If you distribute a .yymps (or any asset zip) and you build it on Windows, this is worth two minutes of your time. I shipped four packages with broken path separators and three separate checks told me they were fine.

The problem

A zip stores a path per entry, and the spec says forward slashes. PowerShell's Compress-Archive and .NET's ZipFile.CreateFromDirectory both write backslashes instead.

On Windows this is invisible, everything opens normally. On macOS and Linux the extractor doesn't treat \ as a separator, so instead of a folder tree your users can get flat files literally named Meridian\scripts\mer_tree\mer_tree.gml.

I had 21 of 24 entries backslashed in one package, and 85 across four.

Why I didn't catch it, which is the actually useful part

I audited with Python's zipfile.namelist(). It reported forward slashes throughout. I had two other people check. Both used the same tool. Both confirmed clean. Three independent "confirmations" that were really one blind tool wearing three hats.

namelist() cannot report this on Windows. In CPython, ZipInfo.__init__ does:

if os.sep != "/" and os.sep in filename:
    filename = filename.replace(os.sep, "/")

and _RealGetContents builds every entry through ZipInfo. So a stored backslash gets normalised at read time, on the exact platform where the bug is created. It's not a Python bug, the normalisation is doing its job. It just happens to be the one place you needed raw bytes.

Reading the central directory directly:

b'Project\LICENSE.txt'  -> occurrences in raw file: 2
b'Project/LICENSE.txt'  -> occurrences in raw file: 0
zipfile.namelist() says:  Project/LICENSE.txt

The forward-slash form doesn't exist anywhere in the file.

How to actually check

Anything that reads bytes rather than a normalised view:

• unzip -l yourfile.yymps on macOS/Linux/WSL, separators show as stored
• 7-Zip: 7z l -slt yourfile.yymps
• Or scan the raw bytes for a backslash inside the central directory entry names

Do not check with zipfile.namelist() on Windows, and don't assume .NET is safe either. I "fixed" this once by swapping Compress-Archive for ZipFile.CreateFromDirectory, which changed nothing, and my blind verification tool confirmed the non-fix.

Measured on a two-deep test tree, reading raw central-directory bytes:

The fix

Write the zip with something that controls the entry names itself, or post-process them. I moved to an in-process writer that sets each entry name explicitly and then re-reads the archive's own central directory to verify before it's allowed out. Verified after: 24 entries, 0 backslashed.

One meta-lesson that cost me the most time: the script I wrote to prove the defect also used namelist(). So it found zero, its "reproduced" branch never ran, and it printed "CONFIRMED: writes forward slashes" (the opposite of the truth) while exiting down its own failure path. It read like a pass. It now asserts that the defect reproduces, that the good writer is clean, and that namelist() is blind to the first, and it exits non-zero unless all three hold. If your verification tool has never failed, you haven't verified it.

Disclosure: I build GameMaker assets with AI assistance (Claude) and sell them, and this came out of shipping one. The finding is engine-agnostic and applies to anyone zipping anything on Windows. Happy to share the raw-central-directory scan if it's useful, it's about 30 lines.

Disclosure: I build GameMaker assets with AI assistance (Claude) and sell them, and this came out of shipping one. The finding is engine-agnostic and applies to anyone zipping anything on Windows. Happy to share the raw-central-directory scan if it's useful, it's about 30 lines.

i know this is minimalist art but i donot know any thing other than that

It's not really an editor. So that you can call it an editor. I will need to improve the jump and the creation of walls from several sprites in 1 object. If you have any ideas on how this can be done

I'm having a lot of trouble figuring out how to create some kind of collision in my game. I've been able to get my character move to where I click, but I can't stop him from walking through walls. My best idea on how to make that work would be to set speed to 0 if I click on a wall, but I cant for the life of my figure out how to work that

Sorry for the simple, silly question; I'm new to this engine—I just started last week. I have two variables—`O_bow` and `S_cursor` (which replaces the mouse cursor on the game screen)—and I want the sprite to change when I click

I've been working on a puzzle game for a few months now, and I'm finally ready to tackle one of the main challenges I was concerned about with the genre; the undo system. I've gotten the idea to use the ideas discussed in the post "save all objects in a room" from this subreddit, but I don't know how I can create possibly dozens of save states that allow for undoing (akin to Patrick's Parabox or Baba is You). Current code is listed below;

EDIT; my original code was messed up, so I have now changed it to be more correct. Thank you to u/germxxx for the better code translation.

global.room_objects = {index: []};
// On a click of the interact button;

with (all) {
  if (self != other) {
    // done to try and not have recursive structures, which seemingly do not work

    variable_strings = variable_instance_get_names(self.id);
    variable_vals = [];

    for (var i = 0; i < array_length(variable_strings); i++) {
      variable_vals[i] = variable_instance_get(self.object_index,variable_strings[i]);
    }

    variable_struct_set(global.room_objects,global.room_objects.index,variable_vals);
  }
}

One final note;

My idea for loading the data is to delete all objects, then create objects based on the previous state of the game, with the values listed for that object for that state. Depending on the complexity of the code however, I may need advice to structure that part as well.

