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The thoughts and opinions expressed are those of the writer and not Gamasutra or its parent company.

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FPS (first-person shooter) games have been a staple in the video game industry ever since the explosion of Wolfenstein 3D back in 1992. Since then, the genre has been evolving with graphical upgrades, huge budgets, and an eSports ecosystem. But what about its core, the shooting mechanics? How have we progressed on that front? Why do some guns feel like it’s the real thing, while others feel like toys?

“How do bullets work in video games?”

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In the earlier days, many games relied on a technique called raycasting to render 3D environments onto 2D images (your screen). Raycasting also allows the engine to determine the first object intersected by a ray. Developers then started to question, “What if that ray originated from the muzzle of a gun to mimic a bullet?” With this idea, hitscan was born.

Above: An example of raycasting

In most implementations of a hitscan weapon, when the player shoots a bullet, the physics engine will:

• Figure out the direction the gun is pointing at,
• Cast a ray from the muzzle of the gun until a defined range,
• Use raycasting to determine if the ray hit an object.

If the engine determines that an object is in the line of fire, it will notify it with a message that it was “hit” with a bullet. The target then can do all the calculations needed to register the damage.

Above: From Unity. Point A represents a gun casts a ray until its maximum point B. The ray makes contact with the cube, which the engine will tell it has been hit.

Hitscan is simple at its core, but a lot of different modifications can be made to support other logic:

• If we continue the ray past the first object that it hit, we can penetrate multiple objects in a line, like the railgun in Quake
• Removing the maximum range of the ray means that we can shoot out a laser that will continue forever until we hit something
• Programming certain surfaces to be reflective, to bounce bullets off of

Above: Overwatch. Genji’s deflect is an example of a reflective surface.

The main advantage of using raycasting is that it’s super fast. It’s quick to compute and does not need overhead memory or processing time to build a new physics object. That means the network engineering needed to keep many clients in sync is minimal since the server only needs to keep track of the direction of the ray. Recoil is simple to add, as the addition of a small perturbation in the aim of the gun will mimic the effect.

Thus, it’s no surprise that many games in the industry use hitscan for its shooting logic. Wolfenstein 3D and Doom are classic examples, but even recent games use this technology. Characters such as Soldier 76, McCree and Widowmaker from Overwatch have hitscan weapons, and most Call of Duty guns are hitscan as well.

Below: Examples from Overwatch, Call of Duty, Wolfenstein 3D

So why don’t all games use this method?

First, you may have noticed that rays have an infinite traveling velocity, thus reaching their destination instantly. There is no travel time after you fire a bullet and hit an object. This means it’s impossible to dodge a bullet if a ray is on target, even if the target is miles away.

Above: Halo. Notice how the muzzle flare and the hit effects on the ground show up at the same time.

Second, most implementations of hitscan use straight rays. This means it’s hard to account for wind, gravity, and other external factors that may affect the bullet once it leaves the gun. Programmers can add kinks and bends to the ray to help it mimic real rounds, but once the player shoots a ray, there is no real way to modify its path in the middle.

A lot of “casual” games end up using the hitscan method as it simplifies the learning curve for most beginner players. But what about games that aim to create an “immersive and realistic” shooting experience? They cannot achieve their goals within these constraints. We need to use an alternative method.

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It sounds pretty fancy, but the high-level idea is straightforward. Every bullet or projectile shot out of a weapon creates a new physics object in the environment. It has its own mass, velocity, and hitbox that the engine will track.

Above: Max Payne 3

The advantages of using projectile ballistics shine in games where realism is the top priority. Since every projectile exists on its own, you can now factor in wind, friction, gravity, temperature; any force that should act on the bullet. Now that you can change the physics, players can now use weapons other than simple guns and lasers; you can now add grenade and rockets to your arsenal.

Since bullets under this system aren’t moving at the speed of light, you can also implement temporal features:

• “Bullet-time” as seen in Max Payne, Sniper Elite or Superhot is feasible.
• Travel time for projectiles, which means if you’re taking a long-distance shot (or shooting a slow-moving projectile), aiming ahead becomes crucial.
• Delayed explosions on projectiles, like grenades

With these additional computations, the processing is more taxing relative to using hitscan. Servers will have to do a lot more work to make sure all the objects are in sync, and discrepancies or conflicts in logic across clients have to be resolved not to create inconsistent experiences for players on the same server.

