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/* Copyright (C) 2009 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. 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.
*
* 0 A.D. 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 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* 2D and 3D seamless Perlin noise
*/
// Based on http://www.cs.cmu.edu/~mzucker/code/perlin-noise-math-faq.html
// and http://mrl.nyu.edu/~perlin/paper445.pdf.
// Not optimized for speed yet.
#include "precompiled.h"
#include "Noise.h"
#include <cmath>
#include <boost/random/mersenne_twister.hpp>
namespace
{
/// Random number generator (Boost Mersenne Twister)
boost::mt19937 rng;
/// Utility function for random numbers
float randFloat() {
return ((float)rng()) / 4294967296.0f;
}
/// Utility function used in both noises as an ease curve
float easeCurve(float t)
{
return t*t*t*(t*(t*6-15)+10);
}
}
Noise2D::Noise2D(int f)
{
freq = f;
grads = new CVector2D*[freq];
for(int i=0; i<freq; i++)
{
grads[i] = new CVector2D[freq];
for(int j=0; j<freq; j++)
{
float a = randFloat() * 2 * (float)M_PI;
grads[i][j] = CVector2D(cos(a), sin(a));
}
}
}
Noise2D::~ Noise2D()
{
for(int i=0; i<freq; i++)
{
delete[] grads[i];
}
delete[] grads;
}
float Noise2D::operator()(float x, float y)
{
x *= freq;
y *= freq;
int ix = (int)floor(x);
int iy = (int)floor(y);
float fx = x - ix;
float fy = y - iy;
ix %= freq; if(ix<0) ix += freq;
iy %= freq; if(iy<0) iy += freq;
int ix1 = (ix+1) % freq;
int iy1 = (iy+1) % freq;
float s = grads[ix][iy].Dot(CVector2D(fx, fy));
float t = grads[ix1][iy].Dot(CVector2D(fx-1, fy));
float u = grads[ix][iy1].Dot(CVector2D(fx, fy-1));
float v = grads[ix1][iy1].Dot(CVector2D(fx-1, fy-1));
float ex = easeCurve(fx);
float ey = easeCurve(fy);
float a = s + ex*(t-s);
float b = u + ex*(v-u);
return (a + ey*(b-a)) * .5 + .5;
}
Noise3D::Noise3D(int f, int v) : freq(f), vfreq(v)
{
grads = new CVector3D**[freq];
for(int i=0; i<freq; i++)
{
grads[i] = new CVector3D*[freq];
for(int j=0; j<freq; j++)
{
grads[i][j] = new CVector3D[vfreq];
for(int k=0; k<vfreq; k++)
{
CVector3D vec;
do {
vec = CVector3D(2*randFloat()-1, 2*randFloat()-1, 2*randFloat()-1);
}
while(vec.LengthSquared() > 1 || vec.LengthSquared() < 0.1);
vec.Normalize();
grads[i][j][k] = CVector3D(vec.X, vec.Y, vec.Z);
}
}
}
}
Noise3D::~ Noise3D()
{
for(int i=0; i<freq; i++)
{
for(int j=0; j<freq; j++)
{
delete[] grads[i][j];
}
delete[] grads[i];
}
delete[] grads;
}
float Noise3D::operator()(float x, float y, float z)
{
x *= freq;
y *= freq;
z *= vfreq;
int ix = (int)floor(x);
int iy = (int)floor(y);
int iz = (int)floor(z);
float fx = x - ix;
float fy = y - iy;
float fz = z - iz;
ix %= freq; if(ix<0) ix += freq;
iy %= freq; if(iy<0) iy += freq;
iz %= vfreq; if(iz<0) iz += vfreq;
int ix1 = (ix+1) % freq;
int iy1 = (iy+1) % freq;
int iz1 = (iz+1) % vfreq;
float s0 = grads[ix][iy][iz].Dot(CVector3D(fx, fy, fz));
float t0 = grads[ix1][iy][iz].Dot(CVector3D(fx-1, fy, fz));
float u0 = grads[ix][iy1][iz].Dot(CVector3D(fx, fy-1, fz));
float v0 = grads[ix1][iy1][iz].Dot(CVector3D(fx-1, fy-1, fz));
float s1 = grads[ix][iy][iz1].Dot(CVector3D(fx, fy, fz-1));
float t1 = grads[ix1][iy][iz1].Dot(CVector3D(fx-1, fy, fz-1));
float u1 = grads[ix][iy1][iz1].Dot(CVector3D(fx, fy-1, fz-1));
float v1 = grads[ix1][iy1][iz1].Dot(CVector3D(fx-1, fy-1, fz-1));
float ex = easeCurve(fx);
float ey = easeCurve(fy);
float ez = easeCurve(fz);
float a0 = s0 + ex*(t0-s0);
float b0 = u0 + ex*(v0-u0);
float c0 = a0 + ey*(b0-a0);
float a1 = s1 + ex*(t1-s1);
float b1 = u1 + ex*(v1-u1);
float c1 = a1 + ey*(b1-a1);
return (c0 + ez*(c1-c0)) * .5 + .5;
}
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