Joystick Smoothing

[sweep123]

I have developed a MFC VC++ application with a joystick as an input device.

Does anyone have any code to smooth out the action.

Currently would like roll and pitch smoothed to -/+ 180 from the 0 to 65756 values used by the joystick.

i.e. dip a few desgrees/sec while joystick off-centre.

Any comments?

 

[EMKH]

Hi Sweep123;
I am a student Of electrical engineering.
I want ot simply work with Joystick in VC++ 6.
Can you please help me.
Thank you very much;

 

[dbraunc]

Hi,

you should use a moving average technique for first try (should be appropriate solution).
1. Sum up the last n sampled values
2. divide the result by (n * 360)
3. subtract 180 from result.
4. The result you get it smoothened and mapped to -180..180.

Should be very easy to implement.

Hope I could help you, Daniel

 

[dbraunc]

Sorry,

step 3 should be : divide the result by (n*65756 / 360).

 

[sweep123]

Hi EMKH, sorry for the delay, but some code for you, its MFC C++
// MSCPPDlg.cpp : implementation file
//

#include "stdafx.h"
#include "MSCPP.h"
#include "MSCPPDlg.h"
#include <MMSYSTEM.H>

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

// Global data
JOYINFO joyInfo;
bool testWithMouse = true;
int StartX, StartY; // Declare at the top of the form’s unit
CString strFormatting;
bool ButtonDown = false;
static bool capture = false;

/////////////////////////////////////////////////////////////////////////////
// CAboutDlg dialog used for App About

class CAboutDlg : public CDialog
{
public:
CAboutDlg();

// Dialog Data
//{{AFX_DATA(CAboutDlg)
enum { IDD = IDD_ABOUTBOX };
//}}AFX_DATA

// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CAboutDlg)
protected:
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support
//}}AFX_VIRTUAL

// Implementation
protected:
//{{AFX_MSG(CAboutDlg)
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
//{{AFX_DATA_INIT(CAboutDlg)
//}}AFX_DATA_INIT
}

void CAboutDlg:oDataExchange(CDataExchange* pDX)
{
CDialog:oDataExchange(pDX);
//{{AFX_DATA_MAP(CAboutDlg)
//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
//{{AFX_MSG_MAP(CAboutDlg)
// No message handlers
//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CMSCPPDlg dialog

CMSCPPDlg::CMSCPPDlg(CWnd* pParent /*=NULL*/)
: CDialog(CMSCPPDlg::IDD, pParent)
{
//{{AFX_DATA_INIT(CMSCPPDlg)
// NOTE: the ClassWizard will add member initialization here
//}}AFX_DATA_INIT
// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CMSCPPDlg:oDataExchange(CDataExchange* pDX)
{
CDialog:oDataExchange(pDX);
//{{AFX_DATA_MAP(CMSCPPDlg)
// NOTE: the ClassWizard will add DDX and DDV calls here
//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CMSCPPDlg, CDialog)
//{{AFX_MSG_MAP(CMSCPPDlg)
ON_WM_SYSCOMMAND()
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_BN_CLICKED(IDC_GET_STATUS, OnGetStatus)
ON_WM_LBUTTONUP()
ON_WM_RBUTTONDOWN()
ON_WM_MOUSEMOVE()
ON_WM_LBUTTONDOWN()
//}}AFX_MSG_MAP
ON_MESSAGE(MM_JOY1BUTTONDOWN, OnJoy1ButtonDown)
ON_MESSAGE(MM_JOY1BUTTONUP, OnJoy1ButtonUp)
ON_MESSAGE(MM_JOY1MOVE, OnJoy1Move)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CMSCPPDlg message handlers

BOOL CMSCPPDlg::OnInitDialog()
{
CDialog::OnInitDialog();

// Add "About..." menu item to system menu.

// IDM_ABOUTBOX must be in the system command range.
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
ASSERT(IDM_ABOUTBOX < 0xF000);

CMenu* pSysMenu = GetSystemMenu(FALSE);
if (pSysMenu != NULL)
{
CString strAboutMenu;
strAboutMenu.LoadString(IDS_ABOUTBOX);
if (!strAboutMenu.IsEmpty())
{
pSysMenu->AppendMenu(MF_SEPARATOR);
pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
}
}

// Set the icon for this dialog. The framework does this automatically
// when the application's main window is not a dialog
SetIcon(m_hIcon, TRUE); // Set big icon
SetIcon(m_hIcon, FALSE); // Set small icon

int error;
if(!capture)
{ // Start the capture
error = joySetCapture(this->m_hWnd, JOYSTICKID1, NULL, FALSE);
switch (error)
{
case MMSYSERR_NODRIVER :
MessageBox("The joystick driver is not present", "Error when capturing", MB_ICONERROR);
break;
case MMSYSERR_INVALPARAM :
MessageBox("Windows 95/98/Me: Invalid joystick ID or hwnd is NULL.", "Error when capturing", MB_ICONERROR);
break;
case JOYERR_NOCANDO :
MessageBox("Cannot capture joystick input because a required service (such as a Windows timer) is unavailable.", "Error when capturing", MB_ICONERROR);
break;
case JOYERR_UNPLUGGED :
MessageBox("The specified joystick is not connected to the system. ", "Error when capturing", MB_ICONERROR);
break;
default :
MessageBox("The joystick has been captured");
capture = true;
}

}
else
{ // Release the Joystick capture
joyReleaseCapture(JOYSTICKID1);
capture = false;
MessageBox("The joystick has been released");
}
return TRUE; // return TRUE unless you set the focus to a control
}

void CMSCPPDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
if ((nID & 0xFFF0) == IDM_ABOUTBOX)
{
CAboutDlg dlgAbout;
dlgAbout.DoModal();
}
else
{
CDialog::OnSysCommand(nID, lParam);
}
}

