Tag: c#

Change Color on Raycast Hit

Change Color on Raycast Hit

In the process of developing the RB controller, one of the functions I wanted to incorporate was highlighting objects when hit by the raycast. This has been on the dev list for some time, so this basic prototype is well overdue.

The starting point for this functionality is this forum post:


This functionality has been highlighted in a previous post about the Pick Up and Throw functionality, but one bug in the setup was related to the colors ‘sticking’ and not reverting to their original state:

Tangled up in blue – previously selected objects not reverting to their original color

Turns out the reason for this unwanted behaviour was attaching the function to the main player manager and trying to read and store color values on a case by case basis.

By moving the script on to the object itself and allowing that to check for raycast hits, the ‘sticky color’ problem has been resolved while simultaneously streamlining my logic:

  • Each ‘interactable’ object can now have bespoke color values even though they all share the same class
  • No need to compare tags as the interaction is calculated by the object
Testing color change on hit using multiple objects and colors

Heres the related code snippet in the object class – only called if the object is hit:

    public Color defaultColor;
    public Color highlightColor;
    public Transform previousObject = null;
    new Renderer renderer;

//Get the renderer component on this object:
renderer = GetComponent<Renderer>();

//is raycast hitting THIS object?
        if (playerManager.rayCastHit == this.transform)
            //Check if this hit is the same as the stored hit:
            if (previousObject != this.transform)
                //store hit object:
                previousObject = this.transform;

                //change hit object color:
                renderer.material.color = highlightColor;

        //if no raycast hit:
            //Reset hit object material
            renderer.material.color = defaultColor;

            //Clear reference
            previousObject = null;

This basic functionality can now be extended to use a better highlighting effect by utilising Unity’s Shader Graph to produce an edge glow effect. This effect will target the material (not just the color) and offer better representation of selected objects.

I will also post about changing the Interactable Object class to a Scriptable Object that should allow these objects to be instantiated with custom data including materials/textures and bespoke UI messages/information.

Custom Colliders for RigidBodies

Custom Colliders for RigidBodies

While making good progress developing a new RB version of the player (which I’ll post about elsewhere), I stumbled on the issue that the Daleks solved back in the 80s – stairs!!!

After some searching through the forums I found the simplest solution (these things usually end up being quite simple) that I wanted to record here.

The issue is that when importing/using custom objects, Unity will automatically generate a mesh collider for the object using the objects’ base mesh. Thats great and makes for realistic interactions…if you’re using the character controller. Not so great if using a RB based controller as the collision will stop the player dead.

At the start of this project that was one of my reasons for going with a CC based controller, but I wanted to experiment with a RB controller and I’ve found that I prefer it – especially for physics interactions that seem much more fluid, realistic and immersive.

At this point, my RB player is using about 150 lines of code in a player manager along with a few classes ( of < 60 lines of code each) handling things like movement, power updates, raycasts, and writing some outputs to the UI. This compares to my CC main class that was > 880+ lines of code plus extra classes for raycasting etc.

In fact the new RB controller does everything the old CC based controller did, but with a better ‘feel’ , less code (therefore less bug tracking issues) and less (Ahem…..) ‘physics malfunctions‘.

  • I use the term ‘less physics malfunctions’ there as opposed to ‘no physics malfunctions……where the term ‘malfunction’ is best defined as shouting ‘What the hell is going on!!!!’ quite loudly…….

So thats all good apart from the stairs.

The solution is simply to replace the mesh collider generated by Unity with a (or series of) primitive collider(s) (in this case box colliders) as required to ‘approximate’ the overall shape of the mesh.

Colliders are added as Empty children of the mesh and adjusted using their transforms to create a RB friendly shape:

Hierarchy view of stairs and colliders
Side view: fist collider is just a box (in green) that covers the last (topmost) stair
Side View: 2nd collider is a rotated box collider (in green) that changes the ‘surface’ into a ramp
Example of RB player navigating stairs. Left stairs have mesh collider, right stairs have simplified colliders that create a ramp.

So thats it – the simple primitive based series of colliders transforms the stairs into a ramp that an RB can climb.

Some extra trickery can help achieve ‘stair-ness’ such as running a movement script/animation on the camera/player on entering the collider that takes into account current velocity (now easily accessible from the RB player!) and adds an appropriate bob/move/climb action.

