Decrease the default soft shadow quality to improve performance #54158
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Soft shadows are relatively expensive to filter. However, with the default blur factors, it's not needed to use too many samples (unless PCSS-like shadows are used with a large size). Textures and screen-space antialiasing can also be used to mask the noise pattern effectively. On a GeForce GTX 1080, going from Medium to Low for both shadow types saves 0.2-0.4 ms of GPU time per frame in 2560×1440 resolution. This can translate to significantly higher savings on lower-end GPUs. Given how the shader works, this improves rendering performance even if lights with shadows are never used.
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After my findings in #53961, we could consider disabling shadow dithering as an alternative to decreasing the shadow quality. Doing both at the same time may look bad, so we should settle for one or the other. |
clayjohn
approved these changes
Feb 10, 2022
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Thanks! |
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Follow-up to #50329.
Soft shadows are relatively expensive to filter. However, with the default blur factors, it's not needed to use too many samples (unless PCSS-like shadows are used with a large size). Textures and screen-space antialiasing can also be used to mask the noise pattern effectively.
On a GeForce GTX 1080, going from Medium to Low for both shadow types saves 0.2-0.4 ms of GPU time per frame in 2560×1440 resolution. This can translate to significantly higher savings on lower-end GPUs.
Given how the shader works, this improves rendering performance even if lights with shadows are never used.
If you need higher quality shadows, the option to change the soft shadow quality in the Project Settings remains.
Preview
Click to view at full size. This is a rather extreme scenario, as there are no textures and FXAA is disabled.
Before (old default)
After (new default)