On certain linux, macOS environment, there is already a system getopt. This often creates conflict when compiling filament. Here we alias utils::getopt to either the system getopt (if present) or third_party/getopt. Fixes #7551
Normal Blending
normal_blending is a simple tool that can be used to combine two normal maps in a single texture.
This tool uses the blending technique called Reoriented Normal Mapping which offers mathematically correct results (as opposed to common techniques such as linear or overlay blending).