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网孔

2024-5-18 18:38| 发布者: admin| 查看: 294| 评论: 0|原作者: admin|来自: AutoCAD

网孔

网格是存储顶点的参数化矩形网格的有效方法。网格的几何图形按行顺序指定为行数、列数和顶点列表：

virtual Adesk::Boolean
AcGiWorldGeometry::mesh(
    const Adesk::UInt32 rows,
    const Adesk::UInt32 columns,
    const AcGePoint3d*  pVertexList,
    const AcGiEdgeData* pEdgeData = NULL,
    const AcGiFaceData* pFaceData = NULL,
    const AcGiVertexData* pVertexData = NULL) const = 0;

该函数具有三个可选参数，用于将属性数据附加到边、面或顶点。对于网格中的边，可以附加颜色、图层、线型、GS 标记和可见性属性。例如，您可以使用将不同的颜色附加到网格的每个边。在颜色列表中，首先列出所有行边的颜色，然后列出所有列边的颜色。下图显示了示例网格的边属性数据的顺序：mesh()AcGiEdgeData::setColors()

以下示例代码创建网格并使用边数据和人脸数据指定颜色。它构造了一个带有青色行和绿色列的四乘四网格。

      Adesk::Boolean     
      AsdkMeshSamp::subWorldDraw(AcGiWorldDraw* pW)     
 { 
      Adesk::UInt32       i, j, k;     
      Adesk::UInt32       numRows = 4;     
      Adesk::UInt32       numCols = 4;     
      AcGePoint3d       *pVerts =     
      new       AcGePoint3d[numRows * numCols];     
  
      for (k = 0, i =       0; i < numRows; i++) {     
      for (j = 0; j       < numCols; j++, k++) {     
      pVerts[k].x =       (double)j;     
      pVerts[k].y =       (double)i;     
      pVerts[k].z =       0.;     
 } 
 } 
  
      // Construct an       array of colors to be applied to each     
      // edge of the       mesh.  Here, let the rows be cyan and     
      // the columns       be green.     
 // 
      AcGiEdgeData       edgeInfo;     
      Adesk::UInt32       numRowEdges = numRows * (numCols - 1);     
      Adesk::UInt32       numColEdges = (numRows - 1) * numCols;     
      Adesk::UInt32       numEdges = numRowEdges + numColEdges;     
      short       *pEdgeColorArray = new short[numEdges];     
  
      for (i = 0; i       < numEdges; i++) {     
      pEdgeColorArray[i] =     
      i <       numRowEdges ? kCyan : kGreen;     
 } 
      edgeInfo.setColors(pEdgeColorArray);     
  
      // Make the       first face transparent and the rest     
      // different       colors.     
 // 
      Adesk::UInt32       numFaces = (numRows - 1)     
      * (numCols -       1);     
      Adesk::UInt8       *pFaceVisArray =     
      new       Adesk::UInt8[numFaces];     
      short       *pFaceColorArray = new short[numFaces];     
      AcGiFaceData       faceInfo;     
      faceInfo.setVisibility(pFaceVisArray);     
  
      for (i = 0; i       < numFaces; i++) {     
      pFaceVisArray       [i] =     
      i ?       kAcGiVisible : kAcGiInvisible;     
      pFaceColorArray[i] = (short)(i + 1);     
 } 
      faceInfo.setColors(pFaceColorArray);     
  
      // If the fill       type is kAcGiFillAlways, then a shell,     
      // mesh, or       polygon will be interpreted as faces;     
      // otherwise,       they will be interpreted as edges.     
  
      // Output mesh       as faces.     
 // 
      pW-       >subEntityTraits().setFillType(kAcGiFillAlways);     
      pW->geometry       ().mesh(numRows, numCols, pVerts, NULL,     
      &faceInfo);     
  
      // Output mesh       as edges over the faces.     
 // 
      pW-       >subEntityTraits().setFillType(kAcGiFillNever);     
      pW->geometry       ().mesh(numRows, numCols, pVerts,     
      &edgeInfo);     
  
      delete []       pVerts;     
      delete []       pEdgeColorArray;     
      delete []       pFaceColorArray;     
      delete []       pFaceVisArray;     
  
      return       Adesk::kTrue;     
 }

对于网格中的面，可以附着颜色、图层、GS 标记、法线和可见性特征。要为网格中的面指定属性，请按行顺序列出面的值，如下图所示：