Joystick position

Joystick position
You are encouraged to solve this task according to the task description, using any language you may know.

The task is to determine the joystick position and represent this on the display via a crosshair. For a centred joystick, the crosshair should appear in the centre of the screen. If the joystick is pushed left or right, then the cross hair should move left or right according to the extent that the joystick is pushed.

If the joystick is pushed forward or pulled back, then the crosshair should move up or down according to the extent that that joystick is pushed or pulled. The edges of the display represent maximum extents for joystick movement.

For example, a joystick pushed fully forward would raise the crosshair to the top centre of the screen.

A joystick pulled backwards and to the right would move the crosshair to the bottom right of the screen (except for a small area reserved to show joystick status). Implementations can use a graphical display method to produce the crosshair, or alternatively represent the crosshair using a plus symbol on a terminal, and move the plus symbol position according to the joystick. The bottom part of the display can hide or show an alphanumeric sequence to represent the buttons pressed.

For example, if pushbuttons 1,4 and 10 are depressed, we could display "1 4 A".

The implemented code should continue to redraw the crosshair according to the joystick position and show the current pushbutton statuses until the task is terminated. Digital joysticks that produce no extent data, should have their position indicated as full extent movement of the crosshair.

For the purpose of this task, we assume that the joystick is calibrated and that the first joystick is being used.
The task implementer could at their option provide a solution that includes a joystick selection facility, enabling the user to choose which joystick is to be used for this task.

Applesoft BASIC

<lang ApplesoftBasic>100 GOSUB 400 110 P2 = PDL(2) : IF P2 <> O2 THEN O2 = P2 : VTAB 23 : HTAB 33 : PRINT P2; TAB(37); 120 B2 = FNB(2) : IF B2 <> N2 THEN N2 = B2 : VTAB 24 : HTAB 15 : PRINT P$(B2); 130 P3 = PDL(3) : IF P3 <> O3 THEN O3 = P3 : VTAB 23 : HTAB 37 : PRINT P3; : CALL -868 140 X = INT(P3 * RX) : Y = INT(P2 * RY(F)) 150 O = (X1 = X2 AND Y1 = Y2) + 1 160 N = (X = X1 AND Y = Y1) + 1 170 IF X <> X2 OR Y <> Y2 THEN XDRAW N AT X, Y : XDRAW O AT X2, Y2 : X2 = X : Y2 = Y : O = N 200 P0 = PDL(0) : IF P0 <> O0 THEN O0 = P0 : VTAB 22 : HTAB 33 : PRINT P0; TAB(37); 210 B0 = FNB(0) : IF B0 <> N0 THEN N0 = B0 : VTAB 22 : HTAB 15 : PRINT P$(B0); 220 P1 = PDL(1) : IF P1 <> O1 THEN O1 = P1 : VTAB 22 : HTAB 37 : PRINT P1; : CALL -868 230 B1 = FNB(1) : IF B1 <> N1 THEN N1 = B1 : VTAB 23 : HTAB 15 : PRINT P$(B1); 240 X = INT(P0 * RX) : Y = INT(P1 * RY(F)) 250 O = (X1 = X2 AND Y1 = Y2) + 1 260 N = (X = X2 AND Y = Y2) + 1 270 IF X <> X1 OR Y <> Y1 THEN XDRAW N AT X, Y : XDRAW O AT X1, Y1 : X1 = X : Y1 = Y 300 K = PEEK(-16384) : IF K < 128 THEN 110 310 POKE-16368,0 320 IF K = 198 OR K = 200 THEN F = PEEK(-16302) ^ 0 : GOTO 110HIDE 330 IF K = 155 OR K = 211 THEN F = PEEK(-16301) * 0 : GOTO 110SHOW 340 TEXT : END 400 HOME : HGR 410 DEF FN B(B) = PEEK(49249 + B) > 127 420 P$(0) = "NOT PRESSED" : P$(1) = "PRESSED " 430 VTAB 21 : PRINT "BUTTON:"; 440 PRINT TAB(28); "JOYSTICK:" 450 PRINT " OPEN APPLE "P$(0); 460 PRINT TAB(29); "ONE" 470 PRINT " CLOSED APPLE "P$(0); 480 PRINT TAB(29); "TWO" 490 PRINT TAB(9); "SHIFT "P$(0); 500 RX = 35 / 32 : RY(0) = 5 / 8 : RY(1) = 3 / 4 510 DATA2,0,6,0,3,0,29,15,20,6,0 520 FOR I = 768 TO 778 : READ B 530 POKE I, B : NEXT : POKE 232, 0 : POKE 233, 3 550 ROT = 0 : SCALE = 7 : XDRAW 1 AT X1, Y1 560 O0 = -1 : O1 = O0 : O2 = O0 : O3 = O0 570 RETURN</lang>

