trpage_managers.h

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/* ************************
   Copyright Terrain Experts Inc.
   Terrain Experts Inc (TERREX) reserves all rights to this source code
   unless otherwise specified in writing by the President of TERREX.
   This copyright may be updated in the future, in which case that version
   supercedes this one.
   -------------------
   Terrex Experts Inc.
   4400 East Broadway #314
   Tucson, AZ  85711
   [e-mail]
   Tel: [phone]
   ************************
   */

#ifndef _trpage_managers_h_
#define _trpage_managers_h_

#include <deque>

/* This file contains class definitions for managers
	that help you keep track of data related to
	paging.  For instance, which tiles to load
	in at any given time and what textures you need
	to read for a given tile.
 */

class trpgPageManager;

// Grid and file location of a tile
struct TileLocationInfo
{
    TileLocationInfo(): x(-1), y(-1), lod(-1) {}
    TileLocationInfo(int gx, int gy, int glod, const trpgwAppAddress& gaddr): x(gx), y(gy), lod(glod), addr(gaddr) {}
    int x, y, lod;
    trpgwAppAddress addr;
};

/* Managed Tiles are used by the trpgPageManager to keep
	track of which tiles are loaded and what textures (and
	models) they need loaded into memory with them.
 */
TX_EXDECL class TX_CLDECL trpgManagedTile
{
    friend class trpgPageManager;
 public:
    trpgManagedTile(void);

    // Called to clear any info out of this tile
    void Reset(void);

    /* Call this when you hit a tile header in your own
       Scene parser callback.  The managed tile
       can then keep track of which textures and models 
       go with this tile.
    */
    bool ParseTileHeader(trpgReadBuffer &);

    // Check if the tile is loaded (e.g. the header read in)
    bool IsLoaded(void);

    /* Set the tile location.  This resets any internal
       state we may be keeping.
    */
    bool SetTileLoc(int x,int y,int lod);
    // Get the tile location
    bool GetTileLoc(int &x,int &y,int &lod) const;

    // In version 2.1 we no longer have the tile table to
    // find the tiles, only by traversing the parent can it be
    // found. So when we have this info, this is were to save it. 
    void SetTileAddress(const trpgwAppAddress& gAddr);
    void SetTileAddress(int32 file, int32 offset);
    const trpgwAppAddress& GetTileAddress() const;



    // Return a pointer to the tile header
    const trpgTileHeader *GetTileHead(void);

    /* Return a pointer to the list of locally defined
       materials.  As soon as the tile header is read by
       ParseTileHeader (which you call) you'll want to get
       this list and load the pageable textures.  You can
       use SetMatData to keep track of our internal texture
       structures.
    */
    const std::vector<trpgLocalMaterial> *GetLocMatList(void) const;

    /* Returns a pointer to a single local material, if within
       the valid range of local materials for this tile.
    */
    const trpgLocalMaterial *GetLocMaterial(int id) const;

    /* Set Local Data for managed tile.  The local data would
       probably be a pointer to the top of the scene graph you're
       using to represent just this tile.
    */
    void SetLocalData(void *);

    /* Returns the local data you set with SetLocalData.
     */
    void *GetLocalData(void) const;

    /* Associates a void * with one of the materials referenced
       within this tile.  The idea here is that you'll want
       to load the texture for a given local material and then
       pass your own internal texture structure into here as
       a void *.  That way, the trpgPageManager will keep track
       of which textures you should unload when this tile goes
       out of range.
    */
    bool SetMatData(int id,void *);

    /* Gets the void * data you associated with a given local
       material index.  See SetMatData for more information.
    */
    void *GetMatData(int id) const;

    /* Add Group ID to this tile.  This is called by the page
       manager to keep track of which group IDs belong to this tile.
       We use this information to NULL out the appropriate positions
       in the group map help by the page manager.
    */
    void AddGroupID(int id);

    /* Retrieve the list of group IDs for this tile.
     */
    const std::vector<int> *GetGroupIDs(void) const;

    /* Print the current status and information about this managed
       Tile.
    */
    void Print(trpgPrintBuffer &);

