HGRID_2D.cc

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//Copyright (c) 2013-2014, The MercuryDPM Developers Team. All rights reserved.
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#include "HGRID_2D.h"

void HGRID_2D::CheckCell_current(int x, int y, int l, HGrid *grid)
{
    int bucket = grid->ComputeHashBucketIndex(x,y,l);
    if (grid->bucketIsChecked[bucket]) { return; }
    BaseParticle* p1 = grid->objectBucket[bucket];

    while (p1!=NULL)
    {
        BaseParticle* p2 = p1->get_HGRID_NextObject();
        while (p2!=NULL)
        {
            //Check if the particle realy is in the target cell (i.e. no hashing error has occured)
            if ((p1->get_HGRID_x() == p2->get_HGRID_x()) && (p1->get_HGRID_y() == p2->get_HGRID_y()) && (p1->get_HGRID_Level() == p2->get_HGRID_Level()))
            {
                compute_internal_forces(p1,p2);
            }
            p2 = p2->get_HGRID_NextObject();
        }
        p1 = p1->get_HGRID_NextObject();
    }
    grid->bucketIsChecked[bucket] = true;
}

void HGRID_2D::CheckCell(int x, int y, int l, BaseParticle *obj, HGrid *grid)
{
    int bucket = grid->ComputeHashBucketIndex(x,y,l);

    if ((obj->get_HGRID_x() == x) && (obj->get_HGRID_y() == y) && (obj->get_HGRID_Level() == l)) {return; }

    // Loop through all objects in the bucket to find nearby objects
    BaseParticle *p = grid->objectBucket[bucket];

    while (p!=NULL)
    {
        //Check if the particle realy is in the target cell (i.e. no hashing error has occured)
        if ((p->get_HGRID_x() == x) && (p->get_HGRID_y() == y) && (p->get_HGRID_Level() == l)) 
        {
            compute_internal_forces(obj,p);
        }
        p = p->get_HGRID_NextObject();
    }
}

void HGRID_2D::CheckObjAgainstGrid(HGrid *grid, BaseParticle *obj)
{
    unsigned int startLevel     = obj->get_HGRID_Level();
    
    int x, y;
    Mdouble inv_size;
    
    switch(getHGridMethod())
    {
    case BOTTOMUP:
        {   
            int occupiedLevelsMask  = grid->occupiedLevelsMask >> obj->get_HGRID_Level();
            for (unsigned int level = startLevel; level < grid->cellSizes_.size(); occupiedLevelsMask >>= 1, level++) 
            {
                // If no objects in rest of grid, stop now
                if (occupiedLevelsMask == 0) break;

                // If no objects at this level, go on to the next level
                if ((occupiedLevelsMask & 1) == 0) continue;
                
                if (level == startLevel)    
                {
                    x = obj->get_HGRID_x();
                    y = obj->get_HGRID_y();
                    CheckCell_current(x, y, level, grid);
                    CheckCell(x  , y+1, level, obj, grid);
                    CheckCell(x+1, y-1, level, obj, grid);          
                    CheckCell(x+1, y  , level, obj, grid);
                    CheckCell(x+1, y+1, level, obj, grid);
                } 
                else
                {
                    int xs,ys,xe,ye;
                    inv_size = grid->invCellSizes_[level];
                    xs = (int) floor((obj->get_Position().X-obj->get_InteractionRadius()) * inv_size -0.5);
                    xe = (int) floor((obj->get_Position().X+obj->get_InteractionRadius()) * inv_size +0.5);
                    ys = (int) floor((obj->get_Position().Y-obj->get_InteractionRadius()) * inv_size -0.5);
                    ye = (int) floor((obj->get_Position().Y+obj->get_InteractionRadius()) * inv_size +0.5);
                    for(x=xs;x<=xe;x++)
                    {
                        for(y=ys;y<=ye;y++)
                        {
                            CheckCell(x,y,level,obj,grid);
                        }
                    }
                }
            }
        break;
        }
    case TOPDOWN:
        {   
            int occupiedLevelsMask  = grid->occupiedLevelsMask;
            for (unsigned int level = 0; level <= startLevel; occupiedLevelsMask >>= 1, level++) 
            {
                // If no objects in rest of grid, stop now
                if (occupiedLevelsMask == 0) break;