Just to prove the usefulness of this approach (esp as a dev tool) here’s the custom collider for the arrow attached to the RB player that I’m using to debug and test the controller:

Hierarchy of colliders
View of colliders (in green) on arrow

The only issue with this that I immediately foresee is the depth to which the 2nd collider ‘juts’ through the ground plane. Not a problem in my sandbox scene but may become a problem when developing an environment that has multiple levels. In that case the colliders may start to act on objects that are below them and provoke some weird behaviour. One solution may be to add more, gradually smaller colliders to the stairs so the depth of ground penetration can be minimised.

Refactoring UI Elements

Refactoring UI Elements

I started this post with just the reference pic above almost 6 weeks ago, so I’ve been trying to remember exactly what I was trying to tell myself here. Fortunately for me I did annotate the code so I’ve managed to backtrack and figure things out.

As with many posts during a period of review and testing this is again about extensibility, reusability and ease of use.

The issue was with the size of the UI prefab – it had become a bit of a goliath with many interdependent elements (objects) being controlled via the centralised UI controller class. This meant that the the UI was a pain to instantiate in a scene as the references were difficult to ‘find’ and were so interwoven with one another that any bug tracking or recycling/repurposing was getting to be a bit of a chore. What I’m always after is rapid prototyping and that means trying to make things that are for the most part drag and drop.

I’ve read so many times across the Unity fora about the importance of keeping things as simple and independent as possible – I think I’ve written a lot about it too – but as ever the best teacher is failure and thats exactly what my giant prefab brought to the fore.

So as of this last iteration of the UI, all child elements are separated out into their own classes and are saved as individual prefabs. This has simplified matters and allowed the whole thing to be come more extensible and flexible in terms of functionality:

Overview of the UI elements

This new arrangement of prefabs can now be used in a modular way and new elements should be able to be introduced with a minimum of fuss as everything is pretty much separate, with each element of the UI existing as its own class containing its own functions that can be referenced and called from anywhere or anything else.

For example, the prefab element called BroadcastMessages contains:

  • its own class
  • a text (TMP) object
  • a background object
  • an animator component

The class itself becomes very simple to manage as its functionality applies only to its children. This functionality is accessed as a function that displays (and animates) incoming text addressed to that function from elsewhere by calling:


public class BroadCastMessages : MonoBehaviour
    TMP_Text broadcastMessages_Text;
    Animator animator_broadcastMessages;

    void Start()
        broadcastMessages_Text = GetComponentInChildren<TMP_Text>();
        animator_broadcastMessages = GetComponentInChildren<Animator>();
        broadcastMessages_Text.enabled = false;

    //public method for receiving messages:
    public void IncomingBroadcastMessages(string message)
        broadcastMessages_Text.text = message;

        if (broadcastMessages_Text.text != null)
            broadcastMessages_Text.enabled = true;
            animator_broadcastMessages.SetBool("broadcastMessage_FadeUp", true);

        if (broadcastMessages_Text.text == null)
            animator_broadcastMessages.SetBool("broadcastMessage_FadeUp", false);
            broadcastMessages_Text.enabled = false;

The upshot of this is that the UI is now a system of prefab elements responsible (in the main) for their own part of the display using no more that 30-40 lines of code:

Outline of UI structure using individual prefabs with individual classes

The only complication/extension in the display I am currently using is the ScreenToWorldPoint method (outlined in this post) that displays a line linking information boxes to specific objects identified and passed from the raycast function in PlayerInteraction(). This display method can be seen in the screen grab at the top of this post.

The information (text) is passed from the raycast hit object to either the RHS or LHS messages class (depending on the objects’ tag).

The information is then displayed using the ScreenToWorldPoint method which I have now simplified by moving into the class UI_Manager – the same function is called by both the RHS and LHS Messages classes so this saves duplication:

public class UI_Manager : MonoBehaviour

    public void FadeUpLineRenderer(LineRenderer lineRenderer, Transform rayHitTransform,
        TMP_Text text)
        //Fade up and link text to the object in world space

    public void FadeDownLineRenderer(LineRenderer lineRenderer, TMP_Text text)
        if (alpha_lineRenderer > 0)
            //Fade down

So this class (UI_manager) gets called by either LHS of RHS messages which provide references to a lineRederer, a Transform and the text. The LHS/RHS messages are accessed themselves using a unique function.

