Az;
166
167	if (d < 4)
168	{
169	int h = rvmap [0](ix + i) ^ rvmap [1](iy + j) ^ rvmap [2](iz + k);
170	float *G = rvec [h & 0xff];
171
172	float t1 = 1 - d / 4;
173	float t2 = t1 * t1;
174	float t4 = t2 * t2;
175
176	// (4t⁵ - 3t⁴)
177	float p = (4 * t1 - 3) * t4;
178	v += (Ax * G[0] + Ay * G[1] + Az * G[2]) * p;
179	}
180	}
181
182	return clamp (v * 2, -.9999999f, .9999999f);
183	}
184
185	float
186	noise3d::noise (float x, float y, float z, float nx, float ny, float nz)
187	{
188	int ix = floorf (x); float fx = x - ix;
189	int iy = floorf (y); float fy = y - iy;
190	int iz = floorf (z); float fz = z - iz;
191
192	float v = 0;
193
194	for (int j = -1; j <= 2; ++j)
195	for (int i = -1; i <= 2; ++i)
196	for (int k = -1; k <= 2; ++k)
197	{
198	float Dx = fx - i;
199	float Dy = fy - j;
200	float Dz = fz - k;
201
202	float e = Dx * nx + Dy * ny + Dz * nz;
203
204	float o = 1 - abs (e);
205
206	if (o > 0)
207	{
208	float Ax = Dx - e * nx;
209	float Ay = Dy - e * ny;
210	float Az = Dz - e * nz;
211
212	float d = Ax * Ax + Ay * Ay + Az * Az;
213
214	if (d < 4)
215	{
216	int h = rvmap [0](ix + i) ^ rvmap [1](iy + j) ^ rvmap [2](iz + k);
217	float *G = rvec [h & 0xff];
218
219	float t1 = 1 - d / 4;
220	float t2 = t1 * t1;
221	float t4 = t2 * t2;
222
223	float o2 = o * o;
224
225	// (4t⁵ - 3t⁴) * (3o³ - 2o²)
226	float p = (4 * t1 - 3) * t4 * (3 * o2 - 2 * o2 * o);
227	v += (Ax * G[0] + Ay * G[1] + Az * G[2]) * p;
228	}
229	}
230	}
231
232	return clamp (v * 2, -.9999999f, .9999999f);
233	}
234
235	frac_gen::frac_gen (float hurst_expo, float lacunarity)
236	: h (hurst_expo), lac (lacunarity), noise2d (0)
237	{
238	float exsum = 0;
239
240	for (int i = 0; i < MAX_OCTAVES; ++i)
241	{
242	ex [i] = powf (lac, -h * i);
243	exsum += ex [i];
244	fbm_mul [i] = 0.5f / (exsum * 0.75f); // .75f is a heuristic
245	rot [i].set (0.4488f * i);
246	}
247	}
248
249	float
250	frac_gen::fBm (float x, float y, int octaves)
251	{
252	float v = 0.f;
253
254	for (int i = 0; i < octaves; ++i)
255	{
256	rot [i](x, y);
257
258	v += noise (x + i, y) * ex [i];
259
260	x *= lac;
261	y *= lac;
262	}
263
264	return clamp (v * fbm_mul [octaves - 1] + 0.5f, 0.f, .9999999f);
265	}
266
267	float
268	frac_gen::turbulence (float x, float y, int octaves)
269	{
270	float v = 0.f;
271
272	for (int i = 0; i < octaves; ++i)
273	{
274	rot [i](x, y);
275
276	v += fabsf (noise (x + i, y)) * ex [i];
277
278	x *= lac;
279	y *= lac;
280	}
281
282	return clamp (v * fbm_mul [octaves - 1] * 2.f, 0.f, .9999999f);
283	}
284
285	float
286	frac_gen::multifractal (float x, float y, int octaves, float offset)
287	{
288	float v = 1.f;
289
290	for (int i = 0; i < octaves; ++i)
291	{
292	rot [i](x, y);
293
294	v = noise (x, y) ex [i] + offset;
295
296	x *= lac;
297	y *= lac;
298	}
299
300	return clamp (v * 0.5f, 0.f, .9999999f);
301	}
302
303	float
304	frac_gen::heterofractal (float x, float y, int octaves, float offset)
305	{
306	float v = noise (x, y) + offset;
307	int i;
308
309	for (i = 1; i < octaves; ++i)
310	{
311	rot [i](x, y);
312
313	x *= lac;
314	y *= lac;
315
316	v += v * (noise (x, y) * ex [i] + offset);
317	}
318
319	return v / powf (2., octaves);
320	}
321
322	float
323	frac_gen::hybridfractal (float x, float y, int octaves, float offset, float gain)
324	{
325	float v = (noise (x, y) + offset) * ex [0];
326	float weight = v;
327	int i;
