[WF-Protocols] first attempt with xml schema

[Matze Braun]

Hi,

to get things a bit more concrete I started creating a xml schema 
definition for parts of the spec. You can find the files here:

http://www.stud.uni-karlsruhe.de/~uxsm/omf.xsd
http://www.stud.uni-karlsruhe.de/~uxsm/material.xsd
http://www.stud.uni-karlsruhe.de/~uxsm/mesh.xsd
http://www.stud.uni-karlsruhe.de/~uxsm/model.xsd
http://www.stud.uni-karlsruhe.de/~uxsm/skelton.xsd
http://www.stud.uni-karlsruhe.de/~uxsm/test.xml

An examplefile looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<model xmlns="http://www.stud.uni-karlsruhe.de/~uxsm/omf"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.stud.uni-karlsruhe.de/~uxsm/omf 
omf.xsd"
       name="Hugo The Testmodel">
  <mesh name="Head" material="sunnyface">
    <vertices>
      <v x="-1" y="-1" z="-1"/>
      <v x="1" y="-1" z="-1"/>
      <v x="-1" y="1" z="-1"/>
      <!-- More vertices come here. -->
    </vertices>
                                                                                
    <normals>
      <!-- This sections assigns normals to vertices:
         -The first normal belongs to the first vertex...
         -Normals have to be normalized :)
       -->
      <n x="1" y="0" z="0"/>
      <n x="0" y="1" z="0"/>
      <n x="0" y="0" z="1"/>
    </normals>
                                                                                
    <texturecoords>
      <!-- The texturecoordinates assign UV coordinates to vertices:
        -The first texture coord belongs to the first vertex the 2nd 
texture
         coord to the 2nd vertex...
        -You might have several texturecoords sections. You may specify 
exactly
         which textureunit to use as attribute in the texturecoords 
section
      -->
      <t u="0" v="0"/>
      <t u="0" v="1"/>
      <t u="1" v="1"/>
    </texturecoords>
    <polygons>
      <p>0 1 2</p>
      <!-- More polygons come here. Notes:
        -Polygons are specified as space separated list of vertex indices,
         vertices are indexed starting at 0
        -Polygons are 1 sided
        -Polygons have to be convex
        -all vertices of a polygon have to be on the same plane
        -The vertices are in clockwise order (this is used for determining
                                              normals if none are given).
      -->
    </polygons>
  </mesh>
  <!-- More meshes follow here...
  <mesh name="Big Head" material="face">
    ...
  </mesh>
  <mesh name="Right Leg">
  </mesh>
  -->
  <meshgroup name="Head">
    <!-- This group defines swappable meshparts. Only 1 of the meshes here 
is
         used at once. You are able to switch between meshes here.
         The first mentioned mesh is used as default...
    -->
    <mesh>Head</mesh>
    <mesh>Big Head</mesh>
  </meshgroup>
</model>

Now some notes I wrote down while doing this stuff, where I'm waiting for 
comments:

-should we use space separated vertex list in polygons or tags?
  <p>0 1 2</p> vs. <p> <v>0</v><v>1</v><v>2</v> </p>
-How should we reference to the textureunits? currently you can give a 
integer
  number like this:
  <texturecoords textureunit="1"/>
-Should we allow swappable parts? If yes how?
-Should names have special constraints? (At the moment I'm allowing every
  string, we could even think about UTF-8...)
-I didn't include support for special datatypes like trianglestrips or 
 trianglefans. Do they make sense in the format? Can't we let the 
 converters calculate such special formats?
-I didn't include support for LOD yet as I was unsure how todo it.
-Also I wonder if the method of grouping meshs should be more flexible 
 (ie. multiple meshes for 1 part...)

I'm waiting for comments.

Greetings,
	Matze