AutoHotkey

Works with: AutoHotkey_L

Library: GDIP

Forum thread

Image link <lang AutoHotkey>; Uncomment if Gdip.ahk is not in your standard library

#Include, Gdip.ahk

Comment for lower CPU usage

SetBatchLines, -1

JoystickNumber := 0  ; (1-16) or (0 = Auto-detect) CrosshairSize := 100 BarWidth := 50 BarSpacing := BarWidth + 8 Color1 := 0x99000000 Color2 := 0x99ffffff Color3 := 0x99ff6600 Color4 := 0xff0066ff Color5 := 0xffff6600 Font := "Arial" FontSize1 := 20 FontSize2 := 30 Lineweight1 := 8 Lineweight2 := 3 Lineweight3 := 2 Lineweight4 := 4 Show2ndCrosshair := true AxisLabelHeight := 47

1. SingleInstance, Force
2. NoEnv

OnExit, Exit SysGet, MWA, MonitorWorkArea CrosshairOffset := CrosshairSize // 2 , CircleOffset := CrosshairOffset - 5 , CircleSize := CrosshairSize - 10 , TaskBarHeight := A_ScreenHeight - MWABottom + Lineweight1 // 2 , ScaleX := A_ScreenWidth / 100 , ScaleY1 := (A_ScreenHeight - TaskBarHeight - AxisLabelHeight) / 100 , ScaleY2 := A_ScreenHeight / 100 , BarCenter := (MWABottom - AxisLabelHeight) // 2 + AxisLabelHeight , BorderBot := MWABottom - Lineweight1 // 2 + 2 , PieSize := 400 , PieX := (A_ScreenWidth - PieSize) // 2 , PieY := (A_ScreenHeight - PieSize) // 2 , BarHeight := A_ScreenHeight - AxisLabelHeight - TaskBarHeight , AxisTextOffset := BarWidth > 32 ? (BarWidth - 32) // 2 : 0 , Axis_Array := {"X": "X", "Y": "Y"} , MaxI := 2

Auto-detect the joystick number if called for

if (JoystickNumber < 1) {

   Loop, 16 {
       GetKeyState, Joy_Name, %A_Index%JoyName
       if (Joy_Name) {
           JoystickNumber := A_Index
           break
       }
   }
   if (!JoystickNumber) {
       MsgBox The system does not appear to have any joysticks.
       ExitApp
   }

} else {

   GetKeyState, Joy_Name, %JoystickNumber%JoyName
   if (!Joy_Name) {
       MsgBox The system does not appear to have a joystick number %JoystickNumber%.
       ExitApp
   }

}

if (!pToken := Gdip_Startup()) {

   MsgBox, 48, Gdiplus error!, Gdiplus failed to start. Please ensure you have Gdiplus on your system.
   ExitApp

}

If (!Gdip_FontFamilyCreate(Font)) {

  MsgBox, 48, Font error!, The font you have specified does not exist on your system.
  ExitApp

}

Get joystick information

SetFormat, FloatFast, 03.2 GetKeyState, Joy_Buttons, % JoystickNumber "JoyButtons" GetKeyState, Joy_Info, % JoystickNumber "JoyInfo" Loop, Parse, Joy_Info

   if (A_LoopField != "C" && A_LoopField != "D" && A_LoopField != "P")
       Axis_Array[A_LoopField] := A_LoopField
       , %A_LoopField% := true
       , MaxI++
   else
       %A_LoopField% := true

