vmap/libs/math/line.h
2020-11-17 12:16:16 +01:00

138 lines
3.4 KiB
C++

/*
Copyright (C) 2001-2006, William Joseph.
All Rights Reserved.
This file is part of GtkRadiant.
GtkRadiant 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 2 of the License, or
(at your option) any later version.
GtkRadiant 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 GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#if !defined( INCLUDED_MATH_LINE_H )
#define INCLUDED_MATH_LINE_H
/// \file
/// \brief Line data types and related operations.
#include "math/vector.h"
#include "math/plane.h"
/// \brief A line segment defined by a start point and and end point.
class Line
{
public:
Vector3 start, end;
Line(){
}
Line( const Vector3& start_, const Vector3& end_ ) : start( start_ ), end( end_ ){
}
};
inline Vector3 line_closest_point( const Line& line, const Vector3& point ){
Vector3 v = line.end - line.start;
Vector3 w = point - line.start;
double c1 = vector3_dot( w,v );
if ( c1 <= 0 ) {
return line.start;
}
double c2 = vector3_dot( v,v );
if ( c2 <= c1 ) {
return line.end;
}
return Vector3( line.start + v * ( c1 / c2 ) );
}
class Segment
{
public:
Vector3 origin, extents;
Segment(){
}
Segment( const Vector3& origin_, const Vector3& extents_ ) :
origin( origin_ ), extents( extents_ ){
}
};
inline Segment segment_for_startend( const Vector3& start, const Vector3& end ){
Segment segment;
segment.origin = vector3_mid( start, end );
segment.extents = vector3_subtracted( end, segment.origin );
return segment;
}
inline unsigned int segment_classify_plane( const Segment& segment, const Plane3& plane ){
double distance_origin = vector3_dot( plane.normal(), segment.origin ) + plane.dist();
if ( fabs( distance_origin ) < fabs( vector3_dot( plane.normal(), segment.extents ) ) ) {
return 1; // partially inside
}
else if ( distance_origin < 0 ) {
return 2; // totally inside
}
return 0; // totally outside
}
class Ray
{
public:
Vector3 origin, direction;
Ray(){
}
Ray( const Vector3& origin_, const Vector3& direction_ ) :
origin( origin_ ), direction( direction_ ){
}
};
inline Ray ray_for_points( const Vector3& origin, const Vector3& p2 ){
return Ray( origin, vector3_normalised( vector3_subtracted( p2, origin ) ) );
}
inline void ray_transform( Ray& ray, const Matrix4& matrix ){
matrix4_transform_point( matrix, ray.origin );
matrix4_transform_direction( matrix, ray.direction );
}
// closest-point-on-line
inline double ray_squared_distance_to_point( const Ray& ray, const Vector3& point ){
return vector3_length_squared(
vector3_subtracted(
point,
vector3_added(
ray.origin,
vector3_scaled(
ray.direction,
vector3_dot(
vector3_subtracted( point, ray.origin ),
ray.direction
)
)
)
)
);
}
inline double ray_distance_to_plane( const Ray& ray, const Plane3& plane ){
return -( vector3_dot( plane.normal(), ray.origin ) - plane.dist() ) / vector3_dot( ray.direction, plane.normal() );
}
#endif