Working with the Skyscraper source code can
be intimidating at first, but if you're familiar with C++, the
code has been formatted to be easy to read and hopefully
understand.
The following diagram shows a birds-eye view of the simulator,
when three sim engines are running.
Skyscraper's source code is divided class-wise in order to
create layers of abstraction in the code. This makes it
relatively easy to create object-related code in C++. In
the image above, each major component is in a subfolder in the
"src" directory. The SBS engine, as an example, is in
the "src/sbs" folder. Skyscraper's frontend is
relatively small, and is mainly used as a wxWidgets frontend
to the simulator, the ability to add other frontends is
possible.
Frontend
Skyscraper's frontend is a small wxWidgets
application, and is used for the startup screen, initializing
the simulator, it's initial objects, and the initial wxWidgets
windowing framework.
VM (Virtual Manager)
VM, or Virtual Manager, is a system designed with
the intention to work similar to a nanokernel or hypervisor,
in that it is a monitor and environment for the simulator
engines to run on. VM is responsible for creating
simulator engine instances, shutting down engines, running sim
engines in parallel, and moving between sim engines. It
also manages the client components, such as the GUI and
HAL. VM manages Engine Contexts, which are the basic
environments that host the sim engines and script processors.
GUI
The GUI component is the majority of the
wxWidgets windowing code, used for the simulator's windows and
dialogs. This component is a client of the VM (Virtual
Manager) component.
HAL
The HAL (Hardware Abstraction Layer)
component is responsible for all hardware library-related
functions, such as graphics and sound, currently for the
frontend. In the future this will also handle all
related functions for SBS, currently SBS does most of the same
functionality separately. This component is a client of
the VM (Virtual Manager) component.
Script Processor
The Script Processor component is not only the script
interpreter, but also demonstrates how to perform the C++
equivalents of script code. The script processor is
responsible for translating script commands into C++
functions. The language is loosely based on the
TrueVision3D graphics engine syntax (Visual Basic).
OpenXR
The OpenXR component is an experimental
Virtual Reality feature. Skyscraper currently supports
VR headsets, but doesn't yet support hand controls and some
other things like on-screen displays.
Scalable Building Simulator (SBS)
The Scalable Building Simulator, or SBS, is
a simulation engine designed with vertical simulation in
mind. It is a client of the VM (Virtual Manager)
component. An Engine Context, which is created and
managed by the VM system, is a combination of an instance of
SBS and a Script Processor, together in a context.