text: /********************************************************************************
  * ReactPhysics3D physics library, http://www.reactphysics3d.com                 *
  * Copyright (c) 2010-2022 Daniel Chappuis                                       *
  *********************************************************************************
  *                                                                               *
  * This software is provided 'as-is', without any express or implied warranty.   *
  * In no event will the authors be held liable for any damages arising from the  *
  * use of this software.                                                         *
  *                                                                               *
  * Permission is granted to anyone to use this software for any purpose,         *
  * including commercial applications, and to alter it and redistribute it        *
  * freely, subject to the following restrictions:                                *
  *                                                                               *
  * 1. The origin of this software must not be misrepresented; you must not claim *
  *    that you wrote the original software. If you use this software in a        *
  *    product, an acknowledgment in the product documentation would be           *
  *    appreciated but is not required.                                           *
  *                                                                               *
  * 2. Altered source versions must be plainly marked as such, and must not be    *
  *    misrepresented as being the original software.                             *
  *                                                                               *
  * 3. This notice may not be removed or altered from any source distribution.    *
  *                                                                               *
  ********************************************************************************/
  
  // Libraries
  #include <reactphysics3d/collision/PolygonVertexArray.h>
  
  using namespace reactphysics3d;
  
  // Constructor
  /// Note that your data will not be copied into the PolygonVertexArray and
  /// therefore, you need to make sure that those data are always valid during
  /// the lifetime of the PolygonVertexArray.
  /**
   * @param nbVertices Number of vertices in the array
   * @param verticesStart Pointer to the start of the vertices data
   * @param verticesStride The number of bytes between two consecutive vertices in the array
   * @param indexesStart Pointer to the start of the face indices data
   * @param indexesStride The number of bytes between two consecutive face indices in the array
   * @param nbFaces The number of faces in the array
   * @param nbFaces Pointer to the start of the faces data
   * @param vertexDataType Data type of the vertices data
   * @param indexDataType Data type of the face indices data
   */
  PolygonVertexArray::PolygonVertexArray(uint32 nbVertices, const void* verticesStart, uint32 verticesStride,
                                         const void* indexesStart, uint32 indexesStride,
                                         uint32 nbFaces, PolygonFace* facesStart,
                                         VertexDataType vertexDataType, IndexDataType indexDataType) {
      mNbVertices = nbVertices;
      mVerticesStart = reinterpret_cast<const unsigned char*>(verticesStart);
      mVerticesStride = verticesStride;
      mIndicesStart = reinterpret_cast<const unsigned char*>(indexesStart);
      mIndicesStride = indexesStride;
      mNbFaces = nbFaces;
      mPolygonFacesStart = facesStart;
      mVertexDataType = vertexDataType;
      mIndexDataType = indexDataType;
  }
  
  // Return the vertex index of a given vertex in a face
  /**
   * @return The index of a vertex (in the array of vertices data) of a given vertex in a face
   */
  uint32 PolygonVertexArray::getVertexIndexInFace(uint32 faceIndex32, uint32 noVertexInFace) const {
  
      assert(faceIndex32 < mNbFaces);
  
      // Get the face
      PolygonFace* face = getPolygonFace(faceIndex32);
  
      assert(noVertexInFace < face->nbVertices);
  
      const void* vertexIndexPointer = mIndicesStart + (face->indexBase + noVertexInFace) * mIndicesStride;
  
      if (mIndexDataType == PolygonVertexArray::IndexDataType::INDEX_INTEGER_TYPE) {
          return *((uint*)vertexIndexPointer);
      }
      else if (mIndexDataType == PolygonVertexArray::IndexDataType::INDEX_SHORT_TYPE) {
          return *((unsigned short*)vertexIndexPointer);
      }
      else {
          assert(false);
      }
  
      return 0;
  }
  