139 lines
3.8 KiB
C++
139 lines
3.8 KiB
C++
// vector.cxx -- additional vector routines
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//
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// Written by Curtis Olson, started December 1997.
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//
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// Copyright (C) 1997 Curtis L. Olson - http://www.flightgear.org/~curt
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//
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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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//
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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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//
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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// $Id$
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#include <math.h>
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#include <stdio.h>
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// #include <Include/fg_types.h>
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#include "vector.hxx"
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// calculate the projection, p, of u along the direction of d.
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void sgProjection(sgVec3 p, const sgVec3 u, const sgVec3 d){
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double denom = sgScalarProductVec3(d,d);
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if (denom == 0.) sgCopyVec3(p, u);
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else sgScaleVec3(p, d, sgScalarProductVec3(u,d) / denom);
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}
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// Same thing, except using double precision
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void sgProjection(sgdVec3 p, const sgdVec3 u, const sgdVec3 d){
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double denom = sgdScalarProductVec3(d,d);
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if (denom == 0.) sgdCopyVec3(p, u);
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else sgdScaleVec3(p, d, sgdScalarProductVec3(u,d) / denom);
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}
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// Given a point p, and a line through p0 with direction vector d,
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// find the closest point (p1) on the line
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void sgClosestPointToLine( sgVec3 p1, const sgVec3 p, const sgVec3 p0,
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const sgVec3 d ) {
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sgVec3 u, u1;
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// u = p - p0
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sgSubVec3(u, p, p0);
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// calculate the projection, u1, of u along d.
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sgProjection(u1, u, d);
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// calculate the point p1 along the line that is closest to p
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// p0 = p1 + u1
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sgAddVec3(p1, p0, u1);
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}
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// Given a point p, and a line through p0 with direction vector d,
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// find the closest point (p1) on the line
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void sgdClosestPointToLine( sgdVec3 p1, const sgdVec3 p, const sgdVec3 p0,
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const sgdVec3 d ) {
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sgdVec3 u, u1;
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// u = p - p0
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sgdSubVec3(u, p, p0);
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// calculate the projection, u1, of u along d.
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sgProjection(u1, u, d);
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// calculate the point p1 along the line that is closest to p
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// p0 = p1 + u1
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sgdAddVec3(p1, p0, u1);
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}
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// Given a point p, and a line through p0 with direction vector d,
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// find the shortest distance (squared) from the point to the line
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double sgClosestPointToLineDistSquared( const sgVec3 p, const sgVec3 p0,
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const sgVec3 d ) {
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sgVec3 u, u1, v;
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// u = p - p0
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sgSubVec3(u, p, p0);
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// calculate the projection, u1, of u along d.
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sgProjection(u1, u, d);
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// v = u - u1 = vector from closest point on line, p1, to the
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// original point, p.
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sgSubVec3(v, u, u1);
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return ( sgScalarProductVec3(v, v) );
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}
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// Given a point p, and a line through p0 with direction vector d,
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// find the shortest distance (squared) from the point to the line
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double sgdClosestPointToLineDistSquared( const sgdVec3 p, const sgdVec3 p0,
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const sgdVec3 d ) {
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sgdVec3 u, u1, v;
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// u = p - p0
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sgdSubVec3(u, p, p0);
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// calculate the projection, u1, of u along d.
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sgProjection(u1, u, d);
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// v = u - u1 = vector from closest point on line, p1, to the
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// original point, p.
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sgdSubVec3(v, u, u1);
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return ( sgdScalarProductVec3(v, v) );
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}
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// This is a quicker form of
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// sgMakeMatTrans4( sgMat4 sgTrans, sgVec3 trans )
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// sgPostMultMat4( sgMat, sgTRANS );
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void sgPostMultMat4ByTransMat4( sgMat4 src, const sgVec3 trans )
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{
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for( int i=0; i<4; i++) {
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for( int j=0; j<3; j++ ) {
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src[i][j] += (src[i][3] * trans[j]);
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}
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}
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}
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