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Back to General and Gameplay Programming

Reading Indices From DAE File

Started by
1 comment, last by Medo Mex 8 years, 3 months ago

Hi Guys,

I'm getting the vertices POSITION from <float_array id="Box001-POSITION-array"> as the following:


-20.189827 -16.902542 0.000000
20.189827 -16.902542 0.000000
-20.189827 16.902542 0.000000
20.189827 16.902542 0.000000
-20.189827 -16.902542 26.019667
20.189827 -16.902542 26.019667
-20.189827 16.902542 26.019667
20.189827 16.902542 26.019667
What I see is that the indices should be retrieved from <p>:

0 0 9 2 1 11 3 2 10 3 3 10 1 4 8 0 5 9 4 6 8 5 7 9 7 8 11 7 9 11 6 10 10 4 11 8 0 12 4 1 13 5 5 14 7 5 15 7 4 16 6 0 17 4 1 18 0 3 19 1 7 20 3 7 21 3 5 22 2 1 23 0 3 24 4 2 25 5 6 26 7 6 27 7 7 28 6 3 29 4 2 30 0 0 31 1 4 32 3 4 33 3 6 34 2 2 35 0
Now, how I do fill the index buffer from the above data? I mean the indices seem too big, and I only need 36 indices to create a box.
Here is the contents of box.DAE:

<?xml version="1.0" encoding="utf-8"?>
<COLLADA xmlns="http://www.collada.org/2005/11/COLLADASchema" version="1.4.1">
  <asset>
    <contributor>
      <author></author>
      <authoring_tool>FBX COLLADA exporter</authoring_tool>
      <comments></comments>
    </contributor>
    <created>2016-01-11T11:23:05Z</created>
    <keywords></keywords>
    <modified>2016-01-11T11:23:05Z</modified>
    <revision></revision>
    <subject></subject>
    <title></title>
    <unit meter="0.025400" name="centimeter"></unit>
    <up_axis>Y_UP</up_axis>
  </asset>
  <library_geometries>
    <geometry id="Box001-lib" name="Box001Mesh">
      <mesh>
        <source id="Box001-POSITION">
          <float_array id="Box001-POSITION-array" count="24">
-20.189827 -16.902542 0.000000
20.189827 -16.902542 0.000000
-20.189827 16.902542 0.000000
20.189827 16.902542 0.000000
-20.189827 -16.902542 26.019667
20.189827 -16.902542 26.019667
-20.189827 16.902542 26.019667
20.189827 16.902542 26.019667
</float_array>
          <technique_common>
            <accessor source="#Box001-POSITION-array" count="8" stride="3">
              <param name="X" type="float"/>
              <param name="Y" type="float"/>
              <param name="Z" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <source id="Box001-Normal0">
          <float_array id="Box001-Normal0-array" count="108">
0.000000 0.000000 -1.000000
0.000000 0.000000 -1.000000
0.000000 0.000000 -1.000000
0.000000 0.000000 -1.000000
0.000000 0.000000 -1.000000
0.000000 0.000000 -1.000000
0.000000 0.000000 1.000000
0.000000 0.000000 1.000000
0.000000 0.000000 1.000000
0.000000 0.000000 1.000000
0.000000 0.000000 1.000000
0.000000 0.000000 1.000000
0.000000 -1.000000 0.000000
0.000000 -1.000000 0.000000
0.000000 -1.000000 0.000000
0.000000 -1.000000 0.000000
0.000000 -1.000000 0.000000
0.000000 -1.000000 0.000000
1.000000 0.000000 0.000000
1.000000 0.000000 0.000000
1.000000 0.000000 0.000000
1.000000 0.000000 0.000000
1.000000 0.000000 0.000000
1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 1.000000 0.000000
0.000000 1.000000 0.000000
0.000000 1.000000 0.000000
0.000000 1.000000 0.000000
0.000000 1.000000 0.000000
-1.000000 0.000000 0.000000
-1.000000 0.000000 0.000000
-1.000000 0.000000 0.000000
-1.000000 0.000000 0.000000
-1.000000 0.000000 0.000000
-1.000000 0.000000 0.000000
</float_array>
          <technique_common>
            <accessor source="#Box001-Normal0-array" count="36" stride="3">
              <param name="X" type="float"/>
              <param name="Y" type="float"/>
              <param name="Z" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <source id="Box001-UV0">
          <float_array id="Box001-UV0-array" count="24">
0.000000 0.000000
1.000000 0.000000
0.000000 1.000000
1.000000 1.000000
0.000000 0.000000
1.000000 0.000000
0.000000 1.000000
1.000000 1.000000
0.000000 0.000000
1.000000 0.000000
0.000000 1.000000
1.000000 1.000000
</float_array>
          <technique_common>
            <accessor source="#Box001-UV0-array" count="12" stride="2">
              <param name="S" type="float"/>
              <param name="T" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <vertices id="Box001-VERTEX">
          <input semantic="POSITION" source="#Box001-POSITION"/>
        </vertices>
        <triangles count="12">
          <input semantic="VERTEX" offset="0" source="#Box001-VERTEX"/>
          <input semantic="NORMAL" offset="1" source="#Box001-Normal0"/>
          <input semantic="TEXCOORD" offset="2" set="0" source="#Box001-UV0"/>
          <p> 0 0 9 2 1 11 3 2 10 3 3 10 1 4 8 0 5 9 4 6 8 5 7 9 7 8 11 7 9 11 6 10 10 4 11 8 0 12 4 1 13 5 5 14 7 5 15 7 4 16 6 0 17 4 1 18 0 3 19 1 7 20 3 7 21 3 5 22 2 1 23 0 3 24 4 2 25 5 6 26 7 6 27 7 7 28 6 3 29 4 2 30 0 0 31 1 4 32 3 4 33 3 6 34 2 2 35 0</p>
        </triangles>
      </mesh>
    </geometry>
  </library_geometries>
  <library_visual_scenes>
    <visual_scene id="" name="">
      <node name="Box001" id="Box001" sid="Box001">
        <matrix sid="matrix">1.000000 0.000000 0.000000 0.119303 0.000000 0.000000 1.000000 -12.444590 0.000000 -1.000000 0.000000 3.062286 0.000000 0.000000 0.000000 1.000000</matrix>
        <instance_geometry url="#Box001-lib"/>
        <extra>
          <technique profile="FCOLLADA">
            <visibility>1.000000</visibility>
          </technique>
        </extra>
      </node>
      <extra>
        <technique profile="MAX3D">
          <frame_rate>30.000000</frame_rate>
        </technique>
        <technique profile="FCOLLADA">
          <start_time>0.000000</start_time>
          <end_time>3.333333</end_time>
        </technique>
      </extra>
    </visual_scene>
  </library_visual_scenes>
  <scene>
    <instance_visual_scene url="#"></instance_visual_scene>
  </scene>
</COLLADA>
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You can see that in the indices list it tells you that it's storing a set of indices for VERTEX, NORMAL and TEXCOORDs, so if you just want to read vertex positions you need to read on a stride of 3. Eg. 0 0 9 2 1 11 3 2 10 3 3 10 1 4 8 0 5 9...

However, I'd advise using assimp to load in COLLADA files, you'll quickly find that different exporters reference data in many different ways.

@Syntac_: Now I can draw the mesh, but trying to get the UV into the vertex buffer.

I see here that I have 12 UV, while in my vertex buffer I only have 8 vertices, how do I assign 12 UV to 8 vertices?+

Resolved. I created 36 vertices instead of 8 and used the indices to build the vertex buffer.

Thanks,

This topic is closed to new replies.

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