[Game Maker] Some questions

Tuism

This thread is my Q&A for some game maker technical questions, and
I'm gonna summarise what's been solved in this thread in this first post so that it may help others answer some GM Studio questions.

[Solved]
Screen Shake code is wonky
How to get PS3 or xbox360 gamepad working in GMS
Gamepad code makes GMS speed drop to like 2 fps
Version control in GMS - use or not?
Offsetting mouse position to screenshake!

As yet unsolved



Original post-----------------------------------------

Hi guys

Just been doing some screen shake in my game (BEST EFFECT EVER) and I've found that after a while the screen doesn't centre back to the original view anymore, and I can't figure out how or why it's doing that... Mind looking at my code to gimme some pointers?

Much much appreciated!!!

The code runs on every step, and I set global.screenshake so that the bigger the value the longer and bigger the explosion.

// shaker

if(global.screenshake > 0)
    {
    amounty1=-(global.screenshake/2)+round(random(global.screenshake))
    amountx1=-(global.screenshake/2)+round(random(global.screenshake))
    view_yview[0]+=amounty1
    view_hview[0]+=amounty1
    view_xview[0]+=amountx1
    view_wview[0]+=amountx1
    global.screenshake -= 2;
    } else
        {
        view_yview[0] -= (view_yview[0]/2);
        view_xview[0] -= (view_xview[0]/2);
        if (view_yview[0] < 1) and (view_yview[0] > - 1)
            {
            view_yview[0] = 0;
            }
        if (view_xview[0] < 1) and (view_xview[0] > - 1)
            {
            view_xview[0] = 0;
            }
        }

// /shaker

Bensonance

Just from looking at the code briefly, it looks like you're also increasing the height and width of the view? With the lines: view_hview[0] and view_wview[0]. You don't reset these values though so that might be why it looks weird after a while.

Also, a simpler way to do screen shake is:

Step Event:

if(canShake){
     view_yview[0] = random_range(0, shakeIntensity)
}

A larger value of shakeIntensity will have a inteser shake.

When you set canShake to true, also set an alarm for the period you want the screen to shake. In the alarm event set canShake to false and view_yview[0] to 0.

Also, I usually only shake in the vertical axis because it's easier to play with.

Tuism

Thanks! Indeed the width and the height were the culprit! Removed those and they work perfectly :) Thanks! :D

Tuism

How do I use Xbox/ps3 controllers in my game?? (Game Maker Studio)

I'd like to get some multiplayer going so I can test my game but mine has analogue input so it needs two controllers (or port prototype to touchscreen), and it would seem two controllers with analogue stick is the easiest...

After some googling I've not found anything conclusive, according to the documentation in app gamepad_get_description seems to get the type of controller, and it uses a PS3 controller as an example, but I'm not sure if it's a simple matter of plug-n-play for game maker? Do I need any special DLLs to make it work? (a few threads stated as such but I haven't found anything specific...)

Thanks guys :D

Bensonance

The section in documentation under GamePad Input seems to imply that it is just plug and play for Studio. I haven't used controllers before, but I'll be trying them in the next week. As long as you can usually connect the controllers to the PC it should be fine. My impression is that it supports at least Xbox 360 and Ps3 controllers.

It says it's similar to touch controls which means the first controller is device 0 and the second is device 1. So when you use the functions say: gamepad_axis_value(0, gp_axislh) for the first controller and: gamepad_axis_value(1, gp_axislh) for the second.

Tuism

I did some more investigation, it seems that on a PC, getting the PS3 controller to work at all takes quite a bit of doing, so an xbox360 controller seems to be the only way to get one of the big name controllers to work on a PC without too much trouble.

Then there's the question of whether if you just plug in the PS3 controller, and ask game maker nicely it'll just bypass the windows drivers' non-response and just magically work, somehow I doubt it.

Will be doing more investigation with the 360 controller as well... Although anyone with experience in this is more than welcome to chip in :D

Squidcor

A 360 controller in GM will work as is using the joystick functions. The easiest way to use a PS3 controller is to use MotionJoy to emulate a 360 controller.

