From Mod Wiki
Lighting Quality is an option found in the Settings menu of ETQW. It can be set to "Normal" or "High" quality.
- "Normal" quality uses the setting r_megaDrawMethod 3. This skips exterior ambient cubemaps and uses a specified colour for exterior shadows instead of calculating them based on the ambient cubemap.
- "High" quality uses the setting r_megaDrawMethod 0.