Atlas - SDL_touch.c
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[FILE BEGIN]
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#include "../SDL_internal.h"
22
23/* General touch handling code for SDL */
24
25#include "SDL_assert.h"
26#include "SDL_events.h"
27#include "SDL_events_c.h"
28#include "../video/SDL_sysvideo.h"
29
30
31static int SDL_num_touch = 0;
32static SDL_Touch **SDL_touchDevices = NULL;
33
34
35/* Public functions */
36int
37SDL_TouchInit(void)
38{
39    return (0);
40}
41
42int
43SDL_GetNumTouchDevices(void)
44{
45    return SDL_num_touch;
46}
47
48SDL_TouchID
49SDL_GetTouchDevice(int index)
50{
51    if (index < 0 || index >= SDL_num_touch) {
52        SDL_SetError("Unknown touch device index %d", index);
53        return 0;
54    }
55    return SDL_touchDevices[index]->id;
56}
57
58static int
59SDL_GetTouchIndex(SDL_TouchID id)
60{
61    int index;
62    SDL_Touch *touch;
63
64    for (index = 0; index < SDL_num_touch; ++index) {
65        touch = SDL_touchDevices[index];
66        if (touch->id == id) {
67            return index;
68        }
69    }
70    return -1;
71}
72
73SDL_Touch *
74SDL_GetTouch(SDL_TouchID id)
75{
76    int index = SDL_GetTouchIndex(id);
77    if (index < 0 || index >= SDL_num_touch) {
78        if (SDL_GetVideoDevice()->ResetTouch != NULL) {
79            SDL_SetError("Unknown touch id %d, resetting", (int) id);
80            (SDL_GetVideoDevice()->ResetTouch)(SDL_GetVideoDevice());
81        } else {
82            SDL_SetError("Unknown touch device id %d, cannot reset", (int) id);
83        }
84        return NULL;
85    }
86    return SDL_touchDevices[index];
87}
88
89static int
90SDL_GetFingerIndex(const SDL_Touch * touch, SDL_FingerID fingerid)
91{
92    int index;
93    for (index = 0; index < touch->num_fingers; ++index) {
94        if (touch->fingers[index]->id == fingerid) {
95            return index;
96        }
97    }
98    return -1;
99}
100
101static SDL_Finger *
102SDL_GetFinger(const SDL_Touch * touch, SDL_FingerID id)
103{
104    int index = SDL_GetFingerIndex(touch, id);
105    if (index < 0 || index >= touch->num_fingers) {
106        return NULL;
107    }
108    return touch->fingers[index];
109}
110
111int
112SDL_GetNumTouchFingers(SDL_TouchID touchID)
113{
114    SDL_Touch *touch = SDL_GetTouch(touchID);
115    if (touch) {
116        return touch->num_fingers;
117    }
118    return 0;
119}
120
121SDL_Finger *
122SDL_GetTouchFinger(SDL_TouchID touchID, int index)
123{
124    SDL_Touch *touch = SDL_GetTouch(touchID);
125    if (!touch) {
126        return NULL;
127    }
128    if (index < 0 || index >= touch->num_fingers) {
129        SDL_SetError("Unknown touch finger");
130        return NULL;
131    }
132    return touch->fingers[index];
133}
134
135int
136SDL_AddTouch(SDL_TouchID touchID, const char *name)
137{
138    SDL_Touch **touchDevices;
139    int index;
140
141    index = SDL_GetTouchIndex(touchID);
142    if (index >= 0) {
143        return index;
144    }
145
146    /* Add the touch to the list of touch */
147    touchDevices = (SDL_Touch **) SDL_realloc(SDL_touchDevices,
148                                      (SDL_num_touch + 1) * sizeof(*touchDevices));
149    if (!touchDevices) {
150        return SDL_OutOfMemory();
151    }
152
153    SDL_touchDevices = touchDevices;
154    index = SDL_num_touch;
155
156    SDL_touchDevices[index] = (SDL_Touch *) SDL_malloc(sizeof(*SDL_touchDevices[index]));
157    if (!SDL_touchDevices[index]) {
158        return SDL_OutOfMemory();
159    }
160
161    /* Added touch to list */
162    ++SDL_num_touch;
163
164    /* we're setting the touch properties */
165    SDL_touchDevices[index]->id = touchID;
166    SDL_touchDevices[index]->num_fingers = 0;
167    SDL_touchDevices[index]->max_fingers = 0;
168    SDL_touchDevices[index]->fingers = NULL;
169
170    /* Record this touch device for gestures */
171    /* We could do this on the fly in the gesture code if we wanted */
172    SDL_GestureAddTouch(touchID);
173
174    return index;
175}
176
177static int
178SDL_AddFinger(SDL_Touch *touch, SDL_FingerID fingerid, float x, float y, float pressure)
179{
180    SDL_Finger *finger;
181
182    if (touch->num_fingers == touch->max_fingers) {
183        SDL_Finger **new_fingers;
184        new_fingers = (SDL_Finger **)SDL_realloc(touch->fingers, (touch->max_fingers+1)*sizeof(*touch->fingers));
185        if (!new_fingers) {
186            return SDL_OutOfMemory();
187        }
188        touch->fingers = new_fingers;
189        touch->fingers[touch->max_fingers] = (SDL_Finger *)SDL_malloc(sizeof(*finger));
190        if (!touch->fingers[touch->max_fingers]) {
191            return SDL_OutOfMemory();
192        }
193        touch->max_fingers++;
194    }
195
196    finger = touch->fingers[touch->num_fingers++];
197    finger->id = fingerid;
198    finger->x = x;
