noise.cpp

大型多人在线游戏开发,该书光盘上附带的源码

/*
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Copyright (c) 2000, Sean O'Neil
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
* Neither the name of this project nor the names of its contributors
  may be used to endorse or promote products derived from this software
  without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/

#include "Master.h"
#include "Noise.h"

void CNoise::Init(int nDimensions, unsigned int nSeed)
{
	m_nDimensions = MIN(nDimensions, MAX_DIMENSIONS);
	CRandom r(nSeed);

	int i, j, k;
	for(i=0; i<256; i++)
	{
		m_nMap[i] = i;
		for(j=0; j<m_nDimensions; j++)
			m_nBuffer[i][j] = (float)r.RandomD(-0.5, 0.5);
		Normalize(m_nBuffer[i], m_nDimensions);
	}

	while(--i)
	{
		j = r.RandomI(0, 255);
		SWAP(m_nMap[i], m_nMap[j], k);
	}
	//_fpreset();	// Bug in CRandom! Causes messed up floating point operations!
}

float CNoise::Noise(float *f)
{
	int n[MAX_DIMENSIONS];			// Indexes to pass to lattice function
	float r[MAX_DIMENSIONS];		// Remainders to pass to lattice function
	float w[MAX_DIMENSIONS];		// Cubic values to pass to interpolation function

	for(int i=0; i<m_nDimensions; i++)
	{
		n[i] = Floor(f[i]);
		r[i] = f[i] - n[i];
		w[i] = Cubic(r[i]);
	}

	float fValue;
	switch(m_nDimensions)
	{
		case 1:
			fValue = Lerp(Lattice(n[0], r[0]),
						  Lattice(n[0]+1, r[0]-1),
						  w[0]);
			break;
		case 2:
			fValue = Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1]),
							   Lattice(n[0]+1, r[0]-1, n[1], r[1]),
							   w[0]),
						  Lerp(Lattice(n[0], r[0], n[1]+1, r[1]-1),
							   Lattice(n[0]+1, r[0]-1, n[1]+1, r[1]-1),
							   w[0]),
						  w[1]);
			break;
		case 3:
			fValue = Lerp(Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2], r[2]),
									Lattice(n[0]+1, r[0]-1, n[1], r[1], n[2], r[2]),
									w[0]),
							   Lerp(Lattice(n[0], r[0], n[1]+1, r[1]-1, n[2], r[2]),
									Lattice(n[0]+1, r[0]-1, n[1]+1, r[1]-1, n[2], r[2]),
									w[0]),
							   w[1]),
						  Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2]+1, r[2]-1),
									Lattice(n[0]+1, r[0]-1, n[1], r[1], n[2]+1, r[2]-1),
									w[0]),
							   Lerp(Lattice(n[0], r[0], n[1]+1, r[1]-1, n[2]+1, r[2]-1),
									Lattice(n[0]+1, r[0]-1, n[1]+1, r[1]-1, n[2]+1, r[2]-1),
									w[0]),
							   w[1]),
						  w[2]);
			break;
		case 4:
			fValue = Lerp(Lerp(Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2], r[2], n[3], r[3]),
										 Lattice(n[0]+1, r[0]-1, n[1], r[1], n[2], r[2], n[3], r[3]),
										 w[0]),
									Lerp(Lattice(n[0], r[0], n[1]+1, r[1]-1, n[2], r[2], n[3], r[3]),
										 Lattice(n[0]+1, r[0]-1, n[1]+1, r[1]-1, n[2], r[2], n[3], r[3]),
										 w[0]),
									w[1]),
									Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2]+1, r[2]-1, n[3], r[3]),
										 Lattice(n[0]+1, r[0]-1, n[1], r[1], n[2]+1, r[2]-1, n[3], r[3]),
										 w[0]),
									Lerp(Lattice(n[0], r[0], n[1]+1, r[1]-1, n[2]+1, r[2]-1),
										 Lattice(n[0]+1, r[0]-1, n[1]+1, r[1]-1, n[2]+1, r[2]-1, n[3], r[3]),
										 w[0]),
									w[1]),
							   w[2]),
						  Lerp(Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2], r[2], n[3]+1, r[3]-1),
										 Lattice(n[0]+1, r[0]-1, n[1], r[1], n[2], r[2], n[3]+1, r[3]-1),
										 w[0]),
									Lerp(Lattice(n[0], r[0], n[1]+1, r[1]-1, n[2], r[2], n[3]+1, r[3]-1),
										 Lattice(n[0]+1, r[0]-1, n[1]+1, r[1]-1, n[2], r[2], n[3]+1, r[3]-1),
										 w[0]),
									w[1]),
									Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2]+1, r[2]-1, n[3]+1, r[3]-1),
										 Lattice(n[0]+1, r[0]-1, n[1], r[1], n[2]+1, r[2]-1, n[3]+1, r[3]-1),
										 w[0]),
									Lerp(Lattice(n[0], r[0], n[1]+1, r[1]-1, n[2]+1, r[2]-1),
										 Lattice(n[0]+1, r[0]-1, n[1]+1, r[1]-1, n[2]+1, r[2]-1, n[3]+1, r[3]-1),
										 w[0]),
									w[1]),
							   w[2]),
						  w[3]);
			break;
	}
	return CLAMP(-0.99999f, 0.99999f, fValue);
}