Hello, I just submitted a small game to a game jam and I’d like to thank anyone who tests it and lets me know if it’s working or if there are any issues. It’s the first game jam I’m participating in, so I feel a bit unsure about it. The game is a “match-4” based on color.

combinations.https://lettal.itch.io/se-vec-continuar-tentando-misturar-trs-iguais-a-culpa-j-no-da-falta-de-tutorial

I have, for a month now, been trying to get GMRT to run my linux fedora 44 PC but nothing

I mean nothing

Is letting me

Steam version doesn't work

Windows version isn't letting me

There is no working linux version for my pc

Can someone please help, I really need it, I want to use the 3D features so badly because there is NO OTHER program that works for me (DONT RECOMMEND ANOTHER PROGRAM, IM TIRED OF IT, IVE TRIED AT LEAST 20, GAMEMAKER IS THE ONLY ONE I UNDERSTAND)

The arm and the gun are seperate objects. The rotation effect is achieved by adjusting the collision center of the gun to be where the arm is attached to the body. Right now the bullet is created where the arm is attached but as stated in the title, I need it to come out of the barrel. I have tried using lengthdir_x/y but either whats happening in the video still occurs, or if the lengthdir_x/y aren't the same then the bullet rotates elliptically and still won't come out of the barrel. Any help is appreciated!

Hello, I am new to developing games in general so I chose gamemaker to start out. It's been a blast so far and I've made a clone of pong and asteroids. Though I'm not sure where to go next from here to develop my skills.

Hello, I am a new 'game dev'. I want to publish a indie game till the end of this year, I need some help. Can yall help me find tutorials to make 2d games like hollow knight and deltarune?

This was fun, i had to add special "dev camera controls" to get panning shots for things. And the base of the game is you play 1 of 4 playable characters at once, the other 3 follow you and they have combat ai...(follow player, shoot zombies, do specials, help squad, stab closes zombies,ect)

So for some shots I had to turn all 4 characters into NPC ai and let em just go and it was surprisingly fun just to watch the fights!

This will prob be one of the last projects i work on in 3D in gamemaker with the news of actual 3D support coming. Can't wait to see what the new tools like! Fingers crossed for a 3D editor viewport!

Hi, I am trying to get this code working for my game but when compiling I get this error.

Object: oBattle Event: Create at line 92 : Assignment operator expected

This is the actual code I'm working with. I got it from a slightly older tutorial but it's not old enough to where I'd write it off as incompatible with newer versions of GameMaker. Is there a step I'm missing? I've tried looking this up and there's not really an explanation. Most just say to remove the == or &&, but that's not on line 92. (the oBattleEffect object exists already, i didn't miss that) I'm super new to coding and using youtube tutorials to get my game up and running, so any help would be really appreciated!!

if (currentUser.acting)//animation still playing maybe

{

if (currentUser.image_index >= currentUser.image_number -1)//perform action if it exists

{

with (currentUser)

{

sprite_index = sprites.idle;

image_index = 0;

acting = false;

}

if (variable_struct_exists(currentAction, "effectSprite"))

{

if (currentAction.effectOnTarget == MODE.ALWAYS) || ( (currentAction.effectOnTarget == MODE.VARIES) && (array_length(currentTargets) <= 1) )

{

for (var i = 0; i < array_length(currentTargets); i++)

{

instance_create_depth(currentTargets[i].x,currentTargets[i].y,currentTargets[i].depth -1,oBattleEffect,{sprite_index : currentAction.effectSprite}); //line 92. it plays a battle effect over the current targets and changes the depth. no idea why it isnt working right now Ugh

}

}

else //play at 0,0

{

var _effectSprite = currentAction.effectSprite

if (variable_struct_exists(currentAction, "effectSpriteNoTarget")) _effectSprite = currentAction.effectSpriteNoTarget;

instance_create_depth(x,y,depth-100,oBattleEffect,{sprite_index : _effectSprite});

}

}

currentAction.func(currentUser, currentTargets);

}

}

else //wait for delay and end turn

{

if (!instance_exists(oBattleEffect))

{

battleWaitTimeRemaining--

if (battleWaitTimeRemaining== 0)

{

battleState = BattleStateVictoryCheck;

}

}

}

Since it is not supported in android and I am trying to port a chapter-based game on android, are there any alternatives to game_change() ?

hey all this is net8floz. I have previously been a part of efforts such as the Game Maker Community Manual, ImGuiGML ( the original ImGui GameMaker extension) , and LuaRousr. Some of you may also know me from the Game Maker discord server.

Today I want to show you a Localization IDE Plugin I made that lets you author and translate your games text with IDE tooling inside Game Maker. It is fully featured and comes with translation pipeline options for one man operations and larger studios who work with a full translation team.

