Per vertex metadata

[GalaMana]

I find it weird how the meshes and polygons need to share the same metadata. It kinda forces you to have it wrapped in an Option<> which feels unnecessary. ( #31 ) I know I would find use in having separate generics. Maybe even one for vertices. I'm thinking like this: (Simplified)

struct Mesh<Metadata, PerPolygonMetadata, PerVertexMetadata> {
    polygons: Vec<PerPolygonMetadata, PerVertexMetadata>,
    metadata: Metadata,
}

struct Polygon<Metadata, PerVertexMetadata> {
    vertices: Vec<Vertex<PerVertexMetadata>>,
    metadata: Metadata,
}

(I'm new to github. I hope this was clear ^w^)

[timschmidt]

The major reason for the Mesh level metadata is for determining the metadata of newly created Polygons as a result of boolean operations. Boolean results always inherit A's metadata for new Polygons, if it exists. I can't just clone another Polygon level metadata for that purpose in cases where there is more than one value (which to use?). So it's the same as Polygon metadata because in my mind it was representing the metadata value of the "insides" of the A solid. I suppose there's a more semantically obvious way to communicate that.

Thank you for the idea about additional generics. I will consider it. RyanC and I have been working at IndexedMesh, for which I think it is important to have CoW indexed metadata as well, which will vastly reduce memory usage and simplify comparison, making some options here less expensive to implement.