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+++ b/misc/noise.cpp
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+/*
+Minetest-c55
+Copyright (C) 2010-2011 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program 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 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 GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include <math.h>
+#include "noise.h"
+#include <iostream>
+#include "debug.h"
+
+#define NOISE_MAGIC_X 1619
+#define NOISE_MAGIC_Y 31337
+#define NOISE_MAGIC_Z 52591
+#define NOISE_MAGIC_SEED 1013
+
+double cos_lookup[16] = {
+ 1.0,0.9238,0.7071,0.3826,0,-0.3826,-0.7071,-0.9238,
+ 1.0,-0.9238,-0.7071,-0.3826,0,0.3826,0.7071,0.9238
+};
+
+double dotProduct(double vx, double vy, double wx, double wy){
+ return vx*wx+vy*wy;
+}
+
+double easeCurve(double t){
+ return 6*pow(t,5)-15*pow(t,4)+10*pow(t,3);
+}
+
+double linearInterpolation(double x0, double x1, double t){
+ return x0+(x1-x0)*t;
+}
+
+double biLinearInterpolation(double x0y0, double x1y0, double x0y1, double x1y1, double x, double y){
+ double tx = easeCurve(x);
+ double ty = easeCurve(y);
+ /*double tx = x;
+ double ty = y;*/
+ double u = linearInterpolation(x0y0,x1y0,tx);
+ double v = linearInterpolation(x0y1,x1y1,tx);
+ return linearInterpolation(u,v,ty);
+}
+
+double triLinearInterpolation(
+ double v000, double v100, double v010, double v110,
+ double v001, double v101, double v011, double v111,
+ double x, double y, double z)
+{
+ /*double tx = easeCurve(x);
+ double ty = easeCurve(y);
+ double tz = easeCurve(z);*/
+ double tx = x;
+ double ty = y;
+ double tz = z;
+ return(
+ v000*(1-tx)*(1-ty)*(1-tz) +
+ v100*tx*(1-ty)*(1-tz) +
+ v010*(1-tx)*ty*(1-tz) +
+ v110*tx*ty*(1-tz) +
+ v001*(1-tx)*(1-ty)*tz +
+ v101*tx*(1-ty)*tz +
+ v011*(1-tx)*ty*tz +
+ v111*tx*ty*tz
+ );
+}
+
+double noise2d(int x, int y, int seed)
+{
+ int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y
+ + NOISE_MAGIC_SEED * seed) & 0x7fffffff;
+ n = (n>>13)^n;
+ n = (n * (n*n*60493+19990303) + 1376312589) & 0x7fffffff;
+ return 1.0 - (double)n/1073741824;
+}
+
+double noise3d(int x, int y, int z, int seed)
+{
+ int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y + NOISE_MAGIC_Z * z
+ + NOISE_MAGIC_SEED * seed) & 0x7fffffff;
+ n = (n>>13)^n;
+ n = (n * (n*n*60493+19990303) + 1376312589) & 0x7fffffff;
+ return 1.0 - (double)n/1073741824;
+}
+
+#if 0
+double noise2d_gradient(double x, double y, int seed)
+{
+ // Calculate the integer coordinates
+ int x0 = (x > 0.0 ? (int)x : (int)x - 1);
+ int y0 = (y > 0.0 ? (int)y : (int)y - 1);
+ // Calculate the remaining part of the coordinates
+ double xl = x - (double)x0;
+ double yl = y - (double)y0;
+ // Calculate random cosine lookup table indices for the integer corners.
+ // They are looked up as unit vector gradients from the lookup table.
