source: GTP/trunk/Lib/Vis/OnlineCullingCHC/OGRE/src/OgreBvHierarchyCamera.cpp @ 1320

/*
-----------------------------------------------------------------------------
This source file is part of the GameTools Project
http://www.gametools.org

Author: Martin Szydlowski
-----------------------------------------------------------------------------
*/

#include "OgreBvHierarchyCamera.h"

namespace Ogre
{

BvHierarchyCamera::BvHierarchyCamera(const String& name, SceneManager *sm):
Camera(name, sm)
{

}

BvHierarchyCamera::~BvHierarchyCamera()
{

}

//-----------------------------------------------------------------------
// enhanced vis calculation - borrowed from OctreeCamera - indicate when entire box inside the frustum
BvHierarchyCamera::NodeVisibility BvHierarchyCamera::getVisibilityEnhanced(const AxisAlignedBox& box) const
{
        ++ mNumVisQueries;
        
        // Null boxes always invisible
        if ( box.isNull() )
                return BVHNV_NONE;

        // Make any pending updates to the calculated frustum planes
        updateFrustumPlanes();

        // Get corners of the box
        const Vector3* pCorners = box.getAllCorners();

        // For each plane, see if all points are on the negative side
        // If so, object is not visible.
        // If one or more are, it's partial.
        // If all aren't, full

        int corners[ 8 ] = {0, 4, 3, 5, 2, 6, 1, 7};

        int planes[ 6 ] = {FRUSTUM_PLANE_TOP, FRUSTUM_PLANE_BOTTOM,
                FRUSTUM_PLANE_LEFT, FRUSTUM_PLANE_RIGHT,
                FRUSTUM_PLANE_FAR, FRUSTUM_PLANE_NEAR };

        bool all_inside = true;

        for ( int plane = 0; plane < 6; ++plane )
        {

                // Skip far plane if infinite view frustum
                if (mFarDist == 0 && planes[ plane ] == FRUSTUM_PLANE_FAR)
                        continue;

                bool all_outside = true;

                float distance = 0;

                for ( int corner = 0; corner < 8; ++corner )
                {
                        distance = mFrustumPlanes[ planes[ plane ] ].getDistance( pCorners[ corners[ corner ] ] );
                        all_outside = all_outside && ( distance < 0 );
                        all_inside = all_inside && ( distance >= 0 );

                        if ( !all_outside && !all_inside )
                                break;
                }

                if ( all_outside )
                        return BVHNV_NONE;
        }

        if ( all_inside )
                return BVHNV_FULL;
        else
                return BVHNV_PART;
}

//-----------------------------------------------------------------------
// simple vis calculation - does the same as isVisible, only different return type
BvHierarchyCamera::NodeVisibility BvHierarchyCamera::getVisibilitySimple(const AxisAlignedBox& box) const
{
        ++ mNumVisQueries;

        // dummy
        FrustumPlane* culledBy = 0;
        if (mCullFrustum)
        {
                return mCullFrustum->isVisible(box, culledBy) ? BVHNV_PART : BVHNV_NONE;
        }
        else
        {
                return Frustum::isVisible(box, culledBy) ? BVHNV_PART : BVHNV_NONE;
        }
}

} // namespace Ogre