(Better) Object Pooling

Why Reinvent?

Object Pooling 1.0

Yes, I’ve made videos on Object Pooling already. Yes, there a written post on it too. Does the internet really need another Object Pooling post. No, not really. But I wanted something a bit slicker and easier to use. I wanted a system with:

1. No Object Pool manager.

2. Objects can return themselves without needing to “find” the Object Pool.

3. Can store a reference to a component, not just the gameObject.

4. An interface to make the initialization of objects easy and consistent.

Easily the best video on generics I’ve ever made.

So after a lot of staring at my computer and plenty of false starts in the wrong direction, I came up with what I’m calling Object Pool 2.0. It makes use of generics, interfaces, and actions. So it’s not the easiest to understand object pooling solution but it works. It’s clean and easier to use than my past solutions. I like it.

If you’re just here for the code. You can get it on github. But you should definitely skim a bit further to see how it’s implemented.

If you’re asking why not just use the Unity 2021 object pool solution. Well, I’m scared of Unity 2021 (at this point in time) AND I’ve seen some suggestions that it’s not quite ready for prime time. Plus my solution has some features that Unity’s doesn’t and creating an object pooling solution isn’t hard.

Implementation

Maybe this seems backward. Maybe it is? But I think in the case of this object pool solution, it makes sense to show how it’s implemented before going into the gory details. It’s a reasonably abstract solution and that can make it difficult to wrap your head around. So let’s start with how to use it. Then we’ll get to how it works.

First, there needs to be an object that is responsible for spawning the objects. This object owns the pool and needs a reference to the object being pooled - in the case shown I’m using a gameObject prefab. The spawner object then creates an instance of the object pool and sends a reference to the prefab to the pool so it knows what object it is storing and what to create if it runs out and more are being asked for. To get an object from the pool, we simply need to call Pull.

Spawning object with the Object Pool

Just Slap on the Pool Object component and you’re good to go.

The objects being stored also need some logic to work with the pool. The easiest way to attach that logic is to slap on the Pool Object component to the object prefab. This default component will return the object to the object pool when the object is disabled.

Do you see why I like this solution? Now on to the harder part. Maybe even the fun part. Let’s look at how it works.

A Couple Interfaces

To get things started, I created two interfaces. The first one could be useful if I ever have a need to pool non-monobehaviour objects - but is admittedly not 100% necessary at the moment.The second interface, however, is definitely useful and is a big part of this system working smoothly.

But let’s start with the first interface which helps define the object pool. It has just two functions, a push and a pull. It is a generic interface, where the generic parameter is the type of object that will be stored. This works nicely as then our push and pull functions know what types they will be handling

Is this strictly necessary? Probably not.

The second interface is used to define objects that can be in the object pool. When used as intended the object pool can only contain types that implement the IPoolable interface.

This interface has an initialize function that takes in an Action. This action will get set in the object pool and is intended to be the function that returns the object to the pool. This action is then invoked inside of the ReturnToPool function.

If that doesn’t all make sense. Well, that’s reasonable. It can feel a bit circular. Let’s hope that’s not still the case by the time we get finished.

Creating the Pool

Let’s next take a look at the Object Pool definition - or at least the definition I’m using for monobehaviours. The Object pool itself has a generic parameter T and implements the IPool interface. T is then constrained to be a monobehaviour that must also implement the IPoolable interface.

Next, come the variables and properties for the object pool.

First up are two optional actions. These actions can be assigned in a constructor. This allows you to call a function (or multiple functions) EVERY time an object is pulled out of the pool or pushed back to the pool. This could be used to play SFX, increment a score counter or just about anything. It seemed useful so I stuck it in there.

Next is the stack (first in first out collection) that holds all the pooled objects.

Since we know the object being stored is a component we also know it’s attached to a gameObject. It’s this gameObject that will be instantiated if and when the pool runs out of objects in the stack.

Lastly, I added a property to count the number of objects in the pool. I stole this directly from the Unity object pool solution. I haven’t found a use for it yet, but maybe at some point.

Constructors

When we create a pool we need to tell it what object it will store and I think the easiest and best way to do that is to inject the object (prefab) using a constructor. In some cases, it’s also nice to pre-fill the pool. So the first constructor (and easily added to the second) takes in a number of objects to pre-spawn using the Spawn function.

