So Tango C API offers its main way of getting the TangoCameraIntrinsics struct using the TangoService_getCameraIntrinsics function call but its support library also offers the TangoSupport_getCameraIntrinsicsBasedOnDisplayRotation function call
I have looked and can't really understand what the use of passing the display rotation does different.
This function will query the camera intrinsics and rotate them according to the display rotation.
Won't it return the camera intrinsics based on the rotation by default anyway?
As I understand, the camera intrinsics are fixed per device, so the first function will not change based on rotation, no.
The rotation version is useful for making a 3D camera that has the same FOV and projection matrix as the color camera.