Some time ago, I announced that the Molecule Engine uses C++ as a scripting language. Today, I can share implementation details and a few additional tricks that were used to keep compilation times and executable sizes down.
Serialization, reflection, and other mechanisms are often used for saving data in an editor or a tool like the asset pipeline, and then loading that data into the engine at run-time. This process is well-known, flexible, and allows us to store the data in any format conceivable. Still, all those techniques show certain weaknesses when it comes to keeping iteration times to an absolute minimum.
Even though Molecule’s run-time engine exclusively uses binary files without doing any parsing, the asset pipeline uses a human-readable non-binary format for storing pretty much everything except raw asset files like textures or models. This post explains the process behind translating data from such a human-readable format into actual instances of C++ structs with very little setup code required.
In performance-sensitive applications like games it is crucial to access data in a cache-friendly manner. Especially when dealing with a large number of objects of the same type, e.g. individual components in an entity-component-architecture, we should make sure to read as little data as possible. However, simple arrays-of-structures are often not suited for this, with structures-of-arrays yielding better performance. But the latter are not natively supported by the C++ language.
Today’s post is less of an insight into how Molecule works, and more of an announcement about an upcoming feature we are very proud of!
Molecule Engine’s scripting system uses runtime-compiled C++ code as a scripting language, and you can see the system in action here (please make sure to watch the video in original quality).
This allows the engine to leverage the full performance potential of native C++ code, while providing designers and scripters with extremely short iteration times, commonly only experienced when using traditional scripting languages such as lua, python, or others.
Scripters won’t have to deal with internal engine details, and don’t need to worry about pointers or other low-level language stuff. They only work with a pure C-interface and opaque structs, as can be seen in the video. But programmers can easily dive in and feel right at home with the whole engine available to them in native C++-code.
Furthermore, programmers can aid scripters easily by using their favourite debuggers and IDEs for debugging and development. Scripters will love certain IDE features such as IntelliSense, completion listboxes, and other things a modern IDE provides!
Let us know what you think in the comments!
Having finished the third part of this series about data ownership, we will turn our attention to performance optimizations and data layout again in this post. More specifically, we will detail how character skinning can be optimized with a few simple code and data changes.
In the last installment of this series, we talked about handles/internal references in the Molecule Engine, and discussed their advantages over raw pointers and plain indices.
In a nutshell, handles are able to detect double-deletes, accesses to freed data, and cannot be accidentally freed – please read the previous blog post for all the details.