The second constructor takes in the prefab as well as references for the pullObject and pushObject actions.

Push and Pull

The pull function is called whenever an object from the pool is needed.

First, we check if there are objects in the pool, if there are we pop one out. The gameObject is then set to active and the initialize function on the IPoolable object is called. Notice here that we are providing a reference to the Push function. This is the secret sauce.

This push function is the function used to return an object to the pool. This means the spawned object has a reference to this function and can return itself to the pool. We’ll take a closer look at how this happens later.

We then check if the pullObject action was assigned and if it was we invoke it and pass in the object being spawned.

Finally! We return the object so that whatever object asked for it, can have a reference to it.

The push function is pretty simple. It takes in the object and pushes it onto the stack. It then checks if the pushObject action was assigned and invokes it if it was. Lastly, the gameObject is turned off.

As a side note. the turning on and off of the object in the pull and push functions is not 100% needed, but is there to ensure the object is toggled on and off correctly and to help keep the initialize functions clean.

Poolable Objects

Every object that can go into this pool needs to implement the IPoolable interface. Now in some cases, you might want to implement the interface specifically for a given class.

Both as an example of how to implement the interface and also to provide an easy to use and reusable solution I created the PoolObject class. This component can simply be added to any prefab to allow that prefab to work with the object pool.

When implementing the IPoolable interface we should set the generic parameter to the class that is implementing the interface - PoolObject in the example.

The class will also need an action to store a reference to the push function. The value of this action is set in the initialize function - which was called in the Pull function of the object pool.

The ReturnToPool function, in this example, is called in the OnDisable function. This means all we need to do to return the object to the pool is turn the object off! Inside the function, we check if the returnToPool action has a value and if so, we invoke the action and pass in a reference to the object being sent to the object pool.

Overloads

To make the object pool a bit more useful and user friendly I also added several overloads for the Pull function. These allow the position and rotation of the object to be set when pulling it.

I also created functions that return a gameObject, as in some cases this is what is really needed and not the poolable object component.

One More Example

Since actions (and delegates) can be confusing I thought I’d toss in one more example - that of using the second constructor and assigning functions that will be called EVERY time an object is pushed or pulled from the instance of the object pool.

In this example, I’ve added the CallOnPull and CallOnPush functions. Notice that they must have the input type that is being stored in the object pool. Again the idea here is that these functions could trigger an animation, SFX, a UI counter, just about anything.

And that’s it. It’s an abstract solution but actually pretty simple (note that simple is not the same as easy). That’s both why it took a while to create and why I like it.

Designing a New Game - My Process

Some of my projects….

This is my process. It’s been refined over 8+ years of tinkering with Unity, 2 game jams, and 2 games published to Steam.

My goal with this post is just to share. Share what I’ve learned and share how I am designing my next project. My goal is not to suggest that I’ve found the golden ticket. Cause I haven’t. I’m pretty sure the perfect design process does not exist.

So these are my thoughts. These are the questions I ask myself as I stumble along in the process of designing a project. Maybe this post will be helpful. Maybe it won’t. If it feels long-winded. It probably is.

I’ve tried just opening Unity and designing as I go. It didn’t work out well. So again, this is just me sharing.

TL;DR

• Set a Goal - To Learn? For fun? To sell?

• Play games as research - Play small games and take notes.

• Prototypes system - What don’t you know how to build? Is X or Y actually doable or fun?

• Culling - What takes too long? What’s too hard? What is too complicated?

• Plan - Do the hard work and plan the game. Big and small mechanics. Art. Major systems.

• Minimal Viable Product - Not the game just the basics. Is it fun? How long did it take?

• Build it! - The hardest part. Also the most rewarding.

What Is The Goal?

When starting a new project, I first think about the goal for the project. For me, this is THE key step in designing a project - which is a necessary step to the holy grail of actually FINISHING a project. EVERY other step and decision in the process should reflect back on the goal or should be seen through the lens of that goal. If the design choice doesn’t help to reach the goal, then I need to make a different decision.

Am I making a game to share with friends? Am I creating a tech demo to learn a process or technique? Am I wanting to add to my portfolio of work? What is the time frame? Weeks? Months? Maybe a year or two (scary)?

I want another title in this list!

For this next project, I want to add another game to the OWS Steam library and I’d like to generate some income in the process. I have no dreams of creating the next big hit, but if I could sell 1000 or 10,000 copies - that would be awesome.