Below: Examples from Superhot, Battlefield 1, Overwatch

There are many ways around this to squeeze out as much performance as possible. An example of engine optimization is to have a “pool” of objects loaded before playtime, and “warp in and enable” them when needed. Once it hits a surface, you can play a ballistics animation and disable the projectile, saving it for later. This method will reduce some computation and memory costs from creating and destroying objects over and over again.

There are also multiple ways to do the computations, but the high-level difference is where they decide to process a “tick” of a game, a unit of time measurement:

• The tick is calculated separately from the rendering logic, which means the game will have a more accurate representation of the objects even if there are frame skips. More logic is needed to calculate the exact time that passed since the last render.
• Calculating the tick on every frame; binding the physics to the frame rate. If you disable frame rate caps or start to drop frames, you can see the accelerated or choppy effects on the world.

The consequence of tying movement to ticks is clear when projectiles are moving fast enough to cover large amounts of distance between ticks. You may run into situations where objects seem to “phase through” each other since they were never overlapping in the engine.

All of this sounds fancy, thus leading many people to think that this is a relatively new method; but it actually predates hitscan! Before FPS games, there were already many top-down shooters, such as Asteroids, Space Invaders or Galaxian. These are arcade games from the 70s that were already implementing projectile ballistics, albeit a bit primitive.

Above: Asteroids. The bullets are a bit hard to see, but they are there!

Even with all these features, we’re not able to create a realistic representation of the real world. Is there a way we can get the advantages of both methods?

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Yes, we can!

Most game engines can handle both types of bullet simulations: hitscan and projectile ballistics. This gives the option to have a huge variety of weapons; games such as Halo, GTA, and Half-Life have weapons that can support both types of physics.

Below: Halo. The Assault Rifle uses hitscan; the Needler uses projectile ballistics

Developers can also mix two techniques to cover the weaknesses of each system to provide an even more life-like experience. For example, to fix the issue of objects phasing through each other from projectile ballistics, each bullet can draw a ray every tick of the engine. This helps the engine to see if any of the rays would intersect between ticks, colliding mid-air.

They can also be blended to enhance features in a game. A great example of this is in the Sniper Elite series; after pulling the trigger, the engine uses hitscan to determine if the shot is close enough to any detectable target to trigger slow motion. If true, it will fire a bullet with projectile ballistics in bullet-time.

Above: Sniper Elite

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And that about covers the basics about how bullets work in video games! It’s interesting to see that the field is more focused on smaller refinements and improvements rather than massive overhauls. We haven’t made significant bounds and leaps after the first few revolutionary games were released.

So what now? What lies on the road ahead?

I don’t see the hybrid approach going away anytime soon due to the extra features it provides, but I predict a lot of the improvements will happen on projectile ballistics. As we continue to increase the frequency of the tick computation (with increased CPU power), we will be able to approach the asymptotic limit of “real-life” bullet simulation.

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This article was based on a Quora answer I posted. I would like to thank Pavel Drotár, Renaud Kyokushin, Paul Winstone, and Jason Fletcher for their comments.

Originally published on my Medium account. You can find me on Twitter.

Chooseco, the owner of the “Choose Your Own Adventure” trademark and the publisher behind the modern run of “Choose Your Own Adventure” gamebooks, has issued takedown notices to a number of indie games hosted on itch.io over their use of “Choose Your Own Adventure” in the descriptions for their games.

From Barcade to Kleenex, it’s not uncommon for trademarked product names to slip into the common lexicon and become informal ways to describe similar products. Though, as Chooseco’s trademark infringement notices highlight, adopting those terms leaves developers open to legal complications.

In the case of “Choose Your Own Adventure”, the term is often informally used to describe the sorts of interactive stories where players are able to make choices that send a story down diverging paths both in video games, books, and other interactive media as a whole.

