Calc Ray Reflections

[kevin]

This is a bit of quick hack to the ray intersection example.  Figured you might like to know how to calc the angle of reflection.   So here it is

PlayBASIC Code: [Select]

   WorldWidth=GetScreenWidth()
   WorldHeight=GetScreenHeight()

; create a Camera
   CreateCamera 1

; 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 10
     xpos#=50+rnd(worldwidth-100)
     zpos#=50+rnd(worldheight-100)
     size=rndrange(30,100)
     angle=rnd(359)
     Make_Convex(rndrange(3,20),xpos#,zpos#,Size,angle)       
  next lp

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


; statrt of DO/Loop
   Do
   ; capture to scene and grab the world info
  CaptureToScene
  ClsScene
  capturedepth 100
  CameraGrabWorld 1,2

  
   ; Get the mouse position
  mx#=mousex()
  my#=mousey()

   ; Cast 150 rays out fomr the mouses position 
  rays=50
  For Ray=1 to Rays
     angle#=(360.0/Rays)*Ray  
     x2#=cosnewvalue(mx#,angle#,300)
     y2#=sinnewvalue(my#,angle#,300)
     if RayIntersectWOrld(2,mx#,my#,x2#,y2#)=true
       x2#=getintersectx#(0)
       y2#=getintersecty#(0)
       nx#=getnormalx#(0)
       ny#=getnormaly#(0)

       capturedepth 10
       circlec x2#,y2#,3,1,rgb(255,0,0)

    ; Calc reflection Direction
       WallAngle#=AtanFull(ny#,nx#)
       RayAngle#=GetAngle2d(x2#,y2#,mx#,my#)
       ReflectAngle#=WrapAngle(WallAngle#,WallAngle#-RayAngle#)
       
       x3#=cosnewvalue(x2#,ReflectAngle#,50)
       y3#=sinnewvalue(y2#,ReflectAngle#,50)
       linec x2#,y2#,x3#,y3#,rgb(255,255,0)

     endif
     capturedepth 20
     line mx#,my#,x2#,y2#

  next

; draw the camera  
  DrawCamera 1

; show the fps rate and continue this loop
  text 0,0,fps()
  sync
   loop
   
 
; This function creates a convex polygon shape

Function Make_Convex(edges,xpos#,ypos#,Size,angle)
  sa#=360.0/edges
  c=rndrgb()
  for lp=0 to edges-1
     a#=angle+(lp*sa#)
     x1#=xpos#+cosRadius(a#,size)
     y1#=ypos#+SinRadius(a#,size)
     if lp<(edges-1)
    a#=angle+((lp+1)*sa#)
     else
    a#=angle
     endif
     x2#=xpos#+cosRadius(a#,size)
     y2#=ypos#+SinRadius(a#,size)
     line x2#,y2#,x1#,y1#
  next lp
endfunction i