The snippet below is from the LHS_messages class. Its is a slightly more complex version of the Broadcast Messages class but basic functionality is the same – messages are passed to it using the call:


Then the appropriate elements are passed to the function in UI_Manager:




public class LHS_Messages : MonoBehaviour

//Incoming messages public method
    public void IncomingMessages(string message)
        LHS_messageText.text = message;

    void Update()
        //If no raycast hits turn off the displays
        if (playerInteraction.rayCastHitObject == null)
                //fade down UI window
                LHS_messageAnimator.SetBool("LHS_Panel_FadeUp", false);

                //set the rayHitTransform to null
                rayHitTransform = null;

                //Fade Down LineRenderer:
                uI_Manager.FadeDownLineRenderer(lineRenderer, LHS_messageText);

        //if raycast hit display if tag is "Interactable"
        if (playerInteraction.rayCastHitObject != null
            && playerInteraction.rayCastHitObject.CompareTag("Interactable"))
            //turn on this element
            LHS_messageText.enabled = true;
            lineRenderer.enabled = true;

            //Fade up via Animator
            LHS_messageAnimator.SetBool("LHS_Panel_FadeUp", true);

            // set up the generic Transform component:
            rayHitTransform = playerInteraction.rayCastHitObject;

            //ADD THE LINE
            uI_Manager.FadeUpLineRenderer(lineRenderer, rayHitTransform,

Summing up what this approach and refactoring has helped achieve is a more extensible, easier to track/debug and generally much more flexible series of prefabs/classes that can be adapted, reused, repurposed and rewritten as circumstances require.

For example the UI_Manager class is now nothing more complex than an extra function holder that can be logically extended to include and execute any repeated functions that occur within the UI as a whole – I do believe I’m not far away form understanding Properties here so no doubt at some point down the line I’ll have an Aha! moment and write a new post referencing and ridiculing my clumsiness in this one….

That plus perhaps a more important point for me – by trying to employ a more sensible, simplified approach to writing the code in the first place I’m able to come back after a complete absence of some 6 weeks and take only 20 minutes or so to see what I’m doing.

Knowing what I’m trying to do is mostly a good thing…..leaving easy to read comments is definitely a good thing.

Better Referencing in Unity

Better Referencing in Unity

After several months of development trying to keep things as simple as possible has become increasingly important.

With only a few elements on the game sandbox its sometimes been a struggle to quickly iterate and change functionality without breaking relationships and spending hours trawling through the code trying to find bugs and/or having to reattach or redefine references.

In my recent elevator script development this took an extreme turn as the relationships between objects became overly complex and lacking centralised control, so I spent some time looking at ways to simplify the process.

Component references:

Having to constantly drag and drop game object and component references into the script window, the following methods have proved to be useful:

void Start()
            //Cache references in Start() to save memory:

            //get component attached to this game object:
            component = GetComponent<Type>();

            lineRenderer = GetComponent<LineRenderer>();

            //Using the Find method is useful to search the scene but can eventually lead to performance issues
            //so used by caching reference and assigned in Start()

            reference = Type.Find("Name");

            //this can be use in tandem with GetComponent:
            //example from the UI:
            //GET THE GO and derive elements from that:
            LHS_messageObject = GameObject.Find("LHS_Messages");

            //Attached components:
            LHS_messageRectTransform = LHS_messageObject.GetComponent<RectTransform>();
            LHS_messageText = LHS_messageObject.GetComponent<TMP_Text>();
            LHS_messageAnimator = LHS_messageObject.GetComponent<Animator>();

             //Find of Type:
            //This method is useful for finding specific components by type
            //like other classes:

            reference = Component.FindObjectOfType<Type>();

            //example grabbing the player interaction class in the UI:
            playerInteraction = GameObject.FindObjectOfType<PlayerInteraction>();

These methods have been useful in referencing objects/classes and when used in tandem with arrays have proved themselves useful in quickly creating and editing core functionality of the controller class.