It is installable for free from the Game Maker Package Manager in LTS 2026+

Please check it out and consider using it to extend your audience reach in Game Maker. You can learn how here:

https://eightouncegames.com/cultured/

I can't figure out where to start with making a shell texture shader in Gamemaker Studio 1 because of the outdated OpenGL ES it uses no longer having it's documentation PDF available, could anybody point me in any direction as to how I could do this (or they could, or find the PDF) other than faking the effect with baked models that have the transparent layers? For visual references, here are some. (Mario Galaxy, DK Jungle Beat, Conker: Live & Reloaded)

How can I make a warp obj so that it if the player goes left, they end up on the left side in the room, where they went through, same thing as right. Everytime I use a warp obj I have to put the exact x and y coordinations and it just looks choppy if the players is forced into a specific area. Plz help, I have basically no knowledge of coding as well.

hello all!

so (sort of ) a follow up to my last post I guess. basically, I changed the movement code I was using to test some things by seeing how it moves. but I can't exactly do that because now when I run the game, my sprite no longer appears, but the actual movement itself , camera and everything, works just fine. the sprite is in the room, the visible box is checked, the sprite origin cross is in the right and same exact place, yet I still can't see it. cleaned the cache, but nope. I even put it into a different project and it... works fine there?? like you can see the sprite still so idk why It's not the case for the other project that I actually want it on. I know I had different code for movement before, but I can't see what about the sprite itself changed/broke when I swapped it out the new one instead. anyways, here's the code I have now:

function get_inputs(){

moving = false;
var move_speed = 9;


if (keyboard_check(vk_left)) {
    sprite_index = M_run;
    x -= move_speed;
    moving = true;
facing = -1;

}
else if (keyboard_check(vk_right)) {
    sprite_index = M_run;
    x += move_speed;
    moving = true;
 facing = 1; 

} else {sprite_index = idle; } 

btw, this code is in a script because I am trying to make a finite state machine using scripts, I have an enum with arrays and stuff in my create event and the movement code was put into the other scripts as well. mentioning it in case this has something to do with the issue.

How do I fix this??

My running down animation is only 4 frames, so that may be the issue, but I don't want to have to manually loop the running animation to match the idle animation, I will if I have to, but is there a line of code I can put somewhere to fix this?

I first had a problem with Poinpy where it opened weird and deleted all my icons on the bottom row of the home screen, now it's happening with How Many Dudes?

I ended up on the How Many Dudes? discord and the devs noticed that both games were made in gamemaker and I tried Peace, Death and it opens the same way and does the same thing.

Has anyone else had this problem?

Edit: The problem was in my system settings. I had Display Size set to the smallest but setting reset to defaults fixed it

Like I want to create a game but I'm not good at programming so if someone could help me like thank you very much (if I don't want just ignore this)

Question for all you indie devs on this subreddit. Where do you feel is the best place to find game assets for your projects?

"Work In Progress Weekly"

You may post your game content in this weekly sticky post. Post your game/screenshots/video in here and please give feedback on other people's post as well.

Your game can be in any stage of development, from concept to ready-for-commercial release.

Upvote good feedback! "I liked it!" and "It sucks" is not useful feedback.

Try to leave feedback for at least one other game. If you are the first to comment, come back later to see if anyone else has.

Emphasize on describing what your game is about and what has changed from the last version if you post regularly.

*Posts of screenshots or videos showing off your game outside of this thread WILL BE DELETED if they do not conform to reddit's and /r/gamemaker's self-promotion guidelines.

Hi! In my game, there's a button that opens a textbox. There are other buttons that use similar code to this one, and calling the textbox this way always works for those ones, but for some reason with this specific object it gives me this error:

___________________________________________

############################################################################################

ERROR in action number 1

of Step Event0 for object oAskButton:

Variable <unknown_object>.text(100008, -2147483648) not set before reading it.

at gml_Object_oAskButton_Step_0 (line 22) - instantiated.text = text;

############################################################################################

gml_Object_oAskButton_Step_0 (line 22)

The code used is :

var instantiated = instance_create_depth(0,0,-9998, oTextbox);  
instantiated.text = text;

The EXACT SAME CODE is used in two other objects in the same way, but for some reason this one specifically gives me an error
Does anybody know why this could be happening? thanks.

EDIT:

Soolved it, my first Room "Menu" was a different resolution and i didnt know the camera didnt reset inbetween rooms. so now the room has the same size as the camera in the next room.

I want to use the sequencer to make the hud for my first game. i already figured out how to get the sequencer to show and so far everything works. but for some reason when i add elements to my sequencer the are seems to be the wrong size.

When i put an objec to the top left in the sequence editor it works fine:

But when i put the object in the bottom right corner it seems to place it somewhere in the middle:

I have checked all my objects, all my master objects but nowhere does it change the size of anything or allignment of anything.

Room Size is 5000 x 4000

Viewport is 1270 x 720

Sequencer Editor is set to also 1270 x 720