Godot Recipe: AI - Context-based Steering

We get a lot of questions about AI. Here's a simplistic algorithm that produces great results.
Text version & link to download the sample project:
godotrecipes.co...
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[@DriftWare]

How is this done with a 3d object? There's all kinds of vector functions that don't translate from 2d to 3d.

[@syllight9053]

This is one of the most valuable programming channels out there! These ones are rare and is like a jewel. I am 14 and started gamedev on 13 and I love this channel for supporting kids like us to get onto programming! Keep up the great content!

[@theeox]

I would have really liked to see an implementation for 3D. I'm not really grasping it, doesn't help that godot 4 has different nodes and functions.

[@jmbiv_dev]

Glad to see videos coming again! I've been seeing context-based algorithms (as opposed to/in modification of traditional steering behaviors) gaining a lot of attention recently, such as Game Endeavor's AI video. I've been working on a couple implementations of my own and have enjoyed seeing how others have gone about doing it. Great video that explains a nice, scalable way to implement this.

[@JahznCentral]

hi everyone. if you want the code to add interest to the opposite ray of the ray that sees danger, write the choose direction function like this func choose_direction(): > for i in num_rays: > > if danger[i] > 0.0 > > > if i > num_rays/2: > > > > interest[i - (num_rays/2) - 1] = added_interest > > > else: > > > > interest[i + (num_rays/2) - 1] = added_interest > > > interest[i] = 0.0 added_interest will be any arbitrary high number. you will have to fiddle with this. i found 20.0 works for my project.

[@ollereberg7828]

Could you do a version of this for 3D pathfinding, like for space ship where you you actually need to use x, y, and z? Been trying to figure out proper 3D pathfinding in not just this but in Unity too and I always get stuck

[@jordymendoza8192]

Can I get the code for the debugdraw node u had on the agent

[@neto9348]

Lol, that’s exactly what I need for a game that I’m making on Godot and it just randomly appeared on my home page. I had a rudimentary code using the same concept, this will help me a lot, thanks.

[@normaldefault2206]

So, I'm working on an RTS-style thing, and I figured I'd add this to my pathfinding to stop units from bumping into each other and generally getting in each others way. When it works, it's awesome, I love making little crowds of units cross paths with each other and shuffling out of each other's way; however, if two happen to collide head on, and ONLY the forward facing ray is blocked, the average vector is still straight ahead and they don't get anywhere. I can add if cases to get around this, but it doesn't feel quite so elegant...

[@andrewvickerman1940]

Instead of the 0deg ray, make it -0.1deg or 0.1deg randomly. This is almost the same except that agents will favor one side slightly more than their other.

[@TheDuckCow]

Really appreciated this - both the video and the webpage! Though I had to take a few extra steps to make it applicable for my own vehicle body-based car, was able to get this working nicely.

[@vatrenikrug]

any chance that you can share some project? i cant get it working :( and i was copying from website :(

[@TheDuckCow]

@@vatrenikrug sadly not open sourced or avail right now, although if you are curious how far I was able to get with it, you can check see it here: kzbin.info/www/bejne/nme6lHWAfsqKiNE It's slightly more than a copy paste though, I recommend just going one step at a time, and really make use of those debug drawing vectors.

[@yatchan]

Thanks for the great video! I've tried it out and in a scenario like this, with a simple obstacle course, you don't even have to set up a track. The boids are managing very well with just going forward :) With a little tweaking, it can be applied for example to a monster wandering randomly around a cave.

[@couscous4349]

Great video! Any chance you could upload the project so I could take a look at the code you use to draw the arrows? Thanks!

[@JamesKelly89]

This seems like it would work well using a navmesh where you want to follow the path given by the navmesh agent but also want to avoid obstacles and other agents. So the get path direction could just just a vector to the next waypoint given by the navmesh.

[@mrrandle5776]

Yo dude, im trying this right now and cant for the love of me get it to work, any clue how you would write the get_path_direction to work with the navmesh? I have the nav agent drawing the path to the target. but nothing i write in the get path direction seems to make the interest follow it

[@loot6]

Seems good in theory but in practise has flaws. For example if the target is east and east is blocked by a small NPC in front of the target, just large enough to block only one ray, the best directions will be diagonal NE and SE to take you around the object. But if you take the average of those it's obviously east...which moves you into the NPC...

[@cheapmeow8478]

Constraint AI that if you can't "see" target, then you can't be interested by it, may help avoid this problem.

[@raremc1620]

Hey, thanks I was literally just planning of doing something similar before I noticed your new video!

[@Knutmeister]

Thanks a lot! I like the direction, all those car related video are going.

[@vatrenikrug]

your recepies are amazing,i do hope to make my first games and to be able to give some back for your amazing work. thanks for being a teacher on godot :)

[@tPlayerioT]

it seems godot has now a built in simple steering behavior. Its called "Navigation obstacle" and you put them inside the thing you want to avoid. then enable "Avoidance" in your navmesh character.

[@lumenwrites]

What an amazing tutorial, thank you so much!