Setup Gdip

Gui, 1: -Caption +E0x80000 +LastFound +AlwaysOnTop +ToolWindow +OwnDialogs Gui, 1: Show, NA hwnd1 := WinExist() , hbm := CreateDIBSection(A_ScreenWidth, A_ScreenHeight) , hdc := CreateCompatibleDC() , obm := SelectObject(hdc, hbm) , G1 := Gdip_GraphicsFromHDC(hdc) , Gdip_SetSmoothingMode(G1, 4) , pPen1 := Gdip_CreatePen(Color1, Lineweight1) , pPen2 := Gdip_CreatePen(Color2, Lineweight2) , pPen3 := Gdip_CreatePen(Color4, Lineweight3) , pPen4 := Gdip_CreatePen(Color5, Lineweight4) , pBrush1 := Gdip_BrushCreateSolid(Color1) , pBrush2 := Gdip_BrushCreateSolid(Color3)

Crosshair 2

if ((R || U) && Show2ndCrosshair) {

   pPen5 := Gdip_CreatePen(Color5, Lineweight3)
   , pPen6 := Gdip_CreatePen(Color4, Lineweight4)
   , joy_r := joy_u := 50

}

Bar X-offsets

for key, val in Axis_Array

   %val%X := A_ScreenWidth - MaxI * BarSpacing + BarSpacing * (A_Index - 1) + 3

Info box

IBH1 := 150 , IBW1 := 450 , IBX1 := A_ScreenWidth - MaxI * BarSpacing - IBW1 , IBY1 := A_ScreenHeight - TaskBarHeight - IBH1 + Lineweight1 // 2 , IBH2 := IBH1 - 8 , IBW2 := IBW1 - 8 , IBX2 := IBX1 + 4 , IBY2 := IBY1 + 4 , FontOptions1 := "x" (IBX1 + 8) " y" (IBY1 + 8) " w" IBW1 - 20 " Left c" SubStr(Color2, 3) " r4 s" FontSize1 " Bold"

Axis box

ABH1 := AxisLabelHeight + 4 , ABW1 := MaxI * BarSpacing , ABX1 := A_ScreenWidth - MaxI * BarSpacing , ABY1 := 0 , ABH2 := ABH1 - 16 , ABW2 := ABW1 - 8 , ABX2 := ABX1 + 4 , ABY2 := ABY1 + 4 , FontOptions2 := " y" ABY1 + AxisLabelHeight - 40 " w" ABW1 - 10 " Left c" SubStr(Color2, 3) " r4 s" FontSize2 " Bold"

Update graphics

Loop, {

   Buttons_Down := ""
   Loop, %Joy_Buttons% {
       GetKeyState, joy%A_Index%, %JoystickNumber%joy%A_Index%
       if (joy%A_Index% = "D")
           Buttons_Down .= " " A_Index
   }

   ; Info & axis boxes
   InfoText := Joy_Name " (#" JoystickNumber "):`n" Axis_Info "`nButtons Down: " Buttons_Down "`n`n(Ctrl+Esc to exit)"
   , Gdip_FillRoundedRectangle(G1, pBrush1, IBX1, IBY1, IBW1, IBH1, 5)
   , Gdip_DrawRoundedRectangle(G1, pPen2, IBX2, IBY2, IBW2, IBH2, 5)
   , Gdip_TextToGraphics(G1, InfoText, FontOptions1, Font, A_ScreenWidth, A_ScreenHeight)
   , Gdip_FillRoundedRectangle(G1, pBrush1, ABX1, ABY1, ABW1, ABH1, 5)
   , Gdip_DrawRoundedRectangle(G1, pPen2, ABX2, ABY2, ABW2, ABH2, 5)

   ; Axis bars
   Axis_Info := ""
   for key, val in Axis_Array {
       GetKeyState, joy_%val%, % JoystickNumber "Joy" val
       Axis_Info .= val joy_%val% "  "
       if (joy_%val% > 50)
           %val%Y := BarCenter
           , %val%h1 := (joy_%val% - 50) * ScaleY1
       else
           %val%Y := AxisLabelHeight + joy_%val% * ScaleY1  ;
           , Sc - (joy_%val% - 50) * ScaleY1
           , %val%h1 := BarCenter - %val%Y
       Gdip_FillRoundedRectangle(G1, pBrush2, %val%X, %val%Y, BarWidth, %val%h1, 2)
       , Gdip_DrawRoundedRectangle(G1, pPen1, %val%X, AxisLabelHeight, BarWidth, BarHeight, 5)
       , Gdip_DrawRoundedRectangle(G1, pPen2, %val%X, AxisLabelHeight, BarWidth, BarHeight, 5)
       , Gdip_TextToGraphics(G1, val, "x" (%val%X + AxisTextOffset) FontOptions2, Font, A_ScreenWidth, A_ScreenHeight)
   }

