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[JMickle]

instead of adding another line, change the parent of o_basicarrow_hit to o_jumpthru, saves you messing up the code too much. I don't know if this will fix it, though, but chances are it will work better.

I don't know how to go about fixing that angled fallthru, though, Maybe have to hack it by making it so you can't stand on arrows that hit more than 45 degrees into the wall? seems realistic enough to me.

[Gabriel Verdon]

instead of adding another line, change the parent of o_basicarrow_hit to o_jumpthru, saves you messing up the code too much. I don't know if this will fix it, though, but chances are it will work better.

I don't know how to go about fixing that angled fallthru, though, Maybe have to hack it by making it so you can't stand on arrows that hit more than 45 degrees into the wall? seems realistic enough to me.

Good idea regarding the making the arrow a child of jumpthru. This didn't seem to fix the problem though, but it probably makes the game run a bit faster.

I don't think the slope issue is much of a problem now that I've played around some more.

I think I've figured out more specifically what the issue is though - it seems that if you are moving downwards, and there is an arrow below you, normally you would collide with it. However, if you are moving downwards and there is an arrow below you BUT you are also currently overlapping with another arrow, you won't collide with the one below because it seems to consider them all to be like on big arrow.

Ha, it's actually quite useful to elaborate the problem in a post because now I think I might know how to fix it.

[Damian]

Hi, I've been using this engine for a while now and I pretty much know it off by heart. But for the life of me I just can't figure out how to make the player object jump down through a wall object. I've played around with obj_moveable to see if it was a fault with that part of the code. It wasn't, I managed to have all enemy sprites move through but not the player. I'm still playing with the player object to try and  work this out. I think someone else has managed to tackle this problem and if anybody could help me out I'd be very grateful.

Damian

[Sheep]

Do you mean with the jumpthru platforms?

I added !keyboard_check(vk_down) in the checkBelow script, and it worked

return place_meeting( x, y+1, obj_floor )
    or (place_meeting( x, y+1, obj_jumpthru ) && !place_meeting( x, y, obj_jumpthru ) && !keyboard_check(vk_down))

Not sure if that was your problem, but it was mine, so my problem is solved xD

[Damian]

  Thank you. I actually have that code already. But seeing that it worked for you and not for me confused me. It seemed logical. My mistake was making new objects and parenting the object floor in my idiocy instead of the jumpthrough object. Again thank you 

[Jawnsunn]

http://www.mediafire.com/?k2oddbn9tsnqf5w
Here's a backup since the link stopped working.

[PlasmaMan]

I'm an almost-absolute-beginner at Gamemaker, and a definite-absolute-beginner with GML. I really can't thank you enough for making this available, it's been a fantastic teaching tool.

[HarrisonJK]

Hey the link to this has gone bad. Is it still on the internet somewhere?

EDIT: Sorry, I just looked through the rest of the thread and found that Jawnsunn's link still works.  

[Matt Thorson]

Fixed the link again! Sorry for always forgetting about it when I change hosts haha. It's at http://mattmakesgames.com/matt/GrandmaEngine.gmk

[Erinock]

Thanks for this, it showed me a different and simpler way to warp between rooms compared to how I used to do it. Thanks, and will give credit when I use it. 

[PureQuestion]

Is this even still linked anywhere on your site, or is it basically just here?

[lasttea999]

Is this even still linked anywhere on your site, or is it basically just here?

Fixed the link again! Sorry for always forgetting about it when I change hosts haha. It's at http://mattmakesgames.com/matt/GrandmaEngine.gmk

---

So I've been using the methods of the Grandma Engine in GM and also in Java, leaving the core algorithm (?) mostly intact, and in my opinion the movement feels great, it's really smooth. But I've been wondering about the efficiency of the method. It does a LOT of collision-checking that other collision-checking methods may not have to do, right?

If I remember correctly, though, I think I was able to get about 100 or 200 simple objects going without lag in GM with this method? It might even be possible to have more objects. I haven't really tested it in Java.

My apologies if this issue has already been discussed within the thread. Thoughts?

[Squid Party]

good engine

[caiys]

@lasttea999 I'm not 100% but I think the only difference in terms of collision detection is that this engine checks for a collision before movement while GM's inbuilt collision detection checks for a collision after movement. So they are both doing the same amount of checking, it's just at different points in the code.

[lasttea999]

@lasttea999 I'm not 100% but I think the only difference in terms of collision detection is that this engine checks for a collision before movement while GM's inbuilt collision detection checks for a collision after movement. So they are both doing the same amount of checking, it's just at different points in the code.

I don't know about GM, but I think--- based on what little I've learned about other collision-checking systems--- that some other systems do things like

-move every object *once* according to their velocities, look for collisions among objects, and then move each colliding object out of its collisions once,

whereas the Grandma engine

-moves each object floor(abs(velocity)) times, checking each time if that object collides with each other object.

So basically, with Grandma's method, the checks rapidly increase with the number of objects and the speed of each object. It seems that the only big advantages this method has over the other method I mentioned is its simplicity and the amount of control you get over the movement. I rather like this advantage, but I want to know if it's worth the loss in efficiency. And while I probably won't need a more advanced engine, for more advanced physics, the capabilities of Grandma's method seem a bit narrow.

EDIT: Oh, allow me to mention that I like how the positions of objects are always restricted to integers, which I guess is part of the simplicity of the engine.