Beginning Scripts

Due to the nature of this game project and its requirements of containing 2D minigames, which all revolve around the mouse - clicking, dragging, dropping. One of the first scripts I made was the DragAndDrop script. This was to be a versatile script with the main purpose of allowing the player with basic mouse controls suitable for a 2D environment. These could then be repurposed into multiple 2D minigames.

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Using the UnityEngine.EventSystems I inherited IPointerDownHandler, IBeginDragHandler, IEndDragHandler, and IDragHandler so the scripts could detect the mouse. Each of these interfaces I have used, send a Debug.Log describing what happens, for example:

• OnPointerDown - tells me the user has clicked

• OnBeginDrag - this shows me when the user begins to drag the GameObjects

• OnDrag - prints log during the drag

• OnEndDrag - prints only when the user lets go and stops dragging

Here is the code for each:

public void OnPointerDown(PointerEventData eventData)
    {
        Debug.Log("Pointer Down");   
    }

public void OnBeginDrag(PointerEventData eventData)
    {
        Debug.Log("Begin Drag");             
        canvasGroup.alpha = .6f;              
        canvasGroup.blocksRaycasts = false;                                          
    }

 public void OnDrag(PointerEventData eventData)
    {
        Debug.Log("During Drag");    
        itemRectTransform.anchoredPosition += eventData.delta / canvas.scaleFactor; 
    }

public void OnEndDrag(PointerEventData eventData)
    {
        Debug.Log("End Drag");        
        canvasGroup.alpha = 1f;           
        canvasGroup.blocksRaycasts = true;  
    }

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Variables and Referencing I've used:

• [SerializeField] private Canvas canvas

We use the serializeField attribute to mark our private canvas variable as serializable

• private RectTransform itemRectTransform

This is to hold the transform details of the item moving

• private CanvasGroup canvasGroup

This creates a reference to the canvas group component so we can use it in our code

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Using these interfaces allow for a classic drag and drop system, think similar to cooking mama on the DS. In further posts, I'm going to show how I have adapted this code for slightly different requirements and minigames.