extrude-polyline
Extrudes a 2D polyline with a given line thickness and the desired join/cap types. Tries to maintain visual consistency with HTML5 2D context stroking.
var polylne = [ [25, 25], [15, 60] ]
var stroke = require('extrude-polyline')({
thickness: 20,
cap: 'square',
join: 'bevel',
miterLimit: 10
})
var mesh = stroke.build(polyline)
The returned mesh is a simplicial complex.
{
positions: [ [x,y], [x,y] ],
cells: [ [a,b,c], [a,b,c] ]
}
variable thickness
Currently, to achieve variable thickness you can provide a mapThickness
function to the stroke instance before building. By default, it will simply return the current thickness.
stroke.mapThickness = function(point, index, points) {
return this.thickness * index/(points.length-1)
}.bind(stroke)
demo
Git clone, npm install
, then npm run test
Usage
stroke = Extrusion([opt])
Creates a new path builder with the given settings:
thickness
the line thicknessmiterLimit
the limit before miters turn into bevels; default 10join
the join type, can be 'miter'
or 'bevel'
- default 'miter'cap
the cap type, can be 'butt'
or 'square'
- defalut 'butt'
mesh = stroke.build(points)
Builds a stroke with the specified list of 2D points. Returns a simplicial complex.
Roadmap
Some features that could be useful to add at a later point. PRs welcome.
- round corners
- round end caps
- use consistent winding order so we don't need to disable gl.CULLING
- connecting start and end points
- optimizations for flat arrays (Float32Array) ?
- optimizations for GC (pooling, etc)
- handling anti-aliasing
- degenerate triangles or some other form of supporting disconnected lines
- unify codebase with polyline-normals
License
MIT, see LICENSE.md for details.