io3fix/src/utils/data3d/buffer/get-polygon.js

toolkit for interior apps

'use strict';

// dependencies

import triangulate2d from './triangulate-2d'

var generatePolygonBuffer = function(options) {

  // API

  var inputVertices = options.outline
  var holes = options.holes
  var uvx = options.uvx || 0
  var uvz = options.uvz || 0
  var y = options.y || 0
  var flipSide = !!options.flipSide

  // internals
  var i, l, iv, iuv
  var indices

  // triangulate
  if (inputVertices.length === 4 && (holes === undefined || holes.length === 0)) {
    // its a quad - no triangulation needed
    indices = [1,0,3,3,2,1]
  } else {
    // use "earcut" triangulation
    if ( holes && holes.length > 0 ) {
      // has holes
      var holeIndices = new Array(holes.length)
      for (i = 0, l = holes.length; i < l; i++) {
        holeIndices[i] = inputVertices.length / 2
        inputVertices = inputVertices.concat(holes[i])
      }
      indices = triangulate2d(inputVertices, holeIndices)
    } else {
      // has no holes
      indices = triangulate2d(inputVertices)
    }

  }

  var outputVertices = new Float32Array(indices.length * 3)
  var outputUvs = new Float32Array(indices.length * 2)

  if (flipSide) {

    for (i = 0, l = indices.length; i < l; i += 3) {
      iv = i * 3
      iuv = i * 2
      // vertices
      outputVertices[ iv ] = inputVertices[ indices[ i + 2 ] * 2 ]
      outputVertices[ iv + 1 ] = y
      outputVertices[ iv + 2 ] = inputVertices[ indices[ i + 2 ] * 2 + 1 ]
      outputVertices[ iv + 3 ] = inputVertices[ indices[ i ] * 2 ]
      outputVertices[ iv + 4 ] = y
      outputVertices[ iv + 5 ] = inputVertices[ indices[ i ] * 2 + 1 ]
      outputVertices[ iv + 6 ] = inputVertices[ indices[ i + 1 ] * 2 ]
      outputVertices[ iv + 7 ] = y
      outputVertices[ iv + 8 ] = inputVertices[ indices[ i + 1 ] * 2 + 1 ]
      // uvs
      outputUvs[ iuv ] = inputVertices[ indices[ i + 2 ] * 2 +1 ] + uvz
      outputUvs[ iuv + 1 ] = inputVertices[ indices[ i + 2 ] * 2 ] + uvx
      outputUvs[ iuv + 2 ] = inputVertices[ indices[ i ] * 2+1 ] + uvz
      outputUvs[ iuv + 3 ] = inputVertices[ indices[ i ] * 2 ] + uvx
      outputUvs[ iuv + 4 ] = inputVertices[ indices[ i + 1 ] * 2+1 ] + uvz
      outputUvs[ iuv + 5 ] = inputVertices[ indices[ i + 1 ] * 2 ] + uvx
    }

  } else {

    for (i = 0, l = indices.length; i < l; i += 3) {
      iv = i * 3
      iuv = i * 2
      // vertices
      outputVertices[ iv ] = inputVertices[ indices[ i + 2 ] * 2 ]
      outputVertices[ iv + 1 ] = y
      outputVertices[ iv + 2 ] = inputVertices[ indices[ i + 2 ] * 2 + 1 ]
      outputVertices[ iv + 3 ] = inputVertices[ indices[ i + 1 ] * 2 ]
      outputVertices[ iv + 4 ] = y
      outputVertices[ iv + 5 ] = inputVertices[ indices[ i + 1 ] * 2 + 1 ]
      outputVertices[ iv + 6 ] = inputVertices[ indices[ i ] * 2 ]
      outputVertices[ iv + 7 ] = y
      outputVertices[ iv + 8 ] = inputVertices[ indices[ i ] * 2 + 1 ]
      // uvs
      outputUvs[ iuv ] = inputVertices[ indices[ i + 2 ] * 2+1 ] + uvz
      outputUvs[ iuv + 1 ] = inputVertices[ indices[ i + 2 ] * 2 ] + uvx
      outputUvs[ iuv + 2 ] = inputVertices[ indices[ i + 1 ] * 2+1 ] + uvz
      outputUvs[ iuv + 3 ] = inputVertices[ indices[ i + 1 ] * 2 ] + uvx
      outputUvs[ iuv + 4 ] = inputVertices[ indices[ i ] * 2+1 ] + uvz
      outputUvs[ iuv + 5 ] = inputVertices[ indices[ i ] * 2 ] + uvx
    }

  }

  return {
    vertices: outputVertices,
    uvs: outputUvs
  }

}

export default generatePolygonBuffer