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Hi! Great engine! I'm new to 3d and was wondering how I extend the range of sight? Thanks!

(Edited 3 times) (+1)

Hi Yal,

I'm loving the engine and the work you've put into it, thanks!

I have two things I need help with:

-I want to alter the starting position of the bullet so it doesn't always spawn in the center of the screen, and instead I can alter it's starting coordinates so it always spawns at the tip of the gun (so I can move it left/right, up/down relative to screen, so no matter the size of the gun sprite I can always center it at the end of the barrel); I'm at work at the moment so I can't recall the exact names of the scripts but there was one with cx, cy, cz variables that I figured defined the bullet starting position, but no matter how much I played around with them I just couldn't get the desired result.

*The yellow circle is the bullet - I need it to spawn at the very end of the gun barrel*

-Another thing I need helping with is - I can't seem to find where I can set the size of the "level grid", that is, how do I define where is the border of the level itself and where the upper layers of the level begin within the room (I hope this question makes sense).

Any help is greatly appreciated!
Best regards,

First of all,  the easy thing: the level grid size is based on the width of the background you use for the level grid. (See the script terrain_flat_to_3d for the details). So basically, if you want a grid that's 2560 pixels wide, use a background that's 2560 pixels wide. Any size should work, but unless it's a multiple of your room grid size it's gonna be hard to keep objects from different layers aligned :P

For the second question... the 3D maths is kinda hard... which is why I skipped that part in the engine :P You'll need to find a reference point (e.g. the player's x, y and zbottom), then find the delta X/Y/Z to the tip of the gun, then spawn the bullet there. If you know the length of all the 'moving parts' (e.g. "spine", "shoulders" and "arm+gun"), you could just compute the X/Y/Z vectors of each part individually and then the tip of the gun should be there.

For each thing...

  • X coordinate should be lengthdir_x(1,angle against 'forwards')*lengthdir_x(1,angle against 'up')*(length of thing along X axis)
  • Y coordinate should be lengthdir_y(1,angle against 'forwards')*lengthdir_x(1,angle against 'up')*(length of thing along Y axis)
  • Z coordinate should be lengthdir_y(1,angle against 'up')*(length of thing along Z axis)

And since the spine is always just Z coordinate and shoulders are always just XY coordinates, this should be possible to simplify a bit. But yeah, it won't really get any easier than this, so guess why games like Wolfenstein and Doom had the gun in the middle so you didn't need to keep track of anything other than the Z coordinate :P


Thanks Yal! The "layering" level 3D system is very clever. Regarding the positioning of the bullets - I got that eventually resolved on the GM forum, and you are right - it's very hard and I don't think I'm yet at the level to properly utilize them complex maths and matrices needed for what I'm trying to achieve. So I guess for now I'll just stick with the "gun at the center of the screen"


Sounds like a plan... it's always possible to change it later in case you get better at 3D maths later, and working with 3D is a good way to learn about 3D, I guess :P

IMO the hardest part is figuring out how 3D vectors work (which needs linear algebra so you can actually do math with them - but you need to learn visualizing them as well in order to figure out HOW to use them for any given problem), once you've got that part down you can solve more or less any problem by doodling down a few lines on paper and putting variable names at all angles and lengths you'll need to use in the game. Don't underestimate doodling on paper, it helps visualizing stuff MUCH better than the maths formulae on their own :3


Indeed, doodling (& writing) on paper does wonders for me. Good to know that it's helping you out too, Yal :)

What is the easiest way to add a smooth crouching feature into this engine?

Nice and smooth engine btw ;)

I'd probably go about it this way, editing obj_player a bit:

  • Add a new variable iscrouching which defaults to false, is set to true in the step event whenever the crouching key is held (you'll need to edit the get_keys script to add in checks for the new crouch key) and false otherwise.
  • Add in a new code block in the Begin Step event:  when the crouching variable is true, lower zheightmovespeedmax and jumpspeed to something lower than their defaults, when it's false set them back to their default values. zheight in particular influences both the player's collision checking and where the 3D camera is located.
  • If you want the camera position to smoothly move up and down, you could use the lerp function rather than setting the zheight variable directly to the values for crouching/standing.
  • In order to avoid collision issues where the player crouches, gets under something low, and then un-crouches, you'll probably want to only allow switching from crouching to standing when there's enough free space over you that you can stand there with your original zheight. Depending on how you design your levels, though, this might not be a problem (e.g. if the player never crawls under anything and all ceilings are so high you can't bop your head into them, they can't get into a situation where this collision thing becomes an issue)

Let me know if something's unclear, and good luck :)

Would this work on GMS2?

It should work in theory (since there's compatibility scripts converting the old 3D functionality into new), but I've had some issues converting other 3D engines to GMS2 so I can't say with certainty it will. (For instance, there's a bug with drawing transformed models with <1 scaling factors that causes massive slowdowns). Still a bit torn whether it'd be better to make a GMS2 version from scratch of all my engines or convert them and try to deal with version differences.


Your call :P I bought your other engine to learn GML. There's not a lot of great source material out there. So, I'm trying to learn it all (last GM i used was 8)

At least it shouldn't be too hard to relearn Studio, it's basically GM8 with some stuff removed (execute_string() being the most important loss, a lot of people used that, and also sleep() and screen_redraw())... and some stuff added, like room/image editors where you can scroll and pan with the mouse wheel. Also, you can resize instances in the room editor now, which is wonderful for a lot of cases.

...oh, wait, you were talking about Studio 2. Derp. How do I forget things like this so easily x3

Studio 2 definitely is a bigger step up since it's based on the new stuff in Studio 1 more than it's based on its GM8 roots, but it's still mostly the same core loop. All the changes done from GM8--->GMS1 still apply, but on top of that:

  • Layers is a pretty major feature, and can be used in various ways... there's functions to only check a particular layer for instances/tiles, so you can have layers for each floor of a building etc.
  • Views has been generalized to cameras, which basically is the d3d_set_perspective() function except it now can view 2D planes as well. You can have more cameras than you have views and switch what cameras are displayed in which view on the fly, letting you make dramatic camera movements and stuff more easily.
  • Tiles has been revamped to allow autotiles and animated tiles, but this is mostly an editor thing.
  • Backgrounds and sprites have been merged into one resource.
  • Sprite editor supports layers for each subimage and you can draw while a sprite is animated, which lets you do some animations much easier.

I'm pretty new to GMS2 myself, but hopefully this helped you in some way :P

Yea, I've been trying to learn GMS2. It's a bit different than GMS 1.4 (I have both anyways so it doesn't really matter) Converting some of my projects has worked "successfully" but things dont function as they should. So just trying to figure things out xD

So am I free to use all these assets? Anyway, nice engine. I actually recently got my own FPS engine working with slopes so it's neat to see how you did it :)

Yup. They're so placeholder-y that I don't see why you would want to use them, but they're included in the price :)

are the codes commented?