Plot the price of bitcoin directly on the command line

Here's a python script to plot the price of cryptocurrencies directly on the command line. 

This a single python script, which depends on the requests, pandas, and numpy packages. It uses the Symbols for Legacy Computing unicode block for plotting directly inside the terminal emulator. Most terminals based on the Gnome terminal support these characters.

I make no apologies for the garish color scheme, which is based on what I imagine people in the 1980s imagined the future would look like. You can edit the ANSI color codes in the source to suit.

This pulls price data from the Kraken exchange, but it is not affiliated with Kraken in any way. It's intended as a minimal demo of interfacing with Kraken's REST API, as well as a demonstration of the possibilities of semigraphics characters in modern terminal emulators.

To changes colors, styles, defaults, etc, edit the python source code. This is provided as a self-contained demonstration of calling Kraken's REST API and plotting using unicode characters in the command line. The expectation is that users will modify/incorporate parts of this into their own script.

Random noise textures on the GPU in WebGL

Procedural rendering routines often need pseudorandom numbers. For graphics rendering, we usually prefer correct-ish and fast code over properly "correct" code. My approach to random number generation is usually to intermittently seed a weak pseudo-random number generator, like a linear-feedback shift register, from a stronger source like Javascript's Math.random(). 

On the GPU, things are not so simple: we want a pseudorandom algorithm that is fast, local, and parallel. For compatibility, we should also have this RNG use an 8-bit RGBA texture for its internal state. Bitops are a bit tricky in WebGL shaders (though not impossible), so we'll use a linear congruential generator.

Pixel-art-style Conway's game-of-life using a tile shader in WebGL

Implementation of Conway's game of life cellular automata with a retro-style shader. Added as example on webgpgpu Github.

[view in browser]

[smaller version for mobile]

Sketch of WebGL implementation:

• Underlying cellular automata runs Conway's game of life
• States as game tiles: new cells: small blue; live cells: blue; died: skulls
• Life diffuses out coloring nearby areas
• A single RGBA texture stores the game state. We render to/from this texture as a framebuffer.
• Each color channel in [0,1] can be mapped to a [0,255] byte value
• The green channel stores the game of life state
• The blue channel stores the diffusing field
• The red channel outputs a tile ID value that is passed to a tile shader to render the game