I also want to do it somewhat quickly. Ideally, I could have the project done in 6 to 9 months, but 12 to 18 months is more likely with the time I can realistically devote to the project. One thing I do know, is that whatever amount of time I think it’ll take. It’ll likely take double.

Research!

After setting a goal, the next step is research. Always research. And yes. I mean playing games! I look for games that are of a similar scope to what I think I can make. Little games. Games with interesting or unique mechanics. Games made by individuals or MAYBE a team of 2 or 3. As I play I ask myself questions:

What elements do I find fun? What aspects do I not enjoy? Do I want to keep playing? What is making me want to quit? What mechanics or ideas can I steal? What systems do I know or not know how to make? Which systems are complex? What might be easy to add?

Then there are three more questions. These are key and crucial in designing a game and can help to keep the game scope (somewhat) in check. Which in turn is necessary if a game is going to get finished

How did a game developer’s clever design decisions simplify the design? How does a game make something fun without being complex? Why might the developer have made decisions X or Y? What problems did that decision avoid?

These last questions are tough and often have subtle answers. They take thought and intention. Often while designing a game my mind goes towards complexity. Making things bigger and more detailed! Can’t solve problem A? Well, lets bolt-on solution B!

For example, I’ve wanted to make a game where the player can create or build the world. Why not let the player shape the landscape? Add mountains and rivers? Place buildings? Harvest resources? It would be so cool! Right? But it’s a huge time sink. Even worse, it’s complex and could easily be a huge source of bugs.

So a clever solution? I like how I’m calling myself clever. Hex tiles. Yes. Hex tiles. Let the player build the world, but do it on a grid with prefabs. Bam! Same result. Same mechanic. Much simpler solution. It trades a pile of complex code for time spent in Blender designing tiles. Both Zen World and Dorf Romantic are great examples of allowing the player to create the world and doing so without undue complexity.

Navigation can be another tough nut to crack. Issues and bugs pop up all over the place. Units running into each other. Different movement costs. Obstacles. How about navigation in a procedural landscape? Not to mention performance can be an issue with a large number of units.

My “Research” List

Creeper World 4 gets around this in such a simple and elegant way. Have all the units fly in straight lines. Hover. Move. Land. Done.

I am a big believer that constraints can foster creativity. For me, identifying what I can’t do is more important than identifying what I can do.

When I was building Fracture the Flag I wanted the players to be able to claim territory. At first, I wanted to break the map up into regions - something like the Risk map. I struggled with it for a while. One dead end after another. I couldn’t figure out a good solution.

Then I asked, why define the regions? Instead, let the players place flags around the map to claim territory! If a flag gets knocked down the player loses that territory. Want to know if a player can build at position X or Y? They can if it’s close to a flag. So many problems solved. So much simpler and frankly so much more fun.

With research comes a flood of ideas. And it’s crucial to write them down. Grab a notebook. Open a google doc. Or as I recently discovered Google Keep - it’s super lightweight and easy to access on mobile for those ah-ha moments.

I keep track of big picture game ideas as well as smaller mechanics that I find interesting. I don’t limit myself to one idea or things that might nicely fit together. This is the throwing spaghetti at the wall stage of design. I’m throwing it out there and seeing what sticks. Even if, maybe especially if, I get excited about one idea I force myself to think beyond it and come up with multiple concepts and ideas. This is not the time to hyper focus.

At this stage, I also have to bring in a dose of reality. I’m not making an MMO or the next E-Sports tile. I’m dreaming big, but also trying not to waste my time with completely unrealistic dreams. I should probably know how to make at least 70, 80 or maybe 90 percent of the game!

While you’re playing games as “research” support small developers and leave them reviews! Use those reviews to process what you like and what you don’t like. What would you change? What would you keep? What feels good? What would feel better? Those reviews are so crucial to a developer. Yes, even negative ones are helpful.

Prototype Systems - Not The Game

At this point in the process, I get to start scratching the itch to build. Up until now, Unity hasn’t been opened. I’ve had to fight the urge, but it’s been for the best. Until now.

Now I get to prototype systems. Not a game or the game. Just parts of a potential game. This is when I start to explore systems that I haven’t made before or systems I don’t know how to make. I focus on parts that seem tricky or will be core to the game. I want to figure out the viability of an idea or concept.

