HI Lukasz, On 10 October 2013 13:40, Lukasz Izdebski <[email protected]> wrote:
> good question :). And I have few answers. > 1. Speed of calculation. I will need quaternions in my project for > Embedded Systems. > Have you do any benchmarking on your target platform to test whether use of float Quat makes any measurable difference? > 2. End point of this change I think is to enable full float pipe line of > OSG( for speed ), and full double pipeline of OSG ( for precision ). This > is my next challenge. > In my humble opinion OSG need a refresh of his math. I have a question > what is your opinion on added a SSE version of math classes? Scene graphs are principally bandwidth limited so cost of maths operations during traversal are normally trivial and don't have a noticeable effect performance. It's only doing intersection calculations that one might expect to see a performance difference with using float over double, and an advantage with using SSE maths. SSE maths is only really an advantage when processing lots of data the same way, have the the CPU go into SSE mode do calculations then out of SSE drop isn't something that can be justified for a small number of maths operations. I have yet to see a compelling reason for SSE maths support in the core OSG. Please remember the OSG's focus is a high performance, portable, general purpose scene graph, not a platform specific, application specific scene graph. Choice made have to reflect the needs of maintaining the code base that is clear and functional. Robert.
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