UnderwareDESIGN

  PlayBASIC LIVE: Render (Event) Stacks  More Flexible Main Loop (2017-05-28)

Welcome...   This video looks at alternative ways we can set up the so called 'main loop' in our games in a more flexible fashion.  What we can do is separate our rendering / processing / logic code up into a series of events that need to performed to build each frame.   You can think of this as a 'to do'  or 'job' list. This allows us to change what jobs (and order) need to be performed,  as well allowing us to control this externally.  So your level editing tool/person can tweak things themselves without the programmer having to hard code every changing into your main loop(s)..





 Example:

[pbcode]


      setfps 20

      Dim EventStack(255)
      EventStack(10) = 100      ; CLS
      EventStack(20) = 200      ; Draw Backdrop
      EventStack(30) = 500      ; Draw Sprites
      EventStack(40) = 1000      ; Call SYNC
      

      do
         
         For Lp=0 to 255
            
            Select EventStack(lp)

                  case 100
                        Event_Cls()      
         
                  case 200
                        Event_drawbackdrop()
                     
                  case 201
                        Event_drawbackdrop2()

                  case 500
                        drawsprites()

                  case 1000
                        Event_SYNC()      

            endselect
               
         next
                     

         IF FUNCTIONkEYS(1)
               EventStack(25) = 201   
         ELSE
               EventStack(25) = 0   
         ENDIF   
         
         
      loop






function Event_Cls()
               cls rgb(200,0,0)
EndFunction
   
function Event_Sync()
               sync
EndFunction


function Event_drawbackdrop()
            shadebox 100,100,700,500,$11223344, $ff00ff, $00ff00,$00ff80
endfunction


function Event_drawbackdrop2()
         circleC 0,0,100,true,$445566
endfunction




function drawsprites()

         randomize 57

         static scrollX
         ScrollX=mod(ScrollX-1,800)

         for lp =0 to 10
                  x=scrollX+rnd(800)
                  y=rnd(600)
                  col=rndrgb()
                  circlec x,y,32,true,col
            
         next            
            
      
endfunction


[/pbcode]


  Related To:

      - Execution Stack Example (http://www.underwaredesign.com/forums/index.php?topic=4282.0)
      - Triggers Time Based Model (http://www.underwaredesign.com/forums/index.php?topic=3684.0)
      - Abstraction Layer (http://www.underwaredesign.com/forums/index.php?topic=3611.0)
      - Timer Based Life Spans (http://www.underwaredesign.com/forums/index.php?topic=3106.0)
      - Action GUI (http://www.underwaredesign.com/forums/index.php?topic=3899.0)