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/* |
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* This file is part of Deliantra, the Roguelike Realtime MMORPG. |
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* |
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* Copyright (©) 2010 Marc Alexander Lehmann / Robin Redeker / the Deliantra team |
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* |
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* Deliantra is free software: you can redistribute it and/or modify it under |
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* the terms of the Affero GNU General Public License as published by the |
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* Free Software Foundation, either version 3 of the License, or (at your |
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* option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the Affero GNU General Public License |
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* and the GNU General Public License along with this program. If not, see |
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* <http://www.gnu.org/licenses/>. |
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* |
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* The authors can be reached via e-mail to <support@deliantra.net> |
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*/ |
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|
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#include "noise.h" |
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|
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noise_gen::noise_gen (uint32_t seed) |
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{ |
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seedable_rand_gen rng (seed); |
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|
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for (int i = 0; i < 256; ++i) |
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{ |
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for (int j = 0; j < 2; ++j) |
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rvec [i][j] = rng () - 0.5f; |
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|
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// normalise |
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float mag = 1.f / sqrtf (rvec [i][0] * rvec [i][0] + rvec [i][1] * rvec [i][1]); |
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|
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rvec [i][0] *= mag; |
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rvec [i][1] *= mag; |
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} |
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|
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rvmap [0].seed (rng); |
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rvmap [1].seed (rng); |
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} |
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|
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float |
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noise_gen::noise (float x, float y) |
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{ |
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int ix = floorf (x); float fx = x - ix; |
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int iy = floorf (y); float fy = y - iy; |
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|
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float v = 0; |
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|
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for (int j = -1; j <= 2; ++j) |
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for (int i = -1; i <= 2; ++i) |
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{ |
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float Ax = fx - i; |
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float Ay = fy - j; |
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|
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float d = Ax * Ax + Ay * Ay; |
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|
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if (d < 4) |
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{ |
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int h = rvmap [0](ix + i) ^ rvmap [1](iy + j); |
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float *G = rvec [h & 0xff]; |
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|
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float t1 = 1 - d / 4; |
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float t2 = t1 * t1; |
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float t4 = t2 * t2; |
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|
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float p = (4 * t1 - 3) * t4; |
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v += (Ax * G[0] + Ay * G[1]) * p; |
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} |
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} |
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|
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return clamp (v * 2, -.9999999f, .9999999f); |
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} |
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|
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frac_gen::frac_gen (float hurst_expo, float lacunarity) |
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: h (hurst_expo), lac (lacunarity), noise_gen (0) |
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{ |
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float exsum = 0; |
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|
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for (int i = 0; i < MAX_OCTAVES; ++i) |
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{ |
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ex [i] = powf (lac, -h * i); |
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exsum += ex [i]; |
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fbm_mul [i] = 0.5f / (exsum * 0.75f); // .75f is a heuristic |
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rot [i].set (0.4488f * i); |
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} |
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} |
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|
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float |
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frac_gen::fBm (float x, float y, int octaves) |
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{ |
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float v = 0.f; |
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|
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for (int i = 0; i < octaves; ++i) |
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{ |
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rot [i](x, y); |
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|
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v += noise (x + i, y) * ex [i]; |
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|
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x *= lac; |
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y *= lac; |
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} |
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|
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return clamp (v * fbm_mul [octaves - 1] + 0.5f, 0.f, .9999999f); |
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} |
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|
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float |
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frac_gen::turbulence (float x, float y, int octaves) |
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{ |
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float v = 0.f; |
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|
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for (int i = 0; i < octaves; ++i) |
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{ |
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rot [i](x, y); |
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|
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v += fabsf (noise (x + i, y)) * ex [i]; |
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|
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x *= lac; |
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y *= lac; |
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} |
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|
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return clamp (v * fbm_mul [octaves - 1] * 2.f, 0.f, .9999999f); |
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} |
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|
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float |
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frac_gen::multifractal (float x, float y, int octaves, float offset) |
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{ |
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float v = 1.f; |
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|
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for (int i = 0; i < octaves; ++i) |
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{ |
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rot [i](x, y); |
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|
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v *= noise (x, y) * ex [i] + offset; |
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|
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x *= lac; |
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y *= lac; |
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} |
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|
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return clamp (v * 0.5f, 0.f, .9999999f); |
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} |
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|
