C++ Keeps Game Engines Competitive: Why Developers Still Build Custom Engines
C++ remains the backbone of modern game engine development, offering low-level control and predictable performance that drive developers to build custom engines.
FACTUAL ACCURACY
Why C++ still matters for game engines
C++ is presented in this piece as the language that continues to dominate game development because it provides a rare combination of low-level resource control and higher-level abstractions. Developers choose C++ when they need deterministic behavior, fine-grained memory management, and the ability to optimize for processor caches and platform-specific characteristics. At the same time, modern C++ delivers constructs—classes, templates, containers, smart pointers, RAII, and lambdas—that enable large, modular architectures when applied judiciously. Other languages such as Python, JavaScript, C#, and Java excel for scripting, tooling, or user-facing systems because of managed runtimes and convenience, but their managed memory models and runtime overhead make them less suitable for engine-level subsystems that demand strict performance predictability.
What a game engine is, and why definitions vary
A game engine is more than a collection of libraries; it is the integrated set of subsystems and workflows that let teams build and ship games. Historically, engines were bespoke pieces of technology written from scratch for each title. Over time, common subsystems coalesced—graphics, physics, animation, audio, AI, UI, scripting, networking, data systems—and design patterns such as entity-component systems, behavior trees, deferred rendering, and rollback-based concurrency became widespread. The article emphasizes that an engine acquires its identity when games are built on top of it: libraries glued together with build scripts remain tools, while an engine is a practical platform proven by actual projects.
Why you might build your own engine
The decision to create a custom engine is framed as both a technical and a personal choice. Motivations listed include learning deep systems-level engineering, gaining control over every part of the stack, tailoring behavior to a specific genre or platform, keeping distribution sizes small, and building a demonstrable skill set that employers value. The author describes how building engines teaches practical engineering intuition—how to avoid loading textures mid-frame, how to design cache-friendly data structures, and how to trace hard-to-find runtime issues. Real-world experience with engine internals can make a developer more effective at diagnosing engine-level bugs and discussing architecture in technical interviews.
Who should avoid reimplementing an engine
Custom engines are time-consuming and rarely profitable on their own. The article cautions that replicating the breadth and polish of mature commercial engines is usually unrealistic for small teams; it cites the large investment required by major vendors as context for that scale. For teams seeking to ship a game quickly, established engines offer the fastest route because they provide out-of-the-box features, tooling, and ecosystems. The author advises that if the main goal is fast release, using a ready-made engine is the pragmatic choice; building an engine makes sense when the goal is long-term learning, specific technical control, or reuse across multiple projects and if the team has sufficient time and energy.
Why libraries and build tools are not the same as an engine
A set of libraries—windowing, input, graphics APIs, audio middleware, or build tooling like CMake—does not by itself constitute a game engine. The article illustrates this with examples: SDL, SFML, Allegro, Vulkan, DirectX, and audio tools provide essential building blocks and can enable complete games, but an engine implies a cohesive architecture, pipeline, and production-proven workflows. A game built on a set of libraries can be excellent—the example of a small indie title built from such components is used to show that a game can exist independently of an engine—but the distinction remains: libraries are ingredients; an engine is a prepared, tested recipe plus the kitchen.
Practical components that typically coalesce into every engine
Even small engines tend to converge on a set of practical subsystems as they grow. The article lists several components that repeatedly become essential:
- Scene and level management: treated as managed containers of objects, logic, and transitions rather than flat lists.
- Entity manager: handles creation, destruction, identification, component access, tagging, and debugging.
- Serialization and save systems: used for save/load, auto-save, state transfer between scenes, replay systems, and rollback.
- Variable inspector: runtime panels to observe and tweak variables, flags, and ticks for debugging behavior without recompilation.
- Resource manager: packaging, indexing, compression, and hot reloading to keep iteration times low and builds efficient.
These systems emerge from practical needs: iteration speed, runtime performance, debugging efficiency, and the logistics of shipping across platforms.
How programming models differ inside engines
The article contrasts classic code-based development with visual scripting systems. Visual tools like Blueprints and VisualScript are legitimate programming models that abstract constructs such as classes and control flows into node-based workflows and are especially handy for designers and artists to prototype mechanics quickly. Implementing visual scripting substantially increases engine complexity because it requires editors, debuggers, optimizers, and a robust backing implementation—BluePrints in large engines is cited as an example of code-level infrastructure rivaling other major subsystems. Conversely, text-based code remains the most flexible approach for systems-level work but carries the cost of recompilation cycles and the need for developer expertise.
Windowing and graphics: the visible stack
At the base of any desktop or native game is the window and its graphics context. Window creation and graphics API context setup (OpenGL, Vulkan, DirectX) are platform-dependent and often seen as “messy” boilerplate; many developers hide that complexity behind libraries such as SDL2, GLFW, or SFML. Rendering strategies depend on engine focus: a tile-and-sprite 2D renderer can be simple and tailored to the game’s needs, while engines aiming for broader functionality may rely on general-purpose APIs or write specialized renderers per project. Text rendering is called out as a recurring requirement; libraries like FreeType and HarfBuzz are suggested for practical handling of fonts and complex text layout.
Gameplay loop and frame lifecycle
The gameplay loop unifies input handling, simulation updates, and rendering. Whether exposed explicitly (with a visible while(engine::isRunning()) loop) or encapsulated in an engine::run() function that invokes callbacks, the loop is central. The article presents the loop as the place where events are polled, the frame update is executed, and the scene is drawn, stressing that design choices about where and how the loop is exposed affect developer ergonomics and flexibility.
