aabb.h

/*************************************************************************/
/*  aabb.h                                                               */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.                 */
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/*************************************************************************/
#ifndef AABB_H
#define AABB_H



#include "vector3.h"
#include "plane.h"
class AABB {
public:
    Vector3 pos;
    Vector3 size;

    float get_area() const; 
    _FORCE_INLINE_ bool has_no_area() const {

        return (size.x<=CMP_EPSILON || size.y<=CMP_EPSILON  || size.z<=CMP_EPSILON);
    }

    _FORCE_INLINE_ bool has_no_surface() const {

        return (size.x<=CMP_EPSILON && size.y<=CMP_EPSILON  && size.z<=CMP_EPSILON);
    }

    const Vector3& get_pos() const { return pos; }
    void set_pos(const Vector3& p_pos) { pos=p_pos; }
    const Vector3& get_size() const { return size; }
    void set_size(const Vector3& p_size) { size=p_size; }


    bool operator==(const AABB& p_rval) const;
    bool operator!=(const AABB& p_rval) const;

    _FORCE_INLINE_ bool intersects(const AABB& p_aabb) const; 
    _FORCE_INLINE_ bool intersects_inclusive(const AABB& p_aabb) const; 
    _FORCE_INLINE_ bool encloses(const AABB & p_aabb) const; 

    AABB merge(const AABB& p_with) const;
        void merge_with(const AABB& p_aabb); 
    AABB intersection(const AABB& p_aabb) const; 
    bool intersects_segment(const Vector3& p_from, const Vector3& p_to,Vector3* r_clip=NULL,Vector3* r_normal=NULL) const;
    bool intersects_ray(const Vector3& p_from, const Vector3& p_dir,Vector3* r_clip=NULL,Vector3* r_normal=NULL) const;
    _FORCE_INLINE_ bool smits_intersect_ray(const Vector3 &from,const Vector3& p_dir, float t0, float t1) const;

    _FORCE_INLINE_ bool intersects_convex_shape(const Plane *p_plane, int p_plane_count) const;
    bool intersects_plane(const Plane &p_plane) const;

    _FORCE_INLINE_ bool has_point(const Vector3& p_point) const;
    _FORCE_INLINE_ Vector3 get_support(const Vector3& p_normal) const;


    Vector3 get_longest_axis() const;
    int get_longest_axis_index() const;
    _FORCE_INLINE_ real_t get_longest_axis_size() const;

    Vector3 get_shortest_axis() const;
    int get_shortest_axis_index() const;
    _FORCE_INLINE_ real_t get_shortest_axis_size() const;

    AABB grow(real_t p_by) const;
    _FORCE_INLINE_ void grow_by(real_t p_amount);

    void get_edge(int p_edge,Vector3& r_from,Vector3& r_to) const;
    _FORCE_INLINE_ Vector3 get_endpoint(int p_point) const;

    AABB expand(const Vector3& p_vector) const;
    _FORCE_INLINE_ void project_range_in_plane(const Plane& p_plane,float &r_min,float& r_max) const;
    _FORCE_INLINE_ void expand_to(const Vector3& p_vector); 
    operator String() const;

    _FORCE_INLINE_ AABB() {}
    inline AABB(const Vector3 &p_pos,const Vector3& p_size) { pos=p_pos; size=p_size; }


};

inline bool AABB::intersects(const AABB& p_aabb) const {

    if ( pos.x >= (p_aabb.pos.x + p_aabb.size.x) )
                return false;
    if ( (pos.x+size.x) <= p_aabb.pos.x  )
                return false;
    if ( pos.y >= (p_aabb.pos.y + p_aabb.size.y) )
                return false;
    if ( (pos.y+size.y) <= p_aabb.pos.y  )
                return false;
    if ( pos.z >= (p_aabb.pos.z + p_aabb.size.z) )
                return false;
    if ( (pos.z+size.z) <= p_aabb.pos.z  )
                return false;

