quakeforge/tools/qflight/source/noise.c
Bill Currie 6d5ffa9f8e [build] Move to non-recursive make
There's still some cleanup to do, but everything seems to be working
nicely: `make -j` works, `make distcheck` passes. There is probably
plenty of bitrot in the package directories (RPM, debian), though.

The vc project files have been removed since those versions are way out
of date and quakeforge is pretty much dependent on gcc now anyway.

Most of the old Makefile.am files  are now Makemodule.am.  This should
allow for new Makefile.am files that allow local building (to be added
on an as-needed bases).  The current remaining Makefile.am files are for
standalone sub-projects.a

The installable bins are currently built in the top-level build
directory. This may change if the clutter gets to be too much.

While this does make a noticeable difference in build times, the main
reason for the switch was to take care of the growing dependency issues:
now it's possible to build tools for code generation (eg, using qfcc and
ruamoko programs for code-gen).
2020-06-25 11:35:37 +09:00

139 lines
3.7 KiB
C

/*
noise.c
3d noise functions.
Copyright (C) 2000 Seth Galbraith <sgalbrai@linknet.kitsap.lib.wa.us>
Author: Seth Galbraith <sgalbrai@linknet.kitsap.lib.wa.us>
Date: 2000/11/23
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:
Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <math.h>
#include "QF/qtypes.h"
#include "tools/qflight/include/noise.h"
// returns the 3D noise value for a point in space
float
noise3d (vec3_t v, int num)
{
int n;
n = floor (v[0]) + floor (v[1]) * 57 + floor (v[2]) * 3251;
n = (n << 13) ^ n;
n = n * (n * n * 15731 + 789221) + 1376312589;
return (n & 0x7fffffff) / 2147483648.0;
}
// a variation of Noise3D that takes 3 floats
float
noiseXYZ (float x, float y, float z, int num)
{
vec3_t v;
v[0] = x;
v[1] = y;
v[2] = z;
return noise3d (v, num);
}
// returns a noise value from a scaled up noise pattern
//
// Actually created by sampling points on a certain grid
// and interpolating the inbetween value, making the noise smooth
float
noise_scaled (vec3_t v, float s, int num)
{
float n = 0;
vec3_t a, b, c, d;
a[0] = floor (v[0] / s) * s;
b[0] = a[0] + s;
c[0] = (v[0] - a[0]) / s;
d[0] = 1 - c[0];
a[1] = floor (v[1] / s) * s;
b[1] = a[1] + s;
c[1] = (v[1] - a[1]) / s;
d[1] = 1 - c[1];
a[2] = floor (v[2] / s) * s;
b[2] = a[2] + s;
c[2] = (v[2] - a[2]) / s;
d[2] = 1 - c[2];
n += noiseXYZ (a[0], a[1], a[2], num) * d[0] * d[1] * d[2];
n += noiseXYZ (a[0], a[1], b[2], num) * d[0] * d[1] * c[2];
n += noiseXYZ (a[0], b[1], a[2], num) * d[0] * c[1] * d[2];
n += noiseXYZ (a[0], b[1], b[2], num) * d[0] * c[1] * c[2];
n += noiseXYZ (b[0], a[1], a[2], num) * c[0] * d[1] * d[2];
n += noiseXYZ (b[0], a[1], b[2], num) * c[0] * d[1] * c[2];
n += noiseXYZ (b[0], b[1], a[2], num) * c[0] * c[1] * d[2];
n += noiseXYZ (b[0], b[1], b[2], num) * c[0] * c[1] * c[2];
return n;
}
// returns a Perlin noise value for a point in 3D space
//
// This noise function combines noise at several different scales
// which makes it slower than just using one layer of noise
float
noise_perlin (vec3_t v, float p, int num)
{
float n = 0;
n += noise_scaled (v, 1024, num);
n += 0.5 + (noise_scaled (v, 256, num) - 0.5) * p;
n += 0.5 + (noise_scaled (v, 64, num) - 0.5) * p * p;
n += 0.5 + (noise_scaled (v, 16, num) - 0.5) * p * p * p;
return n / 2 - 0.5;
}
// Use to create low-res noise patterns without interpolation
// A good strategy for avoiding seams on terrain and curves
// when called with a scale value of about 32
//
// This is because surfaces have some texture pixels which are
// actually not in the polygon at all so their edges don't
// perfectly fit together.
//
// Creates a random pattern of light and dark squares on flat
// axis aligned surfaces, which is usually not what you want
// but it may have interesting applications
void
snap_vector (vec3_t v_old, vec3_t v_new, float scale)
{
if (scale <= 0) {
v_new[0] = v_old[0];
v_new[1] = v_old[1];
v_new[2] = v_old[2];
} else {
v_new[0] = floor (v_old[0] / scale + 0.5) * scale;
v_new[1] = floor (v_old[1] / scale + 0.5) * scale;
v_new[2] = floor (v_old[2] / scale + 0.5) * scale;
}
}