Atlas - SDL_sysjoystick.c
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1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 Sam Lantinga <[email protected]>
4
5  This software is provided 'as-is', without any express or implied
6  warranty.  In no event will the authors be held liable for any damages
7  arising from the use of this software.
8
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12
13  1. The origin of this software must not be misrepresented; you must not
14     claim that you wrote the original software. If you use this software
15     in a product, an acknowledgment in the product documentation would be
16     appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18     misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20*/
21
22#include "../../SDL_internal.h"
23
24#ifdef SDL_JOYSTICK_EMSCRIPTEN
25
26#include <stdio.h>              /* For the definition of NULL */
27#include "SDL_error.h"
28#include "SDL_events.h"
29
30#include "SDL_joystick.h"
31#include "SDL_assert.h"
32#include "SDL_timer.h"
33#include "SDL_log.h"
34#include "SDL_sysjoystick_c.h"
35#include "../SDL_joystick_c.h"
36
37static SDL_joylist_item * JoystickByIndex(int index);
38
39static SDL_joylist_item *SDL_joylist = NULL;
40static SDL_joylist_item *SDL_joylist_tail = NULL;
41static int numjoysticks = 0;
42static int instance_counter = 0;
43
44static EM_BOOL
45Emscripten_JoyStickConnected(int eventType, const EmscriptenGamepadEvent *gamepadEvent, void *userData)
46{
47    int i;
48
49    SDL_joylist_item *item;
50
51    if (JoystickByIndex(gamepadEvent->index) != NULL) {
52      return 1;
53    }
54
55    item = (SDL_joylist_item *) SDL_malloc(sizeof (SDL_joylist_item));
56    if (item == NULL) {
57        return 1;
58    }
59
60    SDL_zerop(item);
61    item->index = gamepadEvent->index;
62
63    item->name = SDL_strdup(gamepadEvent->id);
64    if ( item->name == NULL ) {
65        SDL_free(item);
66        return 1;
67    }
68
69    item->mapping = SDL_strdup(gamepadEvent->mapping);
70    if ( item->mapping == NULL ) {
71        SDL_free(item->name);
72        SDL_free(item);
73        return 1;
74    }
75
76    item->naxes = gamepadEvent->numAxes;
77    item->nbuttons = gamepadEvent->numButtons;
78    item->device_instance = instance_counter++;
79
80    item->timestamp = gamepadEvent->timestamp;
81
82    for( i = 0; i < item->naxes; i++) {
83        item->axis[i] = gamepadEvent->axis[i];
84    }
85
86    for( i = 0; i < item->nbuttons; i++) {
87        item->analogButton[i] = gamepadEvent->analogButton[i];
88        item->digitalButton[i] = gamepadEvent->digitalButton[i];
89    }
90
91    if (SDL_joylist_tail == NULL) {
92        SDL_joylist = SDL_joylist_tail = item;
93    } else {
94        SDL_joylist_tail->next = item;
95        SDL_joylist_tail = item;
96    }
97
98    ++numjoysticks;
99
100    SDL_PrivateJoystickAdded(numjoysticks - 1);
101
102#ifdef DEBUG_JOYSTICK
103    SDL_Log("Number of joysticks is %d", numjoysticks);
104#endif
105
106#ifdef DEBUG_JOYSTICK
107    SDL_Log("Added joystick with index %d", item->index);
108#endif
109
110    return 1;
111}
112
113static EM_BOOL
114Emscripten_JoyStickDisconnected(int eventType, const EmscriptenGamepadEvent *gamepadEvent, void *userData)
115{
116    SDL_joylist_item *item = SDL_joylist;
117    SDL_joylist_item *prev = NULL;
118
119    while (item != NULL) {
120        if (item->index == gamepadEvent->index) {
121            break;
122        }
123        prev = item;
124        item = item->next;
125    }
126
127    if (item == NULL) {
128        return 1;
129    }
130
131    if (item->joystick) {
132        item->joystick->hwdata = NULL;
133    }
134
135    if (prev != NULL) {
136        prev->next = item->next;
137    } else {
138        SDL_assert(SDL_joylist == item);
139        SDL_joylist = item->next;
140    }
141    if (item == SDL_joylist_tail) {
142        SDL_joylist_tail = prev;
143    }
144
145    /* Need to decrement the joystick count before we post the event */
146    --numjoysticks;
147
148    SDL_PrivateJoystickRemoved(item->device_instance);
149
150#ifdef DEBUG_JOYSTICK
151    SDL_Log("Removed joystick with id %d", item->device_instance);
152#endif
153    SDL_free(item->name);
154    SDL_free(item->mapping);
155    SDL_free(item);
156    return 1;
157}
158
159/* Function to perform any system-specific joystick related cleanup */
160static void
161EMSCRIPTEN_JoystickQuit(void)
162{
163    SDL_joylist_item *item = NULL;
164    SDL_joylist_item *next = NULL;
165
166    for (item = SDL_joylist; item; item = next) {
167        next = item->next;
168        SDL_free(item->mapping);
169        SDL_free(item->name);
170        SDL_free(item);
171    }
172
173    SDL_joylist = SDL_joylist_tail = NULL;
174
175    numjoysticks = 0;
176    instance_counter = 0;
177
178    emscripten_set_gamepadconnected_callback(NULL, 0, NULL);
179    emscripten_set_gamepaddisconnected_callback(NULL, 0, NULL);
180}
181
182/* Function to scan the system for joysticks.
