World Closest POint

[kevin]

This examples show the previous rebound demo hacked to also calc and display the closest World impact points to the sprites axis point.

The command that does this is GetWorldClosestPoint.  This command will mostly be useful in AI, or rolling your own custom collision solutions.
 
GetWorldClosestPoint checks a region within a selected world.   Within this region it's looking to find the closest wall point along a walls to your selected point.
 
The demo is running 250 sprites rebounding and checking a 100*100 unit region around them for the closest points.  The function returns a false if nothing is inside the region your selected.  So your character could get some idea of it's environment perhaps... It's up to you..

PlayBASIC Code: [Select]

  LoadIMage "..\..\..\gfx\Bubble_64x64.bmp",1
  Preparefximage 1

   Makebitmapfont 1,$ffffff

   WorldWidth=3000
   WorldHeight=3000

; create a Camera
   CreateCamera 1
   Limitcamera 1,true
   LimitCameraBounds 1,0,0,WorldWidth+1,WorldHeight+1



Restart:

   if GetWorldStatus(2) then deleteworld 2

; Create world
   CreateWorld 2
   CaptureToWorld 2

; ==============================================
; draw a series of boarder line for this world
; ==============================================
   Dot 0,0
  line 0,0,worldwidth,0
  line worldwidth,0,worldwidth,worldheight
  line worldwidth,worldheight,0,worldheight
  line 0,worldheight,0,0

; draw a series of polygon shaped obejct into the world
  for lp=1 to rndrange(80,120)
     xpos#=50+rnd(worldwidth-100)
     zpos#=50+rnd(worldheight-100)
     size=rndrange(30,100)
     angle=rnd(359)
     Make_Convex(rndrange(3,15),xpos#,zpos#,Size,angle)       
  next lp

; Partition The world up into 32 by 32 cells
   PartitionWorld 2,48
   
; Tell PB to return to Immediate drawing mode
   DrawGfxImmediate



; Create A batch of Ball Sprites



   MaxBalls=250

   Type tBalls
  Angle#
  Speed#
  SpriteINdex
   EndType

   Dim Balls(MaxBalls) as tBalls



   For ThisBall=1 to MaxBalls

  Balls(Thisball).speed#=rndrange(1,6)  
  Balls(ThisBall).Angle#=rnd(359)

   ; Create the Sprite
  CreateSprite ThisBall

   ; Assign this sprite image #1
  SpriteImage ThisBall,1

   ; Set the Sprites to Rotated Draw mode
  SpriteDrawMode ThisBall,2

   ; Center the Sprites handle for this image
  Centerspritehandle ThisBall
    
   ; Set up this sprites collision
  SpriteCollision Thisball,True

   ; Set Sprite to have STICKY World Collision
  SpriteCollisionMode ThisBall, 5

   ; Set sprite to collide with world #2
  SpriteCollisionWorld ThisBall,2

  Scale#=0.5+(rnd(100)/100.0)

   ; Set the Size of the Collision Radius
  SpriteCollisionRadius ThisBall,31*Scale#
   
  ScaleSprite THisBall,Scale#
     
     
   ; Randomly POsition this Sprite within the world     
  Repeat    
     X=rnd(Worldwidth)
     y=rnd(WorldHeight)
     positionSpriteXyz ThisBall,X,y,50
     MoveSprite ThisBall,1,1
  until GetSpriteWorldIMpact(ThisBall)=False
   next  
  
    
  
; Force Sprite #1 to higher speed
  Balls(1).speed#=rndrange(3,6)  
;  Balls(1).speed#=1
  positionSpriteXyz 1,X,y,5


; statrt of DO/Loop
   Do
   ; capture to scene and grab the world info
  CaptureToScene
  ClsScene

  
; Move All the sprites
  For ThisBall=1 to MaxBalls
     Angle#=Balls(ThisBall).Angle#
     Speed#=Balls(ThisBall).Speed#
     MoveSprite ThisBall,cosradius(angle#,speed#),sinradius(angle#,speed#)

  ; Set Sprites drw mode to rotated (2)
     SpriteDrawMode ThisBall,2

  ; Check this sprite hit the world during the last move
     If GetSpriteWorldIMpact(ThisBall)=True

    ; Get the Walls Normals   
       nx#=getnormalx#(0)
       ny#=getnormaly#(0)

       WallAngle#=AtanFull(ny#,nx#)
       Angle#=wrapangle(angle#,180)
       Angle#=WrapAngle(WallAngle#,WallAngle#-Angle#)

    ; Set the balls/sprites new direction
       Balls(ThisBall).Angle#=Angle#

    ; Set sprite to AlphaADD with a random colour so it flashes
       SpriteDrawMode ThisBall,2+4096

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