328
329	for (i = 1; i < octaves; ++i)
330	{
331	rot [i](x, y);
332
333	x *= lac;
334	y *= lac;
335
336	min_it (weight, 1.f);
337
338	float sig = (noise (x, y) + offset) * ex [i];
339	v += weight * sig;
340	weight = gain sig;
341	}
342
343	return clamp (v * 0.5f + 0.5f, 0.f, .9999999f);
344	}
345
346	// http://www.gamasutra.com/view/feature/3098/a_realtime_procedural_universe_.php?page=2
347	float
348	frac_gen::terrain (float x, float y, int octaves)
349	{
350	float v = 0.f;
351
352	for (int i = 0; i < octaves; ++i)
353	{
354	rot[i] (x, y);
355
356	v += noise (x + i, y) * ex [i];
357
358	x *= lac;
359	y *= lac;
360	}
361
362	v *= fbm_mul [octaves - 1];
363
364	return v <= 0.f ? - powf (-v, 0.7f) : powf (v, 1. + noise (x, y) * v);
365	}
366
367	float
368	frac_gen::terrain2 (float x, float y, int octaves)
369	{
370	float a = fBm (x, y, octaves);
371	float b = ridgedmultifractal (x, y, octaves, 1, 8);
372	float fade = fBm (x + 10.3, y + 10.3, octaves);
373
374	const float width = 0.05f;
375
376	if (fade > 0.5f + width)
377	return a;
378	else if (fade < 0.5f - width)
379	return b;
380
381	fade = (fade - 0.5f + width) / (width * 2);
382
383	// sigmoidal curve
384	fade = fade * fade * 2 * (1.5f - fade);
385
386	return a * fade + b * (1 - fade);
387	}
388
389	float
390	frac_gen::ridgedmultifractal (float x, float y, int octaves, float offset, float gain)
391	{
392	float sig = offset - fabsf (noise (x, y));
393	sig *= sig;
394	float v = sig;
395
396	for (int i = 1; i < octaves; ++i)
397	{
398	rot [i](x, y);
399
400	x *= lac;
401	y *= lac;
402
403	float w = clamp (sig * gain, 0.f, 1.f);
404
405	sig = offset - fabsf (noise (x, y));
406	sig *= sig;
407	sig *= w;
408
409	v += sig * ex [i];
410	}
411
412	return clamp (v * 0.25f, 0.f, .9999999f);
413	}
414
415	#if 1
416	void hack()
417	{
418	frac_gen gen (0.5, 2);
419	noise3d n(0);
420
421	#if 1
422	int N = 1024;
423
424	printf ("P5 %d %d 255\n", N, N);
425	// pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm
426	for (int y = 0; y < N; ++y)
427	{
428	if (!(y&63))fprintf (stderr, "y %d\n", y);//D
429	for (int x = 0; x < N; ++x)
430	{
431	putc (127 * gen.noise (x * 0.04, y * 0.04) + 128, stdout);
432	//putc (256 * gen.terrain2 (x * 0.004, y * 0.004, 8), stdout);
433	//putc (256 * gen.fBm (x * 0.01, y * 0.01, 7), stdout);
434	//putc (256 * gen.turbulence (x * 0.004 - 1, y * 0.004 - 1, 8), stdout);
435	//putc (256 * gen.heterofractal (x * 0.008, y * 0.008, 8, -1.1, 2.0), stdout);
436	//putc (256 * gen.ridgedmultifractal (x * 0.001, y * 0.001, 32, 1.001, 32), stdout);
437	}
438	}
439	#else
440	int N = 128;
441
442	//printf ("P6 %d %d 255\n", N, N);
443	// pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm
444	for (int z = 0; z < N; ++z)
445	{
446	if (!(z&4))fprintf (stderr, "z %d\n", z);//D
447	for (int y = 0; y < N; ++y)
448	for (int x = 0; x < N; ++x)
449	{
450	float v = n.noise (x * 0.06 + 0.2, y * 0.06 + 0.2, z * 0.06 + 0.2) * 0.5 + 0.5;
451
452	if (z < 64)
453	v = v * (z * z) / (64 * 64);
454
455	if (v <= 0.1)
456	continue;
457
458	float r[4];
459	int i[4];
460
461	r[0] = x;
462	r[1] = y;
463	r[2] = z;
464	r[3] = v;
465
466	memcpy (i, r, 16);
467
468	i[0] = htonl (i[0]);
469	i[1] = htonl (i[1]);
470	i[2] = htonl (i[2]);
471	i[3] = htonl (i[3]);
472
473	fwrite (i, 4*4, 1, stdout);
474	}
475	}
476	#endif
477
478	exit (0);
479	}
480	#endif