119 lines
2.4 KiB
C
119 lines
2.4 KiB
C
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/*
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3DKIT version 1.3
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High speed 3D graphics and rendering library for Linux.
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Copyright (C) 1996, 1997 Paul Sheer psheer@icon.co.za
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library 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. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA
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*/
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#include <math.h>
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#include "quickmath.h"
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inline double fsqr (double x)
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{
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return x * x;
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}
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inline int lsqr (int x)
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{
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return (int) x * x;
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}
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inline double fmax (double a, double b)
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{
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return max(a, b);
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}
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inline double fmin (double a, double b)
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{
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return min(a, b);
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}
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inline double fsgn (double a)
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{
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return (a == 0.0 ? 0.0 : (a > 0.0 ? 1.0 : -1.0));
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}
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inline double dot (Vec a, Vec b)
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{
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return a.x * b.x + a.y * b.y + a.z * b.z;
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}
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Vec cross (Vec a, Vec b)
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{
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Vec c;
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c.x = a.y * b.z - a.z * b.y;
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c.y = a.z * b.x - a.x * b.z;
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c.z = a.x * b.y - a.y * b.x;
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return c;
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}
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Vec plus (Vec a, Vec b)
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{
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Vec c;
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c.x = a.x + b.x;
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c.y = a.y + b.y;
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c.z = a.z + b.z;
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return c;
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}
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Vec minus (Vec a, Vec b)
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{
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Vec c;
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c.x = a.x - b.x;
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c.y = a.y - b.y;
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c.z = a.z - b.z;
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return c;
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}
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Vec times (Vec a, double f)
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{
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Vec c;
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c.x = a.x * f;
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c.y = a.y * f;
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c.z = a.z * f;
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return c;
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}
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double norm (Vec a)
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{
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return sqrt (sqr(a.x) + sqr(a.y) + sqr(a.z));
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}
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void orth_vectors(Vec X, Vec *r1, Vec *r2, double r)
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{
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if (X.x == 0 && X.y == 0) {
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r1->x = 1;
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r1->y = 0;
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r1->z = 0;
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} else {
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r1->x = X.y / sqrt (X.x * X.x + X.y * X.y);
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r1->y = -X.x / sqrt (X.x * X.x + X.y * X.y);
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r1->z = 0;
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}
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*r1 = times (*r1, r); /* r1 now has length r */
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*r2 = cross (X, *r1);
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*r2 = times (*r2, r / norm (*r2)); /* r2 now has length r */
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/* r1 and r2 are now two vectors prependicular to each other and to (x,y,z) */
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}
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