Barebone examples and slightly friendlier show() for Rust

[teh-cmc]

What the title says.

Most barebone python:

import numpy as np
import rerun as rr

SIZE = 10

rr.spawn()

x, y, z = np.meshgrid(np.linspace(-5, 5, SIZE), np.linspace(-5, 5, SIZE), np.linspace(-5, 5, SIZE))
positions = np.array(list(zip(x.reshape(-1), y.reshape(-1), z.reshape(-1))))

r, g, b = np.meshgrid(np.linspace(0, 255, SIZE), np.linspace(0, 255, SIZE), np.linspace(0, 255, SIZE))
colors = np.array(list(zip(r.reshape(-1), g.reshape(-1), b.reshape(-1))), dtype=np.uint8)

rr.log_points("my_points", positions=positions, colors=colors)

Most barebone rust (hiding helpers, we won't show them in the doc page):

use rerun::external::glam;
use rerun::{ColorRGBA, MsgSender, Point3D, Session};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut session = Session::new();

    let points = grid(glam::Vec3::splat(-5.0), glam::Vec3::splat(5.0), 10)
        .map(Point3D::from)
        .collect::<Vec<_>>();
    let colors = grid(glam::Vec3::ZERO, glam::Vec3::splat(255.0), 10)
        .map(|v| ColorRGBA::from([v.x as u8, v.y as u8, v.z as u8, 255]))
        .collect::<Vec<_>>();

    MsgSender::new("my_point")
        .with_component(&points)?
        .with_component(&colors)?
        .send(&mut session)?;

    session.show()?;

    Ok(())
}

[emilk]

I think these examples are too minimal. Is there really any point to them (pun intended)?

I prefer examples/hello_world/main.py (though it should maybe be renamed to minimal).

If you don't want a dependency on an image or image crate, then perhaps we should log at least a semi-interesting point cloud. All our examples should be interesting in some way imho.

[teh-cmc]

Update: we decided to drop hello_world in favor of minimal, and update minimal to log @jleibs' fancy color-cube rather than a less fancy single point 🥲 (we won't use the demo library though, minimal must be self contained!).

The idea here is that minimal is what we will show on the For {Python/Rust} Users} pages in the docs.

https://rerunio.slack.com/archives/C041NHU952S/p1675933683218999

[emilk]

I wonder if we should put components in a separate module?

Suggested change

	use rerun::{ColorRGBA, MsgSender, Point3D, Session};
	use rerun::{MsgSender, Session, components::{ColorRGBA, Point3D}};

This makes it more clear what you can use as a component. Right now it reads a bit "magic"

[teh-cmc]

Hmmm, actually I keep splitting things up between message-stuff, time-stuff, init-stuff, component-stuff every time I import all of this otherwise it's just too messy to digest... so yeah we might as well make modules I guess. In another PR tho.

[emilk]

It will also give some much-needed structure to the docs of rerun: