OgreAxisAlignedBox.h

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/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2005 The OGRE Team
Also see acknowledgements in Readme.html

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
-----------------------------------------------------------------------------
*/
#ifndef __AxisAlignedBox_H_
#define __AxisAlignedBox_H_

// Precompiler options
#include "OgrePrerequisites.h"

#include "OgreVector3.h"
#include "OgreMatrix4.h"

namespace Ogre {

    class _OgreExport AxisAlignedBox
    {
    protected:
        Vector3 mMinimum;
        Vector3 mMaximum;
        bool mNull;

        Vector3 mCorners[8];

        void updateCorners(void)
        {
            // The order of these items is, using right-handed co-ordinates:
            // Minimum Z face, starting with Min(all), then anticlockwise
            //   around face (looking onto the face)
            // Maximum Z face, starting with Max(all), then anticlockwise
            //   around face (looking onto the face)
            mCorners[0] = mMinimum;
            mCorners[1].x = mMinimum.x; mCorners[1].y = mMaximum.y; mCorners[1].z = mMinimum.z;
            mCorners[2].x = mMaximum.x; mCorners[2].y = mMaximum.y; mCorners[2].z = mMinimum.z;
            mCorners[3].x = mMaximum.x; mCorners[3].y = mMinimum.y; mCorners[3].z = mMinimum.z;            

            mCorners[4] = mMaximum;
            mCorners[5].x = mMinimum.x; mCorners[5].y = mMaximum.y; mCorners[5].z = mMaximum.z;
            mCorners[6].x = mMinimum.x; mCorners[6].y = mMinimum.y; mCorners[6].z = mMaximum.z;
            mCorners[7].x = mMaximum.x; mCorners[7].y = mMinimum.y; mCorners[7].z = mMaximum.z;            
        }        

    public:
        inline AxisAlignedBox()
        {
            // Default to null box
            setMinimum( -0.5, -0.5, -0.5 );
            setMaximum( 0.5, 0.5, 0.5 );
            mNull = true;
        }

        inline AxisAlignedBox( const Vector3& min, const Vector3& max )
        {
            setExtents( min, max );
        }

        inline AxisAlignedBox(
            Real mx, Real my, Real mz,
            Real Mx, Real My, Real Mz )
        {
            setExtents( mx, my, mz, Mx, My, Mz );
        }

        inline const Vector3& getMinimum(void) const
        { 
            return mMinimum; 
        }

        inline const Vector3& getMaximum(void) const
        { 
            return mMaximum;
        }

        inline void setMinimum( const Vector3& vec )
        {
            mNull = false;
            mMinimum = vec;
            updateCorners();
        }

        inline void setMinimum( Real x, Real y, Real z )
        {
            mNull = false;
            mMinimum.x = x;
            mMinimum.y = y;
            mMinimum.z = z;
            updateCorners();
        }

        inline void setMaximum( const Vector3& vec )
        {
            mNull = false;
            mMaximum = vec;
            updateCorners();
        }

        inline void setMaximum( Real x, Real y, Real z )
        {
            mNull = false;
            mMaximum.x = x;
            mMaximum.y = y;
            mMaximum.z = z;
            updateCorners();
        }

        inline void setExtents( const Vector3& min, const Vector3& max )
        {
            mNull = false;
            mMinimum = min;
            mMaximum = max;
            updateCorners();
        }

        inline void setExtents(
            Real mx, Real my, Real mz,
            Real Mx, Real My, Real Mz )
        {
            mNull = false;

            mMinimum.x = mx;
            mMinimum.y = my;
            mMinimum.z = mz;

            mMaximum.x = Mx;
            mMaximum.y = My;
            mMaximum.z = Mz;

            updateCorners();
        }

        inline const Vector3* getAllCorners(void) const
        {
            assert( !mNull && "Can't get corners of a null AAB" );
            return (const Vector3*)mCorners;
        }

        friend std::ostream& operator<<( std::ostream& o, AxisAlignedBox aab )
        {
            if (aab.isNull())
            {
                o << "AxisAlignedBox(null)";
            }
            else
            {
                o << "AxisAlignedBox(min=" << aab.mMinimum << ", max=" << aab.mMaximum;
                o << ", corners=";
                for (int i = 0; i < 7; ++i)
                    o << aab.mCorners[i] << ", ";
                o << aab.mCorners[7] << ")";
            }
            return o;
        }

        void merge( const AxisAlignedBox& rhs )
        {
            // Do nothing if rhs null
            if (rhs.mNull)
            {
                return;
            }
            // Otherwise if current null, just take rhs
            else if (mNull)
            {
                setExtents(rhs.mMinimum, rhs.mMaximum);
            }
            // Otherwise merge
            else
            {
                Vector3 min = mMinimum;
                Vector3 max = mMaximum;
                max.makeCeil(rhs.mMaximum);
                min.makeFloor(rhs.mMinimum);

                setExtents(min, max);
            }

        }
        
        void merge( const Vector3& point )
        {
            if (mNull){ // if null, use this point
                setExtents(point, point);
            } else {
                mMaximum.makeCeil(point);
                mMinimum.makeFloor(point);
                updateCorners();
            }
        }

        void transform( const Matrix4& matrix )
        {
            // Do nothing if current null
            if( mNull )
                return;

