Loops and Bubbles
Some quick fixes for mini bugs. A superfluous for loop, and some visual tweaks to comment bubbles! … Read More
Be Vewwwy Vewwwy Quiet, We’re Hunting UObjects
While hunting down some mysteriously vanishing UObjects we stumbled across a more fundamental problem in the garbage collector. … Read More
Trash Compactor
We recently found a huge leak in the UE4 garbage collector, particularly rearing its head on dedicated servers for large open-world games. Servers for arena type games with short play times (<1 hour) seem to be little affected, and clients don’t see the problem much either. “Huge” is not hyperbole here – we’re talking the garbage collector alone using up to 10 GB of ram in under 24 hours of server operation! … Read More
Placating The Natives
In this article we delve into Blueprint Nativization, a relatively new feature of UE4 that offers significant performance improvements for many projects. Sadly, it often doesn't work out of the box - we've spent some time fixing and improving it for a particular project that we were working on. We have a LOT of changes to present here - some of which have already been implemented into UE4. … Read More
PhysX: The Case Of The Leaky Cloth
We found quite a large leak within Apex 3.4 (currently used in Unreal Engine 4, amongst others) - in a relatively short run of the title that we were working on, we saw over 150mb of leaked memory. Here, we present some changes that will fix this … Read More
Getting Into Games Development (Part 1)
In this post our MD, Robert Troughton, starts his story about how he got into the games industry … Read More
So Long MAX_PATH… And Thanks For All The Fish!
Almost every developer that we've spoken to seems to have, at some point, encountered the MAX_PATH limit problem... this post talks about how to PROPERLY fix it … Read More
Is It A Drive? Is It A Directory? No, It’s…
In this post, we look into why IPlatformFileCreateDirectory() was responsible for nearly 1 million allocations during a full cook of KiteDemo and why FPaths::IsDrive(), a huge 100-line function, is being used just to determine whether a filepath begins with a drive mapping... all for the purpose of further speeding up Unreal's cook process just a little bit more … Read More
Cache-ing Up, Cache-ing In
As part of modifying the file profiler we looked at the file IO activity on starting the UE4 editor with one of the lightweight sample projects, noticing that certain files were being read multiple times. Each was being read in their entirety up to 200 times simply opening the editor. In this post we show you why this was happening and how it can be fixed … Read More
The Improvement of the File Profiler
UE4 has a little-known profiler for analysing file operations (with the intention that this information can then be used to make optimisations). In this post we take a look at that - and we make some improvements to make it (even more) useful … Read More
The Quickening Of The Light Map UV Generation
Lightmap UV generation in UE4 can take a considerable amount of time. Here, we take a look at it and present some optimisations that can yield 5x faster performance … Read More
The Long and Winding Path of the Cook
Long file path problems are commonplace when cooking with UE4. We took a look at it - and found that the engine was being too aggressive with its checks for whether or not a path really was too long … Read More
The Case of the Locked File
We were seeing frequent file IO errors in relation to temporary files created during cooking (particularly when compiling shaders). Our findings for why this were happening were surprising. Here we present a clean way to fix the issues … Read More
Static Code Analysis With PVS-Studio (Part 6)
The sixth part in our series looking at coding errors found by using the static code analysis tool PVS-Studio … Read More
It’s A Size, Jim, But Not As We Know It, Not As We Know It…
A really small bug fix is presented here - with a lot of Trekkie banter to fluff the piece out... and why not? … Read More
Clear And Reset Danger
A common programming mistake is fixed here, this time in the FBX importer … Read More
Sign Of The Times
PVS-Studio pointed us toward some code with suspiciously mixed signed/unsigned math. This was actually causing some issues - and here we tell you how to fix them … Read More
Static Code Analysis With PVS-Studio (Part 5)
The fifth part in our series looking at coding errors found by using the static code analysis tool PVS-Studio … Read More
The Sadness of the Ignored Null Pointer
In this post we present an optimization coming from removing some pointless null pointer checks. The way that we found this was quite interesting … Read More
Speeding Up The Time Limit Controls
When a process takes a long time to complete, it makes absolute sense to put some time limit checks in so that you're not starving other work. What you don't want to do, of course, is to have those checks slow your original task down further by any considerable amount - here, we found that exactly this was happening .. so we present a solution … Read More
The Battle of the Lean and the Inlined Bone Functions
We took a look at the inlining of a certain part of the codebase and were shocked with what we found... we then went about improving it … Read More
ToString() Or Not ToString()… Wait, What’s The Question?
ToString() is one of the most commonly called functions in UE4 - certainly across the editor, the content cooker and such. Here we take a look at it and make it over twice as fast … Read More
Tiny Code Fixes – Part 1
Here we present several small code fixes and improvements in a nice little package … Read More
Package Versioning… How It Works… And An Optimization
UE4's Package Versioning is a bit of a dark art for most.. here we try to remove some of the confusion around it - while, again, offering some improvements through optimization … Read More
Portrait Of A Serialize Perf Killer
With performance critical editor and cooker code, it's well advised to consider performance when adding tests for rare errors. Here we take a look at this and show by, by considering the CPU pipeline and code cache, a simple change can yield a significant performance improvement without reducing stability … Read More
Sweeping Up And Disassembling A Physics Macro
Macros can often be useful to make certain programming tasks simpler - but they can also cause hidden performance headaches that might otherwise be avoided. Here we look at one of those - and how to improve it … Read More
Static Code Analysis With PVS-Studio (Part 4)
The fourth part in our series looking at coding errors found by using the static code analysis tool PVS-Studio … Read More
When Are Shopping Lists A Waste of Time?
We take a look at some list generating code with UE4 - and why it was completely pointless … Read More
Using The Disassembler To Highlight Optimization Targets
We use the debugger's disassembly view to look at FPaths::IsRelative() after it shows up in our profiling tests. Then we optimize it … Read More
Static Code Analysis With PVS-Studio (Part 3)
The third part in our series looking at coding errors found by using the static code analysis tool PVS-Studio … Read More
The Cook, The Resave, His Garbage And Her Optimization
We present here a way to improve cook times by reducing the frequency of garbage collection … Read More
The Case Of The ExportHash String Monster
We found CreateExportHash() was showing up in profiling the cooker - so we optimized it. Our findings and changes are presented here … Read More
Static Code Analysis With PVS-Studio (Part 2)
The second part in our series looking at coding errors found by using the static code analysis tool PVS-Studio … Read More
Patch Content Early – NOT At Runtime
We present an optimization that removes a significant amount of memory churn from the animation code … Read More
Static Code Analysis With PVS-Studio (Part 1)
The first part in our series looking at coding errors found by using the static code analysis tool PVS-Studio … Read More
A Huge PhysX Memory Churn Reduction
Here we implement a scratch buffer to reduce temporary memory churn passing through PhysX … Read More
The Smallest, Coolest Optimization
While profiling a game's runtime, we found that 40% of memory allocations were coming from a single function. The fix/optimization involves adding a single character … Read More
The Clue In The Code Comments
We present a tiny little fix for a simple - but serious - coding error in the UE4 codebase … Read More