Unity Top Down Character Controller

Many people are familiar with game genres such as FPS (First-Person Shooter) and RTS (Real-Time Strategy), but there are also a large number of games that do not fall into just one specific category. One of such games is Top-Down Shooter.

Top-Down Shooter is a type of game where the player is controlled from a top-view perspective.

Examples of top-down shooters are Hotline Miami, Hotline Miami 2, Original Grand Theft Auto, etc.

To make a Top-Down Character Controller in Unity, follow the steps below.

Step 1: Create the Scripts

For this tutorial, we will only need one script.

Create a new script, name it SC_TopDownController, remove everything from it and paste the code below inside it:

SC_TopDownController.cs

using UnityEngine;

[RequireComponent(typeof(Rigidbody))]
[RequireComponent(typeof(CapsuleCollider))]

public class SC_TopDownController : MonoBehaviour
{
    //Player Camera variables
    public enum CameraDirection { x, z }
    public CameraDirection cameraDirection = CameraDirection.x;
    public float cameraHeight = 20f;
    public float cameraDistance = 7f;
    public Camera playerCamera;
    public GameObject targetIndicatorPrefab;
    //Player Controller variables
    public float speed = 5.0f;
    public float gravity = 14.0f;
    public float maxVelocityChange = 10.0f;
    public bool canJump = true;
    public float jumpHeight = 2.0f;
    //Private variables
    bool grounded = false;
    Rigidbody r;
    GameObject targetObject;
    //Mouse cursor Camera offset effect
    Vector2 playerPosOnScreen;
    Vector2 cursorPosition;
    Vector2 offsetVector;
    //Plane that represents imaginary floor that will be used to calculate Aim target position
    Plane surfacePlane = new Plane();

    void Awake()
    {
        r = GetComponent<Rigidbody>();
        r.freezeRotation = true;
        r.useGravity = false;

        //Instantiate aim target prefab
        if (targetIndicatorPrefab)
        {
            targetObject = Instantiate(targetIndicatorPrefab, Vector3.zero, Quaternion.identity) as GameObject;
        }

        //Hide the cursor
        Cursor.visible = false;
    }

    void FixedUpdate()
    {
        //Setup camera offset
        Vector3 cameraOffset = Vector3.zero;
        if (cameraDirection == CameraDirection.x)
        {
            cameraOffset = new Vector3(cameraDistance, cameraHeight, 0);
        }
        else if (cameraDirection == CameraDirection.z)
        {
            cameraOffset = new Vector3(0, cameraHeight, cameraDistance);
        }

        if (grounded)
        {
            Vector3 targetVelocity = Vector3.zero;
            // Calculate how fast we should be moving
            if (cameraDirection == CameraDirection.x)
            {
                targetVelocity = new Vector3(Input.GetAxis("Vertical") * (cameraDistance >= 0 ? -1 : 1), 0, Input.GetAxis("Horizontal") * (cameraDistance >= 0 ? 1 : -1));
            }
            else if (cameraDirection == CameraDirection.z)
            {
                targetVelocity = new Vector3(Input.GetAxis("Horizontal") * (cameraDistance >= 0 ? -1 : 1), 0, Input.GetAxis("Vertical") * (cameraDistance >= 0 ? -1 : 1));
            }
            targetVelocity *= speed;

            // Apply a force that attempts to reach our target velocity
            Vector3 velocity = r.velocity;
            Vector3 velocityChange = (targetVelocity - velocity);
            velocityChange.x = Mathf.Clamp(velocityChange.x, -maxVelocityChange, maxVelocityChange);
            velocityChange.z = Mathf.Clamp(velocityChange.z, -maxVelocityChange, maxVelocityChange);
            velocityChange.y = 0;
            r.AddForce(velocityChange, ForceMode.VelocityChange);

            // Jump
            if (canJump && Input.GetButton("Jump"))
            {
                r.velocity = new Vector3(velocity.x, CalculateJumpVerticalSpeed(), velocity.z);
            }
        }

        // We apply gravity manually for more tuning control
        r.AddForce(new Vector3(0, -gravity * r.mass, 0));

        grounded = false;

        //Mouse cursor offset effect
        playerPosOnScreen = playerCamera.WorldToViewportPoint(transform.position);
        cursorPosition = playerCamera.ScreenToViewportPoint(Input.mousePosition);
        offsetVector = cursorPosition - playerPosOnScreen;

