[GameMaker Tutorial] Enemy AI Maze Pathfinding

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Thank you all so much for your support!

[@NikorasuChan]

GUYS IMPORTANT!!! HeartBeast forgot to destroy the path variable at the end. If you don't destroy it, it will cause memory leak! Just put this at the Room End: path_delete(path); Thank me later ;)

[@uberalex5437]

Thanks I'll remember this

[@Revalopod]

+Nikorasu Chan (Nichii) what is room end?

[@Revalopod]

+Nikorasu Chan (Nichii) I guess you didn't watch 9:15 then

[@NikorasuChan]

+DeathSwagga He only destroyed the grid, not the path.

[@uberalex5437]

+Nikorasu Chan (Nichii) So within the same event as 9 15 put path_delete(path)?

[@moshimooshi]

your channel deserves the world, man

[@blabla5021]

12:12 he discovered the answer of the life, the universe and the rest lol

[@theternal]

It is Vietnam flashback

[@oldschewl]

This is exactly what I was looking for - a no frills introduction to GMS's pathfinding. My most humble thank you!

[@helloofthebeach]

I've been banging my head on this on and off for months, and continued to bang my head with this tutorial since things just weren't working...but I finally got it! Thank you for helping me finally get my head around pathfinding.

[@DanBraithwaite]

Mate I dunno if you read these but I wanna say this was really helpful, and worked a charm. You're also a cool guy!

[@DakNJaxter]

I did this in GMS2, and the the collision detection is set to the centre point rather than being pixel accurate, and its causing the enemy to overlap with the walls which looks bad. Do you know how to fix that?

[@lanelauhoff]

Being able to see you explain the code helps me a lot, man, thanks! Looking forward for more tutorials!

[@WolfySnackrib666]

HeartBeast seem to me like the kind of guy that practices meditation. Waaay calm and zen bru.

[@dirtroadgames1406]

+WolfySnackrib666 haha yeah i think i would be insulting in front the pc screen if i miss something in a vide for youtube

[@WolfySnackrib666]

Dirtroad Games Haha yeap. And then reshoot the whole thing, as a perfectionist :P

[@dinohorseaborus]

Wow ben! this tutorial is "AI-maze-ing!"

[@uheartbeast]

dinohorseaborus Nice haha

[@vertox4837]

amAIzing

[@th3r3ap3r2]

super nice

[@RedstoneAnimatesandmore]

Ayyyyy......

[@omikronweapon]

Nice one as usual Benjamin, thanks. I like the synopsis at the end, just to review.

[@Jakkisle]

This is amazing, I didn't think something like this would be possible with so little code! You've helped me so much, thank you!

[@drsquash2003]

working in GM Studio 2. My enemies are "cutting" corners in a "smooth fashion". As if the corners of the walls are rounded. But I set diagonal motion to false, and triple checked; the collision masks are all square.

[@ericfangrow743]

billy mays here baxck with another GREEEEEAAAAATTTTT PRODUUUUCCCCTTTT

[@habarvaz]

This tutorial was great. Easy to use and to the point. Thank you!

[@NorthStateGames]

Phenomenal work. Glad I bought your book too!

[@colingreenall5049]

Can you do a tutorial to demonstrate how multiple enemies can avoid each other and not overlap?

[@creasu124]

maybe do if the enemy collides with it selfs x =xprevious and y = yprevious

[@liamborella8977]

Nope, then when the enemies collide they just stand there and don't move.

[@violenceisfun991]

i know this is an old comment but if anyone else is still having this problem, try this out: on the enemy object, make a collision event for colliding with itself, and put this code in : { if id > other.id { x+=1; y+=1; } else if id < other.id { x-=1; y-=1; } } ^^this code will make it so that they move diagonaly away from each other if they touch

[@liamborella8977]

+Violence Is Fun another thing you could do is just use the 'step avoiding' event in the drag and drop, make the enemies and the wall solid and set the avoid tab to solid as well. It worked like a charm for me, and there wasn't all that setup

[@violenceisfun991]

Liam Borella, ah cheers, i always forget about using drag and drop in gamemaker. i shall have to give that a try.