Input handling strategies
Input can be surfaced as raw platform events that the game handles directly, or as an integrated event system with handler registration. The raw approach offers maximum flexibility at the cost of verbosity and platform-specific code; the event-driven model simplifies early development by letting developers subscribe to input callbacks (mouse movement, key presses, window events) and focus on gameplay logic. The article warns that as projects scale, a naive event-handler model can become brittle—handler registration, deregistration, priority, and context filtering require a thoughtful architecture to avoid unexpected chains of calls.
Resource management and packaging
Resource management is highlighted as a performance-critical and often underestimated subsystem. Problems arise when assets are duplicated per object, causing bloated stage sizes and long build times. The recommended practices described include packing assets into archives or virtual file systems to reduce file-system overhead, using indexing and compression, or storing assets as separate files during development for rapid iteration and modding. Embedding resources into a single binary blob is discussed as a trade-off that can simplify distribution and certification on consoles but prevents easy post-build modification and modding. The article also covers asset conversion (using libraries to decode image and data formats), the prevalence of scripting VMs for higher-level configuration, and the value of hot reloading for fast iteration. Finally, the importance of platform-aware packaging and delta-based update systems for patches is noted.
Audio: the hidden complexity
Audio output is portrayed as deceptively difficult due to platform quirks and the need for stable, low-latency streaming. Engines either rely on low-level platform APIs or use libraries such as OpenAL or SDL to abstract device idiosyncrasies. A mixer subsystem is usually required to combine music, effects, and voice with correct volume handling, fades, and effects while avoiding artifacts such as clicks or buffer underruns. Implementing a mixer, even a simple one, is a useful educational exercise and often necessary for production-quality sound.
Physics: when you need it, and when you don’t
Not every game requires a full physical simulation. Many titles fake physics with scripted animations and simpler collision logic because full-featured physics engines are heavyweight and unnecessary for some genres. For 2D platformers or strategy games, simple collision and motion systems often suffice and are easier to control. When real physics is required, established libraries (Box2D for 2D, Bullet or PhysX for 3D) are recommended rather than reimplementing complex simulations. The piece stresses learning the concepts but avoiding reinvention when robust libraries already exist.
Development trade-offs and the cost of scope
Several recurring trade-offs are emphasized: time spent on engine infrastructure delays game content; a pursuit of parity with major commercial engines is typically infeasible without a large, funded team; and many early engine projects end up being thrown away as learning artifacts. The author shares a personal anecdote—after multiple attempts, one engine produced three released proprietary games and was eventually sold to a studio—illustrating that persistence and iteration can lead to practical outcomes, but that the path is rarely quick or straightforward.
What building an engine teaches a developer
Beyond producing a reusable codebase, building an engine teaches diagnostic skills, systems thinking, and the ability to discuss architecture concretely in interviews. The author points to the substantial job-market value of having built an engine: real-world experience with resource management, debugging at the engine level, and understanding of core systems gives candidates credibility and opens technical conversations that ordinary resume items do not.
Broader implications for developers, teams, and the industry
The article situates the engine-versus-library debate within broader industry trends. Commercial engines have become comprehensive SDKs that enable teams to produce multiple titles on a unified foundation, which has shifted production toward standardized toolchains and away from single-project bespoke stacks. That maturation lowers the barrier to entry for many developers and fosters vibrant ecosystems, but it also means that teams needing extreme control, deterministic performance, or minimal runtimes still gravitate to building or heavily modifying engine-level code—most often in C++. For studio tooling, asset pipelines, and advanced runtime features (custom rendering techniques, tight memory layouts, custom patch systems), bespoke solutions or deep engine-level work remain useful and sometimes necessary.
Practical guidance for someone starting an engine project
The article consolidates practical advice offered throughout the source:
- Start with a clear goal: shipping a game quickly favors an existing engine; learning or building reusable technology favors a custom approach.
- Expect to discard early prototypes; iterate until you reach a third, stable system.
- Pick the language you understand and can maintain; many engines are written in C++, though others use Rust, Go, Lua, or higher-level languages depending on goals.
- Reuse libraries for complex subsystems like physics or audio when appropriate.
- Prioritize systems that improve developer iteration—hot reloading, asset management, and variable inspectors often pay the fastest dividends.
- Keep scope realistic; a fully featured modern engine requires years and substantial investment.
Author background and perspective
The perspectives in the piece come from Sergei Kushnirenko, who brings two decades of experience in software and game development. His background includes a degree from ITMO National Research University, work on naval simulators and network solutions early in his career, and fifteen years focused on games. He has experience at Electronic Arts working on optimizations for The Sims and SimCity BuildIt and led porting efforts for Gaijin Entertainment to the Nintendo Switch and Apple TV. Sergei also contributes to open-source work, including the ImSpinner library and the Pharaoh (1999) restoration project. His practical experience underpins the article’s emphasis on hands-on learning and the realities of engine development.
C++ and the engine ecosystem remain tightly coupled: when deterministic performance, resource efficiency, and deep system control are central, developers still turn to C++ and, when necessary, build custom engines or extend existing ones. For teams and engineers choosing between off-the-shelf platforms and bespoke stacks, the core trade-offs are time-to-ship versus long-term control, and feature breadth versus the ability to reason about every runtime decision.
Looking ahead, engine development will continue to balance productivity tooling and low-level control: teams will keep leveraging mature engines for rapid production while specialist groups and engine engineers will maintain the custom, performance-critical stacks that power high-end titles and platform-specific optimizations.
