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comparison src/events/SDL_touch.c @ 5126:d79ff339d1f2

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Fixed bug #1056 (Frequent crashes in Touch events by simply touching the screen) Joseba García Echebarria 2010-12-15 01:55:22 PST I believe the crash is caused by a check not being performed on wether an SDL_Touch element is NULL before using it in the SDL_SendTouchMotion function in src/events/SDL_touch.c around line 400. Judging from the rest of the code, there's a missing if (!touch) { return 0; } before using "touch" as SDL_GetFinger(), SDL_GetFingerIndexId() use touch->num_fingers without checking. I can attach a patch if you like. It seems pretty straightforward, though. I have yet to discover why touch is being returned as NULL as this error is only triggered when an actual gesture has been performed, maybe something related to SDL_AddTouch()?
author Sam Lantinga <slouken@libsdl.org>
date Fri, 28 Jan 2011 10:21:58 -0800
parents 8bf5781fc582
children b530ef003506
comparison
equal deleted inserted replaced
5125:dc0dfdd58f27 5126:d79ff339d1f2
395 int 395 int
396 SDL_SendTouchMotion(SDL_TouchID id, SDL_FingerID fingerid, int relative, 396 SDL_SendTouchMotion(SDL_TouchID id, SDL_FingerID fingerid, int relative,
397 float xin, float yin, float pressurein) 397 float xin, float yin, float pressurein)
398 { 398 {
399 int index = SDL_GetTouchIndexId(id); 399 int index = SDL_GetTouchIndexId(id);
400 SDL_Touch *touch = SDL_GetTouch(id); 400 SDL_Touch *touch;
401 SDL_Finger *finger = SDL_GetFinger(touch,fingerid); 401 SDL_Finger *finger;
402 int posted; 402 int posted;
403 Sint16 xrel, yrel; 403 Sint16 xrel, yrel;
404 float x_max = 0, y_max = 0; 404 float x_max = 0, y_max = 0;
405 Uint16 x; 405 Uint16 x;
406 Uint16 y; 406 Uint16 y;
407 Uint16 pressure; 407 Uint16 pressure;
408 408
409 touch = SDL_GetTouch(id);
409 if (!touch) { 410 if (!touch) {
410 return SDL_TouchNotFoundError(id); 411 return SDL_TouchNotFoundError(id);
411 } 412 }
412 413
413 //scale to Integer coordinates 414 //scale to Integer coordinates
416 pressure = (Uint16)((yin+touch->pressure_min)*(touch->pressureres)/(touch->native_pressureres)); 417 pressure = (Uint16)((yin+touch->pressure_min)*(touch->pressureres)/(touch->native_pressureres));
417 if(touch->flush_motion) { 418 if(touch->flush_motion) {
418 return 0; 419 return 0;
419 } 420 }
420 421
422 finger = SDL_GetFinger(touch,fingerid);
421 if(finger == NULL || !finger->down) { 423 if(finger == NULL || !finger->down) {
422 return SDL_SendFingerDown(id,fingerid,SDL_TRUE,xin,yin,pressurein); 424 return SDL_SendFingerDown(id,fingerid,SDL_TRUE,xin,yin,pressurein);
423 } else { 425 } else {
424 /* the relative motion is calculated regarding the last position */ 426 /* the relative motion is calculated regarding the last position */
425 if (relative) { 427 if (relative) {
494 finger->last_y = finger->y; 496 finger->last_y = finger->y;
495 finger->last_pressure = finger->pressure; 497 finger->last_pressure = finger->pressure;
496 return posted; 498 return posted;
497 } 499 }
498 } 500 }
501
499 int 502 int
500 SDL_SendTouchButton(SDL_TouchID id, Uint8 state, Uint8 button) 503 SDL_SendTouchButton(SDL_TouchID id, Uint8 state, Uint8 button)
501 { 504 {
502 SDL_Touch *touch = SDL_GetTouch(id); 505 SDL_Touch *touch;
503 int posted; 506 int posted;
504 Uint32 type; 507 Uint32 type;
505 508
506 509
510 touch = SDL_GetTouch(id);
507 if (!touch) { 511 if (!touch) {
508 return SDL_TouchNotFoundError(id); 512 return SDL_TouchNotFoundError(id);
509 } 513 }
510 514
511 /* Figure out which event to perform */ 515 /* Figure out which event to perform */