At this stage, I dive into different research. Not playing games, but watching and reading tutorials and articles. I take notes. Lots of notes. For me, this is like going back to school. I need to learn how other people have created systems or mechanics. Why re-invent the wheel? Sometimes you need to roll your own solution, but why not at least see how other folks have done it first?

If I find a tutorial that feels too complex. I look for another. If that still feels wrong, I start to question the mechanic itself.

Maybe it’s beyond my skill set? Maybe it’s too complex for a guy doing this in his spare time? Or maybe I just need to slow down and read more carefully?

View fullsize

Some prototype Art for a possible Hex tile Game

Understanding and implementing a hex tile system was very much all of the above. Red Blob Games has an excellent guide to hex grids with all the math and examples of code to implement hex grids into your games. It’s not easy. Not even close. But it was fun to learn and with a healthy dose of effort, it’s understandable. (To help cement my understanding, I may do a series of videos on hex grids.)

This stage is also a chance to evaluate systems to see if they could be the basis of a game. I’ve been intrigued by ecosystems and evolution for a long while. Equilinox is a great example of a fairly recent ecosystem-based game made by a single (skilled) individual. Sebastian Lague put together an interesting video on evolution, which was inspired by the Primer videos. All of these made me want to explore the underlying mechanics.

So, I spent a day or two writing code, testing mechanics, and had some fun but ultimately decided it was too fiddly and too hard to base a game on. So I moved on, but it wasn’t a waste of time!

After each prototype is functional, but not polished, I ask myself more questions.

Does the system work? Is the system janky? What parts are missing or still need to be created? Is it too complex or hard to balance? Is there too much content to create? Or maybe it’s just crap?

For me, it’s also important that I’m not trying to integrate different system prototypes (at this point). Not yet. I for sure want to avoid coupling and keep things encapsulated, but I also don’t want to go down a giant rabbit hole. That time may come, but it’s not now. I’m also not trying to polish the prototypes. I want the systems to work and be reasonably robust, but at this point, I don’t even know if the systems will be in a game so I don’t want to waste time.

(Pre-Planning) Let The Culling Begin!

With prototypes of systems built, it’s now time to start chopping out the fluff, the junk, and start to give some shape to a game design. And yes, I start asking more questions.

What are the major systems of the game? What systems are easy or hard to make? Are there still systems I don’t know how to make? What do I still need to learn? What will be the singular core mechanic of the game?

And here’s a crucial question!

What are the time sinks? Even if I know how to do X or Y will it take too long?

3D Models, UI, art, animations, quests, stories, multiplayer, AI…. Basically, everything is a time sink. But!

Which ones play to my strengths? Which ones help me reach my goal? Which ones can I design around or ignore completely? What time sinks can be tossed out and still have a fun game?

Assets I Use

When I start asking these questions it’s easy to fall into the trap of using 3rd party assets to solve my design problems or fill in my lack of knowledge. It’s easy to use too many or use the wrong ones. I need to be very picky about what I use. Doubly so with assets that are used at runtime (as opposed to editor tools). For me, assets need to work out of the box AND work independently. If my 3rd party inventory system needs to talk to my 3rd party quest system which needs to talk to my 3rd party dialogue system I am asking for trouble and I will likely find it.

The asset store is full of shiny objects and rat holes. It’s worth a lot of time to think about what you really need from the asset store.

What you can create on your own? What should you NOT create on your own? What you can design around? Do you really need X or Y?

For me, simple is almost always better. If I do use 3rd party assets, and I do, they need to be part of the prototyping stage. I read the documentation and try to answer as many questions as I can before integrating the asset into my project. If the asset can’t do what I need, then I may have to make hard decisions amount the asset, my design, or even the game as a whole.

I constantly have to remind myself that games aren’t fun because they’re complex. Or at the very least, complexity does not equal fun. What makes games fun is something far more subtle. Complexity is a rat hole. A shiny object.

Deep Breath. Pause. Think.

At this point, I have a rough sketch in my head of the game and it’s easy to get excited and jump into building with both feet. But! I need to stop. Breathe. And think.

Does the game match my goals? Can I actually make the game? Are there mechanics that should be thrown out? Can I simplify the game and still reach my goal? Is this idea truly viable?

Depending on the answers, I might need be to go back and prototype, do more research, or scrap the entire design and start with something a single guy can actually make.

