src/joystick/win32/SDL_mmjoystick.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#ifdef SDL_JOYSTICK_WINMM

/* Win32 MultiMedia Joystick driver, contributed by Andrei de A. Formiga */

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <mmsystem.h>
#include <regstr.h>

#include "SDL_events.h"
#include "SDL_joystick.h"
#include "../SDL_sysjoystick.h"
#include "../SDL_joystick_c.h"

#define MAX_JOYSTICKS	16
#define MAX_AXES	6       /* each joystick can have up to 6 axes */
#define MAX_BUTTONS	32      /* and 32 buttons                      */
#define AXIS_MIN	-32768  /* minimum value for axis coordinate */
#define AXIS_MAX	32767   /* maximum value for axis coordinate */
/* limit axis to 256 possible positions to filter out noise */
#define JOY_AXIS_THRESHOLD      (((AXIS_MAX)-(AXIS_MIN))/256)
#define JOY_BUTTON_FLAG(n)	(1<<n)


/* array to hold joystick ID values */
static UINT SYS_JoystickID[MAX_JOYSTICKS];
static JOYCAPS SYS_Joystick[MAX_JOYSTICKS];
static char *SYS_JoystickName[MAX_JOYSTICKS];

/* The private structure used to keep track of a joystick */
struct joystick_hwdata
{
    /* joystick ID */
    UINT id;

    /* values used to translate device-specific coordinates into
       SDL-standard ranges */
    struct _transaxis
    {
        int offset;
        float scale;
    } transaxis[6];
};

/* Convert a win32 Multimedia API return code to a text message */
static void SetMMerror(char *function, int code);


static char *
GetJoystickName(int index, const char *szRegKey)
{
    /* added 7/24/2004 by Eckhard Stolberg */
    /*
       see if there is a joystick for the current
       index (1-16) listed in the registry
     */
    char *name = NULL;
    HKEY hTopKey;
    HKEY hKey;
    DWORD regsize;
    LONG regresult;
    char regkey[256];
    char regvalue[256];
    char regname[256];

    SDL_snprintf(regkey, SDL_arraysize(regkey), "%s\\%s\\%s",
                 REGSTR_PATH_JOYCONFIG, szRegKey, REGSTR_KEY_JOYCURR);
    hTopKey = HKEY_LOCAL_MACHINE;
    regresult = RegOpenKeyExA(hTopKey, regkey, 0, KEY_READ, &hKey);
    if (regresult != ERROR_SUCCESS) {
        hTopKey = HKEY_CURRENT_USER;
        regresult = RegOpenKeyExA(hTopKey, regkey, 0, KEY_READ, &hKey);
    }
    if (regresult != ERROR_SUCCESS) {
        return NULL;
    }

    /* find the registry key name for the joystick's properties */
    regsize = sizeof(regname);
    SDL_snprintf(regvalue, SDL_arraysize(regvalue), "Joystick%d%s", index + 1,
                 REGSTR_VAL_JOYOEMNAME);
    regresult =
        RegQueryValueExA(hKey, regvalue, 0, 0, (LPBYTE) regname, &regsize);
    RegCloseKey(hKey);

    if (regresult != ERROR_SUCCESS) {
        return NULL;
    }

    /* open that registry key */
    SDL_snprintf(regkey, SDL_arraysize(regkey), "%s\\%s", REGSTR_PATH_JOYOEM,
                 regname);
    regresult = RegOpenKeyExA(hTopKey, regkey, 0, KEY_READ, &hKey);
    if (regresult != ERROR_SUCCESS) {
        return NULL;
    }

    /* find the size for the OEM name text */
    regsize = sizeof(regvalue);
    regresult =
        RegQueryValueExA(hKey, REGSTR_VAL_JOYOEMNAME, 0, 0, NULL, &regsize);
    if (regresult == ERROR_SUCCESS) {
        /* allocate enough memory for the OEM name text ... */
        name = (char *) SDL_malloc(regsize);
        if (name) {
            /* ... and read it from the registry */
            regresult = RegQueryValueExA(hKey,
                                         REGSTR_VAL_JOYOEMNAME, 0, 0,
                                         (LPBYTE) name, &regsize);
        }
    }
    RegCloseKey(hKey);

    return (name);
}

/* Function to scan the system for joysticks.
 * This function should set SDL_numjoysticks to the number of available
 * joysticks.  Joystick 0 should be the system default joystick.
 * It should return 0, or -1 on an unrecoverable fatal error.
 */
int
SDL_SYS_JoystickInit(void)
{
    int i;
    int maxdevs;
    int numdevs;
    JOYINFOEX joyinfo;
    JOYCAPS joycaps;
    MMRESULT result;

