HPAVC/HPAVC CD-ROM.iso/pc/SPX30.ZIP/SPX_DOC.ZIP/SPX_ES.DOC

Text File | 1994-06-13 | 5.3 KB | 151 lines

{ SPX Library Version 3.0  Copyright 1993 Scott D. Ramsay }

 SPX_ES allows a simplified method to load sprites in expanded memory.
 Turbo Vision's Objects unit is required.

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 Before one would load sprites into main memory by doing the following:

   var
     sprites : array[1..MaxSprites] or pointer;
   begin
     loadVSP('myspr.vsp',sprites);      { load the sprites }
     fput(100,100,sprites[1]^,false);   { display the 1st sprite on screen }
   end;

 This unit's method is very similar except first you have to create a global
 expanded memory area to contain all the sprite data for the program.

   const
     maxSize = 200000;   { about 200k of sprites need to be loaded }

   var
     emsGlobalmem : PEmsStack;

   emsGlobalmem := CreateEmsStack(maxSize);

 The function CreateEmsStack allocates expanded memory and returns a pointer
 type for that area.  If the area could not be allocated, then the function
 returns NIL.

 Once the memory area is created, you just load the sprites just like
 before except the sprite array must be of type PEmsDyData.

     var
       sprites : array[1..MaxSprites] or PEmsDyData;
     begin
       StackLoadVSP('myspr.vsp',sprites,emsGlobalmem,false);
       fput(100,100,vp(sprites[1])^,false);   { display the 1st sprite on screen }
     end;


 StackLoadVSP takes two new arguments compared to LoadVSP.

 You pass in the pointer to the expanded memory area and a boolean value.
 If the boolean value is set to TRUE it forces StackLoadVSP to load the
 sprites in regular heap space.  This way you can automate the load:

   StackLoadVSP('myspr.vsp',sprites,emsGlobalmem,(emsGlobalmem=nil));

 If emsGlobalmem could not be allocated, then the sprites are loaded to
 regular memory.

 Notice in the fput procedure we call the function VP.  The function Vp
 accesses the expanded memory and returns an ACTUAL pointer to the sprite
 data.
   This pointer can point to the temporary buffer created by the unit.  By
 default the unit allocates 16k of memory as a temporary buffer.  If you
 want to change the buffer size, call the procedure ChangeTempBuffer.
   The temporary buffer should be the same size or larger than the largest
 sprite loaded.


 At the end of your program you must call the DeleteEmsStack procedure to
 deallocate your ems global memory.  Since exiting a program does not free
 expanded memory.

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function CreateEmsStack(size:longint):PEmsStack;

    Allocates ems global memory.

    SIZE:   Size of the memory to allocate

    Returns: A pointer that describes the allocated memory area or NIL
             if it could not allocate the memory

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procedure DeleteEmsStack(var p:PEmsStack);

    Deallocate ems global memory.

    P: A pointer to the ems memory structure

     At the end of your program you must call this procedure to
 deallocate your ems global memory.  Since exiting a program does not free
 expanded memory.

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function AddEmsStack(var p:PemsStack;var data;size:word):boolean;

    Adds custom data to the ems memory area.

    P:      A pointer to the ems memory structure
    DATA:   Data to copy to ems memory
    SIZE:   Size of the data to copy

    Returns  TRUE if successful, else returns FALSE if memory area is
      full or other error

   Note:
      The actual position of the data  can be found by following:

       ok := AddEmsStack(emsMem,data,dataSize);
       if ok
         then dataposition := emsMem^.flocator-dataSize;

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function ReadEmsStack(var p:PemsStack;position:longint;var data;size:word):boolean;

    Retreives data from ems memory area.

    P:         A pointer to the ems memory structure
    POSITION:  Offset to start reading
    DATA:      Data array to get the ems memory
    SIZE:      Size of the data to copy

    Returns TRUE if successful

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procedure ChangeTempBuffer(size:word);

    Changes the temporary buffer

    SIZE:  Size to change temporary buffer

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procedure StackLoadVSP(fn:string;var buff;var p:PEmsStack;loadlow:boolean);

   Loads sprites to main memory or expanded memory

   FN:      VSP file name
   BUFF:    a PEmsDyData structure.  Can be a single pointer or an array
            of PEmsDyData.
   P:       A pointer to the ems memory structure to place the sprites
   LOADLOW: Set to TRUE to force to load in main memory

   Sets the variable vspcnt to the number of sprites loaded.

   Note:  When the allocated ems memory becomes full or can not be reached,
   the rest of the sprites are loaded to main memory.

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function vp(var p:PEmsDyData):pointer;

   Returns a pointer to the data specfied by the PEmsDyData structure.

   P: A pointer to the ems memory structure

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