Using Cameras to Follow PLayers

[kevin]

Here's an example of how to get the PlayBASIC to display and follow a player.   This example uses the camera system dynamically.  You could also use the world system to store larger worlds of depth sorted elements.  These can be translated to a camera and viewed at will.   So clipping/draw order are no longer the coders issue.

It should also be noted that you mixed any gfx elements together you wish in the scene buffer/camera, so you can draw text/ vector gfx / maps in front of,  behind sprites (or both)..  as everything is drawn according it their z depth in the scene buffer..

Since this examples creates it's own media, Most of code is just setting up the demo..

PlayBASIC Code: [Select]

;---------------------------------------------------------------------; This example shows a method of attaching a Play Basics camera system; To follow a player and control what the viewer sees.  Cameras handle; render order and clipping for you.  So it'll work out, what needs to; displayed and the order to draw things.  ;---------------------------------------------------------------------
; create a Map #1, assign this map 10 possible LEvels  
 ThisMap=1
 CreateMap ThisMap,10
 
  ; ==================================; CReate an image of blocks; ==================================

 Cls 0

 NumberOfBlocks = 10
 BlockSize=32

 For lp=1 To NUmberOfBlocks    
  x=lp*BlockSize
  BoxC  x,0,X+BlockSize-1,BlockSIze,1,RndRGB()
 Next


 TempIMage=55

 GetImage TempImage,0,0,x,BlockSize
 ; Convert the Image created above To Tiles for THISMAP
 MakeMapGFX ThisMap,TempImage,BlockSize,BlockSize,NumberOfBlocks,RGB(0,0,0)

; create a Level #1 in THisMAp.  of size 300 blocks by 200 blocks
 CreateLevel ThisMap,1,300,200
; fill map full of random tiles
  For ylp=0 To GetLevelHeight(ThisMap,1)
    For xlp=0 To GetLevelWidth(ThisMap,1)
      PokeLevelTile ThisMap,1,xlp,ylp,RndRange(0,NUmberOfBlocks)
    Next
  Next



; Create a camera.. It's size will default to the Current surface. in this case; the current surface is the screen.
; by fault cameras have auto CLS enabled.. So you main loop doesn't need to CLS 
 CreateCamera 1

; Limit This camera movement within the bound of the levels

 LimitCamera  1,True
 LimitCameraBounds 1,0,0,GetLevelABSWidth(thisMap,1),GetLevelABSHeight(thisMap,1)

; set players Initial position
 Player_Xpos=GetScreenWidth()/2
 Player_Ypos=GetScreenHeight()/2
  

Do

  ; Redirect ALL GFX output to the SCENE BUFFER
   CaptureToScene
   
  ; Clear the Scene buffer  of any preview gfx elements
   ClsScene

  ; Tell PB to Capture ALL the follow gfx commands and give them scene depth
  ; of 100
    CaptureDepth  100

  ; DRaw the Level Map to the Scene buffer, not the screen.       
    DrawMap ThisMap,1,0,0
  
 
  ; handle some basic Up/down/left/right styled player controls
    If UpKey() Then DEC player_ypos
    If DownKey() Then INC player_ypos
    If LeftKey() Then DEC player_Xpos
    If RightKey() Then INC player_Xpos
   

  ; Set the scene capture depth to 50.. So this object will be drawn in front of 
  ; Anything else
    CaptureDepth  50
    CircleC PLayer_xpos,PLayer_ypos,40,1,$ff00ff


  ; Set the camera to the Players position
    Speed#=50
    Cam_X#=CurveValue(PLayer_Xpos,Cam_X#,speed#)
    Cam_Y#=CurveValue(PLayer_Ypos,Cam_Y#,speed#)
    PositionCamera  1,cam_X#-(GetCameraWidth(1)/2),cam_y#-(GetCameraHeight(1)/2)
  
 ; The objects in the SCENE BUFFER through CAMERA #1
    DrawCamera 1
   

   Sync   
Loop