quadrilateralcowboy/idlib/bv/Sphere.cpp
2020-06-12 14:06:25 -07:00

155 lines
3.8 KiB
C++

/*
===========================================================================
Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company.
This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).
Doom 3 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 3 of the License, or
(at your option) any later version.
Doom 3 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 Doom 3 Source Code. If not, see <http://www.gnu.org/licenses/>.
In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code. If not, please request a copy in writing from id Software at the address below.
If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
===========================================================================
*/
#include "../precompiled.h"
#pragma hdrstop
idSphere sphere_zero( vec3_zero, 0.0f );
/*
================
idSphere::PlaneDistance
================
*/
float idSphere::PlaneDistance( const idPlane &plane ) const {
float d;
d = plane.Distance( origin );
if ( d > radius ) {
return d - radius;
}
if ( d < -radius ) {
return d + radius;
}
return 0.0f;
}
/*
================
idSphere::PlaneSide
================
*/
int idSphere::PlaneSide( const idPlane &plane, const float epsilon ) const {
float d;
d = plane.Distance( origin );
if ( d > radius + epsilon ) {
return PLANESIDE_FRONT;
}
if ( d < -radius - epsilon ) {
return PLANESIDE_BACK;
}
return PLANESIDE_CROSS;
}
/*
============
idSphere::LineIntersection
Returns true if the line intersects the sphere between the start and end point.
============
*/
bool idSphere::LineIntersection( const idVec3 &start, const idVec3 &end ) const {
idVec3 r, s, e;
float a;
s = start - origin;
e = end - origin;
r = e - s;
a = -s * r;
if ( a <= 0 ) {
return ( s * s < radius * radius );
}
else if ( a >= r * r ) {
return ( e * e < radius * radius );
}
else {
r = s + ( a / ( r * r ) ) * r;
return ( r * r < radius * radius );
}
}
/*
============
idSphere::RayIntersection
Returns true if the ray intersects the sphere.
The ray can intersect the sphere in both directions from the start point.
If start is inside the sphere then scale1 < 0 and scale2 > 0.
============
*/
bool idSphere::RayIntersection( const idVec3 &start, const idVec3 &dir, float &scale1, float &scale2 ) const {
double a, b, c, d, sqrtd;
idVec3 p;
p = start - origin;
a = dir * dir;
b = dir * p;
c = p * p - radius * radius;
d = b * b - c * a;
if ( d < 0.0f ) {
return false;
}
sqrtd = idMath::Sqrt( d );
a = 1.0f / a;
scale1 = ( -b + sqrtd ) * a;
scale2 = ( -b - sqrtd ) * a;
return true;
}
/*
============
idSphere::FromPoints
Tight sphere for a point set.
============
*/
void idSphere::FromPoints( const idVec3 *points, const int numPoints ) {
int i;
float radiusSqr, dist;
idVec3 mins, maxs;
SIMDProcessor->MinMax( mins, maxs, points, numPoints );
origin = ( mins + maxs ) * 0.5f;
radiusSqr = 0.0f;
for ( i = 0; i < numPoints; i++ ) {
dist = ( points[i] - origin ).LengthSqr();
if ( dist > radiusSqr ) {
radiusSqr = dist;
}
}
radius = idMath::Sqrt( radiusSqr );
}