Itch.io founder Leaf Corcoran​ tweeted a word of warning to indie developers that the book publisher was exercising its legal rights as owner of the trademarked term, later telling The Verge that the platform is suspending flagged games to avoid issues with its web host in the meantime.

warning to any devs using the phrase “choose your own adventure” to describe their games, Chooseco is issuing takedown notices to @itchio for trademark infringement. Example game page they went after: pic.twitter.com/YG0JGUoHAA

— leaf @ itch.io ? (@moonscript) December 9, 2019

He tells the publication that this isn’t the first time Chooseco has issued takedown notices against games on itch.io, but notes that the platform typically tries to help the developers of affected games remove infringing content from their itchi.io pages when trademark infringement notices come into play.

While this latest wave of takedowns seems to be aimed at indie developers, Chooseco has taken similar actions against larger entities in the past. At the beginning of 2019 for instance, the company sued Netflix for trademark infringement for its use of the “Choose Your Own Adventure” brand within its interactive film Bandersnatch, accusing the massive entertainment company of purposefully using the brand’s ‘80s roots to “capitalize on viewers’ nostalgia.”

Silverblue is an operating system for your desktop built on Fedora. It’s excellent for daily use, development, and container-based workflows. It offers numerous advantages such as being able to roll back in case of any problems. If you want to update to Fedora 31 on your Silverblue system, this article tells you how. It not only shows you what to do, but also how to revert back if anything unforeseen happens.

Prior the the update to Fedora 31 it is better to do any pending upgrades.

Updating using GNOME Software

Unfortunately the update can’t be done in GNOME Software right now, because of a bug in GNOME Software itself. For additional information please look at upstream issue.

Updating using terminal

If you do not like GNOME Software or like to do everything in terminal, than this next guide is for you.

Updating to Fedora 31 using terminal is easy. First, check if the 31 branch is available, which should be true now:

$ ostree remote refs fedora

You should see the following in the output:

fedora:fedora/31/x86_64/silverblue

Next, rebase your system to the Fedora 31 branch.

$ rpm-ostree rebase fedora:fedora/31/x86_64/silverblue

Finally, the last thing to do is restart your computer and boot to Fedora 31.

How to revert things back

If anything bad happens — for instance, if you can’t boot to Fedora 31 at all — it’s easy to go back. Just pick the previous entry in GRUB, and your system will start in its previous state before switching to Fedora 31. To make this change permanent, use the following command:

$ rpm-ostree rollback

That’s it. Now you know how to rebase to Fedora 31 and back. So why not do it today?

After launching on PC back in December 2014, The Talos Principle is launching on Switch later today almost five years to the day after its debut.

It’s a single-player game from Croatian developer Croteam, the creators of the Serious Sam series, and launched to widespread acclaim five years ago. A first-person narrative puzzler, it features over 120 environmental head-scratchers and has you exploring ancient ruins littered with sexy tech.

Here’s a list of the key features from the game’s page, followed by a few screenshots:

– Overcome more than 120 immersive puzzles in a stunning world.
– Divert drones, manipulate laser beams and even replicate time to prove your worth – or to find a way out.
– Explore a story about humanity, technology and civilization. Uncover clues, devise theories, and make up your own mind.
– Choose your own path through the game’s non-linear world, solving puzzles your way.

No word yet on exactly what makes this the ‘Deluxe Edition’, but we’ll let you know as soon as we find out. It’ll take up 3.5GBs of space on your Switch and will set you back $29.99. We’ll investigate as soon as possible to let you know how the Switch version holds up, but it’s certainly nice to see it on Nintendo’s console.

Kitfox Games has revealed that it is bringing its dating sim/dungeon crawler mashup Boyfriend Dungeon to the Nintendo Switch next year.

Set in a world where boyfriends can also transform into powerful weapons, you’ll need to find the perfect date in order to conquer the game’s monster-filled levels. If you succeed in capturing their hearts, then they will level-up and become even more powerful in battle.

Developed “in coordination with dating-dungeon fans”, Boyfriend Dungeon seems like the perfect counterpoint to Is It Wrong To Try To Pick Up Girls In A Dungeon, if you ask us. Let us know if you’ll be giving it a spin in 2020.