Tuism

OMGEE thanks Squidcor, I've been messing about with this for ever, and your instructions were exactly what I needed to get it working :D

For anyone who also am going to try gamepads in GMS:

1. A 360 wireless controller with the charger cable in will not be picked up as a proper controller. You need the WIRED one, or the official 360 controller wireless receiver.
2. The PS3 controller will only work in GMS if you use MotionJoy to emulate a 360 controller. To get the PS3 gamepad working, follow these instructions precisely: http://www.motioninjoy.com/wiki/en/install/latest
3. Then do a test in GMS with gamepad_is_connected(0) which should return true if working.

YAY!!! :D

Tuism

Leaving this here in case someone else runs into the same problem...

So just as soon as I thought my gamepad controls are implemented and working, the whole game goes into chug-chug lag mode at less than half the usual framerate/speed. So I google around a bit and it seems like Game Maker has always had a history of a bug where gamepads will put the game into over-stress and lag it out. Sometimes it's when you had a gamepad in, or sometimes it's when you plug one out, etc.

I'm gonna have to just work around that, apparently. Looking into it... Hope anyone else may have some suggestions?

OMG...

dislekcia

I assume that checking for a gamepad is pretty slow? Maybe build different input objects for keyboard and gamepad movement and then only instantiate the one you need at the beginning of the game, thus avoiding gamepad checks that might slow you down if there isn't one?

Tuism

Thanks for the input!

My research landed me on people who say the best one can do is to make the game check for a gamepad existing before actually making gamepad calls, and each time one's supposed to make gamepad calls, refer to that check before making the call.

But this was in GM 8.1 apparently! I can't believe they haven't solved this by now...

I'm not by my game at the moment so can't try and implement but I'll give it a shot as soon as I can.

dislekcia

Yeah, that's pretty much what I meant: If you find a gamepad, instantiate the input object that calls the gamepad functions; If you don't find a gamepad, instantiate the input object that never calls gamepad functions so you never have to worry about slowdowns.

The slowdown when asking a gamepad that doesn't exist for information actually makes sense if you think about it: All peripherals are based on polling, so your program goes "Hey, gamepad, tell me what's going on!" and then waits for the gamepad to send it some information back. The reason your program has to wait is because the gamepad could be disconnected at any point - the cable could come out, it could run out of battery, it could be inexplicably placed inside a running microwave, etc. This means that every gamepad poll has a timeout after which the program assumes that the gamepad is just being slow or maybe not there and carries on executing. So all you're going to get happening when you keep asking a gamepad that isn't actually even there in the first place is a lot of timeouts, hence your game being slow while it waits for the call to timeout for every gamepad function you run.

Tuism

Here's the the other thing though - once my game compiles once with the gampad lag, no matter what I do - and that includes plugging in the gamepad, plugging it out, deleting all reference to gamepad code (seriously removing ALL gamepad codes), whatever, the compiled game will lag. It takes a hard reboot to get back into GMS and then it's a gamble whether it'll be lagging this time or not.

So if it were predictable, I could deal with it, but it seems pretty random and out of my control. It hadn't happened all the way through my testing and trying out gamepad code - 2 or 3 days - it's only when I thought I finished it did it start to happen. WEIRD.

dislekcia

Do any services start up when you try to access a gamepad through GM without one plugged in? Same question for if a gamepad exists? If it survives program termination, it's some kind of service or helper. You messed around with gamepad emulators recently, right? Did you do anything else that might have inserted hooks into what Windows might do when it looks for a gamepad?

Tuism

Do you mean to open up task manager and see if services pop up when I do the gamepad call? I'll have to try it out tonight and see, but I don't see how I might be able to pick up how many services there are in task manager, there're TONS.

And the lag only ever affects GMS, I feel it might have to do with the compile and runtime rather than something else... I haven't done anything besides that emulator (which again worked fine at first for a long time while I was still building the controls).

Again, I'll have to experiment tonight and report back!

(I can't believe noone else has run into this before XD)

I found these on my research on the topic, I'll also try their advice out and see if it changes anything:
http://gmc.yoyogames.com/index.php?showtopic=567087

Tuism

SUCCESS!! (of sorts!)

