Calculate the volume of a mesh stored in a VBO-like structure (vertex data in an array and triangle data in another array). Uses gl-matrix

volume.js

var volume = 0;
var v1 = vec3.create(),
    v2 = vec3.create(),
    v3 = vec3.create();
var i,index1,index2,index3;

for(i=0;i<numIndices;) {
  index1 = indices[i++]*3;
  index2 = indices[i++]*3;
  index3 = indices[i++]*3;
  
  vec3.set(v1,vertices[index1],vertices[index1+1],vertices[index1+2]);
  vec3.set(v2,vertices[index2],vertices[index2+1],vertices[index2+2]);
  vec3.set(v3,vertices[index3],vertices[index3+1],vertices[index3+2]);
  
  vec3.cross(v1,v1,v2);
  volume += vec3.dot(v1,v3);
}

volume = Math.abs(volume/6.0);