[geom-splines] expose cubic conversion for polylines

I’m trying to create smooth curve from a polyline and hit a roadblock when realized that cubic-from-controlpoints assumes that curve is closed. Turns of that buildNonUniform is all I needed. Is there an official way to convert list of points to list of Cubics? Currently i’m doing:

let path = [[0, 0, 0], [0.5, 1, 0], [1, 0.25, 0]]

let segments = convertToSegments(path)

let cubics = buildNonUniform(segments, 1, false)
let resampledPath = cubics.reduce((resampledPath, c) => {
  // resample each segment individually, is there better way?
  var curve = sampleCubic(c, 6)
  return resampledPath.concat(curve)
}, [])

// remove overlapping start/end points for each cubic
let smoothPath = simplify(resampledPath, 0, false)

assuming following buildNonUniform from cubic-from-controlpoints

const buildNonUniform = (segments, t = 1) => {
    const res = []
    for (let i = 0, n = segments.length - 2; i < n; i += 2) {
      const a = segments[i]
      const b = segments[i + 1]
      const c = segments[i + 2]
      res.push([a, vec3.lerp([...a], b, t), vec3.lerp([...c], b, t), c])
    }
    return res
  }

and modified segment generation

function convertToSegments(path) {
      const segments = [path[0], path[0]]
      for (let i = 0, num = path.length - 1; i < num; i++) {
        const q = path[i + 1];
        segments.push(vec3.lerp([...path[i]], q, 0.5), [...q]);
      }    
      segments.push(path[path.length-1])
      return segments
}

Note: vec3.lerp comes from pex-math/vec3.js#L150 and is similar to mixN.

[vorg]

Works great! My strange attractors thank you…

[postspectacular]

@vorg - openCubicFromBreakPoints() is now available too…