2026-08-16T00:00:00Zhttps://marekfiser.com/Marek's blogMarek's blog about game dev, computer graphics, programming, and fractals!Marek Fiserblog@marekfiser.comDouble-double arithmetic: 31 digits of precision from two doubles2026-08-16T00:00:00Z2026-08-16T00:00:00Zhttps://marekfiser.com/blog/double-double-arithmeticMarek Fiserblog@marekfiser.comIf you ever need more precision than what 15 decimal digits of the double format can offer, there is a neat trick: glue two doubles together and treat them as one number. This gives you ~31 decimal digits for roughly 9x the cost of a plain double. With no heap allocation and no dependencies, this puts it perf-wise almost exactly halfway between a double and an arbitrary-precision library. This post explains how the format works and the math behind it. It also benchmarks the type against __float128 and MPFR, and shows where the trick runs out of steam.Unity's Mono problem: Why your C# code runs slower than it should2025-12-27T00:00:00Z2025-12-27T00:00:00Zhttps://marekfiser.com/blog/mono-vs-dot-net-in-unityMarek Fiserblog@marekfiser.comExecution of C# code in Unity's Mono runtime is slow by today's standards, much slower than you might expect! Our game runs 2-3x faster on modern .NET compared to Unity's Mono, and in a few small benchmarks I measured speedups of up to 15x. I've spent some time investigating what's going on and in this article I will present my findings and why everyone should want Unity's .NET modernization to become production-ready as soon as possible.IOException: Success2024-12-29T00:00:00Z2024-12-29T00:00:00Zhttps://marekfiser.com/blog/io-exception-successMarek Fiserblog@marekfiser.comSome time ago, I encountered and resolved a truly bizarre issue: certain players were unable to save their game due to an IOException with the error message "Success". To this day, I still receive inquiries from fellow devs about how to address this problem. This article documents the issue and provides a reference for the workaround.Is 16.7 million colors enough?2015-01-05T00:00:00Z2015-01-05T00:00:00Zhttps://marekfiser.com/blog/is-16m-colors-enoughMarek Fiserblog@marekfiser.comThe majority of our devices today can display 16.7 million colors. This may sound like a lot but sometimes the human eye can notice a difference between two neighboring colors. I have encountered this problem while creating some fractal images. The solution to the limitation is the usage of dithering. This article describes the problem and presents a simple solution.Mausr - Marek's Unicode Symbols Recognizer2014-12-21T00:00:00Z2014-12-21T00:00:00Zhttps://marekfiser.com/projects/mausr-mareks-unicode-symbols-recognizerMarek Fiserblog@marekfiser.comMausr is a library and web interface that performs unicode symbols recognition from hand drawn input using a simple neural network. The symbol recognition library is written from scratch without any ML library and it implements a back-propagation learning algorithm as well as basic non-linear optimization algorithms such as gradient descent and iRprop.Internship at NVIDIA 20142014-09-15T00:00:00Z2014-09-15T00:00:00Zhttps://marekfiser.com/blog/internship-at-NVIDIA-2014Marek Fiserblog@marekfiser.comI spent the summer of 2014 as an intern at NVIDIA. That was a quite different experience than the last year in Google. This article describes all the aspects of being an intern in Silicon Valley including tips how to prepare for such an adventure. A big part of the summer was a road trip from Indiana to California and back and I will talk about it as well. After I returned everybody keeps asking me: What is better, NVIDIA or Google? You can find out my personal opinion in the post!Mamex - Marek's Mandelbrot explorer2014-08-04T00:00:00Z2014-08-04T00:00:00Zhttps://marekfiser.com/projects/mamex-mareks-mandelbrot-explorerMarek Fiserblog@marekfiser.comMamex is a Mandelbrot set rendering library written in C# and supports arbitrary precision (provided by GMP) for infinite zoom. The explorer can visualize Mandelbrot and Julia sets and has many additional features such as an interactive color gradient editor, projections support, and batch rendering. Custom anti-aliasing algorithm, sharpening, and color dithering algorithms yield beautiful results.Internship at Google 20132013-09-18T00:00:00Z2013-09-18T00:00:00Zhttps://marekfiser.com/blog/internship-at-Google-2013Marek Fiserblog@marekfiser.comIn the summer of 2013 I had an opportunity to be a part of Google for a whole 14 weeks. This article tells the whole story starting from the application process describing all my great experience. I was interning at Google Headquarters in sunny California and I was a member of the Google Research team. This article is accompanied with around 100 images from Google campus and surrounding areas.Realtime visualization of 3D vector fields using CUDA2013-04-21T00:00:00Z2013-04-21T00:00:00Zhttps://marekfiser.com/projects/realtime-visualization-of-3D-vector-fields-using-CUDAMarek Fiserblog@marekfiser.comThis project demonstrates visualization techniques like glyphs, stream lines, stream tubes, and stream surfaces, all done in real time. The key is an RK4 integrator implemented using CUDA that uses very fast texture lookup functions to access a vector field. This article contains more than 100 images and figures, commented code snippets, and source code available for download.Conway's Game of Life on GPU using CUDA2013-03-17T00:00:00Z2013-03-17T00:00:00Zhttps://marekfiser.com/projects/conways-game-of-life-on-gpu-using-cudaMarek Fiserblog@marekfiser.comThis project compares performance of CPU and GPU in evaluation of famous Conway's Game of Life. The performance was tested on three different implementations. The most sophisticated version of the algorithm on GPU stores data in one bit-per-cell array and leads to a speed-up of 480x compared to the serial CPU algorithm. The best implementation for CPU turned out to be a lookup-table approach leading to 60x speedups over serial CPU. The report contains a detailed explanation of used algorithms, measurements, and code of the whole project for download.