Tuesday, October 30, 2012

Trivial CMAKE for OpenSceneGraph

It is often fun to get open source projects working with Visual Studio since a lot of build systems leave out a few Microsoft specific vagaries. With CMAKE life in the last few years has become much easier, though sometimes it requires a bit of digging to locate the right incantations to pull in the right dependencies for a trivial project.


SET(TARGET_SRC aeroviewer.cpp )

find_package(OpenSceneGraph REQUIRED osgDB osgUtil osgGA osgViewer osgText)



The aim of this quick dash is to add a screen overlay with the company logo to the default osgViewer. This requires adding a geometry node to the scene with some static geometry in camera space. Which ends up being equivalent to a HUD in osg parlance. After a bit of tweaking and rotations in texture space I got this, not too bad for a cold-start in OSG land. This bit of sample code is better for HUD's than the tutorial, the required projection and modelview matrices are encapsulated by the CameraNode.

Saturday, October 20, 2012

Why is gold valuable anyway ? - Midas and Supernovas

Growing up as a child in India in a family of goldsmiths it is hard to ignore the role gold plays in perception of wealth and daily conversation. My uncle would often refer to "stuff" or "maal", meaning gold. On my last visit the regular obsession was checking the current gold price from the wholesalers via SMS. According to a recent article - Man's addiction to gold - India holds pretty large stockpiles of the metal in the proverbial family jewels. It changes hand at marriages as gifts and dowry.

Midas as an allegory of a supernova Gold has no intrinsic bio-chemical value which supports life as the cautionary tale of King Midas points our. Its inherent inertness however gives it great value in the burgeoning electronics industry and it is very rare to start with anyway due to the cosmic element forming processes making it harder and harder to produce heavier elements. The vagaries of nucleosynthesis are so universal that they have even made it to being a Hollywood plot device in "Cowboys and Aliens" where aliens set up a gold mine.

The ultimate statement on how we value things comes down to supply and demand - gold is in short supply due to its nuclear weight and on high demand due to its permanence once acquired. We now just need to find suitable biochemistries or bioelectronics to make it part of a living body. Gold abundance is a measure of the midas touch of supernovas.

Wednesday, October 17, 2012

Making Furniture from Banana

I had a solid grounding in natural fibers and polymer chemistry thanks to my father. My mum still has a picture of him happily holding a sisal leaf. We took this picture in the plantations just outside Mombasa. Well the agave family is pretty notorious, apart from sisal it also gives us pineapples and tequila.
So I tend to talk about the wonders of polymer chemistry often. I kept rambling at the Augustiner Biergarten in Munich about natural fibers, hair and aramids, to slightly disbelieving stares. Ended up learning a bit about making violins out of Kevlar.

The whole chain of thought started on the plane from Adelaide to Kualalumpur. I sat next to Ed organising the overseas operations in Egypt for Papyrus inc and making veneer out of banana stems. He treated me to a nice time in KL on condition that I show the same consideration to any travelling PhD student I meet in the future, when I am a director or something. Otherwise it was a great conference featuring a visit to the EADS solar panel and rocket engine manufacturing facility - which used to serve as the tank manufacturing facility at its inception. As well as plenty of nice technical sessions and a strange conversation regarding compressed sensing and the difference between SAR and optical.

I finally did the IGARSS Conference review survey today, so getting the blog out is timely. May be I will present about point clouds at the next conference and take a break from the SAR stuff. Check this video for what I have been doing recently.