7 Steps To Master Mouse Interaction with 3D Objects (Beginners)

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In this article I will walk through how to interact with your 3D Game objects using your mouse.

1. Mouse Location on Screen

 

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GSMouseInteraction : MonoBehaviour {

    // Game Scorpion Inc.
    // Mouse Interaction Script
    // Usage: 
    // Put this script on the MAIN Camera or on ANY objects you want to have mouse interaction

    // Private Variables
    private bool b_MouseActionsOnGameObject = false;
    private bool b_MouseDown = false;
    private float f_LastMouseXMovementAmount = 0.0f;
    private float f_LastMouseYMovementAmount = 0.0f;

    // Use this when script becomes active
    private void OnEnable()
    {
        // Make sure the object is NOT the main game camera where the script is placed
        if (gameObject.tag != "MainCamera")
        {
            // Enable all Mouse Detection for OnClick, OnEnter, OnExit functionality
            b_MouseActionsOnGameObject = true;
        }
    }

    // Check Mouse Enter
    private void OnMouseEnter()
    {
        if (b_MouseActionsOnGameObject)
        {
            //Debug.Log("Mouse Entered");
        }
    }

    // Check Mouse Exit
    private void OnMouseExit()
    {
        if (b_MouseActionsOnGameObject)
        {
            //Debug.Log("Mouse Exited");
        }
    }

    private void OnMouseOver()
    {
        if (b_MouseActionsOnGameObject)
        {
            //Debug.Log("Mouse Over Me");
        }
    }

    private void OnMouseUp()
    {
        if (b_MouseActionsOnGameObject)
        {
            b_MouseDown = false;
            //Debug.Log("Mouse Up");
        }
    }

    private void OnMouseDown()
    {
        if (b_MouseActionsOnGameObject)
        {
            // Get LAST X Position of mouse and subtract from current position
            //if (f_LastMouseXMovementAmount <= 0.0f)
            //{
            //    f_LastMouseXMovementAmount = Input.mousePosition.x;
            //}

            // Get LAST Y Position of mouse and subtract from current position
            //if (f_LastMouseYMovementAmount <= 0.0f)
            //{
            //    f_LastMouseYMovementAmount = Input.mousePosition.y;
            //}

            b_MouseDown = true;
            //Debug.Log("Mouse Down");
        }
    }

    private void OnMouseDrag()
    {
        if (b_MouseActionsOnGameObject)
        {
            //Debug.Log("Dragging");
        }
    }


    // Use this for initialization
    void Start ()
    {

	}
	
	// Update is called once per frame
	void Update () {
        // Mouse Location
        //Debug.Log("X: " + Input.mousePosition.x + " Y: " + Input.mousePosition.y);

        // Detect an object (WITH A COLLIDER) under the mouse via hovering
        //RaycastHit hit;
        //Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        //if (Physics.Raycast(ray, out hit))
        //{
        //    Debug.Log(hit.collider.name);
        //}

        // Scrolling
        //Debug.Log("Mouse Scroll: " + Input.mouseScrollDelta.y);

        //// Scroll and Zoom Camera
        //// As long as we are THE CAMERA object, do the following
        //if (!b_MouseActionsOnGameObject)
        //{
        //    // How fast we want to move the camera zoom
        //    float f_CameraZoomFactor = 1.0f;

        //    // Get the current X, Y and Z position of the camera
        //    float f_CamX = gameObject.transform.position.x;
        //    float f_CamY = gameObject.transform.position.y;
        //    float f_CamZ = gameObject.transform.position.z;

        //    // Add the scroll value / 100 to the Y value of the main camera
        //    gameObject.transform.position = new Vector3(f_CamX, f_CamY + (Input.mouseScrollDelta.y / f_CameraZoomFactor), f_CamZ);
        //}

        // If the mouse is down and the object is NOT the camera
        //if (b_MouseDown && b_MouseActionsOnGameObject)
        //{
        //    // Movement Factor
        //    float f_MovementFactor = 100.0f;

        //    // Calculate X Movement Range
        //    float f_MovementRangeX = (Input.mousePosition.x - f_LastMouseXMovementAmount) / f_MovementFactor;

        //    // Calculate Z Movement Range
        //    float f_MovementRangeZ = (Input.mousePosition.y - f_LastMouseYMovementAmount) / f_MovementFactor;

        //    // Move object via a drag by following mouse x, y location and translating to object x, z
        //    gameObject.transform.position = new Vector3(f_MovementRangeX, gameObject.transform.position.y, f_MovementRangeZ);
        //}

        // Move Camera based on mouse cursor hover location in the X and Z coordinates
        // Detect if we are on the camera
        if (!b_MouseActionsOnGameObject)
        {
            // Get the MOUSE X,Y location
            float f_MouseX = Input.mousePosition.x;
            float f_MouseY = Input.mousePosition.y;

            // Get the screen size
            float f_ScreenWidth = Screen.width;
            float f_ScreenHeight = Screen.height;

            // This is the movement speed
            float f_MovementSpeed = 1.0f;

            // Check if mouse is outside of X value on either side of screen
            if (f_MouseX <= 0.0f) { // Move Camera LEFT in X (-f_MovementSpeed) gameObject.transform.position = new Vector3(gameObject.transform.position.x - f_MovementSpeed, gameObject.transform.position.y, gameObject.transform.position.z); } else if (f_MouseX >= f_ScreenWidth)
            {
                // Move Camera RIGHT in X (+f_MovementSpeed)
                gameObject.transform.position = new Vector3(gameObject.transform.position.x + f_MovementSpeed, gameObject.transform.position.y, gameObject.transform.position.z);
            }

            // Check if mouse is outside of Y value on either side of screen
            if (f_MouseY <= 0.0f) { // Move Camera DOWN in Z (-f_MovementSpeed) gameObject.transform.position = new Vector3(gameObject.transform.position.x, gameObject.transform.position.y, gameObject.transform.position.z - f_MovementSpeed); } else if (f_MouseY >= f_ScreenHeight)
            {
                // Move Camera UP in Z (+f_MovementSpeed)
                gameObject.transform.position = new Vector3(gameObject.transform.position.x, gameObject.transform.position.y, gameObject.transform.position.z + f_MovementSpeed);
            }
        }


    }
}