[@TackerTacker]

Thanks for the great video. I have one question. How would you handle tracks made out of tiles? Is there a way to combine multiple Path2D nodes into one continues path, or would it be better to keep them separated and somehow set the position to the different tiles one after the other?

[@Kidscancode]

As recommended in the video, it wouldn't affect the agent itself at all. It would be the responsibility of the Tilemap node to provide a `get_path_direction()`. It's hard to be specific, because it depends on how your Tilemap actually works, but maybe you have a direction vector mapped to each tile index.

[@TackerTacker]

@@Kidscancode I meant something like track segments not single directions, tiles with right and left turns, S curves, etc. maybe a crossroad. If I would prepare little track piece tiles in scenes, and every track piece scene has it's own Path2D with some kind of curve, I'm not sure how I would go about connecting these pieces together. I guess I would do path follow and at the end of the a path if there is still movement left I transfer it over to the next segment and start from there with that offset?! What would I do if there is someone fast enough to overshot an entire tile? Hmm, that would probably not happen unless the tiles are pretty small. I'll need to play around with it when I got some time. Again thanks for the tutorial, very inspiring.

[@bamtoday]

Excellent tutorial!

[@szokedencsimarci5668]

thank you for this video!

[@gameanddata3194]

I'm doing my game thanks to this tutorial, awesome.

[@JorgeRosa]

GREAT tutorial! Thankyou!

[@n01487477]

Hi - thanks for all of your really informative tutorials. I note that this one doesn't seem to have a download link. Am I mistaken?

[@pascalcasier959]

Excellent ! thank you so much.

[@NicholasOrlowski]

Another amazing video, thanks!

[@brianbatton9950]

Hi! I know I'm kind of late but I would just like to ask where I can download the source code for this so I can test it out. I went to your website but did not see any download links. If you could help me out I would be very grateful!

[@JohnnyCashOriginal]

the position variable is not defined. var path_direction = owner.get_path_direction(position) ... what is this supposed to be? global position of the object?

[@boerbol9422]

Awesome video. Bless you!

[@rosva4331]

You sir, just saved my ass. Thank you.

[@juanloutech2864]

Brilliant as usual. Thanks man! Very usefull stuff

[@Marduk401]

10:22 but what happens if you place an obstacle that only blocks the middle raycast without touching the others?

[@staticsteam636]

how set this up in 3d???

[@DA-cl4ww]

They seem to get stuck when running into more complicated collision shapes. Is there a better way for them to perhaps consider a direction opposite of all those blocked?

[@gabrielpsych6]

I really can't understand what are these "rays" since there are no rays being cast from the tree nor code. Where are they coming from? I tried following the code but nothing seems to happen.

[@the_cheese_cultist]

you cast the ray through the intersect_ray function.

[@michaelthelen5297]

Wow very cool! How did you deal with the extra axis in 3d? (like avoid the rays hitting the road on an up slope, or missing a wall when cresting a hill) I imagine this could be handled with collision layers and raising collision boxes... just curious

[@toms2oo8]

Not sure but I imagine the same concept works in 3d space, eg. you just project rays from a sphere rather than a circle around the object. And then your follow path can also exist in 3d.

[@Kidscancode]

Depending on your setup, you don't even need that. A 3D car, for example, would still just need a ring of rays horizontally.

[@thelumberjack8838]

Please make a recipe for how to do this in 3D because the difference between 2d and 3D is night and day

[@KibanyaG]

Here's a basic implementation in 3D

[@lutiyoffnik8661]

needed in version 4 godot

[@froggyCodingClub]

Thanks, clear explenation

[@jlebrech]

can the steering angle change the wheel angle and in turn the wheels affect physics of the car?

[@bruceparker6142]

Has anyone got this to work on a 3d track in godot 4? I'm getting errors in the .rotated(rotation) parts.

[@ericcollinseh8916]

Hey, how do you make the characters animation track the mouse ui?

[@piousthepious]

Great tutorial! I do have one question. How do you handle avoidance with the danger? It seems to be the danger simply gets negated but how would I go about making it so the complete opposite direction is desired? My first thought is to add interest to the opposite ray but I have no idea how I would even get the opposite ray. Is there something I'm missing?

[@andrewvickerman1940]

Just search how to get the opposite of a ray. There are a bunch of videos about it.

[@nicolassoriano2621]

it doesnt work, it says "Parser Error: The identifier "position" isn't declared in the current scope."

[@thelumberjack8838]

Thank you so much

[@viniguerrero]

What is the equivalent in 3D for this? var d = ray_directions[i].rotated(rotation).dot(transform.x)

[@Kidscancode]

Dot product is the same in 3D. To convert a vector to a local rotation, you could use `transform.basis.xform(ray_directions[i]`

[@viniguerrero]

@@Kidscancode thank you! But then how do you rotate the vectors for intersection here if they should be vector3? ray_directions[i] = Vector2.RIGHT.rotated(i * 2 * PI / num_rays)

[@bruceparker6142]

Will this work with the vehiclebody3d node?

[@Kidscancode]

This is about choosing what direction to move. It is completely independent of what kind of movement you then do.

[@Edel99]

OMG... this is hard stuff!! I find it hard to visualize all this vector stuff... :(

[@Kidscancode]

This is why I typically recommend beginners start working in 2D first. It's easier to get a handle on vectors, transforms, and the like and then move to 3D where it get significantly more complex.

[@kuroodo_]

Do you still have the code for this? Would love to check it out

[@anindyaroythetechmaster]

Can you please make a video on in app purchases in godot. Your mobile ads video is one of kind still on KZbin. Also, there are no good tutorials for in app purchases. Can you make it for us?

[@andrewvickerman1940]

This is very cool. How is it with performance? I'd like to see the agent code. What you posted doesn't show the rays visually.

[@vatrenikrug]

no there is no visualy... its just a animation for us i gues..? but dint find project to download and i cant geth it working...

[@1littlemaxy]

Great! And how can I make AI to choose exactly one of 8 directions, not a one between them? My game is isomectic 2d with 8 directions

[@Kidscancode]

Maybe just choose the longest interest direction, or round the result to the nearest one.

[@itsME-dc4vm]

Nice ;D

[@CarstenNikiel]

Wouldn't it be better to not cast rays backwards at all? None of the rays that are 90 degree or higher to the forward direction will be able to add to the choosen direction. So you might need less rays for those mainly foward driving agents.

[@Kidscancode]

In this specific example, probably - but this is general algorithm that applies to more than just a forward-moving situation. You could use your backwards-facing rays to decide to hit the gas when somebody's on your tail. You might have multiple "targets" and so your interest array could point in many directions - if one is blocked you'd choose the other.

[@CarstenNikiel]

@@Kidscancode Yes definitely. But in your example with the dot product you eliminate everything that is backward facing. Just thought about the optimization possibilities. But of course you are correct that in other circumstances you might have need for the rays pointing backwards. Thanks for the awesome video, as always. ;-)

[@xegrand7548]

Can you teach how to make a speedometer in 2d ?

[@ShootYourBricks]

Just have the arrow set its rotation to -90 + speed or something like that

[@ShootYourBricks]

The speed would be the linear velocity added together

[@temporal_paradox]

This is really useful, but you don't actually include the project files like you say, and you don't explain how we can actually see the arrows visualized. There's also the 'debugging' with the mysterious variable and key press that makes it all visible.

[@trakegaming79]

Can yo help me to make the car chase the player by some of your codes I really need that 3d

[@Red_Eagle]

we want gears and drift!

[@re-dxealhgamemaker3070]

LIKE.

[@elzemgames]

Nicee

[@bruceparker6142]

I wonder how much of this has changed since godot 4.

[@Kidscancode]

The concept of context based steering is the same regardless of game engine. Some minor implementation details will change from Godot 3 to 4, but the general idea works the same way.

[@oreomoreo2110]

sounds expensive

[@vaibhavpandey6640]

how to use raycast in pygame as we use in godot?

[@Kidscancode]

Pygame doesn't have rays. You'd have to manually build such functionality yourself.

[@vaibhavpandey6640]

@@Kidscancode then what can i use for checking collisions near by to turn my npc

[@Kidscancode]

Same answer. You have to do something like use a collision shape (ie an invisible sprite) and move it around, checking if it collides with anything.

[@hasaranger9845]

Hey man I have a big request ,i want you to make a sidescroller pygame game tutorial series , you are the only guy i can understand and your code is simple. So PLEASEEE MAKE A PLATFORMER TUTORIAL SERIES I BEG U

[@nigeltsuro8631]

The funny thing is I'm a kid🤣🤣

[@saulnores3477]

This is too complicated for me. I've seen easier methods.

[@ShootYourBricks]

I made a 3d car game where I had an area in front of the car and if it was touching something, than it would run a function. When the function ran, it would turn right if a raycast on the right side of the vehicle wasn't touching. If the raycast was touching something, than it would turn left if a second raycast wasn't touching. If both raycasts were touching, it would brake. (That was probably super confusing lol.)

[@saulnores3477]

@@ShootYourBricks Hi. Your method is simpler than the one in this video. I like it.

[@ShootYourBricks]

@@saulnores3477 Thanks! I'm glad you liked it.

[@Kidscancode]

Use what works for your specific application. This is a generic algorithm that scales well and can be applied to a wide variety of situations, not just cars.

[@saulnores3477]

@@Kidscancode Your channel is great but this method is above my gdscript knolewdge and I don't understand some things in it. May be in the future I will.

[@yametekudasai2563]

please make a full mobile fps game in godot please i beg you😢

[@Kidscancode]

My channel is about learning how to make games. If you learn *how* to code and use the tools, you can make any game you want. If I just make a full game and you copy it, will you have learned anything?

[@yametekudasai2563]

@@Kidscancode but i dont know how to code😢

[@Kidscancode]

@@yametekudasai2563 My channel and many others can help you learn.

[@yametekudasai2563]

@@Kidscancode but how😥😥

[@nurwaneduardo7831]

How to make a 3D ai car. Because you toturial in 2D.