This point is a tipping point. I can slow down and potentially re-design the game or spend the next 6 months discovering my mistakes. Or worse, ignoring my mistakes and wasting even more time as I stick my head in the sand and insist I can build the game. I’ve been there. I’ve done that. And it wasn’t fun.

Now We Plan

Maybe a third of the items on my to do list for Grub Gauntlet

Ha! I bet you thought I was done planning. Not even close. I haven’t even really started.

There are a lot of opinions about the best planning tool. For me, I like Notion. Others like Milanote or just a simple google doc. The tool doesn’t matters, it’s the process. So pick what works for you and don’t spend too much time trying to find the “best” tool. There’s a poop ton of work to do, don’t waste time.

Finding the right level of detail in planning is tough and definitely not a waste of time. I’m not creating some 100+ page Game Design Document. Rather I think of what I'm creating as a to-do list. Big tasks. Small tasks. Medium tasks. I want to plan out all the major systems, all the art, and all the content. This is my chance to think through the game as a whole before sinking 100’s or likely 1000’s of hours into the project.

To some extent, the resulting document forms a contract with myself and helps prevent feature creep. The plan also helps when I’m tired or don’t know what to do next. I can pull up my list and tackle something small or something interesting.

Somewhere in the planning process, I need to decide on a theme or skin for the game. The naming of classes or objects may depend on the theme AND more importantly, some of the mechanics may be easier or harder to implement depending on the theme. For example, Creeper World 4’s flying tanks totally work in the sci-fi-themed world. Not so much if they were flying catapults or swordsmen in a fantasy world. Need to resupply units? Creeper World sends the resources over power lines. Again, way easier than an animated 3D model of a worker using a navigation system to run from point A to point B and back again.

Does the theme match the mechanics? Does it match my skillset? Can I make that style of art? Does the theme help reach the goal? Does the theme simplify mechanics or make them more complex?

Minimum Viable Product (MVP)

Upgrade that

Knowlegde

Finally! Now I get to start building the project structure, writing code, and bringing in some art. But! I’m still not building the game. I’m still testing. I want to get something playable as fast as possible. I need to answer the questions:

Is the game fun? Have I over-scoped the game? Can I actually build it with my current skills and available time?

If I spent 3 months working on an inventory system and all I can do is collect bits on a terrain and sell them to a store. I’ve over-scoped the game. If the game is tedious and not fun then I either need to scrap the game or dig deeper into the design and try to fix it. If the game breaks every time I add something or change a system then I need to rethink the architecture or maybe the scope of the game or upgrade my programming knowledge and skill set.

If I can create the MVP in less than a month and it’s fun then I’m on to something good!

Why so short a time frame? My last project, Grub Gauntlet was created during a 48-hour game jam. I spent roughly 20 hours during that time to essentially create an MVP. It then took another 10 months to release! I figure the MVP is somewhere around 1/10th or 1/20th of the total build time.

It’s way better to lose 1-2 months building, testing, and then decide to scrap the project than to spend 1-2 years building a pile of crap. Or worse! Spend years working only to give up without a finished product.

Can I Build It Now?

This is the part we’re all excited about. Now I get to build, polish, and finish a game. There’s no secret sauce. This part is the hardest. It’s the longest. It’s the most discouraging. It’s also the most rewarding.

If I’ve done my work ahead of time then I should be able to finish my project. And that? That is an amazing feeling!

Strategy Game Camera: Unity's New Input System

I was working on a prototype for a potential new project and I needed a camera controller. I was also using Unity’s “new” input system. And I thought, hey, that could be a good tutorial…

There’s also a written post on the New Input System. Check the navigation to the right.

The goal here is to build a camera controller that could be used in a wide variety of strategy games. And to do it using Unity’s “New” Input System.

The camera controller will include:

• Horizontal motion

• Rotation

• Zoom/elevate mechanic

• Dragging the world with the mouse

• Moving when the mouse is near the screen edge

Since I’ll be using the New Input System, you’ll want to be familiar with that before diving too deep into this camera controller. Check either the video or the written blog post.

If you’re just here for the code or want to copy and paste, you can get the code along with the Input Action Asset on GitHub.

Build the Rig

Camera rig Hierarchy

The first step to getting the camera working is to build the camera rig. For my purposes, I choose to keep it simple with an empty base object that will translate and rotate in the horizontal plane plus a child camera object that will move vertically while also zooming in and out.

