docs: function (frameIndex, cx1, cy1, cx2, cy2) {
          var subdiv_step = 1 / 10/*BEZIER_SEGMENTS*/;
          var subdiv_step2 = subdiv_step * subdiv_step;
          var subdiv_step3 = subdiv_step2 * subdiv_step;
          var pre1 = 3 * subdiv_step;
          var pre2 = 3 * subdiv_step2;
          var pre4 = 6 * subdiv_step2;
          var pre5 = 6 * subdiv_step3;
          var tmp1x = -cx1 * 2 + cx2;
          var tmp1y = -cy1 * 2 + cy2;
          var tmp2x = (cx1 - cx2) * 3 + 1;
          var tmp2y = (cy1 - cy2) * 3 + 1;
          var i = frameIndex * 6;
          var curves = this.curves;
          curves[i] = cx1 * pre1 + tmp1x * pre2 + tmp2x * subdiv_step3;
          curves[i + 1] = cy1 * pre1 + tmp1y * pre2 + tmp2y * subdiv_step3;
          curves[i + 2] = tmp1x * pre4 + tmp2x * pre5;
          curves[i + 3] = tmp1y * pre4 + tmp2y * pre5;
          curves[i + 4] = tmp2x * pre5;
          curves[i + 5] = tmp2y * pre5;
      }