vmap/libs/math/aabb.h

/*
   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_AABB_H )
#define INCLUDED_MATH_AABB_H

/// \file
/// \brief Axis-aligned bounding-box data types and related operations.

#include "math/matrix.h"
#include "math/plane.h"

class AABB
{
public:
Vector3 origin, extents;

AABB() : origin( 0, 0, 0 ), extents( -1,-1,-1 ){
}
AABB( const Vector3& origin_, const Vector3& extents_ ) :
	origin( origin_ ), extents( extents_ ){
}
};

const float c_aabb_max = FLT_MAX;

inline bool extents_valid( float f ){
	return f >= 0.0f && f <= c_aabb_max;
}

inline bool origin_valid( float f ){
	return f >= -c_aabb_max && f <= c_aabb_max;
}

inline bool aabb_valid( const AABB& aabb ){
	return origin_valid( aabb.origin[0] )
	       && origin_valid( aabb.origin[1] )
	       && origin_valid( aabb.origin[2] )
	       && extents_valid( aabb.extents[0] )
	       && extents_valid( aabb.extents[1] )
	       && extents_valid( aabb.extents[2] );
}

inline AABB aabb_for_minmax( const Vector3& min, const Vector3& max ){
	AABB aabb;
	aabb.origin = vector3_mid( min, max );
	aabb.extents = vector3_subtracted( max, aabb.origin );
	return aabb;
}

template<typename Index>
class AABBExtend
{
public:
static void apply( AABB& aabb, const Vector3& point ){
	float displacement = point[Index::VALUE] - aabb.origin[Index::VALUE];
	float half_difference = static_cast<float>( 0.5 * ( fabs( displacement ) - aabb.extents[Index::VALUE] ) );
	if ( half_difference > 0.0f ) {
		aabb.origin[Index::VALUE] += ( displacement >= 0.0f ) ? half_difference : -half_difference;
		aabb.extents[Index::VALUE] += half_difference;
	}
}
static void apply( AABB& aabb, const AABB& other ){
	float displacement = other.origin[Index::VALUE] - aabb.origin[Index::VALUE];
	float difference = other.extents[Index::VALUE] - aabb.extents[Index::VALUE];
	if ( fabs( displacement ) > fabs( difference ) ) {
		float half_difference = static_cast<float>( 0.5 * ( fabs( displacement ) + difference ) );
		if ( half_difference > 0.0f ) {
			aabb.origin[Index::VALUE] += ( displacement >= 0.0f ) ? half_difference : -half_difference;
			aabb.extents[Index::VALUE] += half_difference;
		}
	}
	else if ( difference > 0.0f ) {
		aabb.origin[Index::VALUE] = other.origin[Index::VALUE];
		aabb.extents[Index::VALUE] = other.extents[Index::VALUE];
	}
}
};

inline void aabb_extend_by_point( AABB& aabb, const Vector3& point ){
	AABBExtend< IntegralConstant<0> >::apply( aabb, point );
	AABBExtend< IntegralConstant<1> >::apply( aabb, point );
	AABBExtend< IntegralConstant<2> >::apply( aabb, point );
}

inline void aabb_extend_by_point_safe( AABB& aabb, const Vector3& point ){
	if ( aabb_valid( aabb ) ) {
		aabb_extend_by_point( aabb, point );
	}
	else
	{
		aabb.origin = point;
		aabb.extents = Vector3( 0, 0, 0 );
	}
}

inline void aabb_extend_by_aabb( AABB& aabb, const AABB& other ){
	AABBExtend< IntegralConstant<0> >::apply( aabb, other );
	AABBExtend< IntegralConstant<1> >::apply( aabb, other );
	AABBExtend< IntegralConstant<2> >::apply( aabb, other );
}

inline void aabb_extend_by_aabb_safe( AABB& aabb, const AABB& other ){
	if ( aabb_valid( aabb ) && aabb_valid( other ) ) {
		aabb_extend_by_aabb( aabb, other );
	}
	else if ( aabb_valid( other ) ) {
		aabb = other;
	}
}

inline void aabb_extend_by_vec3( AABB& aabb, const Vector3& extension ){
	vector3_add( aabb.extents, extension );
}