        //Camera follow
        playerCamera.transform.position = Vector3.Lerp(playerCamera.transform.position, transform.position + cameraOffset, Time.deltaTime * 7.4f);
        playerCamera.transform.LookAt(transform.position + new Vector3(-offsetVector.y * 2, 0, offsetVector.x * 2));

        //Aim target position and rotation
        targetObject.transform.position = GetAimTargetPos();
        targetObject.transform.LookAt(new Vector3(transform.position.x, targetObject.transform.position.y, transform.position.z));

        //Player rotation
        transform.LookAt(new Vector3(targetObject.transform.position.x, transform.position.y, targetObject.transform.position.z));
    }

    Vector3 GetAimTargetPos()
    {
        //Update surface plane
        surfacePlane.SetNormalAndPosition(Vector3.up, transform.position);

        //Create a ray from the Mouse click position
        Ray ray = playerCamera.ScreenPointToRay(Input.mousePosition);

        //Initialise the enter variable
        float enter = 0.0f;

        if (surfacePlane.Raycast(ray, out enter))
        {
            //Get the point that is clicked
            Vector3 hitPoint = ray.GetPoint(enter);

            //Move your cube GameObject to the point where you clicked
            return hitPoint;
        }

        //No raycast hit, hide the aim target by moving it far away
        return new Vector3(-5000, -5000, -5000);
    }

    void OnCollisionStay()
    {
        grounded = true;
    }

    float CalculateJumpVerticalSpeed()
    {
        // From the jump height and gravity we deduce the upwards speed 
        // for the character to reach at the apex.
        return Mathf.Sqrt(2 * jumpHeight * gravity);
    }
}

Step 2: Create the Shader

This tutorial also requires a custom shader, which is needed to make the Aim target overlay the rest of the Objects (always on top).

Right click on the Project view -> Create -> Shader -> Standart Surface Shader
Name the shader “Cursor”

Open the shader, remove everything inside it then paste the code below:

Cursor.shader

Shader "Custom/FX/Cursor" {
	Properties {
		_MainTex ("Base", 2D) = "white" {}
	}
	
	CGINCLUDE

		#include "UnityCG.cginc"

		sampler2D _MainTex;
		
		half4 _MainTex_ST;
						
		struct v2f {
			half4 pos : SV_POSITION;
			half2 uv : TEXCOORD0;
		};

		v2f vert(appdata_full v) {
			v2f o;
			
			o.pos = UnityObjectToClipPos (v.vertex);	
			o.uv.xy = TRANSFORM_TEX(v.texcoord, _MainTex);
					
			return o; 
		}
		
		fixed4 frag( v2f i ) : COLOR {	
			return tex2D (_MainTex, i.uv.xy);
		}
	
	ENDCG
	
	SubShader {
		Tags { "RenderType" = "Transparent" "Queue" = "Transparent+100"}
		Cull Off
		Lighting Off
		ZWrite Off
		ZTest Always
		Fog { Mode Off }
		Blend SrcAlpha OneMinusSrcAlpha
		
	Pass {
	
		CGPROGRAM
		
		#pragma vertex vert
		#pragma fragment frag
		#pragma fragmentoption ARB_precision_hint_fastest 
		
		ENDCG
		 
		}
				
	} 
	FallBack Off
}

Step 3: Set up Top-Down Character Controller

Let’s set up a Top-Down Character Controller:

Create a new GameObject and call it “Player”
Create a new Cube and scale it (In my case the scale is (1, 2, 1))
Create a second Cube, scale it much smaller and move it to an upper area (This is simply to know which direction the player is looking)
Move both Cubes inside the “Player” Object and remove their BoxCollider components

Now, before going further, let’s create the Aim target prefab:

Create a new GameObject and call it “AimTarget”
Create a new Quad (GameObject -> 3D Object -> Quad) and move it inside the “AimTarget” Object
Assign the Texture below to a Quad and change the Material Shader to ‘Custom/FX/Cursor’

Save the “AimTarget” to Prefab and remove it from Scene

Back to the Player instance:

Attach SC_TopDownController script to the “Player” Object (You will notice that it added some additional components such as Rigidbody and CapsuleCollider)
Scale the CapsuleCollider until it matches the player model (in my case the Height is set to 2 and the Center is set to (0, 1, 0)