I’d also recommend adding in something like a sphere or cube (remove its collider) at the same position as the empty base object. This gives us an idea of what the camera can see and how and where to position the camera object. It’s just easy debugging and once you’re happy with the camera you can delete the extra object.

Camera object transform settings

For my setup, my base object is positioned on the origin with no rotation or scaling. I’ve placed the camera object at (0, 8.3, -8.8) with no rotation (we’ll have the camera “look at” the target in the code).

For your project, you’ll want to play with the location to help tune the feel of your camera.

Input Settings

Input Action Asset for the Camera Controller

For the camera controller, I used a mix of events and directly polling inputs. Sometimes one is easier to use than another. For many of these inputs, I defined them in an Input Action Asset. For some mouse events, I simply polled the buttons directly. If that doesn’t make sense hopefully it will.

In the Input Action Asset, I created an action map for the camera and three actions - movement, rotate, and elevate. For the movement action I created two bindings to allow the WASD keys and arrows keys to be used. It’s easy, so why not? Also important, both rotate and elevate have their action type set to Vector2.

Importantly the rotate action is using the delta of the mouse position not the actual position. This allows for smooth movement and avoids the camera snapping around in a weird way.

We’ll be making use of the C# events. So make sure to save or have auto-save enabled. We also need to generate the C# code. To do this select the Input Action Asset in your project folders and then in the inspector click the “generate C# class” toggle and press apply.

Variables and More Variables!

Next, we need to create a camera controller script and attach it to the base object of our camera rig. Then inside of a camera controller class we need to create our variables. And there’s a poop ton of them.

The first two variables will be used to cache references for use with the input system.

The camera transform variable will cache a reference to the transform with the camera object - as opposed to the empty object that this class will be attached to.

All of the variables with the BoxGroup attribute will be used to tune the motion of the camera. Rather than going through them one by one… I’m hoping the name of the group and the name of the variable clarifies their approximate purpose.

The camera settings I’m using

The last four variables are all used to track various values between functions. Meaning one function might change a value and a second function will make use of that value. None of these need to have their value set outside of the class.

A couple of other bits: Notice that I’ve also added the UnityEngine.InputSystem namespace. Also, I’m using Odin Inspector to make my inspector a bit prettier and keep it organized. If you don’t have Odin, you should, but you can just delete or ignore the BoxGroup attributes.

Horizontal Motion

I’m going to try and build the controller in chunks with each chunk adding a new mechanic or piece of functionality. This also (roughly) means you can add or not add any of the chunks and the camera controller won’t break.

The first chunk is horizontal motion. It’s also the piece that takes the most setup… So bear with me.

First, we need to set up our Awake, OnEnable, and OnDisable functions.

In the Awake function, we need to create an instance of our CameraControls input action asset. While we’re at it we can also grab a reference to the transform of our camera object.

In the OnEnable function, we first need to make sure our camera is looking in the correct direction - we can do this with the LookAt function directed towards the camera rig base object (the same object the code is attached to).

Then we can save the current position to our last position variable - this value will get used to help create smooth motion.

Next, we’ll cache a reference to our MoveCamera action - we’ll be directly polling the values for movement. We also need to call Enable on the Camera action map.

In OnDisable we’ll call Disable on the camera action map to avoid issues and errors in case this object or component gets turned off.

Helper functions to get camera relative directions

Next, we need to create two helper functions. These will return camera relative directions. In particular, we’ll be getting the forward and right directions. These are all we’ll need since the camera rig base will only move in the horizontal plane, we’ll also squash the y value of these vectors to zero for the same reason.

Kind of yucky. But gets the job done.

Admittedly I don’t love the next function. It feels a bit clumsy, but since I’m not using a rigidbody and I want the camera to smoothly speed up and slow down I need a way to calculate and track the velocity (in the horizontal plane). So thus the Update Velocity function.

Nothing too special in the function other than once again squashing the y dimension of the velocity to zero. After calculating the velocity we update the value of the last position for the next frame. This ensures we are calculating the velocity for the frame and not from the start.

The next function is the poorly named Get Keyboard Movement function. This function polls the Camera Movement action to then set the target position.

In order to translate the input into the motion we want we need to be a bit careful. We’ll take the x component of the input and multiply it by the Camera Right function and add that to the y component of the input multiplied by the Camera Forward function. This ensures that the movement is in the horizontal plane and relative to the camera.