template<typename Index>
inline bool aabb_intersects_point_dimension( const AABB& aabb, const Vector3& point ){
	return fabs( point[Index::VALUE] - aabb.origin[Index::VALUE] ) < aabb.extents[Index::VALUE];
}

inline bool aabb_intersects_point( const AABB& aabb, const Vector3& point ){
	return aabb_intersects_point_dimension< IntegralConstant<0> >( aabb, point )
	       && aabb_intersects_point_dimension< IntegralConstant<1> >( aabb, point )
	       && aabb_intersects_point_dimension< IntegralConstant<2> >( aabb, point );
}

template<typename Index>
inline bool aabb_intersects_aabb_dimension( const AABB& aabb, const AABB& other ){
	return fabs( other.origin[Index::VALUE] - aabb.origin[Index::VALUE] ) < ( aabb.extents[Index::VALUE] + other.extents[Index::VALUE] );
}

inline bool aabb_intersects_aabb( const AABB& aabb, const AABB& other ){
	return aabb_intersects_aabb_dimension< IntegralConstant<0> >( aabb, other )
	       && aabb_intersects_aabb_dimension< IntegralConstant<1> >( aabb, other )
	       && aabb_intersects_aabb_dimension< IntegralConstant<2> >( aabb, other );
}

inline unsigned int aabb_classify_plane( const AABB& aabb, const Plane3& plane ){
	double distance_origin = vector3_dot( plane.normal(), aabb.origin ) + plane.dist();

	if ( fabs( distance_origin ) < ( fabs( plane.a * aabb.extents[0] )
	                                 + fabs( plane.b * aabb.extents[1] )
	                                 + fabs( plane.c * aabb.extents[2] ) ) ) {
		return 1; // partially inside
	}
	else if ( distance_origin < 0 ) {
		return 2; // totally inside
	}
	return 0; // totally outside
}

inline unsigned int aabb_oriented_classify_plane( const AABB& aabb, const Matrix4& transform, const Plane3& plane ){
	double distance_origin = vector3_dot( plane.normal(), aabb.origin ) + plane.dist();

	if ( fabs( distance_origin ) < ( fabs( aabb.extents[0] * vector3_dot( plane.normal(), vector4_to_vector3( transform.x() ) ) )
	                                 + fabs( aabb.extents[1] * vector3_dot( plane.normal(), vector4_to_vector3( transform.y() ) ) )
	                                 + fabs( aabb.extents[2] * vector3_dot( plane.normal(), vector4_to_vector3( transform.z() ) ) ) ) ) {
		return 1; // partially inside
	}
	else if ( distance_origin < 0 ) {
		return 2; // totally inside
	}
	return 0; // totally outside
}

inline void aabb_corners( const AABB& aabb, Vector3 corners[8] ){
	Vector3 min( vector3_subtracted( aabb.origin, aabb.extents ) );
	Vector3 max( vector3_added( aabb.origin, aabb.extents ) );
	corners[0] = Vector3( min[0], max[1], max[2] );
	corners[1] = Vector3( max[0], max[1], max[2] );
	corners[2] = Vector3( max[0], min[1], max[2] );
	corners[3] = Vector3( min[0], min[1], max[2] );
	corners[4] = Vector3( min[0], max[1], min[2] );
	corners[5] = Vector3( max[0], max[1], min[2] );
	corners[6] = Vector3( max[0], min[1], min[2] );
	corners[7] = Vector3( min[0], min[1], min[2] );
}

inline void aabb_corners_oriented( const AABB& aabb, const Matrix4& rotation, Vector3 corners[8] ){
	Vector3 x = vector4_to_vector3( rotation.x() ) * aabb.extents.x();
	Vector3 y = vector4_to_vector3( rotation.y() ) * aabb.extents.y();
	Vector3 z = vector4_to_vector3( rotation.z() ) * aabb.extents.z();