+ int n00 = (int)((noise2d(x0, y0, seed)+1)*8);
+ int n10 = (int)((noise2d(x0+1, y0, seed)+1)*8);
+ int n01 = (int)((noise2d(x0, y0+1, seed)+1)*8);
+ int n11 = (int)((noise2d(x0+1, y0+1, seed)+1)*8);
+ // Make a dot product for the gradients and the positions, to get the values
+ double s = dotProduct(cos_lookup[n00], cos_lookup[(n00+12)%16], xl, yl);
+ double u = dotProduct(-cos_lookup[n10], cos_lookup[(n10+12)%16], 1.-xl, yl);
+ double v = dotProduct(cos_lookup[n01], -cos_lookup[(n01+12)%16], xl, 1.-yl);
+ double w = dotProduct(-cos_lookup[n11], -cos_lookup[(n11+12)%16], 1.-xl, 1.-yl);
+ // Interpolate between the values
+ return biLinearInterpolation(s,u,v,w,xl,yl);
+}
+#endif
+
+#if 1
+double noise2d_gradient(double x, double y, int seed)
+{
+ // Calculate the integer coordinates
+ int x0 = (x > 0.0 ? (int)x : (int)x - 1);
+ int y0 = (y > 0.0 ? (int)y : (int)y - 1);
+ // Calculate the remaining part of the coordinates
+ double xl = x - (double)x0;
+ double yl = y - (double)y0;
+ // Get values for corners of cube
+ double v00 = noise2d(x0, y0, seed);
+ double v10 = noise2d(x0+1, y0, seed);
+ double v01 = noise2d(x0, y0+1, seed);
+ double v11 = noise2d(x0+1, y0+1, seed);
+ // Interpolate
+ return biLinearInterpolation(v00,v10,v01,v11,xl,yl);
+}
+#endif
+
+double noise3d_gradient(double x, double y, double z, int seed)
+{
+ // Calculate the integer coordinates
+ int x0 = (x > 0.0 ? (int)x : (int)x - 1);
+ int y0 = (y > 0.0 ? (int)y : (int)y - 1);
+ int z0 = (z > 0.0 ? (int)z : (int)z - 1);
+ // Calculate the remaining part of the coordinates
+ double xl = x - (double)x0;
+ double yl = y - (double)y0;
+ double zl = z - (double)z0;
+ // Get values for corners of cube
+ double v000 = noise3d(x0, y0, z0, seed);
+ double v100 = noise3d(x0+1, y0, z0, seed);
+ double v010 = noise3d(x0, y0+1, z0, seed);
+ double v110 = noise3d(x0+1, y0+1, z0, seed);
+ double v001 = noise3d(x0, y0, z0+1, seed);
+ double v101 = noise3d(x0+1, y0, z0+1, seed);
+ double v011 = noise3d(x0, y0+1, z0+1, seed);
+ double v111 = noise3d(x0+1, y0+1, z0+1, seed);
+ // Interpolate
+ return triLinearInterpolation(v000,v100,v010,v110,v001,v101,v011,v111,xl,yl,zl);
+}
+
+double noise2d_perlin(double x, double y, int seed,
+ int octaves, double persistence)
+{
+ double a = 0;
+ double f = 1.0;
+ double g = 1.0;
+ for(int i=0; i<octaves; i++)
+ {
+ a += g * noise2d_gradient(x*f, y*f, seed+i);
+ f *= 2.0;
+ g *= persistence;
+ }
+ return a;
+}
+
+double noise2d_perlin_abs(double x, double y, int seed,
+ int octaves, double persistence)
+{
+ double a = 0;
+ double f = 1.0;
+ double g = 1.0;
+ for(int i=0; i<octaves; i++)
+ {
+ a += g * fabs(noise2d_gradient(x*f, y*f, seed+i));
+ f *= 2.0;
+ g *= persistence;
+ }
+ return a;
+}
+
+double noise3d_perlin(double x, double y, double z, int seed,
+ int octaves, double persistence)
+{
+ double a = 0;
+ double f = 1.0;
+ double g = 1.0;
+ for(int i=0; i<octaves; i++)
+ {
+ a += g * noise3d_gradient(x*f, y*f, z*f, seed+i);
+ f *= 2.0;
+ g *= persistence;
+ }
+ return a;
+}
+
+double noise3d_perlin_abs(double x, double y, double z, int seed,
+ int octaves, double persistence)
+{
+ double a = 0;
+ double f = 1.0;
+ double g = 1.0;
+ for(int i=0; i<octaves; i++)
+ {
+ a += g * fabs(noise3d_gradient(x*f, y*f, z*f, seed+i));
+ f *= 2.0;
+ g *= persistence;
+ }
+ return a;
+}
+
+// -1->0, 0->1, 1->0
+double contour(double v)
+{
+ v = fabs(v);
+ if(v >= 1.0)
+ return 0.0;
+ return (1.0-v);
+}
+
+double noise3d_param(const NoiseParams &param, double x, double y, double z)
+{
+ double s = param.pos_scale;
+ x /= s;
+ y /= s;
+ z /= s;
+
+ if(param.type == NOISE_PERLIN)
+ {
+ return param.noise_scale*noise3d_perlin(x,y,z, param.seed,
+ param.octaves,
+ param.persistence);
+ }
+ else if(param.type == NOISE_PERLIN_ABS)
+ {
+ return param.noise_scale*noise3d_perlin_abs(x,y,z, param.seed,
+ param.octaves,
+ param.persistence);
+ }
+ else if(param.type == NOISE_PERLIN_CONTOUR)
+ {
+ return contour(param.noise_scale*noise3d_perlin(x,y,z,
+ param.seed, param.octaves,
+ param.persistence));
+ }