void CSeededNoise::Init(unsigned int nSeed)
{
	/*
	for(int y=0; y<64; y++)
	{
		float fDy = (float)y/m_nHeight - 0.5f;
		for(int x=0; x<64; x++)
		{
			float fDx = (float)x/m_nWidth - 0.5f;
			float fDist = sqrtf(fDx*fDx + fDy*fDy);
			float fIntensity = expf(-Max(fDist-fSizeDisc,0)*fExpose);
			m_nBuffer[x][y] = 0;
		}
	}
	*/
}

float CSeededNoise::Noise(float *f)
{
	int n[2];		// Indexes to pass to lattice function
	float r[2];		// Remainders to pass to lattice function
	float w[2];		// Cubic values to pass to interpolation function

	for(int i=0; i<2; i++)
	{
		n[i] = Floor(f[i]);
		r[i] = f[i] - n[i];
		w[i] = Cubic(r[i]);
	}
	float fValue = Lerp(Lerp(m_nBuffer[n[0]][n[1]],
							 m_nBuffer[n[0]+1][n[1]],
							 w[0]),
						Lerp(m_nBuffer[n[0]][n[1]+1],
							 m_nBuffer[n[0]+1][n[1]+1],
							 w[0]),
						w[1]);
	return CLAMP(-0.99999f, 0.99999f, fValue);
}

float CFractal::fBm(float *f, float fOctaves)
{
	// Initialize locals
	float fValue = 0;
	float fTemp[MAX_DIMENSIONS];
	for(int i=0; i<m_nDimensions; i++)
		fTemp[i] = f[i];

	// Inner loop of spectral construction, where the fractal is built
	for(i=0; i<fOctaves; i++)
	{
		fValue += Noise(fTemp) * m_fExponent[i];
		for(int j=0; j<m_nDimensions; j++)
			fTemp[j] *= m_fLacunarity;
	}

	// Take care of remainder in fOctaves
	fOctaves -= (int)fOctaves;
	if(fOctaves > DELTA)
		fValue += fOctaves * Noise(fTemp) * m_fExponent[i];
	return CLAMP(-0.99999f, 0.99999f, fValue);
}

float CFractal::fBmTest(float *f, int nStart, int nEnd, float fInitial)
{
	float fTemp[MAX_DIMENSIONS];
	float fValue = 0, fExp = 2;
	int i;

	// Initialize locals
	for(i=0; i<nStart; i++)
		fExp *= m_fLacunarity;
	for(i=0; i<m_nDimensions; i++)
		fTemp[i] = f[i] * fExp;

	// Inner loop of spectral construction, where the fractal is built
	for(i=nStart; i<nEnd; i++)
	{
		fValue += Noise(fTemp) * m_fExponent[i];
		for(int j=0; j<m_nDimensions; j++)
			fTemp[j] *= m_fLacunarity;
	}

	if(nStart)
		fValue += fInitial;
	if(fValue <= 0.0f)
		fValue = (float)-pow(-fValue, 0.7f);
	else
		fValue = (float)pow(fValue, 1 + Noise(fTemp) * fValue);
	return fValue * 1.33333f;
}

float CFractal::fBmTest(float *f, float fOctaves)
{
	float fTemp[MAX_DIMENSIONS];
	float fValue = 0;
	int i;

	// Initialize locals
	for(i=0; i<m_nDimensions; i++)
		fTemp[i] = f[i] * 2;

	// Inner loop of spectral construction, where the fractal is built
	for(i=0; i<fOctaves; i++)
	{
		fValue += Noise(fTemp) * m_fExponent[i];
		for(int j=0; j<m_nDimensions; j++)
			fTemp[j] *= m_fLacunarity;
	}

	// Take care of remainder in fOctaves
	fOctaves -= (int)fOctaves;
	if(fOctaves > DELTA)
		fValue += fOctaves * Noise(fTemp) * m_fExponent[i];

	if(fValue <= 0.0f)
		fValue = (float)-pow(-fValue, 0.7f);
	else
		fValue = (float)pow(fValue, 1 + Noise(fTemp) * fValue);
	return fValue * 1.33333f;
}

float CFractal::Turbulence(float *f, float fOctaves)
{
	// Initialize locals
	float fValue = 0;
	float fTemp[MAX_DIMENSIONS];
	for(int i=0; i<m_nDimensions; i++)
		fTemp[i] = f[i];

