Description

When Lumen is disabled, but the cvar "r.MeshCardRepresentation" is set to 1, Lumen will continuously enqueue object removal from the Lumen Scene, without ever emptying the array of primitives to remove.

Steps to Reproduce

1. Download the attached repo and be able to open through Visual Studio
2. Add a trace point to the function "FScene::LumenRemovePrimitive(...)" from the file "LumenScene.cpp". The trace point should be on the line:
```
LumenSceneData->PendingRemoveOperations.Add(FLumenPrimitiveGroupRemoveInfo(InPrimitive, PrimitiveIndex));
```
The trace point's action should be:
```
$FUNCTION The value of LumenSceneData.LumenSceneData->PendingRemoveOperations.ArrayNum is

{LumenSceneData.LumenSceneData->PendingRemoveOperations.ArrayNum}

```
3. Observe that the trace point will print the number of elements in the PendingRemoveOperations array to the Debug output in Visual Studio.
4. Run the project with the command-line argument "-game"
5. Execute each of these BugItGo commands in sequence:
```
BugItGo -29.740747 53.875240 287.748841 -30.988928 -147.598175 -0.000001
BugItGo -62333.560102 -79857.832431 9432.021741 -2.588928 -313.998177 -0.000001
BugItGo 84559.473584 -67641.208545 12520.222170 -12.388928 -220.198176 -0.000001
BugItGo 80326.711401 73669.100421 11443.632542 -5.388928 -139.798174 -0.000001
BugItGo -65564.391371 86060.828290 12931.497431 -8.388928 -55.598173 -0.000001
```
6. Observe in the Debug Output that the array size of PendingRemoveOperations is frequently reset.
7. Execute the console command "r.Lumen.DiffuseIndirect.Allow 0"
8. Repeat step 5.
9. Observe in the Debug Output that the array size of PendingRemoveOperations is never reset, and continues to grow.
10. Repeat steps 5 and 9 as many times as needed.
11. Launch the editor again with the command-line options "-game -dpcvars="r.MeshCardRepresentation=0,r.Lumen.DiffuseIndirect.Allow=0" "
12. Repeat step 5
13. Observe that the trace point is never hit

Have Comments or More Details?

There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-220406 in the post.

0
Login to Vote

Unresolved
ComponentUE - Graphics Features - Lumen
Affects Versions5.45.4.3
Target Fix5.5
CreatedJul 29, 2024
UpdatedJul 29, 2024
View Jira Issue