geom:read-ply

(geom:read-ply path &key color label)

The mesh in a PLY (Stanford polygon format) file, as a geom:solid. Both ascii and binary_little_endian bodies are read; binary_big_endian is refused by name -- the bulk binary path is little-endian by contract, and mis-reading every float would be strictly worse than saying so.

The header describes the body -- every element, its count, and every property with its type -- so x, y and z are taken from wherever the vertex element put them, and every other property is read past by its declared width rather than guessed at: the Stanford bunny's confidence and intensity columns, a scanner's per-vertex colours, a per-face colour after the index list. A geom:solid has one colour, so per-vertex and per-face colours are dropped, not averaged. A file with no face element -- a raw range scan -- answers its vertices with no facets rather than an error.

CL-USER> (geom:read-ply "bun_zipper.ply" :color (geom:vec3 0.85 0.72 0.5))
#<GEOM:SOLID 35947 vertices 69451 facets>
CL-USER> (geom:volume *)
7.700565237386743e-4

A binary body whose vertex properties are all float32 is moved by one read-sequence over a packed single-float array -- the whole vertex block in a single native transfer; interleaved colours make the stride non-uniform and cost one extra read per vertex. Faces are two transfers each (one count, one bulk index read), the same shape as geom:read-stl's two a triangle. An ASCII body is scanned character by character like geom:read-obj.

Backend support

Every backend that has a filesystem: the interpreter, a compiled .class/.jar, WASM Preview 1 and the WASI 0.3 component, with the same answer on all four.