            Vector3 min, max, temp;
            bool first = true;
            size_t i;

            for( i = 0; i < 8; ++i )
            {
                // Transform and check extents
                temp = matrix * mCorners[i];
                if( first || temp.x > max.x )
                    max.x = temp.x;
                if( first || temp.y > max.y )
                    max.y = temp.y;
                if( first || temp.z > max.z )
                    max.z = temp.z;
                if( first || temp.x < min.x )
                    min.x = temp.x;
                if( first || temp.y < min.y )
                    min.y = temp.y;
                if( first || temp.z < min.z )
                    min.z = temp.z;

                first = false;
            }

            setExtents( min,max );

        }

        inline void setNull()
        {
            mNull = true;
        }

        bool isNull(void) const
        {
            return mNull;
        }

        inline bool intersects(const AxisAlignedBox& b2) const
        {
            // Early-fail for nulls
            if (this->isNull() || b2.isNull())
                return false;

            // Use up to 6 separating planes
            if (mMaximum.x < b2.mMinimum.x)
                return false;
            if (mMaximum.y < b2.mMinimum.y)
                return false;
            if (mMaximum.z < b2.mMinimum.z)
                return false;

            if (mMinimum.x > b2.mMaximum.x)
                return false;
            if (mMinimum.y > b2.mMaximum.y)
                return false;
            if (mMinimum.z > b2.mMaximum.z)
                return false;

            // otherwise, must be intersecting
            return true;

        }

        inline AxisAlignedBox intersection(const AxisAlignedBox& b2) const
        {
            if (!this->intersects(b2))
            {
                return AxisAlignedBox();
            }
            Vector3 intMin, intMax;

            const Vector3& b2max = b2.getMaximum();
            const Vector3& b2min = b2.getMinimum();

            if (b2max.x > mMaximum.x && mMaximum.x > b2min.x)
                intMax.x = mMaximum.x;
            else 
                intMax.x = b2max.x;
            if (b2max.y > mMaximum.y && mMaximum.y > b2min.y)
                intMax.y = mMaximum.y;
            else 
                intMax.y = b2max.y;
            if (b2max.z > mMaximum.z && mMaximum.z > b2min.z)
                intMax.z = mMaximum.z;
            else 
                intMax.z = b2max.z;

            if (b2min.x < mMinimum.x && mMinimum.x < b2max.x)
                intMin.x = mMinimum.x;
            else
                intMin.x= b2min.x;
            if (b2min.y < mMinimum.y && mMinimum.y < b2max.y)
                intMin.y = mMinimum.y;
            else
                intMin.y= b2min.y;
            if (b2min.z < mMinimum.z && mMinimum.z < b2max.z)
                intMin.z = mMinimum.z;
            else
                intMin.z= b2min.z;

            return AxisAlignedBox(intMin, intMax);

        }

        Real volume(void) const
        {
            if (mNull)
            {
                return 0.0f;
            }
            else
            {
                Vector3 diff = mMaximum - mMinimum;
                return diff.x * diff.y * diff.z;
            }

        }

        inline void scale(const Vector3& s)
        {
            // NB assumes centered on origin
            Vector3 min = mMinimum * s;
            Vector3 max = mMaximum * s;
            setExtents(min, max);
        }

        bool intersects(const Sphere& s) const
        {
            return Math::intersects(s, *this); 
        }
        bool intersects(const Plane& p) const
        {
            return Math::intersects(p, *this);
        }
        bool intersects(const Vector3& v) const
        {
            return(v.x >= mMinimum.x  &&  v.x <= mMaximum.x  && 
                v.y >= mMinimum.y  &&  v.y <= mMaximum.y  && 
                v.z >= mMinimum.z  &&  v.z <= mMaximum.z);
        }
        Vector3 getCenter(void) const
        {
            return Vector3((mMaximum + mMinimum) * 0.5);
        }


    };

} // namespace Ogre

#endif

---

Copyright © 2000-2005 by The OGRE Team

This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License.
Last modified Sun Feb 12 12:59:41 2006