I was ALMOST about to give up, when I discovered the ONE THING that made the game return to un-lag - and that is to unplug the controller and re-plug it in, and re-enable the 360 controller emulation from DS3tool (that's the MotioninJoy Gamepad tool referenced above by squidcor).

I have NO idea why that works, only that it does. And I have to do this every time the game re-starts... or else it lags all over again. Well, hope this find helps the next frustrated GMS gamepad user!

Now I can finally get back to devving game mechanics rather than dumb controller bugger ups XD eventually i'll have to convert to touch controls anyway... eep.

Bensonance

Hey so I finally got round to trying out controllers too, here's my feedback:

I'm using an Xbox 360 Wired controller to connect.

I also got the lag when I started, so I grouped all the scripts together that checked for a gamepad input and only activated them if the gamepad is connected:

So:

if(gamepad_is_connected(0)){
  //Gamepad checks
}

This is more or less what @dislekcia suggested and it does seem to eliminate the lag :).

Tuism

Yeah I also did that, but while I did that it ALSO lagged - that was the problem XD

Now I have this in step:

if gamepad_is_connected(0)
    {
    global.gamepad_1_in = true;
    } else 
        {
        global.gamepad_1_in = false;
        }

And all gamepad code first checks global.gamepad_1_in before executing, which gave me the same results essentially...

But even with that, when the game starts it still will lag, until I unplug and plug in again. Maybe it's got to do with the MotioninJoy convertor. When/if I have a wired xbox controller I'll give it a go...

Tuism

Another question, oh gurus!

So I'm starting to need to branch my code to try different sorts of mechanics to prototype, should I use SVN and version control in GMS, or should I just be the one-man "team" that I am and use "save_as" and just pop out different files at various points when I know I'm stable?

I remember hearing horror stories about version control in GMS, is that true/still the case?

Thanks guys :)

dislekcia

Put specific gameplay mechanic in single controller object. Duplicate object, rename it, mess with gameplay code in new object. Create new room, spawn new controller object instead of old controller object.

Yay!

Bottom line: Swapping out objects that you simply don't use is a lot easier than messing with version control at this point of your life. Don't bother with version control until you have a team that absolutely has to share source.

Tuism

Uh oh... I have a peculiar problem that I'm not sure how to solve...

So I have a screen shake system in place. And my game is controlled via mouse click and drag to set the angle of throwing stuff. Each frame, the game catches how much your mouse has moved, adds that to your angle, and resets the mouse cursor. This is my solution to the cursor falling off the screen sometimes. (Fullscreen will come later... And also I don't know how to make your cursor unable to leave the game, but that's another matter altogether)

So I finally got that to work, BUT... Now when I'm holding the angle of throwing, when something explodes and the screen shakes, it throws my angle out because the view change is registering as a change in device_mouse_x(0)...

I've tried to counteract it by modifying the power value by the value in the screen shake, but it's either "impossible" or I'm just missing something - it just doesn't work.

Can any kind soul please assist? XD

This is the mouse -> power code, on begin step:

if obj_char_1.input_event_hold_down
    {
    global.power_1_x += (device_mouse_x(0) - 509);
    global.power_1_y += (device_mouse_y(0) - 359);
    window_mouse_set(512, 384);
    }

input_event_hold_down is picked up by a mouse click and hold event.
(for some reason I set the mouse to 512,384, but if I set the offset in the calculation to that it doesn't zero... So it's offset by a bit, and I have NO IDEA WHY... XD But it works right now.)

And this is the screen shake code, on step (not begin step):

if(global.screenshake > 0)
    {
    amounty1=-(global.screenshake/2)+round(random(global.screenshake))
    amountx1=-(global.screenshake/2)+round(random(global.screenshake))
    view_yview[0]+=amounty1
    view_xview[0]+=amountx1
    // window_mouse_set(window_mouse_get_x()+amountx1, window_mouse_get_y()+amounty1);
    global.screenshake -= 2;
    } else
        {
        view_yview[0] -= (view_yview[0]/2);
        view_xview[0] -= (view_xview[0]/2);
        // window_mouse_set(window_mouse_get_x()-(view_xview[0]/2), window_mouse_get_y()-(view_yview[0]/2));
        if (view_yview[0] < 1) and (view_yview[0] > - 1)
            {
            view_yview[0] = 0;
            }
        if (view_xview[0] < 1) and (view_xview[0] > - 1)
            {
            view_xview[0] = 0;
            }
        }

the bit I commented out are bits I tried to insert to offset the offset - if that makes sense... But it doesn't work at all.

