Sprite Collision (Pixel Perfect) using Shapes

[kevin]

This example shows how to get pixel perfect collisions using attached vector shapes

requires PlayBASIC V1.075 or above

PlayBASIC Code: [Select]

; ---------------------------------------------------------------------
;       Getting Pixel Perfect Sprite Collision with Vector Shapes 
; ---------------------------------------------------------------------

; Make a Green image
   Cls $00ff00
   GetImage 1,0,0,30,30

; Create Two convex shapes, 
   CreateConvexShape 2,50,5   
   CreateConvexShape 3,40,5   

; Merge Them to create a 'ring'
   Mergeshape 3,2
   ShiftShape 2,50,50

; Create a second image
   CreateImage 2,100,100

; tell PB to redirect all drawing to this image
   RenderToImage 2
; clear it to the BLUE
   cls $ff
; draw the previously created Ring shape to the
   DrawShape 2,0,0,2   

; Randomly Draw 10,000 pixels, but only inside the shape
   lockbuffer  
  For lp =0 to 10000
     x#=rnd(GetImagewidth(2))
     y#=rnd(GetImagewidth(2))
     if pointhitshape(x#,y#,2,0,0) 
    boxc x#,y#,x#+1,y#+1,1,rndrgb()
     endif  
  next   
   unlockbuffer

;  prepare image #2 as FX iamge
   preparefximage 2

; Tell PB to direct all drawing back to the screen
   rendertoscreen

; Assign Shape #2, to Image #2   
   ImageShape 2,2


; Get the Width/height of screen   
   sw=getscreenwidth()
   sh=getscreenHeight()


; Create Sprite #1 (the sprite the user controls in this demo)
   lp=1
  CreateSprite lp
  SpriteIMage lp,1
  SpriteCollision lp,true
  SpriteCollisionClass lp,3
  SpriteCollisionMode lp,0
  PositionSprite LP,Rnd(sw),rnd(sh)
  SpriteCollisionDebug lp,true
  
   
; Create a bunch of randomly positioned sprites 
   MaxSprites=10
   For lp=2 to MaxSprites
    ; CReate this sprite
  CreateSprite lp
    ; Assign Image #2 to this sprite
  SpriteIMage lp,2
    ; Set Sprites Draw Mode to Rotated
  SpriteDRawMode lp,2
    ; Enable Sprite Collision For this sprite
  SpriteCollision lp,true
    ; Enable this Sprites Collsion Class (the class/group it belong too)
  SpriteCollisionClass lp,3
   ; Set this sprites Collision mode to "SHAPE"
   ;  When in Shpe mode, PB uses the current assigned shape of it's image   
  SpriteCollisionMode lp,3

   ; Randomly Enable Sprite Collision Debug Mode      
  SpriteCollisionDebug lp,rnd(true)

   ; Randomly Position this sprite on the screen
  PositionSprite LP,Rnd(sw),rnd(sh)   
   next
  
   
; =====================================
; Start of the Main DO/LOOp
; =====================================

Do
  ; Clear the Screen to black
   Cls 0

; Display a message
   Print "Sprite Collision - Shape Mode"
   Print "Touch the WHITE region in the sprite"

   ; Run through and Turn/Rotate all the sprites
  For lp=2 to MaxSprites
     turnsprite lp,1
  next

  ; Position The users Test Sprite #1, at the mouses position
   PositionSprite 1,mousex(),mousey()

   flashcolour=0  

   ; Check If the Users Sprite Has Hit any of the rotating sprites
  NextSprite=GetFirstSprite()
  repeat
     ThisSprite=SpriteHit(1,NextSprite,%0010)
     if ThisSprite>0
       NextSprite=GetNextSprite(ThisSprite)
       FlashColour=$770000
     endif
  until ThisSprite=0

   ; If there was an impact, Flash the Screen RED
  if flashcolour 
     cls Flashcolour
  else
     print "No Impacts"
  endif
   
   ; Draw all the sprites
  DrawAllSprites   

 ; Show the Screen 
   Sync

; Loop back to the previous DO statement to keep the demo running
loop

 Related Sprite Collision Articles:

 * Walking on Sprite Collision Map
 * Sliding Collision Around A Track
 * Sprite Collision With An Image Mask
 * Circle To Sprite Intersection  
 * Platformer Pixel Collisions Via Ray Casting
  * Manually Doing Pixel Perfect Sprite Collisions (Examples & Video)