"""
Shell3D renderer: the nautilus as a real 3D object with iridescent nacre.
Consumes a SceneGraph and emits a self-contained Three.js scene (in an iframe) that
the user can orbit. The shell GEOMETRY is generated from ShellState (turns, growth,
knots, aperture) so it stays traceable; the MATERIAL is a real physically-based
iridescent surface (mother-of-pearl) whose strength comes from ShellState.iridescence
and whose colours come from the emotional palette. Knots (dead ends) become raised
nubs on the shell body; the aperture (breakthrough) glows.
No API key, no build step: Three.js is loaded from a CDN inside the iframe. WebGL is
the only requirement; available() reports that honestly.
"""
from __future__ import annotations
import html as _html
import json
from scene_graph import SceneGraph
class Shell3DRenderer:
id = "shell3d"
label = "The shell, in 3D"
description = "Your nautilus as a real object you can turn in the light — iridescent nacre."
supported_versions = ("1.0",)
requires_generation = False
def available(self) -> tuple[bool, str]:
# Always offerable; WebGL support is a client-side capability we cannot
# detect server-side. The iframe degrades to a message if WebGL is absent.
return (True, "")
def render(self, scene: SceneGraph) -> dict:
params = {
"turns": scene.shell.turns,
"growth": scene.shell.growth_curve,
"knots": scene.shell.knots,
"jewels": scene.shell.jewels,
"aperture": scene.shell.aperture,
"iridescence": scene.shell.iridescence,
"palette": scene.shell.palette,
"session": scene.session_id,
}
doc = _THREE_DOC.replace("__PARAMS__", json.dumps(params))
escaped = _html.escape(doc, quote=True)
iframe = (
f''
)
return {"kind": "iframe", "html": iframe, "notes": ""}
# The Three.js scene. A log-spiral tube of growing radius (the nautilus), with a
# real iridescent material (KHR-style thin-film via onBeforeCompile is heavy; we
# use MeshPhysicalMaterial.iridescence which three r150+ supports natively), knots
# as small spheres on the centerline, and a glowing aperture sphere at the tip.
_THREE_DOC = r"""
This lens needs WebGL, which your browser
or device did not provide. Try a desktop browser to turn the shell in 3D.