Category: Custom Game Engine

Posts related to the custom game engine that I am developing

Devlog 2024-11-04

This is a regularly-occurring status update. More generally-relevant posts can be found under Features (see Creating a Game and Engine from Scratch for context).

This is the beginning of week 3.

What I have done

  • I have been working on a build system so that I can build code and assets the way that I want to. A dedicated post about it is here.
    • It is possible to define different platforms and configurations (e.g. debug or optimized)
    • It is possible to define three kinds of tasks (C++, copy files, or arbitrary Lua functions)
    • The task dependencies are tracked, and they are only executed if necessary and in the correct order (only single-threaded, although it has been designed for multi-threaded execution)
    • For C++:
      • The installed Visual Studios and Windows SDKs are calculated, and the user can either request the latest by version number or request specific versions if desired
      • Standard library and platform library support can be enabled or disabled (and, when enabled, the appropriate #include paths are set)
      • It is possible to build console applications, windowed applications, shared libraries, or static libraries
      • Exceptions can be enabled or disabled

Next steps

  • It has now been two weeks that I have been working on the build system, and even though I have made good progress it feels like I really need to start working on actual game engine code. There are still obvious missing features in the build system but I think a good strategy now is to add them as they become necessary for the actual code I am working on rather than trying to add more preemptively.
  • One final thing that I think that I want to add is the ability to generate a Visual Studio solution that I can use to debug
    • I think it’s ok initially if I don’t create individual projects for named tasks and instead just have a single project to build the entire solution (it seems ok at least initially to manually find files and open them in the editor)
    • I do, however, want to be able to debug, and having some intellisense would also be nice, and so I might spend some time trying to get that done.
  • Another thing that I know I will want is to be able to set up precompiled header files
    • Being able to do this in a platform-independent way would be nice so that I don’t have to go back and redo it later, but it’s not critical
    • I may or may not add this before moving on to start work on code
  • The initial goal for a program would be to open a window that doesn’t do anything, and that is pretty achievable
  • The next goal would be to clear the color buffer to some hard-coded color
    • This would be quite easy using Direct3D 11, but using Direct3D 12 requires allocating some memory which will require some memory management work with the way I want to do things (rather than just using global new).

Creating a Video Game and Engine from Scratch

I am attempting to make a video game without using an available engine. I am documenting the process with two different kinds of posts:

  • Discussions of Features
    • These posts are made when I have something of interest to say rather than on a regular schedule
    • They can be found using the Game Engine Features category
  • Status Updates
    • These posts are intended to be made weekly and are not intended to be of interest to a general audience
    • Instead, these posts are a way for me to hold myself accountable by reporting what I have worked on during the previous week and what I intend to work on during the upcoming week
    • They can be found using the devlogs category

Why am I doing this?

I am currently unemployed by choice. I have been very fortunate professionally that I have been able to work on interesting projects, but there are also some things that I have never had a chance to work on that I am personally interested in and would like to explore. Primary among these are:

  • Graphics
    • Hardware ray tracing
      • I fell in love with all things ray tracing while a student at the University of Utah but I have not had an opportunity to develop anything since hardware support was added to consumer GPUs
    • HDR
      • Although I understand the concepts of tonemapping I have never had the opportunity to implement it, and after all of the work I have done with color and light it is an obvious next step and gap in my experience that I would like to fill
  • Memory Management
    • I have a fascination with manual memory management, and I am interested in attempting to write software that always uses explicit allocators rather than the global new/delete so that all memory is budgeted and uses appropriate allocation strategies
    • I am also interested in trying to go all-in on “data-oriented design” to gain more experience about how to design large scale software with cache-friendliness and good access patterns as a priority
  • Engine
    • I would like a better custom basis that I can use to create applications (not just necessarily games)
    • I have almost entirely worked with graphics in my professional career and I would like to gain experience and learn the technical aspects of other areas
  • Game Design
    • I have ideas of things that I like and things that I don’t like from playing games, but my actual experience of user-facing design is limited to APIs and GUI properties

It can be hard to find the energy or motivation to do personal projects like this with a full-time job, and especially with jobs in the industries that I work in which tend to be high-demand (which, to be fair, is also what makes them fun). With this in mind I have quit my job and am taking a temporary break from employment so that I can focus full time on learning and implementing some of the things listed above.

Goals and Scope

The time frame for working on this project is quite limited before I will have to find another paying job. If the end goal were to actually create a finished game that could be released and sold then the only reasonable strategy would be to use an established game engine (like Unreal or Unity), and even then the only kind of game that a solo developer could create in a short amount of time would have to be extremely limited in scope. The majority of my goals for this project, however, involve creating the technology from scratch. This means that the actual goal is primarily to create a game engine, and any “games” that I make will be more like tech demos.

The meaning of what a game engine is in the popular imagination seems to have changed over the years and my impression is that today many people think of a “game engine” as something like Unreal or Unity where there is an editor and it is meant to be used by external users to make any kind of game imaginable. That definition is not what I mean when I talk about what I want to work on, however: I am interested in making something just for me that serves as a framework to create interactive applications. Although in real game development tools are incredibly important I don’t anticipate (sadly) creating any editors for my current project, and any tools will be programs that build game-ready assets from authored assets.

My ideal outcome would be to actually create some finished experience that I could release in some way, but due to the uncertainty around the time available I don’t believe that that should be my criterion for evaluating whether the project succeeds or fails. Instead, my intent is to try and create several small applications along the way that are unfinished and unpolished (i.e. not releasable to a general audience) but that allow me to have some small scale goal to work towards when implementing features. I will also try to document milestones along the way with posts here. The true measure of success for me personally will be if I have been able to implement some of the features listed in the bullet points above.

With that being said, as a way of setting realistically low expectations my goals for an eventual releasable program would be:

  • Graphics rendered using hardware ray tracing
  • Audio sound effects that play dynamically in response to something
  • A player avatar in some kind of third-person view that can be controlled using an Xbox controller
  • Some kind of action/interaction that the player character can do with the environment

My graduate students in a semester-long class used to accomplish something similar (without the ray tracing) using a starting engine that I provided and so the list above feels achievable. I will have to decide as time passes whether to try and focus on implementing the above points early and then improving things or whether to be content focusing on the individual features that are interesting in the moment even if it means not finishing a final project.