We then normalize the resulting vector to keep a uniform length so that the speed will be constant even if multiple keys are pressed (up and right for example).

The last step is to check if the input value’s square magnitude is above a threshold, if it is we add our input value to our target position.

Note that we are NOT moving the object here since eventually there will be multiple ways to move the camera base, we are instead adding the input to a target position vector and our NEXT function will use this target position to actually move the camera base.

If we were okay with herky-jerky movement the next function would be much simpler. If we were using the physics engine (rigidbody) to move the camera it would also be simpler. But I want smooth motion AND I don’t want to tune a rigidbody. So to create smooth ramping up and down of speed we need to do some work. This work will all happen in the Update Base Position function.

First, we’ll check if the square magnitude of the target position is greater than a threshold value. If it is this means the player is trying to get the camera to move. If that’s the case we’ll lerp our current speed up to the max speed. Note that we’re also multiplying Time Delta Time by our acceleration. The acceleration allows us to tune how quickly our camera gets up to speed.

The use of the threshold value is for two reasons. One so we aren’t comparing a float to zero, i.e. asking if a float equals zero can be problematic. Two, if we were using a game controller joystick even if it’s at rest the input value may not be zero.

Testing the Code so far - Smooth Horizontal Motion

We then add to the transform’s position an amount equal to the target position multiplied by the current camera speed and time delta time.

While they might look different these two lines of code are closely related to the Kinematic equations you may have learned in high school physics.

If the player is not trying to get the camera to move we want the camera to smoothly come to a stop. To do this we want to lerp our horizontal velocity (calculated constantly by the previous function) down to zero. Note rather than using our acceleration to control the rate of the slow down, I’ve used a different variable (damping) to allow separate control.

With the horizontal velocity lerping it’s way towards zero, we then add to the transform’s position a value equal to the horizontal velocity multiplied by time delta time.

The final step is to set the target position to zero to reset for the next frame’s input.

Our last step before we can test our code is to add our last three functions into the update function.

Camera Rotation

Okay. The hardest parts are over. Now we can add functionality reasonably quickly!

So let’s add the ability to rotate the camera. The rotation will be based on the delta or change in the mouse position and will only occur when the middle mouse button is pressed.

We’ll be using an event to trigger our rotation, so our first addition to our code is in our OnEnable and OnDisable functions. Here we’ll subscribe and unsubscribe the (soon to be created) Rotate Camera function to the performed event for the rotate camera action.

If you’re new to the input system, you’ll notice that the Rotate Camera function takes in a Callback Context object. This contains all the information about the action.

Rotating the camera should now be a thing!

Inside the function, we’ll first check if the middle mouse button is pressed. This ensures that the rotation doesn’t occur constantly but only when the button is pressed. For readability more than functionality, we’ll store the x value of the mouse delta and use it in the next line of code.

The last piece is to set the rotation of the transform (base object) and only on the y-axis. This is done using the x value of the mouse delta multiplied by the max rotation speed all added to the current y rotation.

And that’s it. With the event getting invoked there’s no need to add the function to our update function. Nice and easy.

Vertical Camera Motion

With horizontal and rotational motion working it would be nice to move the camera up and down to let the player see more or less of the world. For controlling the “zooming” we’ll be using the mouse scroll wheel.

This motion, I found to be one of the more complicated as there were several bits I wanted to include. I wanted there to be a min and max height for the camera - this keeps the player from zooming too far out or zooming down to nothingness - also while going up and down it feels a bit more natural if the camera gets closer or farther away from what it’s looking at.

This zoom motion is another good use of events so we need need to make a couple of additions to the OnEnable and OnDisable. Just like we did with the rotation we need to subscribe and unsubscribe to the performed event for the zoom camera action. We also need to set the value of zoom height equal to the local y position of the camera - this gives an initial value and prevents the camera from doing wacky things.

Then inside the Zoom Camera function, we’ll cache a reference to the y component of the scroll wheel input and divide by 100 - this scales the value to something more useful (in my opinion).

If the absolute value of the input value is greater than a threshold, meaning the player has moved the scroll wheel, we’ll set the zoom height to the local y position plus the input value multiplied by the step size. We then compare the predicted height to the min and max height. If the target height is outside of the allowed limits we set our height to the min or max height respectively.