    // Children info, will throw exception if child index is out of bound
    unsigned int GetNbChildren() const
    {
	return (unsigned int)childLocationInfo.size();
    }
    bool SetChildLocationInfo(int childIdx, int x, int y, const trpgwAppAddress& addr);
    bool SetChildLocationInfo(int childIdx, const TileLocationInfo& info);
    const TileLocationInfo& GetChildLocationInfo(int childIdx) const;
    bool GetChildTileLoc(int childIdx, int &x,int &y,int &lod) const;
    const trpgwAppAddress& GetChildTileAddress(int childIdx) const;
   
  
 protected:
    // Set if a tile is currently loaded
    bool isLoaded;
    // Tile location info
    TileLocationInfo location;

    // Tile Header associated with this tile
    trpgTileHeader tileHead;
    // Data to keep associated with each individual local material index
    std::vector<void *> localMatData;
    // Used to keep track of group IDs in this tile
    std::vector<int> groupIDs;
    // Local data (probably the top of the local scene graph)
    void *localData;

    // What are the children: this to be used for version 2.1 and up.
    // Both vector should have the same size
    std::vector<TileLocationInfo> childLocationInfo;

    // Note: Should do models too if anyone wanted them.
};

/* The Page Manager is a helper class that can be used
   to keep track of: (1) which tiles need to be loaded
   into memory for a given viewer position, (2) which tiles
   are currently loaded and (3) which tiles need to be unloaded
   when the viewer position moves.  The tile list this
   class generates is guaranteed to be in the right order
   for loading.  You would use this class if you're implementing
   a TerraPage reader for your visual run-time system.
*/
TX_EXDECL class TX_CLDECL trpgPageManager
{
 public:
    trpgPageManager(void);
    virtual ~trpgPageManager(void);

    // Initialize with an archive
    virtual void Init(trpgr_Archive *);
    virtual void Init(trpgr_Archive *inArch, int maxLod);

    /* Set Paging Distance
       This is the extra distance outside the visible range
       we want to page.  The defaults will be valid.  You would
       set this if you want to pull tiles in earlier.  Be sure
       to call it before you call Init(), however.
    */
    virtual bool SetPageDistFactor(double);

    /* Updates the current location for paging purposes.
       Returns true if any load or unloads need to happen.
    */
    virtual bool SetLocation(trpg2dPoint &);

    /* Get next tile to load.
       The paging manager is keeping track of which tiles
       need to be loaded and in what order.  This method
       returns a pointer to the next one.  The user is
       expected to call AckLoad() after the tile is loaded.
    */
    virtual trpgManagedTile *GetNextLoad(void);
    /*  Acknowledge Tile Load.
	This method should be called when a tile has been
	loaded by the caller.  This method is used in conjunction
	with GetNextLoad().

	Version 2.1 and over supports variable lod so that we cannot know
	from the tile table if a tile exist or not. So to manage this
	the user must parse the loaded tile and extract its list of children
	and pass it on to AckLoad() which will add to the  appropriate lod list 
	the children info. If this is not done then only lod 0 will be pageable.
    */
 
    virtual void AckLoad(std::vector<TileLocationInfo> const& children);

    // Using this call with version 2.1 and over will only page lod 0 tiles
    virtual void AckLoad();

    /* Add Group ID to map.
       This should be called when the user encounters a group-like
       object while processing the scene graph data from a tile.
       The groupId is given by TerraPage and the data should be
       the corresponding group object that the user creates in
       their own scenegraph toolkit.  This information can then
       be retrieved later by GetGroupData().
    */
    virtual void AddGroupID(trpgManagedTile *,int groupID,void *data);

    /* Get Group Data fetches the data cached by the user and
       associated with the given groupID.  This would be used in
       conjunction with trpgAttach nodes to implement geometry paging.
    */
    virtual void *GetGroupData(int groupID);

    /* Get next tile to unload.
       The paging manager keeps track of which tiles need
       to be unloaded based on a change of location.  It's
       best if you unload tiles before loading them, but
       that's really up to you.
    */
    virtual trpgManagedTile *GetNextUnload(void);
    /* Acknowledge a tile unload.
       You should call this after you've "unloaded" a tile
       and all its associated textures.
    */
    virtual void AckUnload(void);


    /* Stop paging entirely.  Call this right before you want to
       shut down paging.  Everything active will wind up on the
       unload lists.  Then you can unload those tiles and move on.
    */
    virtual bool Stop(void);

    // Print current status and content information
    virtual void Print(trpgPrintBuffer &);