   ; POV hat
   If (P) {
       GetKeyState, Joy_P, %JoystickNumber%JoyPOV
       Axis_Info .= "  POV" Joy_P
       if (Joy_P > -1) {

StartAngle := (Joy_P > 33750 || Joy_P <= 2250) ? 247.5 ; up : Joy_P > 29250 ? 202.5 ; up left : Joy_P > 24750 ? 157.5 ; left : Joy_P > 20250 ? 112.5 ; down left : Joy_P > 15750 ? 67.5 ; down : Joy_P > 11250 ? 22.5 ; down right : Joy_P > 6750 ? 337.5 ; right : 292.5 ; up right

           , Gdip_FillPie(G1, pBrush2, PieX, PieY, PieSize, PieSize, StartAngle, 45)
           , Gdip_DrawPie(G1, pPen1, PieX, PieY, PieSize, PieSize, StartAngle, 45)
           , Gdip_DrawPie(G1, pPen2, PieX, PieY, PieSize, PieSize, StartAngle, 45)
       }
   }

   ; Crosshair 1
   CenterX := ScaleX * joy_x
   , CenterY := ScaleY2 * joy_y
   , Gdip_DrawLine(G1, pPen3, CenterX-CrosshairOffset, CenterY, CenterX+CrosshairOffset, CenterY)
   , Gdip_DrawLine(G1, pPen3, CenterX, CenterY-CrosshairOffset, CenterX, CenterY+CrosshairOffset)
   , Gdip_DrawEllipse(G1, pPen4, CenterX-CircleOffset, CenterY-CircleOffset, CircleSize, CircleSize)
   , Gdip_DrawEllipse(G1, pPen4, CenterX-3, CenterY-3, 6, 6)

   ; Crosshair 2
   if ((R || U) && Show2ndCrosshair)
       CenterU := ScaleX * joy_u
       , CenterR := ScaleY2 * joy_r
       , Gdip_DrawLine(G1, pPen5, CenterU-CrosshairOffset, CenterR, CenterU+CrosshairOffset, CenterR)
       , Gdip_DrawLine(G1, pPen5, CenterU, CenterR-CrosshairOffset, CenterU, CenterR+CrosshairOffset)
       , Gdip_DrawEllipse(G1, pPen6, CenterU-CircleOffset, CenterR-CircleOffset, CircleSize, CircleSize)
       , Gdip_DrawEllipse(G1, pPen6, CenterU-3, CenterR-3, 6, 6)

   UpdateLayeredWindow(hwnd1, hdc, 0, 0, A_ScreenWidth, A_ScreenHeight)
   , Gdip_GraphicsClear(G1)

} return

^Esc:: Exit: Gdip_Shutdown(pToken) ExitApp</lang>

BBC BASIC

Works with: BBC BASIC for Windows

<lang bbcbasic> VDU 23,22,512;512;8,16,16,0

     VDU 5
     
     GCOL 4,15
     REPEAT
       B% = ADVAL(0)
       X% = ADVAL(1) / 64
       Y% = 1023 - ADVAL(2) / 64
       PROCjoy(B%,X%,Y%)
       WAIT 4
       PROCjoy(B%,X%,Y%)
     UNTIL FALSE
     END
     
     DEF PROCjoy(B%,X%,Y%)
     LOCAL I%
     LINE X%-32,Y%,X%+32,Y% : LINE X%,Y%-32,X%,Y%+32
     VDU 30
     FOR I% = 0 TO 15
       IF B% AND 1<<I% THEN PRINT "Button "; I%+1 " pressed";
       VDU 10,13
     NEXT
     ENDPROC</lang>

GUISS

Graphical User Interface Support Script only makes use of installed applications. So for this task, we use the joystick calibration routine, which shows a joystick position indicator:

<lang guiss>Start,Control Panel, Game Controllers, List:installed controllers,Click:Joystick, Button:Properties,Button:Test</lang>