Once again this function isn’t doing the actual moving it’s just setting a target of sorts. The Update Camera Position function will do the actual moving of the camera.

The first step to move the camera is to use the value of the zoom height variable to create a Vector3 target for the camera to move towards.

Zooming in action

The next line is admittedly a bit confusing and is my attempt to create a zoom forward/backward motion while going up and down. Here we subtract a vector from our target location. The subtracted vector is a product of our zoom speed and the difference between the current height and the target height All of which is multiplied by the vector (0, 0, 1). This creates a vector proportional to how much we are moving vertically, but in the camera’s local forward/backward direction.

Our last steps are to lerp the camera’s position from its current position to the target location. We use our zoom damping variable to control the speed of the lerp.

Finally, we also have the camera look at the base to ensure we are still looking in the correct direction.

Before our zoom will work we need to add both functions to our update function.

If you are having weird zooming behavior it’s worth double-checking the initial position of the camera object. My values are shown at the top of the page. In my testing if the x position is not zero, some odd twisting motion occurs.

Mouse at Screen Edges

At this point, we have a pretty functional camera, but there’s still a bit more polish we can add. Many games allow the player to move the camera when the mouse is near the edges of the screen. Personally, I like this when playing games, but I do find it frustrating when working in Unity as the “screen edges” are defined by the game view…

To create this motion with the mouse all we need to do is check if the mouse is near the edge of the screen.

We do this by using Mouse.current.position.ReadValue(). This is very similar to the “old” input system where we could just call Input.MousePosition.

We also need a vector to track the motion that should occur - this allows the mouse to be in the corner and have the camera move in a diagonal direction.

Screen edge motion

Next, we simply check if the mouse x and y positions are less than or great than threshold values. The edge tolerance variable allows fine tuning of how close to the edge the cursor needs to be - in my case I’m using 0.05.

The mouse position is given to us in pixels not in screenspace coordinates so it’s important that we multiply by the screen width and height respectively. Notice that we are again making use of the GetCameraRight and GetCameraForward functions.

The last step inside the function is to add our move direction vector to the target position.

Since we are not using events this function also needs to get added to our update function.

Dragging the World

I stole and adapted the drag functionality from Game Dev Guide.

The last piece of polish I’m adding is the ability to click and drag the world. This makes for very fast motion and generally feels good. However, a note of caution when implementing this. Since we are using a mouse button to drag this can quickly interfere with other player actions such as placing units or buildings. For this reason, I’ve chosen to use the right mouse button for dragging. If you want to use the left mouse button you’ll need to check if you CAN or SHOULD drag - i.e. are you placing an object or doing something else with your left mouse button. In the past I have used a drag handler… so maybe that’s a better route, but it’s not the direction I choose to go at this point.

I should also admit that I stole and adapted much of the dragging code from a Game Dev Guide video which used the old input system.

Since dragging is an every frame type of thing, I’m once again going to directly poll to determine whether the right mouse button is down and to get the current position of the mouse…

This could probably be down with events, but that seems contrived and I’m not sure I really see the benefit. Maybe I’m wrong.

Inside the Drag Camera function, we can first check if the right button is pressed. If it’s not we don’t want to go any further.

If the button is pressed, we’re going to create a plane (I learned about this in the Game Dev Guide video) and a ray from the camera to the mouse cursor. The plane is aligned with the world XZ plane and is facing upward. When creating the plane the first parameter defines the normal and the second defines a point on the plane - which for the non-math nerds is all you need.

Next, we’ll raycast to the plane. So cool. I totally didn’t know this was a thing!

The out variable of distance tells us how far the ray went before it hit the plane, assuming it hit the plane. If it did hit the plane we’re going to do two different things - depending on whether we just started dragging or if we are continuing to drag.

Dragging the world

If the right mouse button was pressed this frame (learned about this thanks to a YouTube comment) we’ll cache the point on the plane that we hit. And we get that point, by using the Get Point function on our ray.

If the right mouse button wasn’t pressed this frame, meaning we are actively dragging, we can update the target position variable with the vector from where dragging started to where it currently is.

The final step is to add the drag function to our update function.

That’s It!

There you go. The basics of a strategy camera for Unity using the New Input System. Hopefully, this gives you a jumping off point to refine and maybe add features to your own camera controller.