        return true;
}

inline bool AABB::intersects_inclusive(const AABB& p_aabb) const {

    if ( pos.x > (p_aabb.pos.x + p_aabb.size.x) )
                return false;
    if ( (pos.x+size.x) < p_aabb.pos.x  )
                return false;
    if ( pos.y > (p_aabb.pos.y + p_aabb.size.y) )
                return false;
    if ( (pos.y+size.y) < p_aabb.pos.y  )
                return false;
    if ( pos.z > (p_aabb.pos.z + p_aabb.size.z) )
                return false;
    if ( (pos.z+size.z) < p_aabb.pos.z  )
                return false;

        return true;
}

inline bool AABB::encloses(const AABB & p_aabb) const {

    Vector3 src_min=pos;
    Vector3 src_max=pos+size;
    Vector3 dst_min=p_aabb.pos;
    Vector3 dst_max=p_aabb.pos+p_aabb.size;

    return  (
         (src_min.x <= dst_min.x) &&
            (src_max.x > dst_max.x) &&
            (src_min.y <= dst_min.y) &&
            (src_max.y > dst_max.y) &&
            (src_min.z <= dst_min.z) &&
            (src_max.z > dst_max.z) );

}

Vector3 AABB::get_support(const Vector3& p_normal) const {

    Vector3 half_extents = size * 0.5;
    Vector3 ofs = pos + half_extents;

    return Vector3(
            (p_normal.x>0) ? -half_extents.x : half_extents.x,
            (p_normal.y>0) ? -half_extents.y : half_extents.y,
            (p_normal.z>0) ? -half_extents.z : half_extents.z
        )+ofs;
}


Vector3 AABB::get_endpoint(int p_point) const {

    switch(p_point) {
        case 0: return Vector3( pos.x   , pos.y     , pos.z     );
        case 1: return Vector3( pos.x   , pos.y     , pos.z+size.z  );
        case 2: return Vector3( pos.x   , pos.y+size.y  , pos.z     );
        case 3: return Vector3( pos.x   , pos.y+size.y  , pos.z+size.z  );
        case 4: return Vector3( pos.x+size.x    , pos.y     , pos.z     );
        case 5: return Vector3( pos.x+size.x    , pos.y     , pos.z+size.z  );
        case 6: return Vector3( pos.x+size.x    , pos.y+size.y  , pos.z     );
        case 7: return Vector3( pos.x+size.x    , pos.y+size.y  , pos.z+size.z  );
    };

    ERR_FAIL_V(Vector3());
}

bool AABB::intersects_convex_shape(const Plane *p_planes, int p_plane_count) const {

#if 1

    Vector3 half_extents = size * 0.5;
    Vector3 ofs = pos + half_extents;

    for(int i=0;i<p_plane_count;i++) {
        const Plane &p=p_planes[i];
        Vector3 point(
                (p.normal.x>0) ? -half_extents.x : half_extents.x,
                (p.normal.y>0) ? -half_extents.y : half_extents.y,
                (p.normal.z>0) ? -half_extents.z : half_extents.z
            );
        point+=ofs;
        if (p.is_point_over(point))
            return false;
    }

    return true;
#else
    //cache all points to check against!
// #warning should be easy to optimize, just use the same as when taking the support and use only that point
    Vector3 points[8] = {
        Vector3( pos.x  , pos.y     , pos.z     ),
        Vector3( pos.x  , pos.y     , pos.z+size.z  ),
        Vector3( pos.x  , pos.y+size.y  , pos.z     ),
        Vector3( pos.x  , pos.y+size.y  , pos.z+size.z  ),
        Vector3( pos.x+size.x   , pos.y     , pos.z     ),
        Vector3( pos.x+size.x   , pos.y     , pos.z+size.z  ),
        Vector3( pos.x+size.x   , pos.y+size.y  , pos.z     ),
        Vector3( pos.x+size.x   , pos.y+size.y  , pos.z+size.z  ),
    };

    for (int i=0;i<p_plane_count;i++) { //for each plane

        const Plane & plane=p_planes[i];
        bool all_points_over=true;
        //test if it has all points over!

