@jscad/modeling
Version:
Constructive Solid Geometry (CSG) Library for JSCAD
26 lines (23 loc) • 920 B
JavaScript
const vec3 = require('../../maths/vec3')
/**
* Measure the signed volume of the given polygon, which must be convex.
* The volume is that formed by the tetrahedron connected to the axis [0,0,0],
* and will be positive or negative based on the rotation of the vertices.
* @see http://chenlab.ece.cornell.edu/Publication/Cha/icip01_Cha.pdf
* @param {poly3} polygon - the polygon to measure
* @return {Number} volume of the polygon
* @alias module:modeling/geometries/poly3.measureSignedVolume
*/
const measureSignedVolume = (polygon) => {
let signedVolume = 0
const vertices = polygon.vertices
// calculate based on triangular polygons
const cross = vec3.create()
for (let i = 0; i < vertices.length - 2; i++) {
vec3.cross(cross, vertices[i + 1], vertices[i + 2])
signedVolume += vec3.dot(vertices[0], cross)
}
signedVolume /= 6
return signedVolume
}
module.exports = measureSignedVolume