        //example using arrays of components:         
        elevatorMechanics = GameObject.FindObjectOfType<ElevatorMechanics>();

        doors = new Transform[elevatorMechanics.numStoreysInThisBuilding];
        doorAnimators = new Animator[elevatorMechanics.numStoreysInThisBuilding];
        doorIsOpen = new bool[elevatorMechanics.numStoreysInThisBuilding];

        for (int i = 0; i < elevatorMechanics.numStoreysInThisBuilding; i++)
            if (transform.GetChild(i).name.Contains("Placeholder"))
                doors[i] = transform.GetChild(i);
                doorAnimators[i] = doors[i].GetComponentInChildren<Animator>();
                doorIsOpen[i] = false;

Saying that, its important to mention (again) that having a centralised point (object/class) within the hierarchy that deals with all the ‘thinking’ of the structure is massively important. Using this approach during the elevator development I was able to cut down hundreds of lines of code across 5 classes to less that 50 lines across 4 of the attached scripts (dealing with individual functions like the buttons control panel, call buttons, triggers and doors) plus a longer ‘controller’ class that deals with the core mechanics of moving, UI, calculating floors and triggering events.

In this hierarchical structure the controller class is ‘aware’ of its own immediate environment in terms of how it should be affected in the world plus a deeper awareness of its children – doors, platform, buttons etc.

In turn, the child elements are aware of nothing except their own functionality and pass that functionality on to the controller class.

As a final note on referencing now that I’ve veered off into architecture, this post is worth mentioning as an extension method for finding objects within a hierarchy structure: https://answers.unity.com/questions/183649/how-to-find-a-child-gameobject-by-name.html

GameObject GetChildWithName(GameObject obj, string name) {
     Transform trans = obj.transform;
     Transform childTrans = trans. Find(name);
     if (childTrans != null) {
         return childTrans.gameObject;
     } else {
         return null;

Elevator Prefab

Elevator Prefab

After more than 2 weeks of wrestling with this idea, illness and the slaughter of more than 2500 orcs in Shadow of War (go go Batman in Mordor!!!) the elevator prefab is now functionally complete.

The idea was to create a functional prefab that would take input from the Inspector and set up arrays of elements allowing the player to interact via:

  • elevator call buttons: one on each floor to call the elevator to that floor if not present
  • a control panel of buttons that allow player to select desired floor.
  • an array of doors that open and close as the elevator reaches their floor

The Inspector takes arguments for number of floors and floor height in order to set up an array of floors that have index of floor number and elements of floor heights. Each floor is modular and modelled and imported from Blender. At this point the structure is built in the Inspector to allow easy access to editing functions:

A note on riding platforms:

After finding some really nasty jitter issues with the character when riding rigidbody platforms I found a solution using this thread to derive the following script. This is attached to the rigidbody collider object in the scene (the elevator platform). The main lines are:

  • other.transform.SetParent(this.transform) – sets the GO OnTriggerEnter as child of the RB object (the GO is the player but not explicit in this example)
  • other.transform.SetParent*null) – remove the parent OnTriggerExit
    private void OnTriggerEnter(Collider other)
    numObjsInTrigger += 1;    
    //In order to stop the jittering caused by riding platforms
    //set the other as a child of the empty parent of the platform


    //Catch trigger events caused by any of the attached GOs
    //whose names contain 'elevator' and return (nullify)
    //the trigger action . Also remove the registered
    //numObjsInTrigger call
    if (other.gameObject.name.Contains("Elevator"))
        numObjsInTrigger -= 1;

    if (numObjsInTrigger >= elevatorMechanics.numObjsToTrigger)
        if (other.transform.CompareTag("Player"))
            //Send the bool message
            playerIsInElevator = true;

private void OnTriggerExit(Collider other)
    numObjsInTrigger -= 1;

    //remove the parenting

    //This stops activation when there is still more
    //than one object in the trigger
    if (numObjsInTrigger < elevatorMechanics.numObjsToTrigger)
        if (other.transform.CompareTag("Player"))
            //send the bool message
            playerIsInElevator = false;


This process has served as a great learning experience especially in terms of organising hierarchy and how that relates to script functionality. In the current iteration of this prefab the top level element (Elevator) controls all movement/animation functions by taking references from children.

This has resulted in an efficient code structure that ensures control functions are accessed within the parent object – the ‘brain’ of this structure – by reaching out to the child elements for references to individual elements – doors, control panel, call buttons and trigger events.

In this way the only loops running at Update exist in the parent object – all children may run loops to set up their own arrays at Start but have no update function. This centralisation of functionality will make this prefab extensible in the future – e.g. while this moves a platform on Y, it would be straightforward (until Quaternions!) to make a platform move on X/Z.

