prerendered backgrounds and depth buffer question

[half shale]

hi i recently saw this video and i wonder if its possible to do in godot.
https://youtu.be/OdlQMwFJuwA?t=811

so i have in godot my prerendered bg and depth image for it. how now i can i draw this background parts above (in front of) character if the character is behind some object on this image.

[versed basin]

I haven't watched the whole video but by your description I believe you are looking for something like this.

https://godotengine.org/qa/36050/2d-texture-mask-shader-to-simply-mask-part-of-sprite-in-godot

I think that's probably the easiest method. However, you can find several alternatives to achieve the same/similar effect here:
https://www.reddit.com/r/godot/comments/tt3twq/i_have_updated_the_mask_guide_with_the/

[versed basin]

Just to clarify, if you use the first method I linked, you should apply the shader to your character.

And pass your depth texture to it.

So in reality is not that you paint the background in front of the character. Is that you hide areas of your character to create the illusion that the character is "behind".

[half shale]

Hi, thanks alot for help. Althrough im bad at shaders and as much i understand this wont work with 3d character moving in 3d world with prerendered bg under character and camera matched to render. Am i right? If so is this easy to rewrite for 3d?

[versed basin]

https://www.youtube.com/watch?v=DbgAougy-CA

That shows a technique using VisualShaders.

And here you can read how to do the same using Godot Shader language.
https://godotengine.org/qa/13010/alpha-masking-a-3d-object-using-materialshader-language

[half shale]

Okay thank you brother. Its called alpha masking. I could google it if i knew it ealier

[versed basin]

No problem. 😉
Good luck with your project

[half shale]

hi man, sorry to bother you again, this helped a bit but still there is nothing about depth buffer and i have no idea how to do it. ill show you images to give you idea what i am trying to do

this is my example prerendered background, i setup cameras to match perspective and when i move character over this it looks very good, like its 3d enviorment

but when i go behind the car then you know, it does not look like character is behind it

i learned to do it i need depth buffer image so i made one

it looks like this:

its basically a heightmap but can be used to determine depth in this case

soooo, i have no idea how to make a shader that will do the thing, it must know position of character in 3d space and somehow figure out if character is behind or in front od car

so i guess its not so simple

[half shale]

btw this is how it looks like if i use second image as heighmap and put first image as texture

well discord messed quality but u can see its 3d

[versed basin]

I have never done what you are asking and don't have shader experience myself. However, have a look at this in case it helps you to achieve what you want:
https://youtu.be/x1dIJdz8Uj8

It shows how you can get the depth-buffer of your game at runtime. With that and the depth-buffer of your scenario it seems possible to hide pixels from your character with a darkest color than the scenario depth texture (further away) but maybe I'm wrong and it doesn't work like that

On top of that, I can't imagine how you can handle believable collisions using this approach though.