I feel like there must be an easier way that doesn't get thrown by view_xview[0], but I don't know what it is... Is there?

Any assist greatly appreciated!

dislekcia

You need to store the amounts that your screenshake is moving the screen (so that amountx1 and amounty1 that you're using) so that you can use them in the calculation as an offset to where your mouse has moved when you do the mouse position check.

if obj_char_1.input_event_hold_down
{
    global.power_1_x += (device_mouse_x(0) - 509) - amountx1;
    global.power_1_y += (device_mouse_y(0) - 359) - amounty1;
    window_mouse_set(512, 384);
}

What this does is "undo" the movement of the screen from the mouse's perspective. The reason it didn't work the way you were doing it before is because the mouse was being moved by your command and then moved again when it actually checked the mouse's position. All you need to do is set amountx1 and amounty1 to 0 when whatever control object this is is created.

Tuism

Thanks for the assist! :D

The code still has some drift, I don't know if it's because of something I'm missing, or if it's because the mouse detection happens before the shake (it's in a begin step, and the shake is in a regular step). In fact I don't know if both of them were in begin step which one would run first...

The detection needs to be in a begin step because I need the mouse values picked up before other steps access those values, and the shake isn't in a begin step object... Should I extract the shake into a begin step object? Does that make a difference?

I've got another idea, to use the absolute screen pixels that's unrelated to view - but it seems device_mouse_x(0) can't be unrelated to the view, and I'll need to use devices if this will eventually go to a touch device (that's the idea)...

OMG MY HEAD.

dislekcia

Oh, derp. Of course it'll drift because you're not always setting amountx1 and amounty1 when there's screen movement - you've got that whole "calm down" from a shake happening too...

if obj_char_1.input_event_hold_down
{
    global.power_1_x += (device_mouse_x(0) - 509) - view_xview[0];
    global.power_1_y += (device_mouse_y(0) - 359) - view_yview[0];
    window_mouse_set(512, 384);
}

That should "remove" the view offset from the device's mouse co-ordinates that are being returned to you in game-space.

Tuism

OMG THAT WORKS :D

Looks so obvious when you do it XD Thanks a millllll!!! :D

Tuism

Ermmmm, I googled this and couldn't find any answer, so it seems impossible, but so simple, yet... Dunno...

How do I pass a variable NAME into a script as an argument?

like...

var block_array

then in the script count_something

argument0[x] = x*10

Then I do

count_something(block_array);

Where argument0 is an array I'm going to fill with a for ~ do loop or whatever... Everything I try now results in the thing trying to pass the contents of block_array, and that's not what I want... I want it to take "block_array" as an array, not the content of the variable...

Research shows me... apparently you need "pointers" and you don't get those in GM?

Thanks again guys :D

Gazza_N

Sadly, passing by reference isn't available in GML, which makes passing arrays as parameters pretty much impossible. You would probably need to pass each array cell to the script and get a return for each:

block_array[x]=count_something(x);

Count_something

return argument0*10;

There is another trick you can use, although it's super hax and blows encapsulation to pieces. I also don't know if it's been killed in Game Maker Studio or not. That is to create a user event in another object and call it using the event_user_other function. Game Maker will assume that the user event you're calling is within the scope of the script you're calling from, meaning that you can directly manipulate the variable by name.

dislekcia

There are commands to get a variable on an object via string names, will look them up tomorrow.

Although, if you're using arrays like that and you're not sure how many things are in that array, why not either have a separate variable that's supposed to store the number of elements in that array (you'd increment it every time you added something) OR use lists?

