Open in online IDEGraphics 800,600,32,2 SetBuffer BackBuffer() SeedRnd MilliSecs() Type ball Field x,y Field xv,yv End Type Type wall Field x,y,x2,y2,ox,oy Field wd,hg,placed1,placed2,axis ;(1 for x,2 for y) End Type Setup() While Not KeyDown(1) UpdateBalls() UpdateWalls() Draw() Wend End Function Setup() b.ball=New ball b\x=Rand(100,700) b\y=Rand(100,500) b\xv=Rand(-5,5) b\yv=Rand(-5,5) End Function Function UpdateBalls() For b.ball=Each ball b\x=b\x+b\xv b\y=b\y+b\yv If b\x>=800 Then b\xv=-b\xv If b\x<=0 Then b\xv=-b\xv If b\y>=600 Then b\yv=-b\yv If b\y<=0 Then b\yv=-b\yv For w.wall=Each wall If LineOverlapCircle(w\x,w\y,w\x2,w\y2,b\x,b\y,5)=1 Then If w\placed1=1 And w\placed2=1 Then b\xv=-b\xv b\yv=-b\yv Else Delete w Return EndIf EndIf Next Next End Function Function UpdateWalls() p=GetMouse() CheckWallCollisions() For w.wall=Each wall If w\placed1=0 And w\placed2=0 If w\axis=1 Then If Not w\x2>800 And w\placed2=0 Then w\x2=w\x2+2 If Not w\x<0 And w\placed1=0 Then w\x=w\x-2 If w\x<0 And w\x2>800 Then w\placed1=1:w\placed2=1 Else If Not w\y2>600 And w\placed2=0 Then w\y2=w\y2+2 If Not w\y<0 And w\placed1=0 Then w\y=w\y-2 If w\y<0 And w\y2>600 Then w\placed1=1:w\placed2=1 EndIf EndIf Next If MouseHit(1) Then w.wall=New wall w\x=MouseX() w\y=MouseY() w\hg=1 w\wd=1 w\x2=MouseX() w\y2=MouseY() w\ox=MouseX() w\oy=MouseY() w\axis=1 FlushMouse Return EndIf If MouseHit(2) Then w.wall=New wall w\x=MouseX() w\y=MouseY() w\hg=1 w\wd=1 w\x2=MouseX() w\y2=MouseY() w\axis=2 FlushMouse Return EndIf End Function Function Draw() Local draw Cls For b.ball=Each ball Oval b\x,b\y,10,10,1 Next For w.wall=Each wall Line w\x,w\y,w\x2,w\y2 Next Flip End Function Function fLine(x,y,x1,y1,r=255,g=255,b=255) ; fLine will only draw horizonal or vertical lines, no diagonals ; Defaults to a white line. argb=(b Or (g Shl 8) Or (r Shl 16) Or ($ff000000)) If x=x1 If y>y1 Then t=y1:y1=y:y=t For n=y To y1 WritePixel x,n,argb,BackBuffer() Next EndIf If y=y1 If x>x1 Then t=x1:x1=x:x=t For n=x To x1 WritePixel n,y,argb,BackBuffer() Next EndIf End Function Function LineOverlapCircle(x1#,y1#,x2#,y2#,cx#,cy#,Radius#) ;'Calc Closest Point To circle center Local dx31#=cx#-x1# Local dx21#=x2#-x1# Local dy31#=cy#-y1# Local dy21#=y2#-y1# Local d#=((dx21#*dx21#)+(dy21#*dy21#)) If d#<>0 Then d#=((dx31#*dx21#)+(dy31#*dy21#))/d# ;'Clip To the line segments legal bounds If d#<0.0 Then d#=0 If d#>1.0 Then d#=1 Local dx#=cx#-(x1#+(dx21#*d#)) Local dy#=cy#-(y1#+(dy21#*d#)) If Radius# => Sqr((dx#*dx#)+(dy#*dy#)) ;'Line intersects circle Return 1 EndIf Return 0 End Function Function linesIntersect(x1%,y1%, x2%,y2%, x3%,y3%, x4%,y4%) numeratorA# = (x4-x3)*(y1-y3)-(y4-y3)*(x1-x3) numeratorB# = (x2-x1)*(y1-y3)-(y2-y1)*(x1-x3) denominator# = (y4-y3)*(x2-x1)-(x4-x3)*(y2-y1) If denominator = 0.0 Then ; Text(10,20,"No intersection") ; If numeratorA = 0.0 And numeratorB = 0.0 And denominator = 0.0 Then ; Text(10,40,"Lines are coincident") ; Else ; Text(10,40,"Lines are parallel") ; End If Return False Else Ua# = numeratorA/denominator Ub# = numeratorB/denominator range1% = Ua >= 0.0 And Ua <= 1.0 range2% = Ub >= 0.0 And Ub <= 1.0 If range1 And range2 Then intersectX% = Floor(x1 + Ua*(x2-x1)+.5) intersectY% = Floor(y1 + Ua*(y2-y1)+.5) Return True Else ; Text(10,20,"No intersection") Return False End If End If End Function Function CheckWallCollisions() Local x,y,axis,x2,y2 For w.wall=Each wall x=w\x y=w\y axis=w\axis x2=w\x2 y2=w\y2 For w.wall=Each wall If w<>Null If w\axis<>axis If w\axis=1 Then If axis=2 Then If w\x=x Or w\x=x-1 Or w\x=x+1 Then w\placed1=1 If w\x2=x2 Or w\x2=x2-1 Or w\x2=x2+1 Then w\placed2=1 EndIf EndIf EndIf Else If axis=2 Then If w\y=y Or w\y=y-1 Or w\y=y+1 Then w\placed1=1 If w\y2=y2 Or w\y2=y2-1 Or w\y2=y2+1 Then w\placed2=1 EndIf EndIf EndIf EndIf EndIf Next Next End Function
what's the problem with this? I get a memory access in debug mode.