	// Inner loop of spectral construction, where the fractal is built
	for(i=0; i<fOctaves; i++)
	{
		fValue += Abs(Noise(fTemp)) * m_fExponent[i];
		for(int j=0; j<m_nDimensions; j++)
			fTemp[j] *= m_fLacunarity;
	}

	// Take care of remainder in fOctaves
	fOctaves -= (int)fOctaves;
	if(fOctaves > DELTA)
		fValue += fOctaves * Abs(Noise(fTemp) * m_fExponent[i]);
	return CLAMP(-0.99999f, 0.99999f, fValue);
}

float CFractal::Multifractal(float *f, float fOctaves, float fOffset)
{
	// Initialize locals
	float fValue = 1;
	float fTemp[MAX_DIMENSIONS];
	for(int i=0; i<m_nDimensions; i++)
		fTemp[i] = f[i];

	// Inner loop of spectral construction, where the fractal is built
	for(i=0; i<fOctaves; i++)
	{
		fValue *= Noise(fTemp) * m_fExponent[i] + fOffset;
		for(int j=0; j<m_nDimensions; j++)
			fTemp[j] *= m_fLacunarity;
	}

	// Take care of remainder in fOctaves (shouldn't that be a multiply?)
	fOctaves -= (int)fOctaves;
	if(fOctaves > DELTA)
		fValue *= fOctaves * (Noise(fTemp) * m_fExponent[i] + fOffset);
	return CLAMP(-0.99999f, 0.99999f, fValue);
}

float CFractal::Heterofractal(float *f, float fOctaves, float fOffset)
{
	// Initialize locals
	float fValue = Noise(f) + fOffset;
	float fTemp[MAX_DIMENSIONS];
	for(int i=0; i<m_nDimensions; i++)
		fTemp[i] = f[i] * m_fLacunarity;

	// Inner loop of spectral construction, where the fractal is built
	for(i=1; i<fOctaves; i++)
	{
		fValue += (Noise(fTemp) + fOffset) * m_fExponent[i] * fValue;
		for(int j=0; j<m_nDimensions; j++)
			fTemp[j] *= m_fLacunarity;
	}

	// Take care of remainder in fOctaves
	fOctaves -= (int)fOctaves;
	if(fOctaves > DELTA)
		fValue += fOctaves * (Noise(fTemp) + fOffset) * m_fExponent[i] * fValue;
	return CLAMP(-0.99999f, 0.99999f, fValue);
}

float CFractal::HybridMultifractal(float *f, float fOctaves, float fOffset, float fGain)
{
	// Initialize locals
	float fValue = (Noise(f) + fOffset) * m_fExponent[0];
	float fWeight = fValue;
	float fTemp[MAX_DIMENSIONS];
	for(int i=0; i<m_nDimensions; i++)
		fTemp[i] = f[i] * m_fLacunarity;

	// Inner loop of spectral construction, where the fractal is built
	for(i=1; i<fOctaves; i++)
	{
		if(fWeight > 1)
			fWeight = 1;
		float fSignal = (Noise(fTemp) + fOffset) * m_fExponent[i];
		fValue += fWeight * fSignal;
		fWeight *= fGain * fSignal;
		for(int j=0; j<m_nDimensions; j++)
			fTemp[j] *= m_fLacunarity;
	}

	// Take care of remainder in fOctaves
	fOctaves -= (int)fOctaves;
	if(fOctaves > DELTA)
	{
		if(fWeight > 1)
			fWeight = 1;
		float fSignal = (Noise(fTemp) + fOffset) * m_fExponent[i];
		fValue += fOctaves * fWeight * fSignal;
	}
	return CLAMP(-0.99999f, 0.99999f, fValue);
}

float CFractal::RidgedMultifractal(float *f, float fOctaves, float fOffset, float fGain)
{
	// Initialize locals
	float fSignal = fOffset - Abs(Noise(f));
	fSignal *= fSignal;
	float fValue = fSignal;
	float fTemp[MAX_DIMENSIONS];
	for(int i=0; i<m_nDimensions; i++)
		fTemp[i] = f[i];

	// Inner loop of spectral construction, where the fractal is built
	for(i=1; i<fOctaves; i++)
	{
		for(int j=0; j<m_nDimensions; j++)
			fTemp[j] *= m_fLacunarity;
		float fWeight = Clamp(0, 1, fSignal * fGain);
		fSignal = fOffset - Abs(Noise(fTemp));
		fSignal *= fSignal;
		fSignal *= fWeight;
		fValue += fSignal * m_fExponent[i];
	}
	return CLAMP(-0.99999f, 0.99999f, fValue);
}