Graphic Raycaster in Unity

Ever wonder how one can click on GUI elements without using any event script on GUI components.

On button click, On value change are some event driven functions of GUI components but what if I want to perform any action without using these event driven function.

Well there are plenty of ways of doing it but the one I am going to discuss today is GRAPHIC RAYCASTER.

Scene Setup

Step1. Create two images, add any sprite to it and change their name to specify them later on. (For this tutorial purpose let’s assume penguin and polar bear)

Put the images adjacent to each other.

Script

Step2. Create a script and attach it to your canvas.

Write down the following code.

Make sure to call all the libraries.

Next is our global variables

Graphical raycaster is used to call the raycaster attach to your canvas,

Eventsystem is also used to call the event system of canvas.

PointereventData is used to know the mouse position.

Initialize both Raycaster and eventsystem in start method.

In update method whenever the user press the mouse button we initialize the pointer event data and its position as mouse position.

To understand this just try to hover your mouse over images and select eventsystem you will notice some value changing in eventsytem that; what all we are accessing with scripting.

Click on any image and boom name of that image is printed on console.

One other thing to notice in this is if you place your images one above each other the Rayacaster will always point to the lower most GUI element.

To get the name of upper GUI element you can use an array to store all the elements the Raycaster hit and then access it from your array.

Step1. Put all the GUI element above each other.

Step2.Add a list in your script globally.

And add the below red marked line to your script.

Step3. Compile and run and you will notice in your script list is formed and on click it initialize the list with GUI elements the Raycaster Hits.

I have made a game using Grapical Raycaster, so i can say that this technique comes really handy soon going to share the whole game tutorial with you guys.

Till than Happy Coding