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HierMesh.h

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/*
    File:           HierMesh.h

    Function:       Provides a recursively-subdividable mesh of quadrilaterals
                    or triangles.
                    
    Author(s):      Andrew Willmott

    Copyright:      (c) 1997-2000, Andrew Willmott
 */


#ifndef __HierMesh__
#define __HierMesh__

#include "RadMesh.h"

// element capable of hierarchical subdivision...

class HierElem;
typedef Array<HierElem> HierElemList;
typedef HierElem *HierElemPtr;

class HierElem : public NbRadElem
{
public:
                        HierElem();
    virtual             ~HierElem();
    
    virtual Void        SetParent(HierElem &parent);
    virtual HierElem    *New() 
                        { return(new HierElem); };
    
    Bool                HasChildren()
                        { return(child[0] != 0);};
    Void                FreeChildren();

    Void                Draw(Renderer &r);
    virtual Void        DrawLeaf(Renderer &r);
    Void                DrawQuad(Renderer &r, RenderStyle start, Int code,
                                 RadElem *mid);
    Void                DrawTri(Renderer &r, RenderStyle start, Int code, 
                                RadElem *mid);
    Void                ProjQuad(Renderer &r, RenderStyle start, Int code,
                                 RadElem *mid);
    Void                ProjTri(Renderer &r, RenderStyle start, Int code,
                                RadElem *mid);
    
    Void                Reanimate(RadElem *parent);
    Void                ConnectNeighbours();
    Void                Subdivide();

    Void                SetColour(const Colour &c);

    Void                ColourVertices(Int weights[]);
    RadElem             *FindContainer(Coord &coord);
                        // find the leaf element containing this coord.

    Void                CreatePatches(PatchList &patches);
    Void                CreateElements(PatchList &elements,
                                       IndexList &eltParents, Int parent);
    GCLReal             RadError();

    // utilities
    Int                 CalcMidCode(RadElem *mid);
    Void                CollectLeaves(PatchList &leaves);
    Void                SplitElement(Int &numElems, HierElemPtr subElems[5]);
    Void                CorrectLeaves();
        
    // Printing and Parsing
    Void                Print(ostream &s);  
    Void                PrintRec(ostream &s);   
    virtual Void        PrintSelf(ostream &s);  
    Void                Parse(istream &s);  
    virtual Void        ParseSelf(istream &s);  
    Void                PrintID(ostream &s);    // Print code ID.
    StrConst            Name();

    GCLReal             MemoryUse();

    // Accessor functions
    HierElem            *&NbFace(Int i)     
                        { return((HierElem*&) nbFace[i]); };

    // Fields   
    HierElem            *child[4];          // Children, if subdivided...
    HierElem            *parent;    
    Int                 level;      // level of the quadtree.
    UInt32              treeCode;   // used to encode position in quadtree.
};

/*
    Field explanations.
    
    treeCode:   Defines the path from the root of the tree to this node.
                At level i of the tree, (3 & (treeCode >> (2 * (level
                - i)))) is the child to follow.  E.g., treeCode =
                011110 for a level 3 patch: the patch is child 2 of
                child 3 of child 1 of the root.  With 32 bit integers,
                this allows for 16 different levels: the lowest will
                have 1/65535 the side length of the highest, so that
                should be plenty. 
*/

// A grid of HierElems

class HierGrid : public GridBase
{
public:
    Void            CreatePatches(PatchList &patches);
    Void            Draw(Renderer &r);
    Void            ColourVertices(Int weights[]);
    RadElem         *FindContainer(Coord &coord);   
    Void            Reanimate(RadElem *parent);
    
    Void            Print(ostream &s);  
    Void            Parse(istream &s);  
    StrConst        Name();

    RadElemPtr      AddChild(RadElem &quad, Int i, Int j, Int in, Int jn);
                    // override.
    Void            ConnectChildren();

    GCLReal         MemoryUse();

    // Fields
    HierElemList    children;
};

#endif

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