1 reply to this topic

[Pushapjit]

An exception 'System.NullReferenceException' has occured in the classifyPoly() code

// Loop round each of the vertices

    for( int i = 0; i < Poly->nNumberOfVertices; ++i ) 

following is the full code for buildbsptree() and classifyPoly() function. classifyPoly() function is called from buildbsptree() function

//-----------------------------------------------------------------------------

// Name : buildBspTree  (Recursive)

// Desc : Performs the actual BSP Compile when fed a polygon linked list and

//        a valid node (first time this is called this will be the parent of

//        the polygon linked list, and an already created root node.

//-----------------------------------------------------------------------------

void CMyD3DApplication::buildBspTree( NODE *CurrentNode,POLYGON *PolyList )

{

    POLYGON *polyTest    = NULL;

    POLYGON *FrontList   = NULL;

    POLYGON *BackList    = NULL;

    POLYGON *NextPolygon = NULL;

    POLYGON *FrontSplit  = NULL;

    POLYGON *BackSplit   = NULL;


    // Select the best splitter for this set of polygons

    CurrentNode->Splitter = selectBestSplitter(PolyList);

    

    polyTest = PolyList;


    // Begin the loop until we reach the end of the linked list.

    while( polyTest != NULL ) 

    {

        // Remember to store because polytest->Next could be altered

        NextPolygon = polyTest->Next;


        if( polyTest != CurrentNode->Splitter ) 

        {

            switch( classifyPoly( CurrentNode->Splitter, polyTest ) ) 

            {

                case POINTPOSITION_FRONT:

                    polyTest->Next = FrontList;

                    FrontList      = polyTest;      

                    break;


                case POINTPOSITION_BACK:

                    polyTest->Next = BackList;

                    BackList       = polyTest;  

                    break;


                case POINTPOSITION_SPANNING:

                    // Allocate two new polys for this fragment

                    FrontSplit = new POLYGON;

                    BackSplit  = new POLYGON;

                    ZeroMemory(FrontSplit,sizeof(POLYGON));

                    ZeroMemory(BackSplit,sizeof(POLYGON));

                    // Split the poly into two fragments

                    splitPolygon( polyTest, CurrentNode->Splitter, FrontSplit, BackSplit);

                    // Delete the original poly

                    delete polyTest;

                    // Reshuffle linked list

                    FrontSplit->Next = FrontList;

                    FrontList        = FrontSplit;

                    BackSplit->Next  = BackList;

                    BackList         = BackSplit;

                    break;


                default:

                    break;

            }

        }


        // Move onto the next polygon

        polyTest = NextPolygon;

    }


    // If there is nothing left in the front list then add an empty node here, 

    // otherwise carry on building the tree

    if( FrontList == NULL ) 

    {

        NODE *leafnode      = new NODE;

        ZeroMemory(leafnode,sizeof(leafnode));

        leafnode->bIsLeaf   = true;

        leafnode->bIsSolid  = false;    

        leafnode->Front     = NULL;

        leafnode->Back      = NULL;

        leafnode->Splitter  = NULL;

        CurrentNode->Front  = leafnode;

    } 

    else 

    {

        NODE *newnode       = new NODE;

        ZeroMemory(newnode,sizeof(newnode));

        newnode->bIsLeaf    = false;

        CurrentNode->Front  = newnode;

        buildBspTree(newnode,FrontList);

    } // End if frontlist is empty


    // If there is nothing left in the back list then add a solid node here, 

    // otherwise carry on building the tree

    if( BackList == NULL ) 

    {

        NODE *leafnode      = new NODE;

        ZeroMemory(leafnode,sizeof(leafnode));

        leafnode->bIsLeaf   = true;

        leafnode->bIsSolid  = true;

        leafnode->Front     = NULL;

        leafnode->Back      = NULL;

        leafnode->Splitter  = NULL;

        CurrentNode->Back   = leafnode;;

    }

    else 

    {

        NODE *newnode     = new NODE;

        ZeroMemory(newnode,sizeof(newnode));

        newnode->bIsLeaf  = false;

        CurrentNode->Back = newnode;

        buildBspTree(newnode,BackList);

    }

}





//-----------------------------------------------------------------------------

// Name : classifyPoly()

// Desc : Classifies a polygon against the plane passed

//-----------------------------------------------------------------------------

int CMyD3DApplication::classifyPoly( POLYGON *Plane, POLYGON *Poly )

{

    D3DXVECTOR3 *vec1 = (D3DXVECTOR3*)&Plane->VertexList[0];

    int Infront = 0;

    int Behind  = 0;

    int OnPlane = 0;

    float result;

    

    // Loop round each of the vertices

    for( int i = 0; i < Poly->nNumberOfVertices; ++i ) 

    {

        D3DXVECTOR3 *vec2     = (D3DXVECTOR3 *)&Poly->VertexList[i];

        D3DXVECTOR3 Direction = (*vec1) - (*vec2);

        

        result = D3DXVec3Dot(&Direction,&Plane->Normal);

        // Tally up the position of each vertex

        if( result > 0.001f ) 

            ++Behind;

        else if( result < -0.001f ) 

            ++Infront; 

        else 

        {

            ++OnPlane;

            ++Infront;

            ++Behind;

        }

    }


    if( OnPlane == Poly->nNumberOfVertices )

        return POINTPOSITION_FRONT;


    if( Behind  == Poly->nNumberOfVertices )

        return POINTPOSITION_BACK;


    if( Infront == Poly->nNumberOfVertices )

        return POINTPOSITION_FRONT;


    return POINTPOSITION_SPANNING;

}

[pater]

Did you look with the debugger at your code? Which variable is NULL at the time of crash?