Autodesk have just released their annual update to Maya, Maya 2020.  Detailed release notes are currently unavailable so all we have to go off right now is the press release features:

Maya 2020 highlights include:

— Over 60 animation features and updates to the graph editor and time slider.

— Cached Playback: Experience faster animation playback and more predictable results with new preview modes, layered dynamics caching, and more efficient caching of image planes.

— Animation bookmarks: Mark, organize, and navigate through specific events in time and frame playback ranges.

— Arnold GPU: Access Arnold 6 for production rendering on the CPU and GPU.

— Bifrost for Maya: Significant performance improvements, Cached Playback support, and new MPM cloth constraints bring even more power to the visual programming environment.

— Viewport improvements: Interact with and select dense geometry or a large number of smaller meshes faster in the viewport and UV editors.

— Modeling enhancements: Spend more time modeling and less time cleaning up your models, with new Remesh and Retopologize features.

— Rigging improvements: Simplify rig and character TD work with matrix-driven workflows, nodes for precisely tracking positions on deforming geometry, and a new GPU-accelerated wrap deformer.

While not currently updated, you will eventually be able to download a 30 day trial of Maya 2020 here.  Additionally Autodesk have released a short 4min feature video for Maya 2020 available here.  You can learn more about this release in the video below.

Art GameDev News 3D Applications

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At the end of October we reviewed an indie mobile war game called Pacific Fire, where you can play through several scenarios that simulate parts (or all) of the Pacific theatre of World War 2. There are grand campaigns for both the Japanese and the American sides, for example, and as the player you must utilize land, air and sea assets in a WEGO turn-based format to capture victory points and scenario objectives.

It originally launched on Android only, but we’ve been keeping in touch with the developers at Wirraway Software regarding the iOS version. We are pleased to report that it’s now available to purchase on the App Store as well as a Universal app.

You should read our Pacific Fire review in full to get the full details, but here’s an excerpt:

You are given several scenarios to try your hand at, pushing air, land, and sea units between bases in order to complete your objectives for the scenario, generally on a strict turn limit of x amount of months. Notably, the game uses WEGO, a turn method that sees both sides make their moves simultaneously, then showing how the action played out at the beginning of the next turn. This format suits Pacific Fire wonderfully, as the Pacific theatre’s naval engagements were defined by the opposing fleets guessing the other’s position, attempting them to coax them into a decisive battle on their own terms.

We had a quick catch-up with the devs to ask what’s on the horizon for them – more support and content for Pacific Fire is coming, as well as a potential sequel that will use the same core mechanics, but focus on a different war. It’s good to see some fresh spaces in this space, as mobile war gaming has taken a bit of a down-turn in recent years.

If you do end up picking up Pacific Fire on iOS, let us know what you thought in the comments!

Announcing the biggest global TweetMeet to date. Join us on December 17

Following the success of the Best of 2018 TweetMeet, we’re thrilled to offer the biggest global TweetMeet to date on Tuesday, December 17. Share your best stories and experiences from 2019 and what plans for 2020 you look forward to the most. We’re also most interested to learn how you think Microsoft can support you best.

With all this in mind, we welcome you to a 75-minute TweetMeet on Tuesday, December 17 at 10am PST. Do check your local event times.

Don’t miss What’s New in EDU Live on Facebook

We’re launching a new edition of What’s new in EDU looking back at everything that was new with Microsoft Education in 2019.

This episode will go live on Facebook on December 17 at 6am EST

Introducing the hosts

We’ve invited all former hosts to lead this special-edition TweetMeet, and we’re excited to announce that 275+ previous hosts gladly agree to take part in the event. Follow them all through the Twitter List of December’s MSFTEduChat Hosts.

Do you remember all the previous TweetMeets and their hosts? Take a trip down TweetMeet Memory Lane with this new video, which shows all Combined Headshot images since we first started in the summer of 2016:

Flipgrid topic for December 17

Many TweetMeet hosts have exciting stories to tell about their projects and experiences in 2019. And of course, they have plans for 2020 as well. Be inspired with the new Flipgrid topic for December 17: flipgrid.com/fedb380d

Road2TweetMeet Wakelet: what’s it like to be a TweetMeet host?