    /* Reset the joystick ID & name mapping tables */
    for (i = 0; i < MAX_JOYSTICKS; ++i) {
        SYS_JoystickID[i] = 0;
        SYS_JoystickName[i] = NULL;
    }

    /* Loop over all potential joystick devices */
    numdevs = 0;
    maxdevs = joyGetNumDevs();
    for (i = JOYSTICKID1; i < maxdevs && numdevs < MAX_JOYSTICKS; ++i) {

        joyinfo.dwSize = sizeof(joyinfo);
        joyinfo.dwFlags = JOY_RETURNALL;
        result = joyGetPosEx(i, &joyinfo);
        if (result == JOYERR_NOERROR) {
            result = joyGetDevCaps(i, &joycaps, sizeof(joycaps));
            if (result == JOYERR_NOERROR) {
                SYS_JoystickID[numdevs] = i;
                SYS_Joystick[numdevs] = joycaps;
                SYS_JoystickName[numdevs] =
                    GetJoystickName(i, joycaps.szRegKey);
                numdevs++;
            }
        }
    }
    return (numdevs);
}

/* Function to get the device-dependent name of a joystick */
const char *
SDL_SYS_JoystickName(int index)
{
    if (SYS_JoystickName[index] != NULL) {
        return (SYS_JoystickName[index]);
    } else {
        return (SYS_Joystick[index].szPname);
    }
}

/* Function to open a joystick for use.
   The joystick to open is specified by the index field of the joystick.
   This should fill the nbuttons and naxes fields of the joystick structure.
   It returns 0, or -1 if there is an error.
 */
int
SDL_SYS_JoystickOpen(SDL_Joystick * joystick)
{
    int index, i;
    int caps_flags[MAX_AXES - 2] =
        { JOYCAPS_HASZ, JOYCAPS_HASR, JOYCAPS_HASU, JOYCAPS_HASV };
    int axis_min[MAX_AXES], axis_max[MAX_AXES];


    /* shortcut */
    index = joystick->index;
    axis_min[0] = SYS_Joystick[index].wXmin;
    axis_max[0] = SYS_Joystick[index].wXmax;
    axis_min[1] = SYS_Joystick[index].wYmin;
    axis_max[1] = SYS_Joystick[index].wYmax;
    axis_min[2] = SYS_Joystick[index].wZmin;
    axis_max[2] = SYS_Joystick[index].wZmax;
    axis_min[3] = SYS_Joystick[index].wRmin;
    axis_max[3] = SYS_Joystick[index].wRmax;
    axis_min[4] = SYS_Joystick[index].wUmin;
    axis_max[4] = SYS_Joystick[index].wUmax;
    axis_min[5] = SYS_Joystick[index].wVmin;
    axis_max[5] = SYS_Joystick[index].wVmax;

    /* allocate memory for system specific hardware data */
    joystick->hwdata =
        (struct joystick_hwdata *) SDL_malloc(sizeof(*joystick->hwdata));
    if (joystick->hwdata == NULL) {
        SDL_OutOfMemory();
        return (-1);
    }
    SDL_memset(joystick->hwdata, 0, sizeof(*joystick->hwdata));

    /* set hardware data */
    joystick->hwdata->id = SYS_JoystickID[index];
    for (i = 0; i < MAX_AXES; ++i) {
        if ((i < 2) || (SYS_Joystick[index].wCaps & caps_flags[i - 2])) {
            joystick->hwdata->transaxis[i].offset = AXIS_MIN - axis_min[i];
            joystick->hwdata->transaxis[i].scale =
                (float) (AXIS_MAX - AXIS_MIN) / (axis_max[i] - axis_min[i]);
        } else {
            joystick->hwdata->transaxis[i].offset = 0;
            joystick->hwdata->transaxis[i].scale = 1.0; /* Just in case */
        }
    }

    /* fill nbuttons, naxes, and nhats fields */
    joystick->nbuttons = SYS_Joystick[index].wNumButtons;
    joystick->naxes = SYS_Joystick[index].wNumAxes;
    if (SYS_Joystick[index].wCaps & JOYCAPS_HASPOV) {
        joystick->nhats = 1;
    } else {
        joystick->nhats = 0;
    }
    return (0);
}

static Uint8
TranslatePOV(DWORD value)
{
    Uint8 pos;

    pos = SDL_HAT_CENTERED;
    if (value != JOY_POVCENTERED) {
        if ((value > JOY_POVLEFT) || (value < JOY_POVRIGHT)) {
            pos |= SDL_HAT_UP;
        }
        if ((value > JOY_POVFORWARD) && (value < JOY_POVBACKWARD)) {
            pos |= SDL_HAT_RIGHT;
        }
        if ((value > JOY_POVRIGHT) && (value < JOY_POVLEFT)) {
            pos |= SDL_HAT_DOWN;
        }
        if (value > JOY_POVBACKWARD) {
            pos |= SDL_HAT_LEFT;
        }
    }
    return (pos);
}

