src/joystick/windows/SDL_mmjoystick.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_config.h"

#ifdef SDL_JOYSTICK_WINMM

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

#include "../../core/windows/SDL_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 Windows 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);
        joystick->hwdata = NULL;
    }
}

/* 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]);
            SYS_JoystickName[i] = NULL;
        }
    }
}


/* 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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