A list is a structure for storing things, very similar to an array, that grows in size according to how many things are in it. You can easily pass around list identifiers, because you access lists (and other non-array GM data structures) like so:

myListPointer = ds_list_create();
ds_list_add(myListPointer, someValue);
ds_list_add(myListPointer, anotherValue);
stuffInList = ds_list_size(myListPointer);

Actual function names from memory, so may not be reliable. Check up the GM help... Anyway, reason lists are cool = you could go "Count_Something(myListPointer)" and it would actually make sense.

Tuism

Thanks for the info guys!

@Gazza_N I think that may be a way around, I'll have to check the structure of my script...

@dislekcia I think I haven't communicated what I need enough, what I want to do is have a function that can count instances of object X (variable) and put that into an array (variable). The size of the sample I'll also pass into the variable manually, but it's not the focus of the exercise.

So for example I'd call the script like this:

count_instance(obj_block, array_block_, 7, 14)
argument0 = the object type to count
argument1 = the array to put the count result into
argument2 = start with this x position
argument3 = end with this x position

So when I pass argument1 in it tries to take the content instead of the the variable name array_block...

dislekcia

Okay, so your actual problem is that you want a function that returns a set of results instead of a single value. Usually what you'd do in a different programming language is create a place to store the information your function is going to return, populate that with information and then hand it all back to the rest of your program via the address of the storage place (a pointer).

The good news is there are totally ways to do this in GM, multiple ways, in fact!

The first solution to your problem is using the return keyword in a script. That means the script can ouput a value, so you can do something like myResult = someRandomScript(param1, param2, param3). That's really useful. Returning something will also stop a script running further, so you can totally do neatly optimised crap like:

if (argument0 <= 0) {
  return 1000000;
}
return 0;

Anyway, your options in GM are to either build a dummy object to use as a pointer location and store your results there - this object would have no sprites, no interactions and not really have any code. Or you could create a new ds_list to store your results in and then pass that around by identifier, which acts like a pointer. Doing things the list way is great if you want a single coherent set of results - all the x positions of a set of objects that are currently red, for instance - doing things the object way is better if you want multiple sets of results - all the colours AND x positions AND rotations of all the objects currently surrounded by the selection box... The important thing is to clean up after yourself and always delete the thing you created to store your results in when you're done using those results, otherwise it'll hang around forever.

Another thing to keep in mind is that if you really need a ton of results back from a script and think that means you should go the object route, there's probably a better way to go about solving your actual problem. Maybe you could create a dummy object that collides with the things you care about and performs the actions you want on them during its collision event, then kills itself. Maybe you could do all of that with a script that simply stepped through all the objects of a specific type and you didn't need to pass that info around to other scripts in the first place. Coding is fun like that :)

So, now that I understand your problem and you understand how I'm thinking about it, here we go:

You want a bunch of pointers to all the objects of a specific type that fall within a certain bounded area of the screen. We could totally build a dummy collision object to create that list, instead we'll just do the math on each object's position because that's faster and is available instantly.

Script GetObjectsBetweenXPositions(object type, min x, max x) returns list of objects...

var objectType, list, xMin, xMax; //We need to create variables to both limit variable spam and to help the "with"

objectType = argument0;
list = ds_list_create();
xMin = min(argument1, argument2); //paranoia helps
xMax = max(argument1, argument2);

//Now we step through every object of the specific type, yay for the with clause!
with (objectType) {
  //Note that we have to use the "other" keyword to access variables "outside" the with clause
  if ((x >= other.xMin) and (x <= other.xMax)) { //Check to see if the object is where we want it
    ds_list_add(other.list, id); //Add this object's reference to the list, id is each object's unique identifier
  }
}

return list; //Happypants! Sometimes we could return an empty list...

