Wsrtjtyk

I am currently working on an Colladae(.dae) loader for LWJGL which loads full scene information in one class. One of the elements I find it hard to decode is animation.

So basically I want my animator to support any type of animation. Right now it supports Matrix interpolation i.e I extract my translation,rotation,scale values from my matrices and interpolate's them.

The one animation I don't know how to implement is tangent animation. For example
One of samplers has this following structure

<sampler id="Cube_location_X-sampler">

        <input semantic="INPUT" source="#Cube_location_X-input"/>

        <input semantic="OUTPUT" source="#Cube_location_X-output"/>

        <input semantic="INTERPOLATION" source="#Cube_location_X-interpolation"/>

        <input semantic="IN_TANGENT" source="#Cube_location_X-intangent"/>

        <input semantic="OUT_TANGENT" source="#Cube_location_X-outtangent"/>

      </sampler>

      <channel source="#Cube_location_X-sampler" target="Cube/location.X"/>

So The
"INPUT" is nothing but my animation timings(0 to 1)
"OUTPUT" is nothing but my xlocations at every key frame
"INTERPOLATION" for me is always Linear so I don't read that data

"IN_TANGENT" And "OUT_TANGENT" is what I have no idea on what to do with them

When the data is viewed

This is how the "IN_TANGENT" Data looks like

<source id="Cube_location_X-intangent">

        <float_array id="Cube_location_X-intangent-array" count="2">0 -1.061734</float_array>

        <technique_common>

          <accessor source="#Cube_location_X-intangent-array" count="1" stride="2">

            <param name="X" type="float"/>

            <param name="Y" type="float"/>

          </accessor>

        </technique_common>

      </source>

And this is how the "OUT_TANGENT" Data looks like

<source id="Cube_location_X-outtangent">

        <float_array id="Cube_location_X-outtangent-array" count="2">0.08333331 -1.061734</float_array>

        <technique_common>

          <accessor source="#Cube_location_X-outtangent-array" count="1" stride="2">

            <param name="X" type="float"/>

            <param name="Y" type="float"/>

          </accessor>

        </technique_common>

      </source>

Right now both my Tangent data is 2D because I was just moving my cube in one plane in blender but I assume it can be 3D as well(Or maybe not?)

I feel I could use this data for smoother animation but I don't know the mathematics or algorithm to in co-operate this data in my Animator

The Tangents are also available for my rotation as well but again I don't know what to do with them

Eg:

<sampler id="Cube_rotation_euler_Z-sampler">

        <input semantic="INPUT" source="#Cube_rotation_euler_Z-input"/>

        <input semantic="OUTPUT" source="#Cube_rotation_euler_Z-output"/>

        <input semantic="INTERPOLATION" source="#Cube_rotation_euler_Z-interpolation"/>

        <input semantic="IN_TANGENT" source="#Cube_rotation_euler_Z-intangent"/>

        <input semantic="OUT_TANGENT" source="#Cube_rotation_euler_Z-outtangent"/>

      </sampler>

If not Code an bit of mathematics or ideas on what do with these values would be very usefull.
Thank U