101 lines
3.0 KiB
C
101 lines
3.0 KiB
C
/*
|
|
===========================================================================
|
|
Copyright (C) 1999-2005 Id Software, Inc.
|
|
|
|
This file is part of Quake III Arena source code.
|
|
|
|
Quake III Arena source code 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.
|
|
|
|
Quake III Arena source code 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 Quake III Arena source code; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
===========================================================================
|
|
*/
|
|
// tr_noise.c
|
|
#include "tr_common.h"
|
|
|
|
#define NOISE_SIZE FUNCTABLE_SIZE
|
|
#define NOISE_MASK ( NOISE_SIZE - 1 )
|
|
|
|
#define VAL( a ) s_noise_perm[ ( a ) & ( NOISE_MASK )]
|
|
#define INDEX( x, y, z, t ) VAL( x + VAL( y + VAL( z + VAL( t ) ) ) )
|
|
|
|
static float s_noise_table[NOISE_SIZE];
|
|
static int s_noise_perm[NOISE_SIZE];
|
|
static int s_random[NOISE_SIZE];
|
|
|
|
static float GetNoiseValue( int x, int y, int z, int t )
|
|
{
|
|
int index = INDEX( ( int ) x, ( int ) y, ( int ) z, ( int ) t );
|
|
|
|
return s_noise_table[index];
|
|
}
|
|
|
|
void R_NoiseInit( void )
|
|
{
|
|
int i;
|
|
|
|
for ( i = 0; i < NOISE_SIZE; i++ )
|
|
{
|
|
s_noise_table[i] = ( float ) ( ( ( rand() / ( float ) RAND_MAX ) * 2.0 - 1.0 ) );
|
|
s_noise_perm[i] = ( unsigned char ) ( rand() / ( float ) RAND_MAX * 255 );
|
|
s_random[i] = rand() & 0x01;
|
|
}
|
|
}
|
|
|
|
float R_NoiseGet4f( float x, float y, float z, double t )
|
|
{
|
|
int i;
|
|
int ix, iy, iz, it;
|
|
float fx, fy, fz, ft;
|
|
float front[4];
|
|
float back[4];
|
|
float fvalue, bvalue, value[2], finalvalue;
|
|
|
|
ix = ( int ) floor( x );
|
|
fx = x - ix;
|
|
iy = ( int ) floor( y );
|
|
fy = y - iy;
|
|
iz = ( int ) floor( z );
|
|
fz = z - iz;
|
|
it = ( int ) floor( t );
|
|
ft = t - it;
|
|
|
|
for ( i = 0; i < 2; i++ )
|
|
{
|
|
front[0] = GetNoiseValue( ix, iy, iz, it + i );
|
|
front[1] = GetNoiseValue( ix+1, iy, iz, it + i );
|
|
front[2] = GetNoiseValue( ix, iy+1, iz, it + i );
|
|
front[3] = GetNoiseValue( ix+1, iy+1, iz, it + i );
|
|
|
|
back[0] = GetNoiseValue( ix, iy, iz + 1, it + i );
|
|
back[1] = GetNoiseValue( ix+1, iy, iz + 1, it + i );
|
|
back[2] = GetNoiseValue( ix, iy+1, iz + 1, it + i );
|
|
back[3] = GetNoiseValue( ix+1, iy+1, iz + 1, it + i );
|
|
|
|
fvalue = LERP( LERP( front[0], front[1], fx ), LERP( front[2], front[3], fx ), fy );
|
|
bvalue = LERP( LERP( back[0], back[1], fx ), LERP( back[2], back[3], fx ), fy );
|
|
|
|
value[i] = LERP( fvalue, bvalue, fz );
|
|
}
|
|
|
|
finalvalue = LERP( value[0], value[1], ft );
|
|
|
|
return finalvalue;
|
|
}
|
|
|
|
// used in the shader functions (GF_RANDOM) to implement a quasi random flickering.
|
|
#define VALR( a ) s_random[ ( a ) & ( NOISE_MASK )]
|
|
int R_RandomOn(double t)
|
|
{
|
|
return VALR((unsigned int) floor(t));
|
|
}
|