Player: UI Info Overlay

Player: UI Info Overlay

Solution to displaying interactable object information on `UI based on https://forum.unity.com/threads/get-ui-placed-right-over-gameobjects-head.489464/

    //send the ray from the **CAMERA** (not the player)
    rayDirection = camera.transform.TransformDirection(Vector3.forward);
    //point of origin is LOOK - from the camera
    ray_pointOfOrigin = camera.transform.position;
    if (Physics.Raycast(ray_pointOfOrigin, rayDirection,
        out interactableObjectHit, scanRange))
        //Change the color based on object in range
        //Check if the hit obj has Interactable Tag
        if (interactableObjectHit.transform.CompareTag("Interactable"))
            crosshair.color = Color.red;
            //Get the transfrom of the hit object
            rayCastHitObject_transform = interactableObjectHit.transform;
            //Get the name of the hit object
            rayCastHitObject_name = interactableObjectHit.transform.name;
            if (interactableObjectHit.transform == null)
                rayCastHitObject_name = null;
        crosshair.color = Color.white;
        //change the name to null so we can differentiate a
        //no hit event in the UI controller
        rayCastHitObject_name = null;
Running in update to ensure we are updating what we're looking at.
    We are receiveing raycast info from playerinteraction script that gives
    us the name of the object we've hit (we are looking at) using:
    rayCastHitInfo = hit.transform.name;
    We can use this info in the UI to display the name and info about
    the object we're currently looking at.
    if (playerInteraction.rayCastHitObject_name != null)
        //Turn on the components we need in UI
        canvasGroup_interactableObjUI.enabled = true;
        panel_interactableObjUI.enabled = true;
        text_interactableObjUI.enabled = true;
        lineRenderer_hitObjectToUI.enabled = true;
        //add the line
        lineRenderer_hitObjectToUI.startWidth = 0.001f;
        lineRenderer_hitObjectToUI.endWidth = 0.01f;
        //Set up a new V3 to hold the position of the UI element:
        Vector3 UI_element_transform = new Vector3(
            //x and y will attach to pivot points of the UI object set in the Inspector
            //Add 1.0f on z else we won't see the line
        //No. of points on the line (start/end = 2)
        lineRenderer_hitObjectToUI.positionCount = 2;
        //start at position of the UI obj (rayInfo) and change it to World position
        lineRenderer_hitObjectToUI.SetPosition(0, cam.ScreenToWorldPoint(UI_element_transform));
        //second point is position of the object hit by the raycast in playerInteraction
        lineRenderer_hitObjectToUI.SetPosition(1, playerInteraction.rayCastHitObject_transform.position);
        Add the text
        -this needs to pull in pre stored text like a databasethat depends on
        the name of the hit object - playerInteraction.rayCastHitObject_name
Player: Audio Management

Player: Audio Management

After plenty of headaches with audio sources it seems that this solution is best option:

It’s possible to play multiple sounds at once with ONE Audiosource. You can play up to 10-12 audio sources at once (only) by using PlayOneShot(); With it, Unity mix the audio output from the audio clip into a single channel. (Which is why it’s limited to 10-12 clip at once.

The key here is ONLY USING ONESHOT(). The problem comes when using Play() and PlayOneShot() form the same AudioSource.

So the player in the glitch machine has 2 audio source – one for movement and one for SFX that can play simultaneously. The AudioSources are assigned in the Inspector

    public AudioSource audioSourceMovement;
    public AudioSource audioSourceFX;

         MOVEMENT AUDIO (Audio Source 01)
        if (!audioSourceMovement.isPlaying)
            audioSourceMovement.volume = 0.05f;
            audioSourceMovement.pitch = (float)(1.0f +
                (playerDistanceUp * 0.01) + (playerSpeed * 0.01f));
            audioSourceMovement.clip = moveAudio;

         FX AUDIO (Audio Source 02)
        if (!audioSourceFX.isPlaying)
            audioSourceFX.pitch = 1f;
            audioSourceFX.volume = 0.2f;

            if (isBoosting)

            if (playerMovement.current_Power <= 0)

Set up a toggle button using the Input Actions Manager

Set up a toggle button using the Input Actions Manager

Set up a toggle button using the Input Actions Manager: derived from https://forum.unity.com/threads/new-input-system-how-to-use-the-hold-interaction.605587/


if (controls.Gameplay.crouch.triggered) 
{ isCrouching = !isCrouching; //toggle } 
//This will toggle 'crouch' on and off. Also make sure that the 
//controls.Gameplay.crouch.performed/cancelled IS NOT called in