183 * It should return 0, or -1 on an unrecoverable fatal error.
184 */
185static int
186EMSCRIPTEN_JoystickInit(void)
187{
188    int retval, i, numjs;
189    EmscriptenGamepadEvent gamepadState;
190
191    numjoysticks = 0;
192    numjs = emscripten_get_num_gamepads();
193
194    /* Check if gamepad is supported by browser */
195    if (numjs == EMSCRIPTEN_RESULT_NOT_SUPPORTED) {
196        return SDL_SetError("Gamepads not supported");
197    }
198
199    /* handle already connected gamepads */
200    if (numjs > 0) {
201        for(i = 0; i < numjs; i++) {
202            retval = emscripten_get_gamepad_status(i, &gamepadState);
203            if (retval == EMSCRIPTEN_RESULT_SUCCESS) {
204                Emscripten_JoyStickConnected(EMSCRIPTEN_EVENT_GAMEPADCONNECTED,
205                                             &gamepadState,
206                                             NULL);
207            }
208        }
209    }
210
211    retval = emscripten_set_gamepadconnected_callback(NULL,
212                                                      0,
213                                                      Emscripten_JoyStickConnected);
214
215    if(retval != EMSCRIPTEN_RESULT_SUCCESS) {
216        EMSCRIPTEN_JoystickQuit();
217        return SDL_SetError("Could not set gamepad connect callback");
218    }
219
220    retval = emscripten_set_gamepaddisconnected_callback(NULL,
221                                                         0,
222                                                         Emscripten_JoyStickDisconnected);
223    if(retval != EMSCRIPTEN_RESULT_SUCCESS) {
224        EMSCRIPTEN_JoystickQuit();
225        return SDL_SetError("Could not set gamepad disconnect callback");
226    }
227
228    return 0;
229}
230
231/* Returns item matching given SDL device index. */
232static SDL_joylist_item *
233JoystickByDeviceIndex(int device_index)
234{
235    SDL_joylist_item *item = SDL_joylist;
236
237    while (0 < device_index) {
238        --device_index;
239        item = item->next;
240    }
241
242    return item;
243}
244
245/* Returns item matching given HTML gamepad index. */
246static SDL_joylist_item *
247JoystickByIndex(int index)
248{
249    SDL_joylist_item *item = SDL_joylist;
250
251    if (index < 0) {
252        return NULL;
253    }
254
255    while (item != NULL) {
256        if (item->index == index) {
257            break;
258        }
259        item = item->next;
260    }
261
262    return item;
263}
264
265static int
266EMSCRIPTEN_JoystickGetCount(void)
267{
268    return numjoysticks;
269}
270
271static void
272EMSCRIPTEN_JoystickDetect(void)
273{
274}
275
276static const char *
277EMSCRIPTEN_JoystickGetDeviceName(int device_index)
278{
279    return JoystickByDeviceIndex(device_index)->name;
280}
281
282static SDL_JoystickID
283EMSCRIPTEN_JoystickGetDeviceInstanceID(int device_index)
284{
285    return JoystickByDeviceIndex(device_index)->device_instance;
286}
287
288/* Function to open a joystick for use.