You'd use it as follows:

//Get a list of AsplodingBlocks between 10 and 100
objectList = GetObjectsBetweenXPositions(AsplodingBlock, 10, 100);

//Iterate through each object...
for (i = 0; i < ds_list_size(objectList); i += 1) {
  currentBlock = ds_list_find_value(objectList, i);
  //Do stuff to currentBlock
  currentBlock.asploding = true;
  currentBlock.x -= 25;
  ... //blah etc
}

//Delete your temporary list!
ds_list_delete(objectList);

So yeah. You could also keep that list around (or store it in a list of other lists or whatever) if you wanted OR you could easily modify the script above to take a specific list identifier you wanted the objects stored in as a parameter, but you would still have to clean it up eventually... This got a bit long, but I prefer explaining the logic behind a bunch of code, rather than just promoting copy-pasta. Hope that helps.

Tuism

Hi guys, again with some seemingly easy questions, but nothing is coming to mind @_@

Is there a way to do localised collision detection with multiple instances of the same object, without stepping through ALL of the instances of the master object to collide with?

I got a pile of blocks, I want to see which ones are in collision with a certain area, but I imagine stepping through ALL the blocks would be expensive on the cycles if done a lot, so I'm trying to keep it lightweight...

Or should I really not be worrying about this kind of "optimisation"? XD


All the collision detection methods I know basically pick the "topmost" object and stops looking after that, even if a bunch of items are in the hit area.

Thanks ahead of time! Much appreciated! :D

dislekcia

I'd strongly file that under "optimisations that are only worth doing if there's actually slowdown that you give a shit about".

But there are loads of ways to be more efficient if you need to, you could store blocks in a sorted structure, you could have a dummy object that built a list of blocks that it collided with and then only run through those blocks, you could even cycle through every block and only bother doing a collision test if they're close enough to the thing you're testing for.

But yeah, don't worry about that unless it's a real problem.

Tuism

Cool, thanks :) I'm mostly just wondering how it could be done - like you said, I wanted to make a dummy object that counted collisions with it.... But that means running through all the blocks to collide with it - If I ever made a collision detection call it'd return ONE object, and that would be, well, just one of the many.

But yeah I'll worry about this another time, thanks :)

Tuism

Has anyone ever tried the HTML5 compiler for GMS? I made a compile of my game in HTML5 and put it into my Dropbox. I loaded it up, and there was a loading bar and all that, it even goes into the main menu.

But then when I select the option to enter, it just hangs, not sure if it's loading without me knowing or if it just crashed... Can anyone shed any light on this?

https://dl.dropboxusercontent.com/u/15257303/game_dev/Prototype_1/index.html

Thanks!!

Thaumaturge

For what it's worth, I seem to be seeing the same behaviour under Ubuntu. Not being familiar with either Game Maker or web-based games, I'm afraid that I have little more to offer. : /

[edit]
Hmm... Are you sure that it's taking the command to enter? Looking at it again, having reloaded, I can click on an arbitrary part of the window (that's a rather pretty backdrop, by the way ^_^) in the hopes of giving focus to it and allowing me to use keyboard controls to select options, but while the cursor disappears (implying keyboard control), the game doesn't seem to respond to input. Perhaps it's freezing as soon as the game loads?

Tuism

Sorry, that's my shitty programming logic that seems broken... I've taken a click as pressing the button, so that if you click anywhere to get focus the item selected by the cursor selected is, selected. I'll need to change that :P

Then yes it goes into a freeze... In my standalone builds it goes straight into the game, but here, either it *is* loading, and I just can't see it, or it's gone into crash... Either way I've waited for EVER and didn't see it going into the game, so... I can't tell which it is!

(I don't know how to do a loader... Who knows how to do a loader in GMS? I Googled it and really, really can't find anything helpful)

Boysano

Hi I'll give my 2cents on some of your questions here...

Firstly lists and maps are the way to go when working with large amount of instances and or data and stats instead of array in GMS....see the help file in GM. List are really easy to save and load also in one shot as a variable and for building matrixes. Also in the help file which I always use when coding (since I'm self taught) is functions which directly solves your local collision question...I think it's something like collission_rectangle(); etc. and other shapes...but when you are in full control it's a lot more effort to avoid thinks going through walls and other solid objects, etc. This is handy for HTML5 cause its really a bitch coding HTML5 for performance is always a consideration...not to mention screen sizing and rotation.

