jwezorek's software development blog
A couple of months ago, out of boredom, I implemented the old plasma fractals algorithm that is emblematic of the late 1980s/early 1990s demoscene, “rectangle subdivision fractals” or whatever you want to call it. It’s an old hack. I wrote some code that would generate animated GIFs that were cross-fades of plasma fractals but the GIF files came out too large and I lost interest…
A couple of years ago I wrote a blog post about finding the closest point on a cubic bezier to a given point in which I showed how to reduce the problem to solving a quintic equation and provided an implementation in C# that finds the roots of the quintic using Laguerre’s Method. I also mentioned at the end of that post that there is…
Transliterated from java found here:
Recently I looked through a bunch of triangular cellular automata in which each (1) uses two states, (2) uses the simple alive cell count type of rule, and (3) uses the neighborhood around a cell c that is all the triangles that share a vertex with c; that is, the 12 shaded triangles below are the neighborhood around the yellow triangle: These cellular automata have state…
Over the past couple of weeks I wrote some code in C# to generate dissections of the rhombic triacontahedron into golden rhombohedrons. George Hart discusses these types of dissections here and also talks about the problem of enumerating them in an appendix here — briefly, all this material by Hart and others is about how the fact that the rhombic triacontahedron and the rhombic enneacontahedron are…
I put up some code on github that implements basic signals and slots functionality using standards compliant C++. It’s one header file “signals.hpp”. See here: link to github This implementation of signals is a re-work of some code by a user _pi on the forums for the cross-platform application framework Juce — that thread is here — which was itself a re-work of some example…
Father Magnus Wenninger died last month.
Probably the most read post on this blog is about sprite packing in Python, here. At the time I didn’t have a github account and was planning to make a small desktop application out of the algorithm as a way of learning Qt, which maybe I really will do some day, but in the meantime here is the latest version of this code and that…
I’ve posted a new repository on GitHub for doing mean shift segmentation in C++ using OpenCV: see here. OpenCV contains a mean shift filtering function and has a GPU, I think CUDA, implementation of mean shift segmentation. I didn’t evaluate the GPU implementation because I’m personally not interested in GPU for the project I am working on. I did take a look at turning cv::pyrMeanShiftFiltering(…)…
One irritating thing about OpenCV is that as a computer vision library it doesn’t actually offer a lot of routines for dealing with connected components easily and efficiently. There’s cv::findContours and two versions of cv::connectedComponents — the regular one and one “WithStats”. The trouble is findContours returns polygons when what you often want is raster blob masks. connectedComponents returns a label image but OpenCV doesn’t…