Haskell

Half-solution of the problem, exhibits X and Y coordinates of the joystick; works on Windows (Haskell Platform):

<lang Haskell>import qualified Graphics.UI.GLFW as GLFW -- cabal install GLFW-b import Graphics.Win32.Key import Control.Monad.RWS.Strict (liftIO)

main = do

   liftIO $ do
         _ <- GLFW.init
         GLFW.pollEvents
         (jxrot, jyrot) <- liftIO $ getJoystickDirections GLFW.Joystick'1
         putStrLn $ (show jxrot) ++ " " ++ (show jyrot)
         w <- getAsyncKeyState 27 -- ESC pressed?
         if (w<1) then main else do 
                    GLFW.terminate
                    return ()
                    

getJoystickDirections :: GLFW.Joystick -> IO (Double, Double)

getJoystickDirections js = do

   maxes <- GLFW.getJoystickAxes js
   return $ case maxes of
     (Just (x:y:_)) -> (-y, x)
     _ -> ( 0, 0)

</lang>

Liberty BASIC

<lang lb> 'disable text window

   nomainwin

   'set window size
   WindowWidth  = 308
   WindowHeight = 331

   'center window on screen
   UpperLeftX = int((DisplayWidth-WindowWidth)/2)
   UpperLeftY = int((DisplayHeight-WindowHeight)/2)

   'open graphics window
   open "Joystick Position" for graphics_nf_nsb as #m

   'trap window closing
   #m "trapclose [quit]"

   'put pen down
   #m "down"

   'get center of graphics window
   #m "home"
   #m "posxy CenterX CenterY"

   'draw sprite for crosshair
   #m "backcolor black; color black"
   #m "place 0 20;boxfilled 20 40"
   #m "line  0 10 20 10"
   #m "line 10  0 10 20"
   #m "place 10 10; circle 10"
   #m "backcolor white; color red"
   #m "line  0 30 20 30"
   #m "line 10 20 10 40"
   #m "place 10 30; circle 10"
   #m "flush"

   'get sprite image
   #m "getbmp plus 0 0 20 40"
   #m "cls"

   'create sprite from image
   #m "addsprite crosshair plus"
   #m "centersprite crosshair"
   #m "spritexy crosshair "; CenterX; " "; CenterY
   #m "drawsprites"

   'check joystick every 100 milliseconds
   timer 100, [CheckJoystick]
   wait

[CheckJoystick]

   readjoystick 1

   'calculate crosshair position
   PosX = int(CenterX*Joy1x/32767)
   PosY = int(CenterY*Joy1y/32767)

   'update crosshair position
   #m "spritexy crosshair "; PosX; " "; PosY
   #m "drawsprites"

   'display button information
   if Joy1button1 > 0 then #m "place 0 0;\\Button 1 pressed"
   if Joy1button2 > 0 then #m "place 0 0;\\\Button 2 pressed"

   wait

[quit]

   timer 0
   close #m
   unloadbmp "plus"
   end</lang>

Locomotive Basic

<lang locobasic>10 MODE 1:BORDER 14:x=320:y=200:d=1 20 a=JOY(0) ' read state of first joystick 30 IF d THEN q$="*" ELSE q$=" " 40 IF a THEN MOVE x-8,y+8:TAG:PRINT q$;:TAGOFF 50 IF (a AND 1) AND y<380 THEN y=y+10 60 IF (a AND 2) AND y>20 THEN y=y-10 70 IF (a AND 4) AND x>20 THEN x=x-10 80 IF (a AND 8) AND x<620 THEN x=x+10 90 IF a AND 16 THEN LOCATE 1,1:PRINT "Fire1 pressed":d=1 100 IF a AND 32 THEN LOCATE 1,2:PRINT "Fire2 pressed":d=0 110 IF a<16 THEN LOCATE 1,1:PRINT " ":PRINT " " 120 MOVE x-8,y+8:TAG:PRINT "X";:TAGOFF 130 GOTO 20</lang>

Output (this version supports drawing with the cursor):

Mathematica

<lang Mathematica>Slider2D[Dynamic[ControllerState[{"X", "Y"}]], ImageSize -> {500, 500}]</lang>

