Genmesh

genmesh is a library for building vertex pipelines. The goal is help facilitate polygon assembly. This is done by building on top of the of the Iterator trait. A pipeline stage is a lazy iterator the consumes the input, and produces a new polygon based on the stage.

This also provides some generators for creating primitives at runtime.

Currently supported stages

• vertex maps a function to each vertex in a polygon
• triangulate triangles Quads to Triangles
• vertices turns a poly pipeline into a vertices pipeline

Primitive generators

• Cone
• Cube
• Cylinder
• Plane
• SphereUV
• Torus

Vertex attributes

• pos: position
• normal: normal

Utility

• LruIndexer translate a vertex into a index, emitting a new vertex if the current vertex is not in the Lru cache.
• Neighbors work with mesh as a whole by querying normals and neighbors on either vertex or polygon levels.

Primitives

• Triangle
• Quad
• Polygon an enum of both Triangle and Quad

Example

    let vertex_data: Vec<MyVertex> = Cube::new()
        .vertex(|v| MyVertex::new(v.pos, [0., 0.]))
        .map(|Quad{x: v0, y: v1, z: v2, w: v3}| {
            Quad::new(MyVertex::new(v0.a_Pos, [0., 0.]),
                      MyVertex::new(v1.a_Pos, [1., 0.]),
                      MyVertex::new(v2.a_Pos, [1., 1.]),
                      MyVertex::new(v3.a_Pos, [0., 1.]))
        })
        .triangulate()
        .vertices()
        .collect();

Here Cube generates six faces, one per side this is presented as a Quad<Vertex3<f32>>.

vertex maps a function to each vertex in each face, in this case we want to convert from genmes's internal vertex format to our own. We now have a Quad<MyVertex>>.

We can do a polygon level transform and modify the polygon as a whole. In the example we add a valid texture coordinate to each face. Since genmesh is just an extension of iterators we can do a polygon level transform using just map.

triangulate will convert the Quad<MyVertex> to a Triangle<MyVertex>>. This will produce two polygons and six vertices. Some of the verticies are cloned in order to complete this operation.

verticies now unwraps each triangle and returns the vertices in-order. This will obviously produce 3 results for each polygon.

collect is a standard Iterator operation.