function getTriangles(object) {
if (object.geometry.type === 'Polygon') {
var coords = computeWalkableArea(object);
var perimeter = coords[0];
var contour = [];
for(j in perimeter) {
contour.push(new poly2tri.Point(perimeter[j][0], perimeter[j][1]));
}
var swctx = new poly2tri.SweepContext(contour);
for (var i = 1; i < coords.length; i++) { //scorro eventuali holes
var perimeter = coords[i];
var hole = [];
for (j in perimeter) { //scorro le singole coordinate dei vari perimetri
hole.push(new poly2tri.Point(perimeter[j][0], perimeter[j][1]));
}
swctx.addHole(hole);
}
swctx.triangulate();
var triangles = swctx.getTriangles();
return triangles;
}
else {
console.log('error, you can triangulate only polygons');
}
}
const polygonToOBJ = function (geometry, opts) {
opts.OBJ += `o ${opts.fileName}_object_${opts.count}\n`
let id = 0
const points = geometry.coordinates[0].map(
p => { return {x:p[0], y:p[1]} }
).filter(
(it, index, ar) => ar.find(
(cur) => (it !== cur) && (cur.x === it.x) && (cur.y === it.y)
) === undefined
)
points.forEach(
p => p.id = ++id
)
const pointsLength = points.length
poly2tri.noConflict()
const swctx = new poly2tri.SweepContext(points, {cloneArrays:true})
try {
swctx.triangulate()
} catch (ex) {
return
}
const tris = swctx.getTriangles()
const output = argv.xz ? (x,y,z) => `\tv ${x} ${z} ${y}\n` : (x,y,z) => `\tv ${x} ${y} ${z}\n`
points.forEach(
p => opts.OBJ += output(p.x * opts.scale, p.y * opts.scale, 0)
)
points.forEach(
p => opts.OBJ += output(p.x * opts.scale, p.y * opts.scale, opts.depth)
)
const short = (i, p, o) =>tris[i].getPoint(p).id + o
let off = opts.vertexCount
opts.OBJ += `\tg ${opts.fileName}_bottom_${opts.count}\n`
for (let i = 0, len = tris.length; i < len; ++i) {
opts.OBJ += `\tf ${short(i,0,off)} ${short(i,1,off)} ${short(i,2,off)}\n`
}
off = opts.vertexCount + pointsLength
opts.OBJ += `\tg ${opts.fileName}_top_${opts.count}\n`
for (let i = 0, len = tris.length; i < len; ++i) {
opts.OBJ += `\tf ${short(i,0,off)} ${short(i,1,off)} ${short(i,2,off)}\n`
}
opts.OBJ += `\tg ${opts.fileName}_walls_${opts.count}\n`
opts.OBJ += `s 1`
for (let i = 0; i < pointsLength; ++i) {
const j = (i + 1) % pointsLength
const i1 = i + opts.vertexCount + 1
const i2 = j + opts.vertexCount + 1
const i3 = i1 + pointsLength
const i4 = i2 + pointsLength
opts.OBJ += `\tf ${i1} ${i2} ${i3}\n`
opts.OBJ += `\tf ${i3} ${i2} ${i4}\n`
}
opts.vertexCount += pointsLength * 2
}