Managing Arrays - 2D Grids

[kevin]

  Managing Arrays - 2D Grids

      This example uses the power of returning arrays from functions/psubs to dynamical create and manage various 2D Arrays.   For the purpose of the example,  each grid is has it's own position, two colour palette, grid block size as well as width and height.   Each grid's properties are stored in a typed array, the actual map/grid data stored in a dynamically created array.    So the parent tgrid structure doesn't contain the grid data, just the handle of the array.  We can access the array's data through an array stub via MakeArray.    So we make the array (whatever you wanna call it/whatever type you need) then assign the handle to the stub.   The stub now points and acts upon the Handled array.   So for all intensive purposes it becomes the array.    

PlayBASIC Code: [Select]

   Type tGrid
         Xpos#
         Ypos#
         BlockSize   
         Buffer            
         
         Palette(1)   
         DeleteTime

   EndType

   Dim Grid(0) as tGrid
   
   setfps 30
   

   Do
      cls 

      if SpaceKey()=true
      
         Width=rndrange(10,20)
         Height=rndrange(10,20)
         Index=NewGrid(Width,Height)

         POsitionGrid(index,rnd(800),rnd(600))
         flushkeys         
      endif 
   
      DrawAllGRids()   
      
   
      Sync
   loop
   

   

Psub NewGrid(Width,Height)

      Index=GetFreeCell(Grid())

      Grid(index) = New tGrid      
      grid(index).BlockSize=rndrange(8,32)

      Grid(index).Buffer=Alloc2DArray(Width,Height)
      
      Grid(index).Palette(0)=rndrgb()
      Grid(index).Palette(1)=rndrgb()
      
      Grid(Index).DeleteTime=Timer()+rndrange(500,1000)

EndPsub Index





Psub DeleteGRid(Index)
   if ValidGrid(index)

         MAkeArray Array()
         Array()=Grid(index).buffer
         undim Array()
         Grid(index)= Null
         
   endif
EndPsub

Psub POsitionGrid(index,Xpos#,Ypos#)

   if ValidGrid(index)
      grid(Index).xpos=Xpos#
      grid(Index).ypos=Ypos#
   
   endif

EndPsub



Psub ValidGrid(index)
   Status=false
   if Index>0 
      if Index<=GetArrayElements(Grid())
            Status=Grid(index)<>0
      endif
   endif      
EndPsub Status




psub DrawAllGRids()

   currenttime=timer()

   For lp =1 to GetArrayElements(Grid())
         if Grid(lp)
                  
                  if CurrentTime<=grid(lp).DeleteTime
                     drawgrid(lp)

                  else
                     deletegrid(lp)                  
                  
                  endif
                  
                  
         endif
   next

Endpsub




Psub DrawGrid(Index)


   CurrentTime=Timer()
   MakeArray Array()
   
   if ValidGrid(index)
         Array()=Grid(Index).Buffer

         Width=GetArrayElements(Array())
         Height=GetArrayElements(Array(),2)

                  Xpos=Grid(index).Xpos
                  Ypos=Grid(index).Ypos

                  BlockSize=grid(index).blockSize

                  RowToggle=0

                  lockbuffer
                  For Ylp=0 to Height
                     ScreenY1=Ypos+(Ylp*BlockSize)   
                     ScreenY2=Ypos+((Ylp+1)*BlockSize)   
                     RowToggle=1-RowToggle
                     Toggle=RowToggle

                     For Xlp=0 to Width
                  
                        ScreenX1=Xpos+(Xlp*BlockSize)   
                        ScreenX2=ScreenX1+BlockSize   
                        Toggle=1-Toggle

Login required to view complete source code

  Related Articles

   * Using 1D arrays as a 2D array
   * Ideas for Managing A Character Inventory (Typed Arrays)
   * Dynamic Array Allocation
   * Dynamically Creating Objects From Data Statements
   * Quick Sort Typed Arrays
   * Swapping Typed Cells In Arrays