# Genmesh
[](https://travis-ci.org/gfx-rs/genmesh)
[](https://docs.rs/genmesh)
[](https://crates.io/crates/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
**Currently Supported Generators**
- `Plane`
- `Cube`
- `Cylinder`
- `SphereUV`
**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
```rust
let vertex_data: Vec<MyVertex> = Cube::new()
.vertex(|(x, y, z)| MyVertex::new([x, y, z], [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.