Build your first AR glasses lens in 10 minutes (no hardware needed)

#beginners #tutorial #opensource #python

DreamLayer is an open source memory layer for AR glasses (Apache-2.0). It has a plugin system, called lenses, and the smallest complete one is about 25 lines of Python. Here's the whole thing, start to finish, no hardware required.

What a plugin actually is

A plugin is a register(ctx) function plus a factory that wraps it:

from dreamlayer.plugins import make_plugin

def draw_hello_card(draw, card):            # fn(draw, card): paint the 256px glass
    draw.text((128, 118), card.get("text", "hello, world"),
              fill=(44, 199, 154, 255), anchor="mm")

def register(ctx):
    ctx.add_card_renderer("HelloCard", draw_hello_card)

def make():                                  # the manifest's entry point
    return make_plugin("hello-lens", register, requires=("cards",))

That's it. ctx is a narrow context object, a plugin can extend the registries and read a couple bits of state, and nothing else. requires names the capabilities you actually need (cards, vision, network, mesh, shop, and a handful more), and the host grants or skips your plugin based on that, cleanly.

Run it locally

pip install -e "host-python[dev]"
cd host-python && python -m pytest -q -k hello_lens

Or use the CLI directly, from the plugin's folder:

dreamlayer plugins validate .    # runs the full store gate
dreamlayer plugins preview .     # renders your card through the real 256px glass

No glasses needed for any of this. There's also a browser simulator that runs the real renderer and orchestrator if you want to see it live: dreamlayer.app/simulator.html.

Package it

dreamlayer plugins pack .        # -> a store-ready package JSON

This computes a checksum binding your manifest and module together, no manual hashing. Every install replays a validation gate: manifest shape, checksum integrity, a static scan proving your code never touches a capability it didn't declare, and a smoke load.