[@codytremblay6513]

how do i add more then 1 instance. I tried just placing it under but the enemy went right through

[@MyNameIssaSimon]

How can I use this with gamemakers physics engine? My enemies stop if I active physics on them.

[@naptan7866]

I've seen your courses on udemy. Your awesome. I might buy your course. keep going.

[@kroutonjr]

trying to incorporate this with your rts tutorial... right now i am having and issue where it will sometimes go through the objects but about 90% of the time it will find a way around my object. this is also in my step event for my unit as thats where the move state is in if (state == 'move') { scr_wizard_move() if instance_exists(target) if (mp_grid_path(global.grid, path, x, y, target.x, target.y, 1)) { path_start(path, spd, path_action_stop, false) }; }

[@Kezarus]

Man, this is awesome! Definetly going to use it on my next RPG game. Thanks!

[@uberalex5437]

How can I make it so that the enemy following the grid collides with other enemies instead of overlapping?

[@XDRosenheim]

enemy->collision->enemy - Step event - Empty code.

[@antuankerbage]

No.. The code would be like this or similar. mp_grid_clear////0 with (obj_parent) { if id != other.id { mp_grid_add_cell(....)///1 } }

[@antuankerbage]

Or when character moves, mark 1 in the coords to walk in the grid and then a 0 in the previous coords

[@uberalex5437]

there would only be an empty code if I'm using physics but I'm not. I used 'if other.x > x { x += 1; }' etc.

[@antuankerbage]

Use mp_grid (is the best option for me) or, another example... if !instance_place...

[@dirtroadgames1406]

amazing tutorial my friend,exactly what i was needing,cheers

[@KB_United]

I'm in the process of learning how to make a top down shooter. I programmed a modified version of Shaun Spauldings collision code for platformers so it would work with my Top down shooter. I have a 3 burst machine gun and I can't wait to implement this when I get my enemies into the game. 😁

[@glxxm]

For those having difficulty, try making sure it's a global mouse click. This is working for me in GMS:2.

[@ChrisRid]

This is awesome, thank you! So easy to quickly add AI into the game.

[@ikonhero]

Question, is it also possible to use a tile-based pathfinding system, so without having to set wall objects? For instance, when u create generated map using wall and floor tiles.

[@EdoPlayer37]

Thank you very much. I've been looking for this for a while now and you explained it really good.

[@uheartbeast]

Edo Player Glad I could help :D

[@guigrillo101]

Once I try to use this method but the enemy was intersecting a bit with the wall. I'm not sure why, but I started to use an a* extension.

[@steview77]

When I do this the enemy crosses over the walls too, unless I set wall to solid then they just get stuck! Cant get the enemy to just avoid the wall!

[@DFILL450]

+guigrillo101 Is your enemy sprite centered?

[@cheezysqueezy]

Nice tutorial! Thanks a lot!

[@dinobudic4492]

Great video. I would like my enemy to navigate on dynamic objects. Example : Player casts nova spell and it creates few ice walls around him that should block the way. Should I just then update the grid ? What's the best way to detect new added "walls"?

[@kankykune6459]

I've tried to figure this out on my own but what do I type instead of (mouse_x div 32)*32+16; if I want the object to follow obj_player?

[@kyle4760]

this doesnt work they completely ignore walls added to the grid

[@jasonp7091]

obj_player.x and obj_player.y are the (x,y) coordinates for your player

[@sully9088]

You are the best my friend.

[@juliusherrmann1054]

Thats really ggod because I needed it for my game! Thank you!

[@uheartbeast]

Julius Herrmann Glad I could help

[@RKCYOUTH]

thank you so much for this amazing tutorial

[@sheeplavender3261]

Gms2 trial version doesn't allow for Path_Add

[@wipedowt]

awesome tutorial HeartBeast, interested to know how the A* Algo could be used in a platformer scenario where players and enemies need to take into consideration obsticles (obj_wall) and gravity + jumping. would you perhaps be able to create in the future a tutorial like this? Thanks!

[@KB_United]

So what is the point of creating a variable call path and putting it equal to path add? I understand it all the way up until that point and then i see that and dont see a point to the path variable.

[@biggriz7161]

Cheers! Great tutorial.

[@jasonjewik4349]

My enemy partially phases through walls sometimes. I followed this tutorial exactly with the only exception that I made the enemy chase a player object. What is wrong?

[@ikonhero]

Awesome! thanks for the video.

[@LiamDoesProgramming]

Is there a way to do this with ds_grids? so I can combine this with the Random World gen tutorial

[@purpleice2343]

+LiamDoesProgramming Why not just make two grids? Generation grid won't ever be used again after it generates the world anyway... Unless you want it to be infinite, well still, you won't be generating all the time, pathfinding will be used more.

[@aliyarahmanajihati708]

when I add more than 1 enemy, obviously all of them will move toward the Player once the Player get into the range "to be detected" by one of the enemies. How do I make it so that it's only that certain Enemy (that the Player approach) to chase after the Player, not triggering all Enemies?

[@LukeAps]

This is excellent, thanks HeartBeast. I wish you would do a new video on this for people looking for GMS2 ( Even though this is still compatible. )

[@SubWolfIV]

You saved me! Thanks so much!

[@cryodoctor7713]

+HeartBeast How could you adapt this for a platformer like with gravity and such

[@loganbevans4347]

Hey How would i go about adding this to a game where the room is expanding as i move around

[@Peckan]

Would it be possible to spawn the enemy object into the room and have it path towards another object instead of the mouse? I'm thinking along the lines of a Tower Defense game where the path changes depending on how the player decides to place their towers. Also if there are anymore great tutorials relating to TD games, let me know please!

[@vinzhu3893]

Is there an option to remove an object from the grid? My player can destroy the walls so I want the enemy to be able to go through the space where the walls used to be.

[@sdaqs2333]

you probably figured this out but you could update the grid each time (You would need to destroy the other to avoid a memory leak)

[@nicholasrusciano5523]

Is it possible to do this in the Standard Edition of Gamemaker? Its not recognizing some functions...

[@gaurdian0digger]

To go along with this video, could you also go over some of the maze/dungeon creation algorithms?

[@uheartbeast]

gaurdian0digger I shared a useful video on that a few days ago. Let me see if I can find it for you: kzbin.info/www/bejne/rZOZpmWAftKmr6c

[@kryptkeeper2303]

would this work with the AI we made for the Slimes in the Rpg beginner series? if so how do i set it up

[@BeanBunnyBass]

Is there a way to make an object follow a precise path through code?

[@jiaska3889]

Would I need to recreate the grid between rooms? Or change the values on room start?

[@codingprinting3dandcnc191]

Easy follow, thank you!

[@MsAkbar14]

hi, how can i do this if my wall is mask with tiles collision mask?

[@Baconlovar]

omgosh this is amazing ty so much

[@sachonski]

Hey, great tutorial, but how would you aproach a everchanging enviroment? Meaning you have to create and destroy the grids for new results in the pathfinding?

[@stijnd.6320]

+sachonski You can add and delete objects from the grid with: mp_grid_clear_all and mp_add_instances

[@marcosandrade9074]

Hello guys! I wonder if there is any way to find a path at an X / Y point. Something like the instance_position, which returns true if a path were located in the inserted coordinates. I looked in the documentation but found nothing about it. The two functions (path_get_x / path_get_y) however they show the value of X / Y already inside the path. Thank you all!

[@TheMrPopper69]

Amazing, thank you so much

[@ericfangrow743]

when I try to do this it gives me an error message in line two of the grid object, the equal sign is unexpected. any reason why?

[@temps1959]

How would i change the xscale based on where he is going? Please help.

[@lildgamedev6885]

great tutorial thanks heartbeast!! now any idea how I can give the enemies collision with eachother on top of this pathfinding? If i added the obj_enemies to the grid like we did the walls, they cant move at all because it's checking for its own instance I think.

[@DeadManRising36]

Could you do a tutorial about self learning algorithms?

[@masterrender]

owesome could you help me id like using sprite idle animation and it with walking jumping and so on. so may you to give the code where the enemy searcing by walking trough the wall and jump to find player

[@Chuckyboy311]

I know this isn't related but I couldn't find anything on it and I've learned the most from you so here we go. Would you be able to/ willing to make a tutorial on skill trees, and also like a level cap of sorts? I've tried a few ways but couldn't get any results.

[@uheartbeast]

Chuckyboy311 Hmmm, that sounds like it might take some thought for sure. I'll have to think about how I might teach that best.

[@Chuckyboy311]

HeartBeast Cool, thanks for the reply man

[@pivotguy]

wow been along ime since i wach one of your vids(probably because i switched to unity3d) but sill good tutorial

[@Oliwarder]

if my obj_player collisiob with obj_wall, obj_enemy stops how know how to fix this?

[@pipulese1775]

How would you go about adding collisions with multiple enemies or moving entities with a grid system?

[@MrTheDlanor]

For anyone else wondering and still stuck a few years down the line: pathList = []; //need to store paths so they can be deleted later var i; for (i = 0; i < instance_number(obj_enemy_base); i += 1){ enemyIds[i] = instance_find(obj_enemy_base,i); pathList[i] = path_add(); show_debug_message("creating path " + string(pathList[i])); enemyIds[i] .path = pathList[i]; } Then delete with: var i; for (i = 0; i < array_length_1d(pathList); i += 1){ path_delete(pathList[i]); show_debug_message("deleting path " + string(pathList[i])); } where appropriate for your code.

[@TheFlameincchannel]

Hey Ben, I am trying to use the path finding with an RTS system it works but, the characters move up and down and around very violently which seems weird, can you supply a solution.

[@TheFlameincchannel]

TheFlameincchannel ***** HeartBeast Instead of a grid will I need to use mp_linear functions followed by mp_potential functions? If you have a solution, reply and I will contact you personally.

[@cernos7230]

Will it lag if there are..let's say 500 AIs? each have different paths?

[@Keizor1997]

Great, it worked, thanks!

[@gekkyt]

How do I change pathfinder from following mousex and y to following the players constant coordinates?

[@AnEnormousNerd]

replace mouse_x and mouse_y to object_player.x and obj_player.y If your player object isn't called object_player, alter that as necessary.

[@jackthake7209]

will it still work if you put the grid code in a script and have the enemy run that script?

[@fivoscapone9377]

probably

[@Hatmaster]

So if I use this in a desktop defender type game, where you can place towers and the enemies have to update their path whenever you do so, is it going to lag badly?

[@jaimied.5417]

You would probably have to delete the current grid and add more "wall" objects. Otherwise, that is a great way to use this algorithm. :D

[@uheartbeast]

No you should be fine. Just update the grid and paths with each new placed tower :)

[@davidhoracek8937]

Awfulmasterhat Just a little tip if you don't know it yet. Use 'mp_grid_add_cell()' for new towers... it's a lot faster than deleting grid and adding all the towers etc again. You just have to calculate a position of that cell... X and Y indices which is just X, Y div wcell, hcell (if you start grid at [0, 0]). On the other hand... if you... lose/destroy any tower use 'mp_grid_clear_cell()'... same as above but it marks that cell as free in your grid.

[@Hatmaster]

David Horáček Thank you!