	corners[0] = aabb.origin + -x +  y +  z;
	corners[1] = aabb.origin +  x +  y +  z;
	corners[2] = aabb.origin +  x + -y +  z;
	corners[3] = aabb.origin + -x + -y +  z;
	corners[4] = aabb.origin + -x +  y + -z;
	corners[5] = aabb.origin +  x +  y + -z;
	corners[6] = aabb.origin +  x + -y + -z;
	corners[7] = aabb.origin + -x + -y + -z;
}

inline void aabb_planes( const AABB& aabb, Plane3 planes[6] ){
	planes[0] = Plane3( g_vector3_axes[0], aabb.origin[0] + aabb.extents[0] );
	planes[1] = Plane3( vector3_negated( g_vector3_axes[0] ), -( aabb.origin[0] - aabb.extents[0] ) );
	planes[2] = Plane3( g_vector3_axes[1], aabb.origin[1] + aabb.extents[1] );
	planes[3] = Plane3( vector3_negated( g_vector3_axes[1] ), -( aabb.origin[1] - aabb.extents[1] ) );
	planes[4] = Plane3( g_vector3_axes[2], aabb.origin[2] + aabb.extents[2] );
	planes[5] = Plane3( vector3_negated( g_vector3_axes[2] ), -( aabb.origin[2] - aabb.extents[2] ) );
}

inline void aabb_planes_oriented( const AABB& aabb, const Matrix4& rotation, Plane3 planes[6] ){
	double x = vector3_dot( vector4_to_vector3( rotation.x() ), aabb.origin );
	double y = vector3_dot( vector4_to_vector3( rotation.y() ), aabb.origin );
	double z = vector3_dot( vector4_to_vector3( rotation.z() ), aabb.origin );

	planes[0] = Plane3( vector4_to_vector3( rotation.x() ), x + aabb.extents[0] );
	planes[1] = Plane3( -vector4_to_vector3( rotation.x() ), -( x - aabb.extents[0] ) );
	planes[2] = Plane3( vector4_to_vector3( rotation.y() ), y + aabb.extents[1] );
	planes[3] = Plane3( -vector4_to_vector3( rotation.y() ), -( y - aabb.extents[1] ) );
	planes[4] = Plane3( vector4_to_vector3( rotation.z() ), z + aabb.extents[2] );
	planes[5] = Plane3( -vector4_to_vector3( rotation.z() ), -( z - aabb.extents[2] ) );
}

const Vector3 aabb_normals[6] = {
	Vector3( 1, 0, 0 ),
	Vector3( 0, 1, 0 ),
	Vector3( 0, 0, 1 ),
	Vector3( -1, 0, 0 ),
	Vector3( 0,-1, 0 ),
	Vector3( 0, 0,-1 ),
};

const float aabb_texcoord_topleft[2] = { 0, 0 };
const float aabb_texcoord_topright[2] = { 1, 0 };
const float aabb_texcoord_botleft[2] = { 0, 1 };
const float aabb_texcoord_botright[2] = { 1, 1 };


inline AABB aabb_for_oriented_aabb( const AABB& aabb, const Matrix4& transform ){
	return AABB(
		matrix4_transformed_point( transform, aabb.origin ),
		Vector3(
			static_cast<float>( fabs( transform[0]  * aabb.extents[0] )
			                    + fabs( transform[4]  * aabb.extents[1] )
			                    + fabs( transform[8]  * aabb.extents[2] ) ),
			static_cast<float>( fabs( transform[1]  * aabb.extents[0] )
			                    + fabs( transform[5]  * aabb.extents[1] )
			                    + fabs( transform[9]  * aabb.extents[2] ) ),
			static_cast<float>( fabs( transform[2]  * aabb.extents[0] )
			                    + fabs( transform[6]  * aabb.extents[1] )
			                    + fabs( transform[10] * aabb.extents[2] ) )
			)
		);
}

inline AABB aabb_for_oriented_aabb_safe( const AABB& aabb, const Matrix4& transform ){
	if ( aabb_valid( aabb ) ) {
		return aabb_for_oriented_aabb( aabb, transform );
	}
	return aabb;
}

inline AABB aabb_infinite(){
	return AABB( Vector3( 0, 0, 0 ), Vector3( c_aabb_max, c_aabb_max, c_aabb_max ) );
}

#endif