+ else if(param.type == NOISE_PERLIN_CONTOUR_FLIP_YZ)
+ {
+ return contour(param.noise_scale*noise3d_perlin(x,z,y,
+ param.seed, param.octaves,
+ param.persistence));
+ }
+ else assert(0);
+}
+
+/*
+ NoiseBuffer
+*/
+
+NoiseBuffer::NoiseBuffer():
+ m_data(NULL)
+{
+}
+
+NoiseBuffer::~NoiseBuffer()
+{
+ clear();
+}
+
+void NoiseBuffer::clear()
+{
+ if(m_data)
+ delete[] m_data;
+ m_data = NULL;
+ m_size_x = 0;
+ m_size_y = 0;
+ m_size_z = 0;
+}
+
+void NoiseBuffer::create(const NoiseParams &param,
+ double first_x, double first_y, double first_z,
+ double last_x, double last_y, double last_z,
+ double samplelength_x, double samplelength_y, double samplelength_z)
+{
+ clear();
+
+ m_start_x = first_x - samplelength_x;
+ m_start_y = first_y - samplelength_y;
+ m_start_z = first_z - samplelength_z;
+ m_samplelength_x = samplelength_x;
+ m_samplelength_y = samplelength_y;
+ m_samplelength_z = samplelength_z;
+
+ m_size_x = (last_x - m_start_x)/samplelength_x + 2;
+ m_size_y = (last_y - m_start_y)/samplelength_y + 2;
+ m_size_z = (last_z - m_start_z)/samplelength_z + 2;
+
+ m_data = new double[m_size_x*m_size_y*m_size_z];
+
+ for(int x=0; x<m_size_x; x++)
+ for(int y=0; y<m_size_y; y++)
+ for(int z=0; z<m_size_z; z++)
+ {
+ double xd = (m_start_x + (double)x*m_samplelength_x);
+ double yd = (m_start_y + (double)y*m_samplelength_y);
+ double zd = (m_start_z + (double)z*m_samplelength_z);
+ double a = noise3d_param(param, xd,yd,zd);
+ intSet(x,y,z, a);
+ }
+}
+
+void NoiseBuffer::multiply(const NoiseParams &param)
+{
+ assert(m_data != NULL);
+
+ for(int x=0; x<m_size_x; x++)
+ for(int y=0; y<m_size_y; y++)
+ for(int z=0; z<m_size_z; z++)
+ {
+ double xd = (m_start_x + (double)x*m_samplelength_x);
+ double yd = (m_start_y + (double)y*m_samplelength_y);
+ double zd = (m_start_z + (double)z*m_samplelength_z);
+ double a = noise3d_param(param, xd,yd,zd);
+ intMultiply(x,y,z, a);
+ }
+}
+
+// Deprecated
+void NoiseBuffer::create(int seed, int octaves, double persistence,
+ bool abs,
+ double first_x, double first_y, double first_z,
+ double last_x, double last_y, double last_z,
+ double samplelength_x, double samplelength_y, double samplelength_z)
+{
+ NoiseParams param;
+ param.type = abs ? NOISE_PERLIN_ABS : NOISE_PERLIN;
+ param.seed = seed;
+ param.octaves = octaves;
+ param.persistence = persistence;
+
+ create(param, first_x, first_y, first_z,
+ last_x, last_y, last_z,
+ samplelength_x, samplelength_y, samplelength_z);
+}
+
+void NoiseBuffer::intSet(int x, int y, int z, double d)
+{
+ int i = m_size_x*m_size_y*z + m_size_x*y + x;
+ assert(i >= 0);
+ assert(i < m_size_x*m_size_y*m_size_z);
+ m_data[i] = d;
+}
+
+void NoiseBuffer::intMultiply(int x, int y, int z, double d)
+{
+ int i = m_size_x*m_size_y*z + m_size_x*y + x;
+ assert(i >= 0);
+ assert(i < m_size_x*m_size_y*m_size_z);
+ m_data[i] = m_data[i] * d;
+}
+
+double NoiseBuffer::intGet(int x, int y, int z)
+{
+ int i = m_size_x*m_size_y*z + m_size_x*y + x;
+ assert(i >= 0);
+ assert(i < m_size_x*m_size_y*m_size_z);
+ return m_data[i];
+}
+
+double NoiseBuffer::get(double x, double y, double z)
+{
+ x -= m_start_x;
+ y -= m_start_y;
+ z -= m_start_z;
+ x /= m_samplelength_x;
+ y /= m_samplelength_y;
+ z /= m_samplelength_z;
+ // Calculate the integer coordinates
+ int x0 = (x > 0.0 ? (int)x : (int)x - 1);
+ int y0 = (y > 0.0 ? (int)y : (int)y - 1);
+ int z0 = (z > 0.0 ? (int)z : (int)z - 1);
+ // Calculate the remaining part of the coordinates
+ double xl = x - (double)x0;
+ double yl = y - (double)y0;
+ double zl = z - (double)z0;
+ // Get values for corners of cube
+ double v000 = intGet(x0, y0, z0);
+ double v100 = intGet(x0+1, y0, z0);
+ double v010 = intGet(x0, y0+1, z0);
+ double v110 = intGet(x0+1, y0+1, z0);
+ double v001 = intGet(x0, y0, z0+1);
+ double v101 = intGet(x0+1, y0, z0+1);
+ double v011 = intGet(x0, y0+1, z0+1);
+ double v111 = intGet(x0+1, y0+1, z0+1);
+ // Interpolate
+ return triLinearInterpolation(v000,v100,v010,v110,v001,v101,v011,v111,xl,yl,zl);
+}
+
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