// If you add a minimize button to your dialog, you will need the code below
// to draw the icon. For MFC applications using the document/view model,
// this is automatically done for you by the framework.

void CMSCPPDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // device context for painting

SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;

// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CDialog::OnPaint();
}
}

// The system calls this to obtain the cursor to display while the user drags
// the minimized window.
HCURSOR CMSCPPDlg::OnQueryDragIcon()
{
return (HCURSOR) m_hIcon;
}

void CMSCPPDlg::OnGetStatus()
{
/* This procedure determines the status of any joysticks that the system may
have. If none is detected then the user is informet. */

CString formatData;
JOYCAPS joyCaps; // This structure contains information about the
// joysticks capabilities
if(joyGetDevCaps(JOYSTICKID1, &joyCaps, sizeof(joyCaps)) == JOYERR_NOERROR)
{
// Joystick detected
SetDlgItemText(IDC_STATUS,"Joystick 1 Detected");
formatData.Format("%d", joyCaps.wMid);
SetDlgItemText(IDC_MANU2, formatData);
formatData.Format("%d", formatData);
SetDlgItemText(IDC_MANU3, formatData);
formatData.Format("%d", joyCaps.szPname);
SetDlgItemText(IDC_MANU4, formatData);
// SetDlgItemText(lblNoButtons->Caption + joyCaps.wNumButtons);
// SetDlgItemText(lblNoButtons->Caption + " Max No of Axes = ");
// SetDlgItemText(lblNoButtons->Caption + joyCaps.wMaxAxes);
// SetDlgItemText(lblNoButtons->Caption + " Number Used = ");
// SetDlgItemText(lblNoButtons->Caption + joyCaps.wNumAxes);
formatData.Format("%d", joyCaps.wXmin);
SetDlgItemText(IDC_XMIN,formatData);
formatData.Format("%d", joyCaps.wYmin);
SetDlgItemText(IDC_YMIN,formatData);
formatData.Format("%d", joyCaps.wZmin);
SetDlgItemText(IDC_ZMIN,formatData);
formatData.Format("%d", joyCaps.wXmax);
SetDlgItemText(IDC_XMAX,formatData);
formatData.Format("%d", joyCaps.wYmax);
SetDlgItemText(IDC_YMAX,formatData);
formatData.Format("%d", joyCaps.wZmax);
SetDlgItemText(IDC_ZMAX, formatData);
}
else
{
SetDlgItemText(IDC_STATUS,"Joystick Driver Not Detected");
}
}


LRESULT CMSCPPDlg::OnJoy1ButtonDown(WPARAM wParam, LPARAM lParam)
{
if (wParam & JOY_BUTTON1)
MessageBox("The joystick Button 1 Pressed");
else if (wParam & JOY_BUTTON2)
MessageBox("The joystick Button 2 Pressed");
else if (wParam & JOY_BUTTON3)
MessageBox("The joystick Button 3 Pressed");
else if (wParam & JOY_BUTTON4)
MessageBox("The joystick Button 4 Pressed");
return 0;
}
LRESULT CMSCPPDlg::OnJoy1Move(WPARAM wParam, LPARAM lParam)
{
int errorVal; // Error returned from the joyGetPos call

errorVal = joyGetPos(JOYSTICKID1, &joyInfo);
switch (errorVal)
{
case MMSYSERR_NODRIVER :
MessageBox("The joystick driver is not present");
break;
case MMSYSERR_INVALPARAM :
MessageBox("An invalid parameter was passed");
break;
case JOYERR_UNPLUGGED :
MessageBox("The joystick is not connected");
break;
default : // Update the joysticks x,y,z position
strFormatting.Format("%d", joyInfo.wXpos);
SetDlgItemText(IDC_X_DATA, strFormatting);
strFormatting.Format("%d", joyInfo.wYpos);
SetDlgItemText(IDC_Y_DATA, strFormatting);
strFormatting.Format("%d", joyInfo.wZpos);
SetDlgItemText(IDC_Z_DATA, strFormatting);
UpdateData();
}

return 0;
}
LRESULT CMSCPPDlg::OnJoy1ButtonUp(WPARAM wParam, LPARAM lParam)
{
/* This procedure will annotate the joystrick button that has been released. */
if(wParam & JOY_BUTTON1CHG)
{
MessageBox("The joystick Button 1 Released");
}
else
if(wParam & JOY_BUTTON2CHG)
{
MessageBox("The joystick Button 2 Released");
}
else
if(wParam & JOY_BUTTON3CHG)
{
MessageBox("The joystick Button 3 Released");
}
else
if(wParam & JOY_BUTTON4CHG)
{
MessageBox("The joystick Button 4 Released");
}
return 0;
}

void CMSCPPDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
if ( ButtonDown ) return;
ButtonDown = TRUE;
SetCapture();
}

void CMSCPPDlg::OnLButtonUp(UINT nFlags, CPoint point)
{
if ( !ButtonDown ) return;
ReleaseCapture();
ButtonDown = false;
}

void CMSCPPDlg::OnMouseMove(UINT nFlags, CPoint point)
{
if ( !ButtonDown ) return;

strFormatting.Format("%d", point.x);
SetDlgItemText(IDC_X_DATA_MOUSE, strFormatting);
strFormatting.Format("%d", point.y);
SetDlgItemText(IDC_Y_DATA_MOUSE, strFormatting);
UpdateData();
}
when capturing",