uspol 

They helpfully summarised all the lies Trump told during his presidential term in one article (there are 30573 of them)

RT twitter.com/ThePlumLineGS/stat

A good choice is the x/y/z axis corresponding to the largest |x|, |y|, |z| of the first vector. 2nd vector is always well-separated from that as it's perpendicular to the first. Now matrix needs 3+1=4 floats, or 2+1=3 if you use the above normalised-vector-in-2-floats encoding.

Show thread

Alright, how do you store an entire orthonormal 3-basis (SO(3) rotation matrix)? Can store first vector and then only need one angle to get 2nd vector, then cross product gives your 3rd. However, angle about what axis? A fixed axis always has degenerate cases.

Show thread

However, this loses half your digits of precision near z=0. More accurate alternative is to slice into 6 parts depending on which of |x|, |y|, |z| is largest and its sign. Then store two smaller components (and apply offset as before).

Show thread

/comp/graphics note: how to store a normalised 3-vector as 2 floats? Storing x,y *almost* allows you to determine z=±√1-x²-y² but there's a sign choice. However, could do x->x+3 if z negative, since x range is [-1,1] normally, so can be [2,4] for other "side" of sphere.

https://www.raspberrypi.org/products/raspberry-pi-pico/
Raspberry Pi Pico
> The new flexible $4 microcontroller board from Raspberry Pi

:comfyeyes:
i don't need it
i don't need it
i don't need it

You can't see Jupiter and Saturn in the evening any more but the solar observatory can see them

RT twitter.com/SungrazerComets/st

If you could go anywhere in the world, where would you go?

> The parrot control room_

Show older
Mastodon

The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!