Opengl - get rid of glu dll

[phibermon]

I'd not come across this approximation either - thanks very much for the info both! exactly the kind of esoteric little trick I love to explore

Reading up, it was apparently used before our lord and saviour Carmack did, as was the famous 'Carmack's Reverse' technique for shadow volumes.

But John is a master of applied mathematics in the field of 3D - had he been born 10 years earlier we'd probably of seen Doom on the Amiga at full speed because he found some trick you could pull with the floppy drive

[Chebmaster]

exactly the kind of esoteric little trick I love to explore

Just don't forget: on modern hardware this vintage method has the same speed(x86) or is three times *slower*(Raspberry Pi) than honest 1/sqrt(x) while the dedicated SSE instruction RSQRTPS leaves it in the dust, being more than 8 times faster (although it is not deterministic) because it does that trick *in hardware* operating on 4 floats in parallel.

See my research results @ http://openarena.ws/board/index.php?topic=5379.0

So, be wary of stale methodologies and remember: modern hardware demands different optimizations!

[JernejL]

Just don't forget: on modern hardware this vintage method has the same speed(x86) or is three times *slower*(Raspberry Pi) than honest 1/sqrt(x) while the dedicated SSE instruction RSQRTPS leaves it in the dust, being more than 8 times faster (although it is not deterministic) because it does that trick *in hardware* operating on 4 floats in parallel.

See my research results @ http://openarena.ws/board/index.php?topic=5379.0

So, be wary of stale methodologies and remember: modern hardware demands different optimizations!

This is gold, i didn't even consider this, and yeah we did come into era of 8 and 16 core processor with massive IPCs and internal optimizations, i guess it is time to put some of these old methods to rest.