load-collada-dae/test/test-utils/keyframes-to-dual-quats.js

Load the WebGL graphics buffer data from a collada .dae model and return a draw command that accepts options

var mat3FromMat4 = require('gl-mat3/from-mat4')
var quatMultiply = require('gl-quat/multiply')
var quatFromMat3 = require('gl-quat/fromMat3')
var quatScale = require('gl-quat/scale')

module.exports = keyframesToDualQuats

// collada-dae-parser exports joint matrices
// here we convery them into dual quaternions
function keyframesToDualQuats (jointMatrices) {
  var rotQuaternions = []
  var transQuaternions = []

  jointMatrices.forEach(function (joint, index) {
    // Create our dual quaternion
    var rotationMatrix = mat3FromMat4([], joint)
    var rotationQuat = quatFromMat3([], rotationMatrix)
    var transVec = [joint[12], joint[13], joint[14], 0]
    var transQuat = quatScale([], quatMultiply([], transVec, rotationQuat), 0.5)

    rotQuaternions.push(rotationQuat)
    transQuaternions.push(transQuat)
  })

  return {
    rotQuaternions: rotQuaternions,
    transQuaternions: transQuaternions
  }
}