FDeferredDecalProxy always fade because InitializeFadingParameters is always called and leaves InvFadeDuration at 1.0 and the LifetimeAlpha calculation in FDeferredDecalPS::SetParameters gets a very large negative number for the portion using InvFadeDuration, and the LifetimeAlpha resolves to 0, resulting in an invisible decal.


In order to have FDeferredDecalProxies that don't fade out, you must constantly update the decal proxy with the latest world time or it will start to fade out.

Steps to Reproduce
  1. Download the project from the additional info URL and assign it to a local 5.4 engine
  2. Build and open the project
  3. Open the DecalProxyDemo level
  4. Hit Play (or Simulate)

All decals are visually the same opacity

Decals on one half - the ones without the hack - fade over time

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ComponentUE - Rendering Architecture
Affects Versions5.4
Target Fix5.5
CreatedMay 16, 2024
UpdatedMay 20, 2024
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