Easy Tile collision - Tutorial - GMS2

Ever wondered how to make easy tile collisions? Then this video is what you are looking for. I will explain how my collision script works, and how to use it.

The script is really small and easier to code than other solutions i have found.

I really hope you will enjoy the content ^^

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[Shrooblord]

Epic idea! Thank you for this code. I had a thought to improve the 'meeting =' part of this with a loop to check for all pixels along the BBox edges:

var meeting = false;
for (var i = bbox_right; i <= bbox_left; i++)
{
meeting = tilemap_get_at_pixel(tilemap, i, bbox_top);
if (meeting) { break; } //kill the for loop once we hit something
}

You have now checked for one entire edge of the bounding box.

Do the same but iterating between bbox_bot and bbox_top while keeping bbox_right as your X-coord, and you've got another edge. Do it twice more for the remaining edges and you've checked all pixels along the bounding box.

For more precise collision-checking. :)

P.S.
Also remember to check before running those three other for loops whether meeting == true already. We don't want to run additional tests (and potentially invalidate the result of the first) if we already know that we've hit something.

[RhanW]

this doesn't work unless you replace
tile_meeting(x+sign(spdx), y, "Tiles_1")
with
tile_meeting(x+sign(spdx), y, )
Then it works great!Thanks!

[softbabymonkey]

Dude thank you so much, this saves me so much time!

[cossin]

For me it clips into tiles if it hits them on the corner. Is there any way to fix it?

[evanroderick]

I'm new to game maker studio. How did you get the GML editor window on the right side of another one? And what is

[mehmetyigitkeskin]

Can i use this code in my commercial game?

[takomeulenbeld]

hey man, it seems the script is working, cuz i'm not getting any errors and the game runs. But my player-object still doesn't collide with said tilesets that I use for collision, it just goes through. Now i already checked the width and height of the sprite and it's even smaller than the tile.

[MrJacovorster]

Can you please make a video that uses tile collision but links up with your "perfect top down movement video" I can't seem to figure out how to apply this with the velocity array method you used in the other vidoe

[FaramurDodecuai]

Hello, thank you for taking the time doing your tutorial.

I've a question: Well, actually I don't quite understand how the spdx and spdy are called, I tried the code exact in my game but it tells me that such variables aren't defined; so I placed instead the hspd and vspd my character uses to move, but it still says the same...

How do I make the End Event realise that they are already declared? Thank you.

[RagingSunbeam]

So I messed around with this, and it works GREAT- that is UNTIL you try to use a Gamepad for controls. Then it stops working altogether. Anyone out there have any troubleshooting advice? I feel like I'm SO close to getting this to work! Thanks!!

[veruticon]

so it says tile_meeting isn't a function in my version but it is the latest gms2. What should I use instead?

[conoma]

The whole "move player into the wall then move them out" is a very messy approach; it's much better to check your x/y value plus your speed variable for the tile, then use a loop to make sure you can approach the tile without going into it

[blazecreates]

Nice, I liked it.
Easy to follow, familiar concepts (at least for me anyway). You should have mentioned though, that this doesn't handle slopes/curved tiles, though I guess that's why it's "Easy"

[TToxicom]

it says the variable spdx isnt defined :(

[PoseidonLP]

It doesn't work. It always occurs the error:
tilemap_get_at_pixel() - couldn't find specified tilemap
Can anybody help me?

[seditt]

You seem to be performing the 4 collision checks X's 4 making 16 checks and this is assuming you have only collided somewhere by a single pixel. If not you run while(!tile_meeting) multiple multiple times. This is EXTREMELY inefficient code which there seems to be little point in. I am ok with inefficient if it gets the job done no other way could be this seems extremely pointless to do all 4 checks when you could get away with a single check in the while loop can't you?

[morphball]

hmmm... my character goes straight through, no matter what... gms doesn't give me any errors, so, I don't know what's going on !

[badwrong]

You're using a loop in place of basic math. So much extra stuff going on for no reason.