GPUParticles3D don't render

[dmaz]

Godot version

v4.0.beta.custom_build [8e14f9b]

System information

windows 10

Issue description

I can't get any GPUParticles3D to work at all. Any already existing or even opening a new project. I'm seeing no errors in verbose debug or debug_release builds. will pull earlier build to try and find fault

Steps to reproduce

for a new test

1. create a scene with with a root GPUParticles3D.
2. in process_material add a ParticleProcessMaterial.
3. in draw_passes/pass1 add a mesh (boxmesh).

Minimal reproduction project

No response

[clayjohn]

I can reproduce this in latest master (62792ee) but not in beta 1, so this is a recent regression

[dmaz]

I've not been able to find a working commit... what I thought was for sure a bug is looking more like maybe an issue with the local build on windows. I downloaded the built beta and it shows GPU particles fine aside from the fixed "!multimesh" spam. I pulled multiple versions and none will render a GPU particle though everything else "seems" fine. I've run both scons clean and git cleans with no difference. I've removed editor_settings-4 so it's rebuilt.

If I build the beta I still get none

[clayjohn]

I've not been able to find a working commit... what I thought was for sure a bug is looking more like maybe an issue with the local build on windows. I downloaded the built beta and it shows GPU particles fine aside from the fixed "!multimesh" spam. I pulled multiple versions and none will render a GPU particle though everything else "seems" fine. I've run both scons clean and git cleans with no difference. I've removed editor_settings-4 so it's rebuilt.

If I build the beta I still get none

I've just reached the same conclusion, I built the beta in debug and have the same issue. I'm now trying to build release_debug from the beta commit and we'll see if that helps. Its not a windows-specific bug as I am on PopOS.

[dmaz]

2d9583f works... I'm going to work back up from there

[clayjohn]

2d9583f works... I'm going to work back up from there

In that case there is a good chance that #65418 is the culprit

[dmaz]

yeah I was wondering... I just pulled the commit right before that one

[dmaz]

yep... a9b04b9 works and f709596 has the issue
why does the released beta work I wonder?

[Calinou]

why does the released beta work I wonder?

Release builds are compiled with LTO enabled, whereas self-compiled builds are not unless you pass the lto=full SCons option when building (or the production=yes shorthand).

[dmaz]

ok trying that... yeah latest master with lto=full which took a long time to link, still no luck, no particles

[clayjohn]

Got a fix figured out. Uninitialized memory bugs are always a pain :(

[dmaz]

I pulled that pr and it doesn't seem to fix the issue. as mentioned above I also built with lto and that didn't work for me.

[dmaz]

wait hold on... this kinda does fix the issue. without this patch nothing seems to show particles. with this patch I still got nothing until I chose "Restart" then they showed up in the editor but still not during a run. if I closed the scene and reopened it they would not show in the editor. pressing "Restart" worked again.

then I changed the default scale in the process material and they showed up... I set the scale back to default and now even if I close the scene and reopen they continue to show even through a Godot restart.

I don't have this test app in git so Idk if the scene needed to just be resaved.

another weird thing... some particles are looking different than they used to... I know that's pretty nondescript. but in my main project they are being rendered differently... in one case they are definitely larger than they should be. in another collisions seem to now be very inconsistent.

[clayjohn]

@dmaz do you have more than one particles node in the scene? I've noticed another issue with MultiMesh/particles where they sometimes don't appear in the scene if there is only one node. But seem to always render fine if 2 or more nodes are in the scene.

[akien-mga]

I merged the fix for uninitialized memory, I would suggest opening a new issue to keep track of remaining problems with MultiMeshes and particles.

[dmaz]

@clayjohn these tests were generally just done with single node scenes. I do though have a few that were multinode and I'm pretty sure they were having this render issue as well. I know they are currently having other ender issues. Also yes, there are a more issues now that I will describe in another ticket.

[dmaz]

oh the size issue mentioned above... it seems default size for quads changed to "2"

[A-Lamia]

This was closed but particle collisions are still broken and attracter is also not working.

Tested on #66303.

[akien-mga]

That's a separate issue, please open a new bug report.

This report was about particles not rendering at all.