[@rellosorrell9265]

I actually seem to have this working with the Random Levels right now. I know it's not terribly optimal, but there's always time for amendments later. Okay, so in the level creating object from the other videos, I created the MP_GRID stuff *at the bottom, after where I handle the walls and enemy spawns*. For me, it's global.mpgrid = mp_grid_create(0,0, LEVEL.width, LEVEL.height, CELL_WIDTH, CELL_HEIGHT); mp_grid_add_instances(global.mpgrid, obj_test_wall, false); Then, at the segment where you declare where walls are placed, I added a line to create the wall objects. For example: if (grid[# xx+1, yy] != FLOOR) {grid[# xx+1, yy] = WALL; instance_create(((xx+1)*CELL_WIDTH),(yy*CELL_HEIGHT),obj_test_wall);} This seems to be working throughout a few dozen maps so far. Just make sure to have your walls' opacity to 0!

[@rellosorrell9265]

The only issue is that I cannot get the collision detection to work quite right with the enemies. Probably due to the tileset sizes and the object sizes not quite being right.

[@Parlakotta]

Is there a way that instead of the enemy avoiding the walls while moving, it went over those walls as if they were a path, a street or something similar

[@jasonp7091]

Just have the walls outline the space you want your enemy to follow

[@tuckertcs]

wow that was easier than I thought it'd be :)

[@panagiotisiatrou6041]

Yep, thats right, you are the best!

[@Mafon2]

Great tutorial though I followed the instructions and still can't make the skeleton move.

[@cyber_tech2872]

that codes are compatible whit the game maker 8 ?

[@askplays]

how do i do this with the built in physics engine?

[@ProjectDT88]

How do you make gamemaker tell you if you are giving it an impossible path? Currently if you click where it can't reach, the enemy just gives up. I want the game to basically check to see if a path is possible before allowing it... how would I do that? Example: Tower Defense game. Enemy moves from point A to point B. You build a full wall between A and B and enemies just give up.... how do I prevent the game from allowing a perfect wall?

[@helderperez1474]

Check a path is possible from a point A to point B of your choice each time you build a wall block. If it is possible then allow placement otherwise prevent it being made.

[@blah979]

Awesome tutorial. Worked first time with GM2.

[@rellosorrell9265]

How would this go along with the DS Grid we created in the Random Level generating? Edit: I now see that there are already a few posts asking about this, haha

[@x7-a.i.208]

Thats awesome! lot of thx !

[@gekoghost806]

how can add two instance collision for the grid??

[@docnathan3959]

I have an app called 001 Game Creator and the you do not need to code the enemy path finding as they can navigate in mazes without coding the AI

[@Ivan-hi8vx]

can you help me out with path find but for platform?

[@jamesdrake8084]

Hey Heartbeast, I'm currently making an isometric game (30 degree angles) and am in need of pathfinding. Is there a way to make the AI snap to the isometric grid and only use 4 way movement? I can't find anything on it anywhere and don't know where to begin. Thanks :)

[@auraoctane9112]

+james drake I do not know what you mean 30 degree angle im not fond of isometric games but you could just try writing some if's on direction or hspeed n vspeed and set vertical movement on pathing to false so it move left right up and down and say if direction = 0 90 180 270 etc as many angles so if you decided to add diagnal movement and then do like image_index or sprite_index depending on how you send up you're images/animations

[@muddykat-tech]

