- Status Unconfirmed
- Percent Complete
- Task Type Bug Report
- Category 2D Art → Effects
- Assigned To No-one
- Operating System Linux
- Severity Low
- Priority Very Low
- Reported Version 0.7.55 Unreal
- Due in Version Undecided
-
Due Date
Undecided
- Votes
- Private
FS#8171 - huge performance drop when someone uses Magic Light spell
During GM events I found that in case someone casts Magic Light I experience a huge performance drop.
If for example FPS are at 25 to 30 frame rate can easily drop down to 10-15 FPS. If several people are using Magic Light even below 10 FPS.
This is on a ThinkPad T14 AMD Gen 5 with AMD Radeon 780M integrated graphics which is easily more powerful than the newer AMD Radeon 840M (which has less pipelines for example). In performance mode it can do 25 to 35 FPS in Hydlaa and easily 50 FPS or even a bit more in Gugrontid. This gives a comfortable enough or even quite comfortable gaming experience. I am using Devuan Ceres (based on Debian Unstable aka Sid) with self-compiled 7.1.7 kernel and KDE Plasma 6.7.2 on Qt 6.10.2 with Wayland.
As far as I remember some people confirmed a similar performance drop in group chat. Feel free to comment here to confirm.
Yet, if FPS drop below 10 in case (a lot of) Magic Light is going on everything feels quite sluggish. It kind of breaks immersion.
Compared to that if one or several people use a torch there is not nearly that much of a performance drop. As far as I observed there one or several torches just use up 2-4 FPS. Also they give way more light. Magic Light does not really do much to light up a dark scenery. I would expect more, especially if cast by a Way Master of Crystal Way.
Expected results: More and more performant light with Magic Light.
Probably related: FS#7725 - Magic light is giving no light with low graphic settings
Effects were set to "High" during writing above report.
In Secret Garden I tried with different settings without changing anything else – using performance power profile:
- Magic Light with effects set to "Low": 36 to 38 FPS¹.
- Magic Light with effects set to "Medium": 36 to 38 FPS.
- Magic Light with effects set to "High": 19 to 20 FPS.
- No Magic Light: 36 to 38 FPS.
So it seems I can work around the performance drop by setting effects to "Medium" instead of "Low". I will look at this during the GM event today.
If setting to "Medium" or even "Low" helps during events that surely lowers the severity of this report quite a bit. Still a 20 FPS drop with effects set to "High" while the Magic Light effect produces almost no effect to really light up the surrounding scenery is quite hefty. I can check how "Medium" versus "High" affects FPS during other spell effects to compare.
[1] I see a light with effects set to "Low". I will comment on FS#7725.
More specific: The huge performance drop seems to be related to whether the Magic Light effect actually lights up the surrounding area at least a bit¹. In the comment on FS#7725 I wrote: »I do see a light effect even with "Low", but it does nothing to light up the surrounding scenery. Beginning with "High" I see it light up the surrounding scenery at least a bit. I see no difference when switching to "Epic".«
Whenever it actually lights up the surrounding area at least a bit I see the massive performance drop. However torches do always light up the surrounding area without that drop. Even on effects set to "Medium" or "Low". So maybe something can be learned to how the light source of using a torch is implemented in comparison to how the light source of Magic Light is implemented?
[1] I still think even with effects set to "High" or "Epic" Magic Light does a lot less to light up the surrounding area than using a torch. Actually before looking carefully at FS#7725 I did not even notice the difference.