If you’ve ever dabbled in Unreal Engine development, you know it’s a powerhouse of features and capabilities. But with great power comes… well, sometimes, great headaches. Let me take you on a rollercoaster ride through my 2-3 weeks-long battle with memory corruption, all thanks to the elusive UPROPERTY().
The Unexpected Nightmare
We’ve all been there, I’m knee-deep in developing my app, which is essentially a video player build in Unreal Engine, everything’s running smoothly—or so I thought. Then, out of nowhere, as I’m testing on budget hardware, the game starts acting up. Crashes, weird behaviors, you name it. It was like my project had been possessed by some mischievous ghost. I was battling this issue nonstop, desperate to get my app back on track.
The Hunt Begins
At first, I was convinced it was a bug in the video subsystem that was out of my control. Then I thought that the cheap $200 PC I was targeting with Intel UHD graphics just wasn’t up to the challenge. I tweaked settings, double-checked my code, and even resorted to some good old-fashioned “turn it off and on again.” Nothing worked. The memory corruption was taunting me, slipping through my fingers like smoke. I was stuck in a loop of frustration, watching my progress unravel.
The Lightbulb Moment
After weeks of long days and long nights, and long conversations with ChatGPT that sent me chasing red herring upon red herring, and wild goose after wild goose, I finally figured it out. You see I’m not a fan of “blueprints” for coding (they’re great for shaders, but not for traditional code). I am a coder, and that bizarre spaghetti mess didn’t appeal to me. I read somewhere that you put UPROPERTY() in front of stuff you want to expose to blueprints, and frankly, I had no desire to build blueprints… so I used it very rarely. But the thing is UPROPERTY() does more than just expose members to blueprints.
Understanding UPROPERTY()
For those not in the know, UPROPERTY() is more than just a tool for Blueprint exposure. It plays a crucial role in Unreal Engine’s memory management. Without it, the garbage collector doesn’t recognize your pointers, leading to dangling references and, ultimately, memory corruption. I thought it was just for Blueprints.
The Fix
Armed with this newfound knowledge, I dove back into my code. I meticulously went through every UObject-derived pointer, ensuring they were marked with UPROPERTY(). And finally… my next build went from crashing every 5-20 minutes to completely stable.
For Example:
// Before
ULevelSequencePlayer* LevelSequencePlayer;
// After
UPROPERTY()
ULevelSequencePlayer* LevelSequencePlayer;
Lessons Learned
- Don’t Underestimate UPROPERTY(): It’s not just for Blueprints. It’s vital for memory management and preventing corruption.
- Reading the Documentation probably doesn’t help: Unreal Engine’s docs are extensive. But important details like this are buried footnotes somewhere…. upon writing this article I tried to google information about UPROPERTY in the unreal documentation and it did not mention the word “memory” anywhere in it. Public consensus is that if you’re writing C++ code in Unreal, the best documentation is to actually read the source code, not the docs… and this nightmare was case and point. AI is great at scraping the spaghetti-mess that is unreal’s documentation, and pitiful support forums while digging for real answers.
- Patience is Key: Debugging can be frustrating, but perseverance pays off.
Final Thoughts
This experience was a harsh reminder of how critical certain aspects of Unreal Engine are, even ones that might seem straightforward. So, the next time your game starts behaving like it has a mind of its own, take a step back, breathe, and consider the basics. You might just find the solution lurking in places you least expect.