It impacts all renderers. It ought to fix issue in GTA radiosity,
Shadows in Jak series. (note shadows will suck in upscaling)
Implementation is really brutal. Expect a massive slow down, but at least we can test the effect
easily.
Normally perf impact will remain reasonable if the game doesn't use a Read-Write effect
Performances number are welcomes (my guess is really awful in HW mode, slow in SW mode).
You can enable it with "UserHacks_AutoFlush = 1"
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