OCaml

Library: SFML

Using the SFML with its OCaml bindings ocaml-sfml:

<lang ocaml>let remove x = List.filter (fun y -> y <> x) let buttons_string b =

 String.concat " " (List.map string_of_int b)

let position app x y =

 let view = SFRenderWindow.getView app in
 let width, height = SFView.getSize view in
 let hw = width /. 2.0 in
 let hh = height /. 2.0 in
 (hw +. ((x /. 100.0) *. hw),
  hh +. ((y /. 100.0) *. hh))

let cross =

 [|  1.0,   1.0;  10.0,   1.0;  10.0, -1.0;    1.0, -1.0;
     1.0, -10.0;  -1.0, -10.0;  -1.0, -1.0;  -10.0, -1.0;
   -10.0,   1.0;  -1.0,   1.0;  -1.0, 10.0;    1.0, 10.0; |]

let () =

 let app = SFRenderWindow.make (800, 600) "Joystick Position" in
 let text = SFText.make "" in
 let shape = SFShape.create cross in
 SFShape.setFillColor shape SFColor.white;
 SFShape.setOutlineColor shape SFColor.white;
 SFShape.setOutlineThickness shape 1.0;
 let rec display ((x, y), b) =
   SFText.setString text (buttons_string b);
   let x, y = position app x y in
   SFShape.setPosition shape x y;
   SFRenderWindow.clear app SFColor.black;
   SFRenderWindow.drawText app text ();
   SFRenderWindow.drawShape app shape ();
   SFRenderWindow.display app;
 and loop joyd =
   let get_joystick (((x, y), b) as joyd) = function
   | SFEvent.JoystickButtonPressed (0, button) -> ((x, y), button::b)
   | SFEvent.JoystickButtonReleased (0, button) -> ((x, y), remove button b)
   | SFEvent.JoystickMoved (0, SFEvent.JoystickX, av) -> ((av, y), b)
   | SFEvent.JoystickMoved (0, SFEvent.JoystickY, av) -> ((x, av), b)
   | _ -> joyd
   in
   let rec proc_event joyd =
     match SFRenderWindow.pollEvent app with
     | Some SFEvent.KeyPressed (SFKey.Escape,_,_,_,_)
     | Some SFEvent.Closed -> ()
     | Some event ->
         let joyd = get_joystick joyd event in
         proc_event joyd
     | None ->
         display joyd;
         loop joyd
   in
   proc_event joyd
 in
 loop ((0.0, 0.0), [])</lang>

PicoLisp

This is for the 64-bit version.

Library: GLUT

Note: The code is not yet tested with a real joystick (I don't have one), it was just simulated with dummy functions. Can somebody having a joystick please test it, and remove this message? <lang PicoLisp>(load "@lib/openGl.l")

(setq *JoyX 0.0 *JoyY 0.0)

(glutInit) (glutInitDisplayMode (| GLUT_RGBA GLUT_DOUBLE GLUT_ALPHA GLUT_DEPTH)) (glutInitWindowSize 400 400) (glutCreateWindow "Joystick")

(glClearColor 0.3 0.3 0.5 0)

(displayPrg

  (glClear GL_COLOR_BUFFER_BIT)
  (glBegin GL_LINES)
  (glVertex2f *JoyX (- *JoyY 0.1))  # Draw crosshair
  (glVertex2f *JoyX (+ *JoyY 0.1))
  (glVertex2f (- *JoyX 0.1) *JoyY)
  (glVertex2f (+ *JoyX 0.1) *JoyY)
  (glEnd)
  (glFlush)
  (glutSwapBuffers) )

1. Track joystick position

(native `*GlutLib "glutJoystickFunc" NIL

  (lisp 'joystickFunc
     '((Btn X Y Z)
        (msg                          # Display buttons
           (make
              (for (B 1 (n0 Btn) (inc B))
                 (and (bit? 1 Btn) (link B))
                 (setq Btn (>> 1 Btn)) ) ) )
        (setq                         # Move crosshair
           *JoyX (*/ X 1.0 1000)
           *JoyY (*/ Y 1.0 1000) )
        (glutPostRedisplay) ) )
  100 )