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float |
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frac_gen::heterofractal (float x, float y, int octaves, float offset) |
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{ |
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float v = noise (x, y) + offset; |
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int i; |
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|
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for (i = 1; i < octaves; ++i) |
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{ |
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rot [i](x, y); |
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|
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x *= lac; |
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y *= lac; |
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|
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v += v * (noise (x, y) * ex [i] + offset); |
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} |
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|
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return v / powf (2., octaves); |
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} |
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|
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float |
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frac_gen::hybridfractal (float x, float y, int octaves, float offset, float gain) |
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{ |
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float v = (noise (x, y) + offset) * ex [0]; |
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float weight = v; |
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int i; |
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|
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for (i = 1; i < octaves; ++i) |
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{ |
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rot [i](x, y); |
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|
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x *= lac; |
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y *= lac; |
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|
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min_it (weight, 1.f); |
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|
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float sig = (noise (x, y) + offset) * ex [i]; |
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v += weight * sig; |
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weight *= gain * sig; |
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} |
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|
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return clamp (v * 0.5f + 0.5f, 0.f, .9999999f); |
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} |
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|
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// http://www.gamasutra.com/view/feature/3098/a_realtime_procedural_universe_.php?page=2 |
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float |
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frac_gen::terrain (float x, float y, int octaves) |
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{ |
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float v = 0.f; |
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|
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for (int i = 0; i < octaves; ++i) |
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{ |
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rot[i] (x, y); |
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|
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v += noise (x + i, y) * ex [i]; |
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|
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x *= lac; |
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y *= lac; |
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} |
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|
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v *= fbm_mul [octaves - 1]; |
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|
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return v <= 0.f ? - powf (-v, 0.7f) : powf (v, 1. + noise (x, y) * v); |
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} |
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|
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float |
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frac_gen::terrain2 (float x, float y, int octaves) |
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{ |
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float a = fBm (x, y, octaves); |
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float b = ridgedmultifractal (x, y, octaves, 1, 8); |
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float fade = fBm (x + 10.3, y + 10.3, octaves); |
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|
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const float width = 0.05f; |
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|
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if (fade > 0.5f + width) |
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return a; |
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else if (fade < 0.5f - width) |
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return b; |
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|
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fade = (fade - 0.5f + width) / (width * 2); |
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|
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// sigmoidal curve |
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fade = fade * fade * 2 * (1.5f - fade); |
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|
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return a * fade + b * (1 - fade); |
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} |
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|
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float |
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frac_gen::ridgedmultifractal (float x, float y, int octaves, float offset, float gain) |
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{ |
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float sig = offset - fabsf (noise (x, y)); |
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sig *= sig; |
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float v = sig; |
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|
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for (int i = 1; i < octaves; ++i) |
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{ |
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rot [i](x, y); |
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|
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x *= lac; |
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y *= lac; |
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|
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float w = clamp (sig * gain, 0.f, 1.f); |
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|
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sig = offset - fabsf (noise (x, y)); |
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sig *= sig; |
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sig *= w; |
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|
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v += sig * ex [i]; |
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} |
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|
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return clamp (v * 0.25f, 0.f, .9999999f); |
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} |
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|
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#if 0 |
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void hack() |
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{ |
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frac_gen gen (0.5, 2); |
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|
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int N = 1024; |
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|
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printf ("P5 %d %d 255\n", N, N); |
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// pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm |
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for (int y = 0; y < N; ++y) |
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{ |
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if (!(y&63))fprintf (stderr, "y %d\n", y);//D |
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for (int x = 0; x < N; ++x) |
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{ |
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//putc (128 + 128 * gen.noise (x * 0.04, y * 0.04), stdout); |
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putc (256 * gen.terrain2 (x * 0.004, y * 0.004, 8), stdout); |
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//putc (256 * gen.fBm (x * 0.001, y * 0.001, 3), stdout); |
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//putc (256 * gen.turbulence (x * 0.004 - 1, y * 0.004 - 1, 8), stdout); |
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//putc (256 * gen.heterofractal (x * 0.008, y * 0.008, 8, -1.1, 2.0), stdout); |
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//putc (256 * gen.ridgedmultifractal (x * 0.001, y * 0.001, 32, 1.001, 32), stdout); |
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} |
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} |
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|
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exit (0); |
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} |
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#endif |
