添加触控支持

要处理触控输入事件,请阅读游戏循环中的 motionEvents 数组。它们包含自上次清空这些数组以来发生的事件。所含事件的数量存储在 motionEventsCount 中。

  1. 迭代和处理游戏循环中的每个事件。在此示例中,以下代码会迭代 motionEvents 并通过 handle_event 进行处理:

    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. 操作完成后,请记得清除刚刚处理的事件队列:

    android_app_clear_motion_events(mApp);