1. Exit upon mouse click

(mouseFunc '((Btn State X Y) (bye))) (glutMainLoop)</lang>

PureBasic

This is limited to only digital joysticks. <lang PureBasic>If InitJoystick() = 0

 MessageRequester("Error!", "Need to connect a joystick", #PB_MessageRequester_Ok)
 End

EndIf

some constants for Window positioning

1. WindowW = 100: #WindowH = 100
2. CrossW = 10
3. p1 = (#WindowW - #CrossW) / 2
4. p2 = (#WindowW / 2 - #CrossW)

If OpenWindow(0, 0, 0, #WindowW * 2 + 10, #WindowH, "Joystick Position", #PB_Window_SystemMenu)

 CreateImage(0, #WindowW, #WindowW)
 ImageGadget(0, 0, 0, 0, 0, ImageID(0))
 TextGadget(2, #WindowW + 5, 10, #WindowW, 20, "Buttons Pressed:")
 CreateImage(1, #WindowW, 40)
 ImageGadget(1,  #WindowW + 5, 30, 0, 0, ImageID(1))
 
 AddKeyboardShortcut(0, #PB_Shortcut_Escape, 0)
 Define event, x_movement, y_movement
 Repeat 
   Repeat
     event = WindowEvent()
     Select event
       Case #PB_Event_Menu
         If EventMenu() = 0
           End
         EndIf
       Case #PB_Event_CloseWindow
         End
     EndSelect
   Until event = 0
   
   Define pressed.s, buttonNum, buttonX, buttonY, buttonText.s, buttonColor
   pressed.s = ""
   If ExamineJoystick(0)
     x_movement = JoystickAxisX(0)
     y_movement = JoystickAxisY(0)
     
     StartDrawing(ImageOutput(1))
       DrawingMode(#PB_2DDrawing_Transparent)
       Box(0, 0, #WindowW, 50, RGB($D4, $D0, $C8)) ;a Gray
       ; check to see if any of the buttons have been pressed
       For buttonNum = 1 To 10
         buttonX = ((buttonNum - 1) * 20 + 10) % #WindowW
         buttonY = ((buttonNum - 1) / 5) * 20 + 10
         If JoystickButton(0, buttonNum)
           buttonColor = RGB($FF, 0, 0) ;Red
         Else
           buttonColor = RGB($80, $80, $80) ;Gray
         EndIf 
         Circle(buttonX, buttonY, 9, buttonColor)
         buttonText = Str(buttonNum)
         DrawText(buttonX - TextWidth(buttonText) / 2, buttonY - TextHeight(buttonText) / 2, buttonText, RGB($FF, $FF, $FF)) ;White
       Next
     StopDrawing()
     
     SetGadgetState(1, ImageID(1))
   EndIf
   
   
   StartDrawing(ImageOutput(0))
     Box(0,0, #WindowW, #WindowW, RGB($FF, $FF, $FF)) ;White
     Line(#p1 + x_movement * #p2, #WindowW / 2 + y_movement * #p2, #CrossW, 1, RGB($FF, 0, 0)) ;Red
     Line(#WindowW / 2 + x_movement * #p2, #p1 + y_movement * #p2, 1, #CrossW, RGB($FF, 0, 0)) ;Red
   StopDrawing()
   
   SetGadgetState(0, ImageID(0))
   
   Delay(10)
 Until event = #PB_Event_CloseWindow

EndIf</lang>

Python

Library: Pygame

<lang Python>import sys import pygame

pygame.init()

1. Create a clock (for framerating)

clk = pygame.time.Clock()

1. Grab joystick 0

if pygame.joystick.get_count() == 0:

   raise IOError("No joystick detected")

joy = pygame.joystick.Joystick(0) joy.init()

1. Create display

size = width, height = 600, 600 screen = pygame.display.set_mode(size) pygame.display.set_caption("Joystick Tester")

1. Frame XHair zone

frameRect = pygame.Rect((45, 45), (510, 510))

1. Generate crosshair

crosshair = pygame.surface.Surface((10, 10)) crosshair.fill(pygame.Color("magenta")) pygame.draw.circle(crosshair, pygame.Color("blue"), (5,5), 5, 0) crosshair.set_colorkey(pygame.Color("magenta"), pygame.RLEACCEL) crosshair = crosshair.convert()

