InFlags are ETextureCacheFlags. InSettingsPerLayerFetchFirst can be nullptr - if not, then the caceh will check if the corresponding texture exists in the DDC before trying the FetchOrBuild settings. FetchFirst is ignored if forcerebuild is passed as a flag. InSettingsPerLayerFetchOrBuild is required. If a texture matching the settings exists in the ddc, it is used, otherwise it is built.