hi big fan love your work, i'm using your level gen system with tiles, ds grids ect. and i tried to overlay an mp_grid with objects in the same place as the wall to see if i can get the ai in this working in the random level gen slight problem it spawns right but as if its a mini map i guess you could say pretty much all of the instances are in the top left corner and seem to map out the same pattern that the level makes anyway i can fix this or is there a way to use the ordinal ds_grid for this without using objects this is what i used to make it happen in player create event var width = room_width div CELL_WIDTH; var height = room_height div CELL_HEIGHT; var cx = width div 2; var cy = height div 2; global.aigrid = mp_grid_create(cx,cy,width,height,CELL_WIDTH,CELL_HEIGHT); mp_grid_add_instances(global.aigrid,obj_ewall,false); in level create event this is in the for loop for creating the walls (btw) if (grid[# xx+1, yy] !=FLOOR) instance_create(grid[# xx+1,noone],grid[# noone,yy],obj_ewall); if (grid[# xx-1, yy] !=FLOOR) instance_create(grid[# xx-1,noone],grid[# noone,yy],obj_ewall); if (grid[# xx, yy-1] !=FLOOR) instance_create(grid[# xx,noone],grid[# noone,yy-1],obj_ewall); if (grid[# xx, yy+1] !=FLOOR) instance_create(grid[# xx,noone],grid[# noone,yy+1],obj_ewall;

[@SnipingZero]

I tried this and many other ways to set a path towards my obj_player for my enemies, but they simply won't move. what can I do?

[@auraoctane9112]

+SnipingZero You must not have all your variables set right make sure you are calling the x and y from the right object if you are calling them at all

[@SnipingZero]

+Aura Octane nah i found then out that this method wasn't working due to physics enabled

[@auraoctane9112]

Ahh ok. I was testing this A* algorithim and I would not know if you knew how to make zombies avoid eachother whilst they avoid walls wouldyou with only small amount of memory. I tryed adding and clearing cells as they walked but what happned was they detected there own cell of course and did not move like your's. without making a grid for every zombie I do not know how to add/fix this. :/

[@xxcassweet322]

My game freezez when i add multiple enemies what do to?

[@time.window]

you're a genius

[@TheLegoMasterMan100]

does anyone know how to add more than one type of object to the grid (buildings or others (say im doing something like starcraft)

[@DaroGonzalez]

I tried to use this on game maker studio 2 and get a massive loss of frames

[@Krix08]

for some reason i get a compile error two even (obj_grid in eventCreate action number 1 at line 5 assignment operator expected) second (obj_grid in eventCreate action number 1 at line 5 malformed assigned statement) WTH i replicated everthing you did but it doesnt work ;(

[@pattyloca4773]

+Samanta Kristera The first compile error means you forgot an operator like "=" for example. the second one means you have a malformed statement, which seems to be a problem originating from the same source. Check the create event of obj_grid at line 5 for such an error and it should take you about 15 seconds to solve ! :)

[@Krix08]

ehhhhh i already have them ill show the code /// create the grid var cell_width = 32; var cell_height = 32; var hcells = room_width div cell width; var vcells = room_height div cell height; global.grid = mp_grid_create(0, 0, hcells, vcells, cell_width, cell_height); // Add The Walls mp_grid_add_instances(global.grid, Obj_wall, false); Hope you respond faster :) (cause i want it done faster)

[@pattyloca4773]

I'm glad I could help, if you a have any other issues related to compile errors, here is the documentation related to them: docs.yoyogames.com/source/dadiospice/002_reference/debugging/compile%20errors.html

[@pattyloca4773]

Does your code work now?

[@Krix08]

i dont really check my notification box that fast XD

[@hydolsrodzas9328]

Thanks, great tutorial!! Is it possible to make it works with physics?

[@uheartbeast]

Roi Díaz Souto That is a good question, you would probably have to do some sort of a work around. I"m not sure how paths work with the physics engine.

[@upidesign896]

HeartBeast, How do you make the camera follow the screen and the sprites still be normal? I create a 1024x768 room, but then I dont know what should I put for the camera...

[@FedeDrenge]

Check Shaun Spalding's video with camera views :) he shows everything

[@auraoctane9112]

+UPI Design well if you are referring to this very example just set your view to the enemie obj... you would have to continously click to move from one side of the room to other but hey... theres others ways that are easy 2 like a invisible object that follows the camera that is controls by arrows or wasd

[@auraoctane9112]

+Aura Octane Would not be very good for a profesional game as it would troubling to know where youre screen object is as when you hit edges of the room the screen stops as the objects continues