testing 3D for open world, looking for advice.

justinbarrett

So I recently started my main project and implemented an inventory system, but when it cam time to involve some rudimentary player movement so I could pick up objects in world, loot chests..whatever I ran into a major issue..I made two trees(just for fun so it didn't bore me to death testing) and I littered about 30-40 of them in the level...it brought the game down to about 90 FPS...I can make some 8 sided imposters(low lod setting) but I'm still concerned about performance considering I have next to no logic running...inventory is reading a left click event and only player rotating and moving forward(move and slide) are in...

I'm running a ryzen 3600 and a 5700XT... so I don't know why it drops from ~500 to ~90...I know it's the trees, but they are not that intensive ~2k verts...which I consider very doable with modern hardware...they are using an opaque prepass for the leaf mask which is not ideal, + disabling the culling for them for obvious reasons.

any thoughts, advice or other..

cybereality

A machine like that should be able to handle more than 30 trees. At least from results I've seen in other engines. Maybe try profiling and see where the bottleneck is? My guess is it would be the transparency, but lots of games have trees and don't have an issue.

I did some tests with a simple cube, and I was able to get around 100,000 cubes using instanced geometry. If the trees are the same (or can be made the same) then you can use instancing and greatly reduce the draw call overhead. I think it's called MultiMeshInstance in Godot.

Dschoonmaker

That's 60k vertices total, if each tree is a separate MeshInstance node and has materials for bark & leaves, 90FPS isn't surprising. My PC would run at more like 5FPS. Multimesh documentation: https://docs.godotengine.org/en/stable/classes/class_multimesh.html

justinbarrett

multimesh does not support collisions...so immediately off the table..unless there is a way to return the transform (loc,rot,scale) for each instance...then I could just add colliders later vial code. Has anyone tried this? I mean I'd hate to spend time trying to figure this out when it's already doomed...

OTOH, I prefer a hand crafted world.

justinbarrett

I am an idiot :) I had all the masked branches as separate meshes..instead of one mesh...seems to have fixed the issue..but frames are still pretty low, needs further testing.

but I am having trouble finding how to adjust mipmap ranges..looking here I am not seeing anything aside from on or off.

Megalomaniak

use separate collider objects. The collider objects don't have to all be visible at the same time, while the visible trees probably do...

justinbarrett

ofc. I always use separate colliders... gotta keep them as simple as possible :)

Dschoonmaker

You can write a script to manually place trees, as well as add collisionShapes for each tree. I didn't know it until recently, but if you put multiple collisionShapes under one staticBody, they will act as if each collisionShape was its own staticBody.

https://godotengine.org/qa/52924/solved-how-set-collisionshape-on-multimeshinstance

justinbarrett

yes, I could use mesh data tool and a bunch of loose triangles and place instances in specific places by manipulating the verts..I've done this before in testing... I think I need to test in a real world scenario though before I make any dicisions yet...

I will make a terrain(mesh terrain hand chunked) and try something with that + MeshDataTool...to see what I get....could we get(return) vertex colors with the MeshDataTool? ..could be hand to define specific vegatation types(not grass, but trees/bushes)... I don't know what the overhead would be for a high density mesh if it's not displayed...it still gets loaded so..I need to check...

sorry, I'm babbling, just got home from work and all of this is just running through my head.

derevotyan

I made 4x4x4 array for my open-world game to keep chunks

justinbarrett

I have considered streaming them as scenes with all the assets in each one(trees, buildings etc... I would probably need about 64 chuncks(scenes) at that point...but I have time...I'm still planning...but I am going to hand model the terrain...I feel you can get much more interesting results this way.