新增觸控支援

如要處理觸控輸入事件，請讀取遊戲迴圈中的陣列 motionEvents。這些事件包含自上次清除這些陣列之後發生的事件。包含的事件數量會儲存在 motionEventsCount 中。

1. 疊代並處理遊戲迴圈中的各個事件。在這個範例中，以下程式碼會疊代 motionEvents，並透過 handle_event 進行處理：

   for(size_t i = 0; i < mApp->motionEventsCount; ++i) {
     GameActivityMotionEvent* motionEvent = mApp->motionEvents[i];
   
     int action = motionEvent->action;
     int actionMasked = action & AMOTION_EVENT_ACTION_MASK;
     int ptrIndex = (action & AMOTION_EVENT_ACTION_POINTER_INDEX_MASK) >>
       AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT;
   
     struct CookedEvent ev;
     memset(&ev, 0, sizeof(ev));
   
     if (actionMasked == AMOTION_EVENT_ACTION_DOWN ||
       actionMasked == AMOTION_EVENT_ACTION_POINTER_DOWN) {
         ev.type = COOKED_EVENT_TYPE_POINTER_DOWN;
     } else if (actionMasked == AMOTION_EVENT_ACTION_UP ||
       actionMasked == AMOTION_EVENT_ACTION_POINTER_UP) {
         ev.type = COOKED_EVENT_TYPE_POINTER_UP;
     } else {
         ev.type = COOKED_EVENT_TYPE_POINTER_MOVE;
     }
   
     ev.motionPointerId = motionEvent->pointers[ptrIndex].id;
     ev.motionIsOnScreen = motionEvent->source == AINPUT_SOURCE_TOUCHSCREEN;
     ev.motionX = GameActivityPointerInfo_getX(
       &motionEvent->pointers[ptrIndex]);
     ev.motionY = GameActivityPointerInfo_getY(
       &motionEvent->pointers[ptrIndex]);
   
     if (ev.motionIsOnScreen) {
       // Use screen size as the motion range.
       ev.motionMinX = 0.0f;
       ev.motionMaxX = SceneManager::GetInstance()->GetScreenWidth();
       ev.motionMinY = 0.0f;
       ev.motionMaxY = SceneManager::GetInstance()->GetScreenHeight();
     }
   
     handle_event(&ev);
   }
   

2. 完成後，請記得清除剛處理的事件佇列：

   android_app_clear_motion_events(mApp);