/* Function to update the state of a joystick - called as a device poll.
 * This function shouldn't update the joystick structure directly,
 * but instead should call SDL_PrivateJoystick*() to deliver events
 * and update joystick device state.
 */
void
SDL_SYS_JoystickUpdate(SDL_Joystick * joystick)
{
    MMRESULT result;
    int i;
    DWORD flags[MAX_AXES] = { JOY_RETURNX, JOY_RETURNY, JOY_RETURNZ,
        JOY_RETURNR, JOY_RETURNU, JOY_RETURNV
    };
    DWORD pos[MAX_AXES];
    struct _transaxis *transaxis;
    int value, change;
    JOYINFOEX joyinfo;

    joyinfo.dwSize = sizeof(joyinfo);
    joyinfo.dwFlags = JOY_RETURNALL | JOY_RETURNPOVCTS;
    if (!joystick->hats) {
        joyinfo.dwFlags &= ~(JOY_RETURNPOV | JOY_RETURNPOVCTS);
    }
    result = joyGetPosEx(joystick->hwdata->id, &joyinfo);
    if (result != JOYERR_NOERROR) {
        SetMMerror("joyGetPosEx", result);
        return;
    }

    /* joystick motion events */
    pos[0] = joyinfo.dwXpos;
    pos[1] = joyinfo.dwYpos;
    pos[2] = joyinfo.dwZpos;
    pos[3] = joyinfo.dwRpos;
    pos[4] = joyinfo.dwUpos;
    pos[5] = joyinfo.dwVpos;

    transaxis = joystick->hwdata->transaxis;
    for (i = 0; i < joystick->naxes; i++) {
        if (joyinfo.dwFlags & flags[i]) {
            value =
                (int) (((float) pos[i] +
                        transaxis[i].offset) * transaxis[i].scale);
            change = (value - joystick->axes[i]);
            if ((change < -JOY_AXIS_THRESHOLD)
                || (change > JOY_AXIS_THRESHOLD)) {
                SDL_PrivateJoystickAxis(joystick, (Uint8) i, (Sint16) value);
            }
        }
    }

    /* joystick button events */
    if (joyinfo.dwFlags & JOY_RETURNBUTTONS) {
        for (i = 0; i < joystick->nbuttons; ++i) {
            if (joyinfo.dwButtons & JOY_BUTTON_FLAG(i)) {
                if (!joystick->buttons[i]) {
                    SDL_PrivateJoystickButton(joystick, (Uint8) i,
                                              SDL_PRESSED);
                }
            } else {
                if (joystick->buttons[i]) {
                    SDL_PrivateJoystickButton(joystick, (Uint8) i,
                                              SDL_RELEASED);
                }
            }
        }
    }

    /* joystick hat events */
    if (joyinfo.dwFlags & JOY_RETURNPOV) {
        Uint8 pos;

        pos = TranslatePOV(joyinfo.dwPOV);
        if (pos != joystick->hats[0]) {
            SDL_PrivateJoystickHat(joystick, 0, pos);
        }
    }
}

/* Function to close a joystick after use */
void
SDL_SYS_JoystickClose(SDL_Joystick * joystick)
{
    if (joystick->hwdata != NULL) {
        /* free system specific hardware data */
        SDL_free(joystick->hwdata);
    }
}

/* Function to perform any system-specific joystick related cleanup */
void
SDL_SYS_JoystickQuit(void)
{
    int i;
    for (i = 0; i < MAX_JOYSTICKS; i++) {
        if (SYS_JoystickName[i] != NULL) {
            SDL_free(SYS_JoystickName[i]);
        }
    }
}


/* implementation functions */
void
SetMMerror(char *function, int code)
{
    static char *error;
    static char errbuf[1024];

    errbuf[0] = 0;
    switch (code) {
    case MMSYSERR_NODRIVER:
        error = "Joystick driver not present";
        break;

    case MMSYSERR_INVALPARAM:
    case JOYERR_PARMS:
        error = "Invalid parameter(s)";
        break;

    case MMSYSERR_BADDEVICEID:
        error = "Bad device ID";
        break;

    case JOYERR_UNPLUGGED:
        error = "Joystick not attached";
        break;

    case JOYERR_NOCANDO:
        error = "Can't capture joystick input";
        break;

    default:
        SDL_snprintf(errbuf, SDL_arraysize(errbuf),
                     "%s: Unknown Multimedia system error: 0x%x",
                     function, code);
        break;
    }

    if (!errbuf[0]) {
        SDL_snprintf(errbuf, SDL_arraysize(errbuf), "%s: %s", function,
                     error);
    }
    SDL_SetError("%s", errbuf);
}

#endif /* SDL_JOYSTICK_WINMM */
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