Over the past months, our hosts have been reflecting on their blog about what it means to be a host on an #MSFTEduChat TweetMeet. The brand-new Road2TweetMeet Wakelet contains the best of these host reflections, live-embedded here:

TweetMeet Fan? Show it off on your Twitter profile!

Show your passion for this month’s Best of 2019 TweetMeet by uploading this month’s #MSFTEduChat Twitter Header Photo as a banner on your own Twitter profile.

Twitter Header Photos are available in many languages and time zones.

Watch the animated GIF:

Create your own TweetMeet Friend Card

Another way to share your enthusiasm about the TweetMeets is to create a TweetMeet Friend Card. Share your own version of this image anytime anywhere, for example when introducing yourself at the start of a TweetMeet. Just follow the steps in the TweetMeet Friend Cards PowerPoint.

Here’s an example:

Looking back on the November MSFTEduChat on Future-Ready Skills and Computer Science

We captured highlights for this TweetMeet event in a new @MicrosoftEDU Twitter Moment. There’s even a comprehensive collection of all tweets from this event in this Wakelet Collection.

Welcoming TweetMeet newcomers

Do you know someone who’s new to the TweetMeets? Our brand-new You can join a #MSFTEduChat TweetMeet video is especially created for newcomers, so please share it with friends and colleagues who might be interested to join:

For educators who are totally new to Twitter and who could use an introduction, we recommend the Twitter EDU tutorial ebook by David Truss @datruss.

Why join the #MSFTEduChat TweetMeets?

TweetMeets are monthly recurring Twitter conversations about themes relevant to educators, facilitated by Microsoft Education. The purpose of these events is to help professionals in education to learn from each other and inspire their students while they are preparing for their future. The TweetMeets also nurture personal learning networks among educators from across the globe.

Former host James Kieft wrote the following blog post describing why educators should consider participating in Twitter chats, and how to get started: Twitter chats explained.

When and how can I join?

Join us Tuesday, December 17 from 10:00 a.m. to 11:15 a.m. PST on Twitter using the hashtags  #BestOf2019, #MSFTEduChat and #MicrosoftEDU. Be sure to double-check your own local event time. You can find the event time for 215 countries with this time zone announcer.

Our next recommendation for you is to set up Twitter dashboard TweetDeck and add columns for the hashtags and for your favorite space geeks. If you are new to TweetDeck, then check out this brief TweetDeck tutorial by Marjolein Hoekstra.

When a tweet appears that you want to respond to, press the retweet button and type your comments.

Additional tips are offered in this animated GIF that you’re most welcome to share with newcomers:

Too busy to join at event time? No problem!

From our monthly surveys we know that you may be in class at event time, busy doing other things or may even be asleep – well, no problem! All educators are most welcome to join any time after the event. Simply look at the questions below and respond to these at a day and time that suit you best.

You can also schedule your tweets in advance. In that case, be sure to include the entire question in your tweet and always mention the hashtag #MSFTEduChat so that everyone knows to which question in which conversation you are responding.

Four discussion questions this time

For this special-edition TweetMeet, we offer four discussion questions instead of five. This means we’ll have more time for each question. Check the timings for each question in the table:

PST	#	#MSFTEduChat TweetMeet question timings
10:00am	Event begins	Welcome. Please introduce yourself. Use #MSFTEduChat.
10:06	1	What was your Best of 2019 experience? Share your story or picture.
10:23	2	Which event, product or announcement wins 1st prize on your Best of 2019 list? Why?
10:40	3	Which people, courses or resources helped you excel this year? How?
10:57	4	How can Microsoft make 2020 an even better year for you and your students?
11:15	Event closes	Announcing the next event and Participant Survey.

Next month’s event: Devices for Student Success

The theme of January 21 will be Devices for Student Success. We’re very much looking forward to this event and hope you’ll spread the word!

Got questions about the #MSFTEduChat TweetMeets?

Please connect with TweetMeet organizer Marjolein Hoekstra @TweetMeet on Twitter if you have any questions about the TweetMeets or about what it takes to be a host on a future event.