        for (int j=0;j<8;j++) {


            if (!plane.is_point_over( points[j] )) {

                all_points_over=false;
                break;
            }

        }

        if (all_points_over) {

            return false;
        }
    }
    return true;
#endif
}

bool AABB::has_point(const Vector3& p_point) const {

    if (p_point.x<pos.x)
        return false;
    if (p_point.y<pos.y)
        return false;
    if (p_point.z<pos.z)
        return false;
    if (p_point.x>pos.x+size.x)
        return false;
    if (p_point.y>pos.y+size.y)
        return false;
    if (p_point.z>pos.z+size.z)
        return false;

    return true;
}


inline void AABB::expand_to(const Vector3& p_vector) {

    Vector3 begin=pos;
    Vector3 end=pos+size;

    if (p_vector.x<begin.x)
        begin.x=p_vector.x;
    if (p_vector.y<begin.y)
        begin.y=p_vector.y;
    if (p_vector.z<begin.z)
        begin.z=p_vector.z;

    if (p_vector.x>end.x)
        end.x=p_vector.x;
    if (p_vector.y>end.y)
        end.y=p_vector.y;
    if (p_vector.z>end.z)
        end.z=p_vector.z;

    pos=begin;
    size=end-begin;
}

void AABB::project_range_in_plane(const Plane& p_plane,float &r_min,float& r_max) const {

    Vector3 half_extents( size.x * 0.5, size.y * 0.5, size.z * 0.5 );
    Vector3 center( pos.x + half_extents.x, pos.y + half_extents.y, pos.z + half_extents.z );

    float length = p_plane.normal.abs().dot(half_extents);
    float distance = p_plane.distance_to( center );
    r_min = distance - length;
    r_max = distance + length;
}

inline real_t AABB::get_longest_axis_size() const {

    real_t max_size=size.x;

    if (size.y > max_size ) {
        max_size=size.y;
    }

    if (size.z > max_size ) {
        max_size=size.z;
    }

    return max_size;
}

inline real_t AABB::get_shortest_axis_size() const {

    real_t max_size=size.x;

    if (size.y < max_size ) {
        max_size=size.y;
    }

    if (size.z < max_size ) {
        max_size=size.z;
    }

    return max_size;
}

bool AABB::smits_intersect_ray(const Vector3 &from,const Vector3& dir, float t0, float t1) const {

    float divx=1.0/dir.x;
    float divy=1.0/dir.y;
    float divz=1.0/dir.z;

    Vector3 upbound=pos+size;
    float tmin, tmax, tymin, tymax, tzmin, tzmax;
    if (dir.x >= 0) {
        tmin = (pos.x - from.x) * divx;
        tmax = (upbound.x - from.x) * divx;
    }
    else {
        tmin = (upbound.x - from.x) * divx;
        tmax = (pos.x - from.x) * divx;
    }
    if (dir.y >= 0) {
        tymin = (pos.y - from.y) * divy;
        tymax = (upbound.y - from.y) * divy;
    }
    else {
        tymin = (upbound.y - from.y) * divy;
        tymax = (pos.y - from.y) * divy;
    }
    if ( (tmin > tymax) || (tymin > tmax) )
        return false;
    if (tymin > tmin)
            tmin = tymin;
    if (tymax < tmax)
        tmax = tymax;
    if (dir.z >= 0) {
        tzmin = (pos.z - from.z) * divz;
        tzmax = (upbound.z - from.z) * divz;
    }
    else {
        tzmin = (upbound.z - from.z) * divz;
        tzmax = (pos.z - from.z) * divz;
    }
    if ( (tmin > tzmax) || (tzmin > tmax) )
        return false;
    if (tzmin > tmin)
        tmin = tzmin;
    if (tzmax < tmax)
        tmax = tzmax;
    return ( (tmin < t1) && (tmax > t0) );
}

void AABB::grow_by(real_t p_amount) {

    pos.x-=p_amount;
    pos.y-=p_amount;
    pos.z-=p_amount;
    size.x+=2.0*p_amount;
    size.y+=2.0*p_amount;
    size.z+=2.0*p_amount;
}

typedef AABB Rect3;

#endif // AABB_H