How To Do Magnify Glass Effect in Unity

Step 1 Introduction

Sometimes it would be very necessary to implement Magnify Glass Effect in the game when objects or targets are small.

Such like these games:

• Connect Dots - A Puzzle Adventure
• Demolition Crew

Step 2 Implementation in Unity

In unity, it is very simple to implement the Magnify Glass Effect. Just follow the following steps to implement the Magnify Glass Effect:

• Create one new camera object and set its projection type as per the main camera i.e. perspective or orthographic.
• As per your requirement, set orthographicSize or fieldOfView of the camera (depending on camera’s projection type).
• Set its pixelrect as per your requirement. For example if you want to show magnify glass at your mouse position and the size of glass to be 100 x 100, set pixelrect as per given below: magnifyCamera.pixelRect = new Rect (Input.mousePosition.x – 100f / 2.0f, Input.mousePosition.y – 100f / 2.0f, 100f, 100f);
• Set the position of the camera. For example, if you want to show the magnify glass effect at your mouse position then set camera’s position at mousePosition’s world point.

Video:

Example:

The following C# script will create MagnifyGlass and move it to the mousePosition.

MagnifyGlass Script:

• Add the following script on an empty game object.

Step 3 Code Sample

using UnityEngine;
using System.Collections;
 
public class MagnifyGlass : MonoBehaviour
{
private Camera magnifyCamera;
private GameObject magnifyBorders;
private LineRenderer LeftBorder, RightBorder, TopBorder, BottomBorder; // Reference for lines of magnify glass borders
private float MGOX,MG0Y; // Magnify Glass Origin X and Y position
private float MGWidth = Screen.width/5f,MGHeight = Screen.width/5f; // Magnify glass width and height
private Vector3 mousePos;
 
void Start ()
{
createMagnifyGlass ();
}
void Update ()
{
// Following lines set the camera's pixelRect and camera position at mouse position
magnifyCamera.pixelRect = new Rect (Input.mousePosition.x - MGWidth / 2.0f, Input.mousePosition.y - MGHeight / 2.0f, MGWidth, MGHeight);
mousePos = getWorldPosition (Input.mousePosition);
magnifyCamera.transform.position = mousePos;
mousePos.z = 0;
magnifyBorders.transform.position = mousePos;
}
 
// Following method creates MagnifyGlass
private void createMagnifyGlass()
{
GameObject camera = new GameObject("MagnifyCamera");
MGOX = Screen.width / 2f - MGWidth/2f;
MG0Y = Screen.height / 2f - MGHeight/2f;
magnifyCamera = camera.AddComponent<Camera>();
magnifyCamera.pixelRect = new Rect(MGOX, MG0Y, MGWidth, MGHeight);
magnifyCamera.transform.position = new Vector3(0,0,0);
if(Camera.main.isOrthoGraphic)
{
magnifyCamera.orthographic = true;
magnifyCamera.orthographicSize = Camera.main.orthographicSize / 5.0f;//+ 1.0f;
createBordersForMagniyGlass ();
}
else
{
magnifyCamera.orthographic = false;
magnifyCamera.fieldOfView = Camera.main.fieldOfView / 10.0f;//3.0f;
}
 
}
 
// Following method sets border of MagnifyGlass
private void createBordersForMagniyGlass()
{
magnifyBorders = new GameObject ();
LeftBorder = getLine ();
LeftBorder.SetVertexCount(2);
LeftBorder.SetPosition(0,new Vector3(getWorldPosition(new Vector3(MGOX,MG0Y,0)).x,getWorldPosition(new Vector3(MGOX,MG0Y,0)).y-0.1f,-1));
LeftBorder.SetPosition(1,new Vector3(getWorldPosition(new Vector3(MGOX,MG0Y+MGHeight,0)).x,getWorldPosition(new Vector3(MGOX,MG0Y+MGHeight,0)).y+0.1f,-1));
LeftBorder.transform.parent = magnifyBorders.transform;
TopBorder = getLine ();
TopBorder.SetVertexCount(2);
TopBorder.SetPosition(0,new Vector3(getWorldPosition(new Vector3(MGOX,MG0Y+MGHeight,0)).x,getWorldPosition(new Vector3(MGOX,MG0Y+MGHeight,0)).y,-1));
TopBorder.SetPosition(1,new Vector3(getWorldPosition(new Vector3(MGOX+MGWidth,MG0Y+MGHeight,0)).x,getWorldPosition(new Vector3(MGOX+MGWidth,MG0Y+MGHeight,0)).y,-1));
TopBorder.transform.parent = magnifyBorders.transform;
RightBorder = getLine ();
RightBorder.SetVertexCount(2);
RightBorder.SetPosition(0,new Vector3(getWorldPosition(new Vector3(MGOX+MGWidth,MG0Y+MGWidth,0)).x,getWorldPosition(new Vector3(MGOX+MGWidth,MG0Y+MGWidth,0)).y+0.1f,-1));
RightBorder.SetPosition(1,new Vector3(getWorldPosition(new Vector3(MGOX+MGWidth,MG0Y,0)).x,getWorldPosition(new Vector3(MGOX+MGWidth,MG0Y,0)).y-0.1f,-1));
RightBorder.transform.parent = magnifyBorders.transform;
BottomBorder = getLine ();
BottomBorder.SetVertexCount(2);
BottomBorder.SetPosition(0,new Vector3(getWorldPosition(new Vector3(MGOX+MGWidth,MG0Y,0)).x,getWorldPosition(new Vector3(MGOX+MGWidth,MG0Y,0)).y,-1));
BottomBorder.SetPosition(1,new Vector3(getWorldPosition(new Vector3(MGOX,MG0Y,0)).x,getWorldPosition(new Vector3(MGOX,MG0Y,0)).y,-1));
BottomBorder.transform.parent = magnifyBorders.transform;
}
 
// Following method creates new line for MagnifyGlass's border
private LineRenderer getLine()
{
LineRenderer line = new GameObject("Line").AddComponent<LineRenderer>();
line.material = new Material(Shader.Find("Diffuse"));
line.SetVertexCount(2);
line.SetWidth(0.2f,0.2f);
line.SetColors(Color.black, Color.black);
line.useWorldSpace = false;
return line;
}
private void setLine(LineRenderer line)
{
line.material = new Material(Shader.Find("Diffuse"));
line.SetVertexCount(2);
line.SetWidth(0.2f,0.2f);
line.SetColors(Color.black, Color.black);
line.useWorldSpace = false;
}
 
// Following method calculates world's point from screen point as per camera's projection type
public Vector3 getWorldPosition(Vector3 screenPos)
{
Vector3 worldPos;
if(Camera.main.isOrthoGraphic)
{
worldPos = Camera.main.ScreenToWorldPoint (screenPos);
worldPos.z = Camera.main.transform.position.z;
}
else
{
worldPos = Camera.main.ScreenToWorldPoint (new Vector3 (screenPos.x, screenPos.y, Camera.main.transform.position.z));
worldPos.x *= -1;
worldPos.y *= -1;
}
return worldPos;
}
}

I hope this blog post will help you to how to do Magnify Glass Effect in Unity. Let me know in a comment if you have any questions regarding Unity. I will reply you ASAP.

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Swati Patel

I am professional Game Developer, developing games in cocos2d(for iOS) and unity(for all platforms). Games are my passion and I aim to create addictive, high quality games. I have been working in this field since 1 year.