Let me tell you a story about my friend Bob. Fresh out of university, he decided to build an MMO with custom physics, real-time global illumination, and procedurally generated llamas wearing hats. Three years later, his “engine” can barely render a rotating cube without setting his GPU on fire. Don’t be Bob.

The Allure of the Custom Engine

We’ve all been there - staring at Unreal Engine’s 12 million lines of C++ code thinking:

// Their way
GetWorld()->SpawnActor<AAwesomeCharacter>(SpawnLocation);
// My hypothetical better way
SpawnCoolDude(x, y, z, swagLevel);

But before you start rewriting mathematics.lib because “you can do it better,” let’s talk reality.

The Reality Check (It’s Not 1999 Anymore)

Modern rendering involves more layers than an onion wearing a trench coat:

graph TD A[Vertex Data] --> B[Vertex Shader] B --> C[Fragment Shader] C --> D[Frame Buffer] D --> E[Post Processing] E --> F[AntiAliasing] F --> G[Color Grading] G --> H[Actual Pixels] H -->|"Wait, where's my 240FPS?"| I[Thermal Throttling]

Now imagine maintaining this while also implementing:

  • 14 different shadow mapping techniques
  • 3 spatial partitioning systems
  • That one weird bug that only appears on NVIDIA’s 2018 mobile GPUs

Time: The Silent Killer

The average modern game engine consists of:

  • 1.2M+ lines of graphics code
  • 300+ shader permutations
  • 4.7 metric tons of driver workarounds Here’s what rendering a triangle looks like in raw OpenGL:
// Only 57 steps to draw a triangle!
GLuint VBO, VAO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glUseProgram(shaderProgram);
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 3);

Compare to Unity:

// Step 1: Create triangle
// Step 2: Look at triangle
// Step 3: Profit

The Expertise Trap

You’ll need to master:

  • Linear algebra (the fun never ends!)
  • SIMD optimization
  • PBR material systems
  • Vulkan/DirectX12 explicit memory management
  • Approximately 37 different coordinate spaces I once spent three weeks debugging z-fighting issues only to discover I’d mixed up view-space and world-space normals. True story.

When It Might Make Sense

pie title "Should You Build It?" "Just Want to Learn" : 45 "Specific Hardware Needs" : 25 "Academic Research" : 15 "Actual Practical Reason" : 15

The valid reasons resemble my laundry habits - rare but occasionally necessary:

  1. You’re developing for experimental hardware (quantum gaming rig?)
  2. You need pixel-perfect control for archival projects
  3. You’re writing a PhD thesis on temporal upsampling
  4. You enjoy pain as a lifestyle choice

The Maintenance Nightmare

Every engine update feels like:

  1. Update graphics drivers
  2. Everything breaks
  3. Curse existence
  4. Roll back drivers
  5. Repeat until retirement Modern engines already handle:
  • Cross-platform compilation
  • Driver workarounds
  • Shader compilation pipelines
  • Memory alignment voodoo As Unity developer Jessica put it: “I’d rather teach my cat C++ than maintain our internal rendering stack again.”

The Productivity Paradox

Let’s crunch numbers:

TaskCustom EngineUnreal Engine
Basic PBR Material2 weeks2 minutes
Deferred Rendering1 month1 checkbox
GPU Crash Debugging3 weeks3 espresso

While you’re busy implementing yet another shadow technique, someone using an existing engine is:

  • Polishing game mechanics
  • Building content
  • Actually shipping their game
  • Having a life

A Better Path Forward

Instead of full engine development, consider:

// Customize, don't rewrite
void MyAwesomeRenderer::ApplyBlackMagic(RenderPass pass) {
    if (Engine->GetSettings()->UseDarkSorcery) {
        // Your special sauce here
        CastVoodooSpell(pass);
        InvokeCthulhu();
    } else {
        Engine->DefaultRender(pass); 
    }
}

Modern engines are more extensible than my excuses for missing deadlines. Epic’s source code access for Unreal Engine costs about the same as a single developer-month’s salary.

Conclusion: Be the Chef, Not the Farmer

Unless you’re specifically in the engine-building business (in which case, why are you reading this?), focus on what matters - creating amazing experiences. The world doesn’t need another half-finished OpenGL wrapper - it needs your unique game ideas. Now if you’ll excuse me, I need to go apologize to my GPU for what I put it through in 2017. It still flashes warning signs whenever I open shader editors.