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/* Copyright (c) 1992 The Geometry Center; University of Minnesota
1300 South Second Street; Minneapolis, MN 55454, USA;
This file is part of geomview/OOGL. geomview/OOGL is free software;
you can redistribute it and/or modify it only under the terms given in
the file COPYING, which you should have received along with this file.
This and other related software may be obtained via anonymous ftp from
geom.umn.edu; email: software@geom.umn.edu. */
/* Authors: Charlie Gunn, Pat Hanrahan, Stuart Levy, Tamara Munzner, Mark Phillips */
#
/*
** hpoint3.c - procedural interface to 3D point geometry
**
** pat hanrahan
*/
#include <math.h>
#include "hg4.h"
#include "point3.h"
#include "hpoint3.h"
#include "hplane3.h"
#include "hline3.h"
#include "transform3.h"
#include "tolerance.h"
void
HPt3Copy( pt1, pt2 )
HPoint3 *pt1, *pt2;
{
*pt2 = *pt1;
}
void
HPt3Normalize( pt1, pt2 )
HPoint3 *pt1, *pt2;
{
if(pt1->w == 1.0 || pt1->w == 0.0) {
*pt2 = *pt1;
} else {
float inv = 1.0/pt1->w;
pt2->x = pt1->x * inv;
pt2->y = pt1->y * inv;
pt2->z = pt1->z * inv;
pt2->w = 1.0;
}
}
/*
* pt2 = pt1 * T
*/
void
HPt3Transform( T, pt1, pt2 )
register Transform3 T;
HPoint3 *pt1, *pt2;
{
register float x = pt1->x, y = pt1->y, z = pt1->z, w = pt1->w;
pt2->x = x*T[0][0] + y*T[1][0] + z*T[2][0] + w*T[3][0];
pt2->y = x*T[0][1] + y*T[1][1] + z*T[2][1] + w*T[3][1];
pt2->z = x*T[0][2] + y*T[1][2] + z*T[2][2] + w*T[3][2];
pt2->w = x*T[0][3] + y*T[1][3] + z*T[2][3] + w*T[3][3];
}
void
HPt3TransformN( T, pt1, pt2, n )
HPoint3 *pt1, *pt2;
int n;
{
while( --n >= 0 )
HPt3Transform( T, pt1++, pt2++ );
}
/*
* Transform and project an HPoint3 onto a plain Point3.
* Transforms pin . T -> pout,
* then projects pout.{x,y,z} /= pout.w.
* Returns pout.w.
*/
HPt3Coord
HPt3TransPt3( T, pin, pout )
Transform3 T;
HPoint3 *pin;
Point3 *pout;
{
HPoint3 tp;
register HPt3Coord w;
HPt3Transform( T, pin, &tp );
if(tp.w != 1.0 && tp.w != 0.0) {
pout->x = tp.x / tp.w;
pout->y = tp.y / tp.w;
pout->z = tp.z / tp.w;
} else {
*pout = *(Point3 *)&tp;
}
return tp.w;
}
/*
* Pt3ToPt4: convert 3-vectors to 4-vectors by padding with 1.0 's.
*
* Charlie Gunn
* Nov 26, 1991: originally written
*/
void
Pt3ToPt4(v3, v4, n)
Point3 *v3;
HPoint3 *v4;
int n;
{
register int i;
for (i = 0; i<n; ++i) {
*(Point3 *)&v4[i] = v3[i];
v4[i].w = 1.0;
}
}
void
HPt3ToPt3(hp, p)
HPoint3 *hp;
Point3 *p;
{
if(hp->w == 1.0 || hp->w == 0.0) {
*p = *(Point3 *)hp;
} else {
p->x = hp->x / hp->w;
p->y = hp->y / hp->w;
p->z = hp->z / hp->w;
}
}
/* also need an in-place dehomogenization routine which
sets the w-coordinate to 1.0, unless the original one is zero */
void
HPt3Dehomogenize(hp1, hp2)
HPoint3 *hp1, *hp2;
{
float inv;
if (hp1->w == 1.0 || hp1->w == 0.0) {
if (hp2 != hp1) *hp2 = *hp1;
return; }
/* else if ( || hp->w == 0.0) hp->w = .000001;*/
inv = 1.0 / hp1->w;
hp2->x = hp1->x * inv;
hp2->y = hp1->y * inv;
hp2->z = hp1->z * inv;
hp2->w = 1.0;
}
void
HPt3SubPt3(register HPoint3 *p1, register HPoint3 *p2, register Point3 *v)
{
if(p1->w == p2->w) {
v->x = p1->x - p2->x; v->y = p1->y - p2->y; v->z = p1->z - p2->z;
} else if(p1->w == 0) {
*v = *(Point3 *)p1;
return;
} else if(p2->w == 0) {
*v = *(Point3 *)p2;
} else {
float s = p2->w / p1->w;
v->x = p1->x*s - p2->x; v->y = p1->y*s - p2->y; v->z = p1->z*s - p2->z;
}
if(p2->w != 1)
v->x /= p2->w, v->y /= p2->w, v->z /= p2->w;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.