Monthly Archives: September 2013

Stackblur – C++ multi-threaded version of fast blur algorithm

I found nice algorithm for blurring images – Stackblur by Mario Klingemann. It could do the job relatively fast and gives decent quality. You can check it here – web demonstration. As you can see it can be usable even in web projects.

stackblursample

As i wanted to include it to my cross-platform engine i found two c++ implementations: 

First is SSE friendly, second contains some division optimization via static tables. However, both are not using all cpu cores. I took second one as foundation for my implementation, as i expected my code to work on mobile devices with no SSE support. Single-core processing of 1920×1200 rgba image with 100 px radius took only 219 ms (Intel Q9550, Windows 7).

I improved stackblur code to multi-threaded version – on my quad-core cpu speed results as expected showed 4x improvement – 63ms for the same task. You can download the part my lib below and use it as a foundation to your needs.

Download multi-threaded 32bit-color (RGBA) version of StackBlur:  stackblur.cpp

I believe algorithm can be optimized even further – any suggestions are welcome.

Compact lib for JSON parsing (cross-platform C++)

Recently i was in search of compact C++ source code for parsing  of JSON format. This is very simple minimalistic format and its very popular – but i was surprised when found a lot of complex parsers and no simple implementation inside one cpp-h pair. So i wrote one.

mvjsonlogo

Here it is – tiny C++ cross-platform solution for JSON decoding without any dependencies like boost or something: MVJSON.cpp MVJSON.h (version 1.0)

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