103 lines
2.2 KiB
C
103 lines
2.2 KiB
C
/*
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Copyright (C) 2002-2007 Victor Luchits
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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// r_math.c
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#include "r_local.h"
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#include "r_math.h"
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#include "mathlib.h"
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/*
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====================
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CalcFov
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====================
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*/
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float CalcFov( float fov_x, float width, float height )
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{
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float x;
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if( fov_x < 1 || fov_x > 179 )
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Host_Error( "bad fov: %f\n", fov_x );
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x = width / tan( fov_x / 360 * M_PI );
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return atan( height / x ) * 360 / M_PI;
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}
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/*
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====================
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AdjustFov
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====================
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*/
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void AdjustFov( float *fov_x, float *fov_y, float width, float height, bool lock_x )
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{
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float x, y;
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if( width * 3 == 4 * height || width * 4 == height * 5 )
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{
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// 4:3 or 5:4 ratio
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return;
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}
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if( lock_x )
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{
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*fov_y = 2 * atan((width * 3) / (height * 4) * tan (*fov_y * M_PI / 360.0 * 0.5) ) * 360 / M_PI;
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return;
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}
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y = CalcFov( *fov_x, 640, 480 );
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x = *fov_x;
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*fov_x = CalcFov( y, height, width );
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if( *fov_x < x ) *fov_x = x;
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else *fov_y = y;
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}
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/*
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=================
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SignbitsForPlane
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fast box on planeside test
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=================
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*/
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int SignbitsForPlane( const cplane_t *out )
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{
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int bits, i;
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for( i = bits = 0; i < 3; i++ )
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if( out->normal[i] < 0.0f ) bits |= 1<<i;
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return bits;
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}
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/*
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=================
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PlaneFromPoints
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=================
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*/
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void PlaneFromPoints( vec3_t verts[3], cplane_t *plane )
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{
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vec3_t v1, v2;
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VectorSubtract( verts[1], verts[0], v1 );
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VectorSubtract( verts[2], verts[0], v2 );
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CrossProduct( v2, v1, plane->normal );
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VectorNormalize( plane->normal );
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plane->dist = DotProduct( verts[0], plane->normal );
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} |