                // If no objects at this level, go on to the next level
                if ((occupiedLevelsMask & 1) == 0) continue;
                
                if (level == startLevel)    
                {
                    x = obj->get_HGRID_x();
                    y = obj->get_HGRID_y();
                    CheckCell_current(x, y, level, grid);
                    CheckCell(x  , y+1, level, obj, grid);
                    CheckCell(x+1, y-1, level, obj, grid);          
                    CheckCell(x+1, y  , level, obj, grid);
                    CheckCell(x+1, y+1, level, obj, grid);
                } 
                else
                {
                    int xs,ys,xe,ye;
                    inv_size = grid->invCellSizes_[level];
                    xs = (int) floor((obj->get_Position().X-obj->get_InteractionRadius()) * inv_size-0.5);
                    xe = (int) floor((obj->get_Position().X+obj->get_InteractionRadius()) * inv_size+0.5);
                    ys = (int) floor((obj->get_Position().Y-obj->get_InteractionRadius()) * inv_size-0.5);
                    ye = (int) floor((obj->get_Position().Y+obj->get_InteractionRadius()) * inv_size+0.5);
                    for(x=xs;x<=xe;x++)
                    {
                        for(y=ys;y<=ye;y++)
                        {
                            CheckCell(x,y,level,obj,grid);
                        }
                    }       
                }
            }
        break;
        }
    }    
}


void HGRID_2D::HGRID_UpdateParticleInHgrid(BaseParticle *obj)
{
    int l = obj->get_HGRID_Level();
    Mdouble inv_size = grid->invCellSizes_[l];

    int x=(int)floor(obj->get_Position().X * inv_size);
    int y=(int)floor(obj->get_Position().Y * inv_size);

#ifdef ContactListHgrid
    if(obj->get_HGRID_x()!=x||obj->get_HGRID_y()!=y||obj->get_PeriodicFromParticle())
    {
        if(!obj->get_PeriodicFromParticle())
        {
            int bucket = grid->ComputeHashBucketIndex(x, y, l);
                    
            //First the object has to be removed
            HGRID_RemoveParticleFromHgrid(obj);

            //Also remove all contact associated with it
            getPossibleContactList().remove_ParticlePosibleContacts(obj);
            
            //And now reinserted
            obj->set_HGRID_NextObject(grid->objectBucket[bucket]);
            if(grid->objectBucket[bucket])
                grid->objectBucket[bucket]->set_HGRID_PrevObject(obj);
            obj->set_HGRID_PrevObject(0);
            grid->objectBucket[bucket] = obj;
        }
        
        obj->set_HGRID_x(x);
        obj->set_HGRID_y(y);
        
        InsertObjAgainstGrid(grid, obj);
    }
#else
    int bucket = grid->ComputeHashBucketIndex(x, y, l);

    obj->set_HGRID_NextObject(grid->objectBucket[bucket]);
    if(grid->objectBucket[bucket])
        grid->objectBucket[bucket]->set_HGRID_PrevObject(obj);
    obj->set_HGRID_PrevObject(0);
    grid->objectBucket[bucket] = obj;

    obj->set_HGRID_x(x);
    obj->set_HGRID_y(y);
#endif
}

void HGRID_2D::HGRID_RemoveParticleFromHgrid(BaseParticle *obj)
{
    int bucket = grid->ComputeHashBucketIndex(obj->get_HGRID_x(),obj->get_HGRID_y(), obj->get_HGRID_Level());
    if(obj->get_HGRID_PrevObject())
        obj->get_HGRID_PrevObject()->set_HGRID_NextObject(obj->get_HGRID_NextObject());
    else
        if(grid->objectBucket[bucket]==obj)
            grid->objectBucket[bucket]=obj->get_HGRID_NextObject();
        
    if(obj->get_HGRID_NextObject())
        obj->get_HGRID_NextObject()->set_HGRID_PrevObject(obj->get_HGRID_PrevObject()); 
}

bool HGRID_2D::TestCell(int x, int y, int l, BaseParticle *obj, HGrid *grid)
{
    bool Test = true;
        
