如何使用SceneKit從COLLADA（.dae）文件中獲取幾何

Question

我需要讀取COLLADA文件中的<geometry> ，以創建變形目標數組並為從基本幾何形狀到目標幾何形狀的網格設置動畫。

我只能從嵌入在Node中的基本幾何圖形訪問幾何圖形（COLLADA文件只有一個<node> ）：

planeNode.geometry = scene!.rootNode.childNodeWithName("Plane", recursively: true)!.geometry

這是COLLADA文件的完整源代碼（具有3個幾何圖形和1個節點，但只能訪問1個幾何圖形）：

<?xml version="1.0" encoding="utf-8"?>
<COLLADA xmlns="http://www.collada.org/2005/11/COLLADASchema" version="1.4.1">
  <asset>
    <contributor>
      <author>Blender User</author>
      <authoring_tool>Blender 2.77.0 commit date:2016-04-05, commit time:18:12, hash:abf6f08</authoring_tool>
    </contributor>
    <unit name="meter" meter="1"/>
    <up_axis>Z_UP</up_axis>
  </asset>
  <library_images/>
  <library_geometries>
    <geometry id="Plane-mesh" name="Plane">
      <mesh>
        <source id="Plane-mesh-positions">
          <float_array id="Plane-mesh-positions-array" count="12">-1 -1 0 1 -1 0 -1 1 0 1 1 0</float_array>
          <technique_common>
            <accessor source="#Plane-mesh-positions-array" count="4" stride="3">
              <param name="X" type="float"/>
              <param name="Y" type="float"/>
              <param name="Z" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <source id="Plane-mesh-normals">
          <float_array id="Plane-mesh-normals-array" count="3">0 0 1</float_array>
          <technique_common>
            <accessor source="#Plane-mesh-normals-array" count="1" stride="3">
              <param name="X" type="float"/>
              <param name="Y" type="float"/>
              <param name="Z" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <vertices id="Plane-mesh-vertices">
          <input semantic="POSITION" source="#Plane-mesh-positions"/>
        </vertices>
        <polylist count="2">
          <input semantic="VERTEX" source="#Plane-mesh-vertices" offset="0"/>
          <input semantic="NORMAL" source="#Plane-mesh-normals" offset="1"/>
          <vcount>3 3 </vcount>
          <p>1 0 2 0 0 0 1 0 3 0 2 0</p>
        </polylist>
      </mesh>
    </geometry>
    <geometry id="Plane-mesh_morph_Key1" name="Key1">
      <mesh>
        <source id="Plane-mesh_morph_Key1-positions">
          <float_array id="Plane-mesh_morph_Key1-positions-array" count="12">-1 -1 0 1 -1 0 -1 1 0 1 2 0</float_array>
          <technique_common>
            <accessor source="#Plane-mesh_morph_Key1-positions-array" count="4" stride="3">
              <param name="X" type="float"/>
              <param name="Y" type="float"/>
              <param name="Z" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <source id="Plane-mesh_morph_Key1-normals">
          <float_array id="Plane-mesh_morph_Key1-normals-array" count="6">0 0 1 0 0 1</float_array>
          <technique_common>
            <accessor source="#Plane-mesh_morph_Key1-normals-array" count="2" stride="3">
              <param name="X" type="float"/>
              <param name="Y" type="float"/>
              <param name="Z" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <vertices id="Plane-mesh_morph_Key1-vertices">
          <input semantic="POSITION" source="#Plane-mesh_morph_Key1-positions"/>
        </vertices>
        <polylist count="2">
          <input semantic="VERTEX" source="#Plane-mesh_morph_Key1-vertices" offset="0"/>
          <input semantic="NORMAL" source="#Plane-mesh_morph_Key1-normals" offset="1"/>
          <vcount>3 3 </vcount>
          <p>1 0 2 0 0 0 1 1 3 1 2 1</p>
        </polylist>
      </mesh>
    </geometry>
    <geometry id="Plane-mesh_morph_Key2" name="Key2">
      <mesh>
        <source id="Plane-mesh_morph_Key2-positions">
          <float_array id="Plane-mesh_morph_Key2-positions-array" count="12">-1 -1 0 1 -1 0 -1 1 0 2 1 0</float_array>
          <technique_common>
            <accessor source="#Plane-mesh_morph_Key2-positions-array" count="4" stride="3">
              <param name="X" type="float"/>
              <param name="Y" type="float"/>
              <param name="Z" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <source id="Plane-mesh_morph_Key2-normals">
          <float_array id="Plane-mesh_morph_Key2-normals-array" count="3">0 0 1</float_array>
          <technique_common>
            <accessor source="#Plane-mesh_morph_Key2-normals-array" count="1" stride="3">
              <param name="X" type="float"/>
              <param name="Y" type="float"/>
              <param name="Z" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <vertices id="Plane-mesh_morph_Key2-vertices">
          <input semantic="POSITION" source="#Plane-mesh_morph_Key2-positions"/>
        </vertices>
        <polylist count="2">
          <input semantic="VERTEX" source="#Plane-mesh_morph_Key2-vertices" offset="0"/>
          <input semantic="NORMAL" source="#Plane-mesh_morph_Key2-normals" offset="1"/>
          <vcount>3 3 </vcount>
          <p>1 0 2 0 0 0 1 0 3 0 2 0</p>
        </polylist>
      </mesh>
    </geometry>
  </library_geometries>
  <library_controllers>
    <controller id="Plane-morph" name="Plane-morph">
      <morph source="#Plane-mesh" method="NORMALIZED">
        <source id="Plane-targets">
          <IDREF_array id="Plane-targets-array" count="2">Plane-mesh_morph_Key1 Plane-mesh_morph_Key2</IDREF_array>
          <technique_common>
            <accessor source="#Plane-targets-array" count="2" stride="1">
              <param name="IDREF" type="IDREF"/>
            </accessor>
          </technique_common>
        </source>
        <source id="Plane-weights">
          <float_array id="Plane-weights-array" count="2">0 0</float_array>
          <technique_common>
            <accessor source="#Plane-weights-array" count="2" stride="1">
              <param name="MORPH_WEIGHT" type="float"/>
            </accessor>
          </technique_common>
        </source>
        <targets>
          <input semantic="MORPH_TARGET" source="#Plane-targets"/>
          <input semantic="MORPH_WEIGHT" source="#Plane-weights"/>
        </targets>
      </morph>
    </controller>
  </library_controllers>
  <library_visual_scenes>
    <visual_scene id="Scene" name="Scene">
      <node id="Plane" name="Plane" type="NODE">
        <matrix sid="transform">1 0 0 0 0 -4.37114e-8 -1 0 0 1 -4.37114e-8 0 0 0 0 1</matrix>
        <instance_geometry url="#Plane-mesh" name="Plane"/>
      </node>
    </visual_scene>
  </library_visual_scenes>
  <scene>
    <instance_visual_scene url="#Scene"/>
  </scene>
</COLLADA>

任何幫助表示贊賞。 謝謝！

Answer 1

您可以使用entryWithIdentifier：withClass：檢索不在場景圖中的對象。 或者，可以在創作工具中將變形器附加到節點，然后使用節點的morpher屬性檢索其目標幾何。