199    finger->y = y;
200    finger->pressure = pressure;
201    return 0;
202}
203
204static int
205SDL_DelFinger(SDL_Touch* touch, SDL_FingerID fingerid)
206{
207    SDL_Finger *temp;
208
209    int index = SDL_GetFingerIndex(touch, fingerid);
210    if (index < 0) {
211        return -1;
212    }
213
214    touch->num_fingers--;
215    temp = touch->fingers[index];
216    touch->fingers[index] = touch->fingers[touch->num_fingers];
217    touch->fingers[touch->num_fingers] = temp;
218    return 0;
219}
220
221int
222SDL_SendTouch(SDL_TouchID id, SDL_FingerID fingerid,
223              SDL_bool down, float x, float y, float pressure)
224{
225    int posted;
226    SDL_Finger *finger;
227
228    SDL_Touch* touch = SDL_GetTouch(id);
229    if (!touch) {
230        return -1;
231    }
232
233    finger = SDL_GetFinger(touch, fingerid);
234    if (down) {
235        if (finger) {
236            /* This finger is already down */
237            return 0;
238        }
239
240        if (SDL_AddFinger(touch, fingerid, x, y, pressure) < 0) {
241            return 0;
242        }
243
244        posted = 0;
245        if (SDL_GetEventState(SDL_FINGERDOWN) == SDL_ENABLE) {
246            SDL_Event event;
247            event.tfinger.type = SDL_FINGERDOWN;
248            event.tfinger.touchId = id;
249            event.tfinger.fingerId = fingerid;
250            event.tfinger.x = x;
251            event.tfinger.y = y;
252            event.tfinger.dx = 0;
253            event.tfinger.dy = 0;
254            event.tfinger.pressure = pressure;
255            posted = (SDL_PushEvent(&event) > 0);
256        }
257    } else {
258        if (!finger) {
259            /* This finger is already up */
260            return 0;
261        }
262
263        posted = 0;
264        if (SDL_GetEventState(SDL_FINGERUP) == SDL_ENABLE) {
265            SDL_Event event;
266            event.tfinger.type = SDL_FINGERUP;
267            event.tfinger.touchId =  id;
268            event.tfinger.fingerId = fingerid;
269            /* I don't trust the coordinates passed on fingerUp */
270            event.tfinger.x = finger->x;
271            event.tfinger.y = finger->y;
272            event.tfinger.dx = 0;
273            event.tfinger.dy = 0;
274            event.tfinger.pressure = pressure;
275            posted = (SDL_PushEvent(&event) > 0);
276        }
277
278        SDL_DelFinger(touch, fingerid);
279    }
280    return posted;
281}
282
283int
284SDL_SendTouchMotion(SDL_TouchID id, SDL_FingerID fingerid,
285                    float x, float y, float pressure)
286{
287    SDL_Touch *touch;
288    SDL_Finger *finger;
289    int posted;
290    float xrel, yrel, prel;
291
292    touch = SDL_GetTouch(id);
293    if (!touch) {
294        return -1;
295    }
296
297    finger = SDL_GetFinger(touch,fingerid);
298    if (!finger) {
299        return SDL_SendTouch(id, fingerid, SDL_TRUE, x, y, pressure);
300    }
301
302    xrel = x - finger->x;
303    yrel = y - finger->y;
304    prel = pressure - finger->pressure;
305
306    /* Drop events that don't change state */
307    if (!xrel && !yrel && !prel) {
308#if 0
309        printf("Touch event didn't change state - dropped!\n");
310#endif
311        return 0;
312    }
313
314    /* Update internal touch coordinates */
315    finger->x = x;
316    finger->y = y;
317    finger->pressure = pressure;
318
319    /* Post the event, if desired */
320    posted = 0;
321    if (SDL_GetEventState(SDL_FINGERMOTION) == SDL_ENABLE) {
322        SDL_Event event;
323        event.tfinger.type = SDL_FINGERMOTION;
324        event.tfinger.touchId = id;
325        event.tfinger.fingerId = fingerid;
326        event.tfinger.x = x;
327        event.tfinger.y = y;
328        event.tfinger.dx = xrel;
329        event.tfinger.dy = yrel;
330        event.tfinger.pressure = pressure;
331        posted = (SDL_PushEvent(&event) > 0);
332    }
333    return posted;
334}
335
336void
337SDL_DelTouch(SDL_TouchID id)
338{
339    int i;
340    int index = SDL_GetTouchIndex(id);
341    SDL_Touch *touch = SDL_GetTouch(id);
342
343    if (!touch) {
344        return;
345    }
346
347    for (i = 0; i < touch->max_fingers; ++i) {
348        SDL_free(touch->fingers[i]);
349    }
350    SDL_free(touch->fingers);
351    SDL_free(touch);
352
353    SDL_num_touch--;
354    SDL_touchDevices[index] = SDL_touchDevices[SDL_num_touch];
355
356    /* Delete this touch device for gestures */
357    SDL_GestureDelTouch(id);
358}
359
360void
361SDL_TouchQuit(void)
362{
363    int i;
364
365    for (i = SDL_num_touch; i--; ) {
366        SDL_DelTouch(SDL_touchDevices[i]->id);
367    }
368    SDL_assert(SDL_num_touch == 0);
369
370    SDL_free(SDL_touchDevices);
371    SDL_touchDevices = NULL;
372    SDL_GestureQuit();
373}
374
375/* vi: set ts=4 sw=4 expandtab: */
376
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