    // Loop through all objects in the bucket to find nearby objects
    int bucket = grid->ComputeHashBucketIndex(x,y,l);
    BaseParticle *p = grid->objectBucket[bucket];
    
    while (Test && p!=NULL)
    {
        if ((p->get_HGRID_x() == x) && (p->get_HGRID_y() == y) && (p->get_HGRID_Level() == l)) 
        {
            Test = Test && TestObject(obj,p);       
        }
        p = p->get_HGRID_NextObject();
    }

    return Test;
}

bool HGRID_2D::TestObjAgainstGrid(HGrid *grid, BaseParticle *obj)
{

    bool Test = true;
    
    int x, y;
    Mdouble inv_size;
    int occupiedLevelsMask = grid->occupiedLevelsMask;
    
    for (unsigned int level = 0; level < grid->cellSizes_.size() && Test; occupiedLevelsMask >>= 1, level++) 
    {
        // If no objects in rest of grid, stop now
        if (occupiedLevelsMask == 0) break;
        
        // If no objects at this level, go on to the next level
        if ((occupiedLevelsMask & 1) == 0) continue;
        
        // Treat level as a third dimension coordinate
        inv_size = grid->invCellSizes_[level];
        
        x = (int)floor(obj->get_Position().X * inv_size);
        y = (int)floor(obj->get_Position().Y * inv_size);

        Test = Test 
                && TestCell(x  , y  , level, obj, grid)
                && TestCell(x  , y-1, level, obj, grid)
                && TestCell(x  , y+1, level, obj, grid)
                && TestCell(x-1, y  , level, obj, grid)
                && TestCell(x+1, y  , level, obj, grid)
                && TestCell(x-1, y-1, level, obj, grid)
                && TestCell(x-1, y+1, level, obj, grid)
                && TestCell(x+1, y-1, level, obj, grid)
                && TestCell(x+1, y+1, level, obj, grid);
    } //end for level

    return Test;
} 

#ifdef ContactListHgrid
void HGRID_2D::InsertCell(int x, int y, int l, BaseParticle *obj, HGrid *grid)
{
    // Loop through all objects in the bucket to find nearby objects
    int bucket = grid->ComputeHashBucketIndex(x,y,l);
    BaseParticle *p = grid->objectBucket[bucket];
    
    while (p!=NULL)
    {
        if ((p->get_HGRID_x() == x) && (p->get_HGRID_y() == y) && (p->get_HGRID_Level() == l) && (obj!=p)) 
        {
            getPossibleContactList().add_PossibleContact(obj,p);
        }
        p = p->get_HGRID_NextObject();
    }
}

void HGRID_2D::InsertObjAgainstGrid(HGrid *grid, BaseParticle *obj)
{
    int xmin,xmax;
    int ymin,ymax;
    Mdouble inv_size;
    int occupiedLevelsMask = grid->occupiedLevelsMask;
    
    inv_size=grid->inv_size[obj->get_HGRID_Level()];
    
    double ownXMin=(obj->get_HGRID_x()-0.5)/inv_size;
    double ownXMax=(obj->get_HGRID_x()+1.5)/inv_size;
    double ownYMin=(obj->get_HGRID_y()-0.5)/inv_size;
    double ownYMax=(obj->get_HGRID_y()+1.5)/inv_size;
    
    for (int level = 0; level < grid->HGRID_MAX_LEVELS; occupiedLevelsMask >>= 1, level++) 
    {
        // If no objects in rest of grid, stop now
        if (occupiedLevelsMask == 0) break;
        
        // If no objects at this level, go on to the next level
        if ((occupiedLevelsMask & 1) == 0) continue;
        
        // Treat level as a third dimension coordinate
        inv_size = grid->inv_size[level];
        
        xmin=(int)floor(ownXMin*inv_size-0.5);
        xmax=(int)floor(ownXMax*inv_size+0.5);
        ymin=(int)floor(ownYMin*inv_size-0.5);
        ymax=(int)floor(ownYMax*inv_size+0.5);
        
        for(int i=xmin;i<=xmax;i++)
            for(int j=ymin;j<=ymax;j++)
                InsertCell(i, j, level, obj, grid); 
    } //end for level
}
#endif