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Fix SDL multitouch tracking (#3810)

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The fingerId from SDL was used as an index into the CORE.Input.Touch
arrays, but it's an opaque / arbitrary int64, way bigger
than MAX_TOUCH_POINTS, so the first non-simulated touch event would segfault.
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mooff 2024-02-29 17:30:38 +00:00 committed by GitHub
parent 6589311a0b
commit 94c79917e3
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1 changed files with 20 additions and 24 deletions
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44
src/platforms/rcore_desktop_sdl.c
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@ -971,6 +971,23 @@ void SetMouseCursor(int cursor)
CORE.Input.Mouse.cursor = cursor;
}
static void UpdateSDLTouchPoints(SDL_TouchFingerEvent event)
{
CORE.Input.Touch.pointCount = SDL_GetNumTouchFingers(event.touchId);
for (int i=0; i<CORE.Input.Touch.pointCount; i++)
{
SDL_Finger *finger = SDL_GetTouchFinger(event.touchId, i);
CORE.Input.Touch.pointId[i] = finger->id;
CORE.Input.Touch.position[i].x = finger->x * CORE.Window.screen.width;
CORE.Input.Touch.position[i].y = finger->y * CORE.Window.screen.height;
CORE.Input.Touch.currentTouchState[i] = 1;
}
for (int i=CORE.Input.Touch.pointCount; i<MAX_TOUCH_POINTS; i++)
CORE.Input.Touch.currentTouchState[i] = 0;
}
// Register all input events
void PollInputEvents(void)
{
@ -1009,15 +1026,7 @@ void PollInputEvents(void)
// Register previous touch states
for (int i = 0; i < MAX_TOUCH_POINTS; i++) CORE.Input.Touch.previousTouchState[i] = CORE.Input.Touch.currentTouchState[i];
// Reset touch positions
// TODO: It resets on target platform the mouse position and not filled again until a move-event,
// so, if mouse is not moved it returns a (0, 0) position... this behaviour should be reviewed!
//for (int i = 0; i < MAX_TOUCH_POINTS; i++) CORE.Input.Touch.position[i] = (Vector2){ 0, 0 };
// Map touch position to mouse position for convenience
// WARNING: If the target desktop device supports touch screen, this behavious should be reviewed!
// https://www.codeproject.com/Articles/668404/Programming-for-Multi-Touch
// https://docs.microsoft.com/en-us/windows/win32/wintouch/getting-started-with-multi-touch-messages
CORE.Input.Touch.position[0] = CORE.Input.Mouse.currentPosition;
int touchAction = -1; // 0-TOUCH_ACTION_UP, 1-TOUCH_ACTION_DOWN, 2-TOUCH_ACTION_MOVE
@ -1207,34 +1216,21 @@ void PollInputEvents(void)
touchAction = 2;
} break;
// Check touch events
// NOTE: These cases need to be reviewed on a real touch screen
case SDL_FINGERDOWN:
{
const int touchId = (int)event.tfinger.fingerId;
CORE.Input.Touch.currentTouchState[touchId] = 1;
CORE.Input.Touch.position[touchId].x = event.tfinger.x * CORE.Window.screen.width;
CORE.Input.Touch.position[touchId].y = event.tfinger.y * CORE.Window.screen.height;
UpdateSDLTouchPoints(event.tfinger);
touchAction = 1;
realTouch = true;
} break;
case SDL_FINGERUP:
{
const int touchId = (int)event.tfinger.fingerId;
CORE.Input.Touch.currentTouchState[touchId] = 0;
CORE.Input.Touch.position[touchId].x = event.tfinger.x * CORE.Window.screen.width;
CORE.Input.Touch.position[touchId].y = event.tfinger.y * CORE.Window.screen.height;
UpdateSDLTouchPoints(event.tfinger);
touchAction = 0;
realTouch = true;
} break;
case SDL_FINGERMOTION:
{
const int touchId = (int)event.tfinger.fingerId;
CORE.Input.Touch.position[touchId].x = event.tfinger.x * CORE.Window.screen.width;
CORE.Input.Touch.position[touchId].y = event.tfinger.y * CORE.Window.screen.height;
UpdateSDLTouchPoints(event.tfinger);
touchAction = 2;
realTouch = true;
} break;