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/*
** Ark - Libraries, Tools & Programs for MMORPG developpements.
** Copyright (C) 1999-2000 The Contributors of the Ark Project
** Please see the file "AUTHORS" for a list of contributors
**
** 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "HFWorld.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h> /* For the random stuff */
namespace Ark
{
static inline short f4 (short a, short b, short c, short d)
{
int r = a + b + c + d;
return short(r >> 2);
}
/* Return a pseudo-random number in [-rnd; rnd] */
static inline short HF_Rnd (int rnd)
{
return (short) (rand() % (rnd + 1) - (rnd / 2));
}
/** \par Creation of a random HeighField.
* This is done in three steps :
* \arg - Assign random values to each points.
* \arg - Add high points (for mounts, by example).
* \arg - Remove any roughness (smooth the HF, averaging values)
*/
void HeightField::Random ()
{
#define HF_Loop() \
for (x = 0; x < m_SizeX; x += bsize) \
for (z = 0; z < m_SizeZ; z += bsize)
size_t x, z;
int i, j;
int bsize, csize;
int rnd, sz2 = m_SizeX * m_SizeZ;
memset (m_Y, 0, sz2);
bsize = m_SizeX;
csize = m_SizeX/2;
rnd = 64;
while(csize > 0)
{
HF_Loop ()
{
Y (x+csize, z+csize) =
f4(Y (x, z),
Y (x + bsize, z),
Y (x + bsize, z + bsize),
Y (x, z + bsize))
+ HF_Rnd (rnd);
}
HF_Loop ()
{
Y (x+csize, z) =
f4(Y (x, z),
Y (x + bsize, z),
Y (x + csize, z + csize),
Y (x + csize, z - csize))
+ HF_Rnd (rnd);
}
HF_Loop ()
{
Y (x, z+csize) =
f4(Y (x, z),
Y (x, z + bsize),
Y (x - csize, z + csize),
Y (x + csize, z + csize))
+ HF_Rnd (rnd);
}
bsize >>= 1;
csize >>= 1;
if(csize < 16)
rnd /= 2;
}
// Add 400+ very high point to create mounts when we'll remove
// roughness.
for(j = 0; j < 4; j++)
{
x = rand() % m_SizeX;
z = rand() % m_SizeZ;
for(i = 0; i < 100; i++)
{
x += rand() % 17 - 8;
z += rand() % 17 - 8;
if (x < 0) x = m_SizeX-1;
if (z < 0) z = m_SizeZ-1;
if (x > m_SizeX) x = 0;
if (z > m_SizeZ) z = 0;
Y (x, z) = 100;
}
}
bsize = 1;
// Remove any roughness from the heightfield by setting the value at
// each point to the average of those of its neighbours.
for(j = 0; j < 8; j++)
{
HF_Loop ()
{
if (Y (x, z) > 255) Y (x, z) = 255;
// Compute the average of the height of the points near (x,y)
i = Y (x-1, z-1) + Y (x, z-1) + Y (x+1, z-1)
+ Y (x-1, z) + Y (x, z) + Y (x+1, z)
+ Y (x-1, z+1) + Y (x, z+1) + Y (x+1, z+1);
Y (x, z) = i / 9;
}
}
}
}
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