Feature flags are intended to be used when a new feature is added to
filament and have generally two purposes:
1) during feature development, the feature can be implemented but
disabled which can help developing large features. This way the
feature can be tested by stakeholders while it's being developed
without impacting other clients.
2) once a feature is ready, its flag can be enabled by default, but
in case the feature breaks something or has unintended consequence,
clients have the option to turn it off.
Feature flags are intended to have a relatively short life span, i.e.
once a feature is stable, the flag fill be removed.
There two types of feature flags. Constant feature flags can only be
set during Engine initialization via Engine::Builder. Non-constant
feature flags can be set at any time.
Feature flags SHOULD NOT be used as configuration or settings.
Feature flags are designed with a few ideas in mind:
- they are very cheap to check inside the engine
- non-constant flags can easily be toggled using ImGUI
b8551e50e1