GameMaker: Passing variables into Create event

Time to time I see questions being asked about whether it's possible to set variables prior to instance' Create event being executed or otherwise passing values into the freshly created instance.

Most often, people will say that, no, you can't do that, but here's a bunch of strange workarounds instead (executing in alarm event \ moving all Create code into a user event).

Now, as you might be suspecting by the title of the post, that is not quite correct - there's a bunch of substantially more valid methods of approaching the problem. This post covers them.

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MouseLock & PointerLock for GameMaker


(click for web demo)

I made a small GameMaker: Studio extension that provides a unified API for "mouselock" between desktop and web (HTML5).

The way this works is by utilizing built-in mouse snapping functions on desktop targets, and using Pointer Lock API on HTML5. It bridges between the two, and you get simple functions like mouse_lock(), mouse_unlock(), and mouse_delta_x & mouse_delta_y for getting the mouse movement offset while mouse is locked.

So, if you ever wanted to make some web-based first-person shooters (or just games with mouselook) with GameMaker: Studio, now you can.

The extension is free and can be downloaded from itch.io or GameMaker: Marketplace.

Introducing: POOL [of doom!]


Game's title screen

This week a One Script Games jam was held on GameMaker forums. In short, the rules are that the entire game must be done inside a single script (function), which is then called once per frame, and must make use of built-in functions to store and process all needed information.

While potentially a little quirky, this seemed like an interesting challenge, so I made a game for it.

The result is a mini-FPS that is a mix of Doom, Quake, and a particular cue sport.

You can download it right now or read the full post for technical details.

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GameMaker: Minifying JSON

If you've spent some time working with JSON in GameMaker: Studio, you may have noticed that the built-in functions aren't exactly interested at making output laconic - they always write numbers with 6-digit precision, meaning that 3.5 always becomes 3.500000 even though the extra zeroes serve no purpose whatsoever.

The problem becomes more prominent when encoding data that is largely numbers - say, if writing down a shuffled sequence of numbers,

var map = ds_map_create();
//
var list = ds_list_create();
for (var i = 0; i < 32; i++) ds_list_add(list, i);
ds_list_shuffle(list);
ds_map_add_list(map, "order", list);
//
var json = json_encode(map);
ds_map_destroy(map); // destroys the list in the map as well
show_debug_message(json);

The output is as following:

{ "order": [ 30.000000, 22.000000, 2.000000, 8.000000, 17.000000, 14.000000, 25.000000, 9.000000, 20.000000, 29.000000, 10.000000, 26.000000, 6.000000, 15.000000, 21.000000, 1.000000, 11.000000, 3.000000, 24.000000, 12.000000, 19.000000, 31.000000, 7.000000, 28.000000, 18.000000, 4.000000, 0.000000, 5.000000, 27.000000, 16.000000, 23.000000, 13.000000 ] }

Where, out of 357 bytes, 250 bytes are whitespace or unneeded "precision".
A little inconvenient, if you don't have a compression algorithm on hand.
But, of course, that can be helped with a script.

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