1 files changed, 93 insertions, 0 deletions
diff --git a/code/renderer/tr_noise.c b/code/renderer/tr_noise.c
new file mode 100644
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+++ b/code/renderer/tr_noise.c
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+/*
+===========================================================================
+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_local.h"
+
+#define NOISE_SIZE 256
+#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];
+
+#define LERP( a, b, w ) ( a * ( 1.0f - w ) + b * w )
+
+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 );
+	}
+}
+
+float R_NoiseGet4f( float x, float y, float z, float 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;
+}