Tuism

@Boysano thanks for your input! I'm also self-taught (past tense? I'm certainly still learning...!!) so high-five! :D

Question though, I know collision_rectangle, collision_line, etc, but do they return more than one instance of collision? That was the crux of my question - let's say I have 10 objects and one explosion, and only 5 are in the explosion, if I want to test for objects caught in the explosion, do I have to initiate the test from each of the 10 objects, or is there a way of testing on the explosion and finding multiple overlaps?

And most of those older questions are out of the way, now I'm stuck on html 5 loading... Dunno if my game just doesn't load into html5 or if it's loading and I don't see it loading.

Any idea on how to do a loading screen between rooms? Google hasn't turned up anything I understand...

Squidcor

The collision functions will not return more than a single instance. However, you can place those tests within a loop like so:

object = collision_rectangle(x,y,explosion etc.);

while (object != noone)
{

    //do stuff to object

    object = collision_rectangle(x,y,explosion etc.);

}

Alternatively, checking for collisions in the object (as you suggested) will work fine, but you'll probably end up doing unnecessary checks.

dislekcia

@Tuism: Your game is probably crashing on some function that isn't supported by HTML5 GM somewhere. First check the help on that, then start with a test room and gradually add your game's stuff in to see where it crashes. That should help you figure out what's going on.

Tuism

@Squidcor does that code assume that the object will disappear or be changed to another object after it's been "processed"? Because if the object remains the same/there, wouldn't the collision test return the same object?

I'm trying to work out how to not do unnecesary checks but I haven't figured out how...

@dislekcia thanks, I'll look into html5 GMS issues!

dislekcia

@Tuism: How many objects do you have that you're worried about doing unnecessary checks, 500, a couple thousand? Seriously, if you have like 50 or whatever, I really don't see the need to worry until you actually have a slowdown problem.

Do you have a slowdown problem?

Tuism

Not yet... Theoretical upper bound for objects right now is about 140, and they're all running physics and some other checks. I haven't gotten to the bit that I need from this yet, it was more a case of I want to learn what the best practice would be...

So yeah, I'll go on until there's actual performance issues :) thanks :)

Squidcor

@Tuism: Yes, that code assumes the object would no longer be colliding after being processed.

Also, can you not just put all this code in a collision event instead?

Tuism

@squidcor, not sure what you mean by putting them in a collision event, is that one of the events like "step" and "create" and etc? How would that help?

Cos right now all my collisions are written into a script in each object's step, and it checks collision, but the question is detection multiple hits from one object.

And I'm gonn take @dislekcia's advice for now and not worry about optimization for the time being :)

Squidcor

Yeah, a collision event is an event like Create or Step, but it's only triggered when the sprites of two specified objects overlap.

Tuism

Hey! I've not actually seen that event, thanks for that! I guess that one would do the detection on everything ever too? Or maybe it's written more efficiently than what I would be able to do.

Thanks :) I wonder if there's not a script way of doing that event, I pretty much dislike using more of those events than the bare basics of create, step and draw :P

dislekcia

WTF? Collision events are wonderful: You just tell an object in GM what type of objects it should care about colliding with and it'll let you know if a collision occurs. It does all sorts of location-specific optimisations to prevent extraneous checks and stuff. Why would you not want to use what the engine gives you for free?

Tuism

That is a very good point: Don't fight the engine. This came up when we were discussing Unity collision detection.

I didn't actually know there was a collision event so I wrote everything into step events, and I'm reluctant to use more events because I thought keeping code contained and together would reduce messiness and make me less likely to be confused by my own code...

But yeah you're right, I'd put code into built-in engine stuff than try to figure out how to solve the same problems solved by people before me!

Thanks!

I'm so behind on this, gonna get cracking this week!

Squidcor

I'm reluctant to use more events because I thought keeping code contained and together would reduce messiness and make me less likely to be confused by my own code...

You might regret this approach when your entire game becomes one monolithic, thousand-line step event monster :P

Tuism

You might regret this approach when your entire game becomes one monolithic, thousand-line step event monster :P

I have indeed considered this more and more lately and begun to shiver at the thought :P

I just wish GM's interface was a bit easier to organise. Even dragging files and folders around can run into retarded situations.