1. Generate button surfaces

writer = pygame.font.Font(pygame.font.get_default_font(), 15) buttons = {} for b in range(joy.get_numbuttons()):

   buttons[b] = [
       writer.render(
           hex(b)[2:].upper(),
           1,
           pygame.Color("red"),
           pygame.Color("black")
       ).convert(),
       # Get co-ords: ((width*slot)+offset, offset). Offsets chosen
       #                                             to match frames.
       ((15*b)+45, 560)
   ]

while True:

   # Pump and check the events queue
   pygame.event.pump()
   for events in pygame.event.get():
       if events.type == pygame.QUIT:
           pygame.quit()
           sys.exit()

   # Black the screen
   screen.fill(pygame.Color("black"))

   # Get joystick axes
   x = joy.get_axis(0)
   y = joy.get_axis(1)

   # Blit to the needed coords:
   # x*amplitude+(centre offset (window size/2))-(xhair offset (xh size/2))
   screen.blit(crosshair, ((x*250)+300-5, (y*250)+300-5))
   pygame.draw.rect(screen, pygame.Color("red"), frameRect, 1)

   # Get and display the joystick buttons
   for b in range(joy.get_numbuttons()):
       if joy.get_button(b):
           screen.blit(buttons[b][0], buttons[b][1])

   # Write the display
   pygame.display.flip()
   clk.tick(40) # Limit to <=40 FPS</lang>

Tcl

Library: Tk

Library: mkLibsdl

<lang tcl>package require Tk 8.6 package require mkLibsdl

1. This code assumes we're dealing with the first pair of axes on the first
2. joystick; modern joysticks are complex...

1. Callback for all joystick activity

proc display {joyDict} {

   global x y buttons message
   set axis -1
   dict with joyDict {

if {$joystick != 0} return if {[info exist button]} { # Handle button presses... set buttons($button) $value set message "Buttons:" foreach b [lsort -integer [array names buttons]] { if {$buttons($b)} { lappend message $b } } } else { # Handle joystick movement... if {$axis == -1} return set value [expr {$value / 32768.0 * 100 + 120}] if {$axis == 0} { set x $value } elseif {$axis == 1} { set y $value } .c coords xhairV $x [expr {$y-5}] $x [expr {$y+5}] .c coords xhairH [expr {$x-5}] $y [expr {$x+5}] $y }

   }

}

1. Make a GUI

set message "Buttons:" pack [canvas .c -width 240 -height 240] [label .l -textvariable message] set x [set y 120] .c create line {120 115 120 125} -tags xhairV .c create line {115 120 125 120} -tags xhairH joystick event eval {display [joystick event peek]}</lang>

ZX Spectrum Basic

Assuming a Kempston joystick interface, fairly standard at the time. Rewriting for the Sinclair Interface 2 involves changing line 80 to 80 LET t=IN 61438, replacing all numbers in the next five lines with 191-said number and reversing each pair of directions.

<lang zxbasic>10 DIM o$(5) 20 LET xm=0: LET xx=31: REM screen limits 30 LET ym=0: LET yx=18 40 LET xo=16: LET yo=9: REM origin 50 LET xc=xo: LET yc=yo 60 PRINT AT yc,xc;" ": REM entry point for scan loop - blank cursor 70 LET xc=xo: LET yc=yo 80 LET t=IN 31 90 IF t=1 OR t=5 OR t=9 OR t=17 OR t=21 OR t=25 THEN LET xc=xx: LET o$(2)="R": REM right 100 IF t=2 OR t=6 OR t=10 OR t=18 OR t=22 OR t=26 THEN LET xc=xm: LET o$(1)="L": REM left 110 IF t=4 OR t=5 OR t=6 OR t=20 OR t=21 OR t=22 THEN LET yc=yx: LET o$(4)="D": REM down 120 IF t=8 OR t=9 OR t=10 OR t=24 OR t=25 OR t=26 THEN LET yc=ym: LET o$(3)="U": REM up 130 IF t>=16 THEN LET o$(5)="F": REM fire 140 PRINT AT 21,0;"Input:";o$ 150 PRINT AT yc,xc;"+" 160 LET o$=" ": REM five spaces to blank output line again 170 GO TO 60</lang>

Output:

+

Input:L  D