289   The joystick to open is specified by the device index.
290   This should fill the nbuttons and naxes fields of the joystick structure.
291   It returns 0, or -1 if there is an error.
292 */
293static int
294EMSCRIPTEN_JoystickOpen(SDL_Joystick * joystick, int device_index)
295{
296    SDL_joylist_item *item = JoystickByDeviceIndex(device_index);
297
298    if (item == NULL ) {
299        return SDL_SetError("No such device");
300    }
301
302    if (item->joystick != NULL) {
303        return SDL_SetError("Joystick already opened");
304    }
305
306    joystick->instance_id = item->device_instance;
307    joystick->hwdata = (struct joystick_hwdata *) item;
308    item->joystick = joystick;
309
310    /* HTML5 Gamepad API doesn't say anything about these */
311    joystick->nhats = 0;
312    joystick->nballs = 0;
313
314    joystick->nbuttons = item->nbuttons;
315    joystick->naxes = item->naxes;
316
317    return (0);
318}
319
320/* Function to update the state of a joystick - called as a device poll.
321 * This function shouldn't update the joystick structure directly,
322 * but instead should call SDL_PrivateJoystick*() to deliver events
323 * and update joystick device state.
324 */
325static void
326EMSCRIPTEN_JoystickUpdate(SDL_Joystick * joystick)
327{
328    EmscriptenGamepadEvent gamepadState;
329    SDL_joylist_item *item = (SDL_joylist_item *) joystick->hwdata;
330    int i, result, buttonState;
331
332    if (item) {
333        result = emscripten_get_gamepad_status(item->index, &gamepadState);
334        if( result == EMSCRIPTEN_RESULT_SUCCESS) {
335            if(gamepadState.timestamp == 0 || gamepadState.timestamp != item->timestamp) {
336                for(i = 0; i < item->nbuttons; i++) {
337                    if(item->digitalButton[i] != gamepadState.digitalButton[i]) {
338                        buttonState = gamepadState.digitalButton[i]? SDL_PRESSED: SDL_RELEASED;
339                        SDL_PrivateJoystickButton(item->joystick, i, buttonState);
340                    }
341
342                    /* store values to compare them in the next update */
343                    item->analogButton[i] = gamepadState.analogButton[i];
344                    item->digitalButton[i] = gamepadState.digitalButton[i];
345                }
346
347                for(i = 0; i < item->naxes; i++) {
348                    if(item->axis[i] != gamepadState.axis[i]) {
349                        /* do we need to do conversion? */
350                        SDL_PrivateJoystickAxis(item->joystick, i,
351                                                  (Sint16) (32767.*gamepadState.axis[i]));
352                    }
353
354                    /* store to compare in next update */
355                    item->axis[i] = gamepadState.axis[i];
356                }
357
358                item->timestamp = gamepadState.timestamp;
359            }
360        }
361    }
362}
363
364/* Function to close a joystick after use */
365static void
366EMSCRIPTEN_JoystickClose(SDL_Joystick * joystick)
367{
368    SDL_joylist_item *item = (SDL_joylist_item *) joystick->hwdata;
369    if (item) {
370        item->joystick = NULL;
371    }
372}
373
374static SDL_JoystickGUID
375EMSCRIPTEN_JoystickGetDeviceGUID(int device_index)
376{
377    SDL_JoystickGUID guid;
378    /* the GUID is just the first 16 chars of the name for now */
379    const char *name = EMSCRIPTEN_JoystickGetDeviceName(device_index);
380    SDL_zero(guid);
381    SDL_memcpy(&guid, name, SDL_min(sizeof(guid), SDL_strlen(name)));
382    return guid;
383}
384
385static int
386EMSCRIPTEN_JoystickRumble(SDL_Joystick * joystick, Uint16 low_frequency_rumble, Uint16 high_frequency_rumble, Uint32 duration_ms)
387{
388    return SDL_Unsupported();
389}
390
391SDL_JoystickDriver SDL_EMSCRIPTEN_JoystickDriver =
392{
393    EMSCRIPTEN_JoystickInit,
394    EMSCRIPTEN_JoystickGetCount,
395    EMSCRIPTEN_JoystickDetect,
396    EMSCRIPTEN_JoystickGetDeviceName,
397    EMSCRIPTEN_JoystickGetDeviceGUID,
398    EMSCRIPTEN_JoystickGetDeviceInstanceID,
399    EMSCRIPTEN_JoystickOpen,
400    EMSCRIPTEN_JoystickRumble,
401    EMSCRIPTEN_JoystickUpdate,
402    EMSCRIPTEN_JoystickClose,
403    EMSCRIPTEN_JoystickQuit,
404};
405
406#endif /* SDL_JOYSTICK_EMSCRIPTEN */
407
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