text: //
  // Copyright (c) 2008-2022 the Urho3D project.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  
  #include "../Precompiled.h"
  
  #include "../Core/Context.h"
  #include "../IO/MemoryBuffer.h"
  #include "../IO/VectorBuffer.h"
  #include "../Physics2D/CollisionChain2D.h"
  #include "../Physics2D/PhysicsUtils2D.h"
  
  #include "../DebugNew.h"
  
  namespace Urho3D
  {
  
  extern const char* PHYSICS2D_CATEGORY;
  
  CollisionChain2D::CollisionChain2D(Context* context) :
      CollisionShape2D(context),
      loop_(false)
  {
      fixtureDef_.shape = &chainShape_;
  }
  
  CollisionChain2D::~CollisionChain2D() = default;
  
  void CollisionChain2D::RegisterObject(Context* context)
  {
      context->RegisterFactory<CollisionChain2D>(PHYSICS2D_CATEGORY);
  
      URHO3D_ACCESSOR_ATTRIBUTE("Is Enabled", IsEnabled, SetEnabled, bool, true, AM_DEFAULT);
      URHO3D_ACCESSOR_ATTRIBUTE("Loop", GetLoop, SetLoop, bool, false, AM_DEFAULT);
      URHO3D_COPY_BASE_ATTRIBUTES(CollisionShape2D);
      URHO3D_MIXED_ACCESSOR_ATTRIBUTE("Vertices", GetVerticesAttr, SetVerticesAttr, PODVector<unsigned char>, Variant::emptyBuffer, AM_FILE);
  }
  
  void CollisionChain2D::SetLoop(bool loop)
  {
      if (loop == loop_)
          return;
  
      loop_ = loop;
  
      MarkNetworkUpdate();
      RecreateFixture();
  }
  
  void CollisionChain2D::SetVertexCount(unsigned count)
  {
      vertices_.Resize(count);
  }
  
  void CollisionChain2D::SetVertex(unsigned index, const Vector2& vertex)
  {
      if (index >= vertices_.Size())
          return;
  
      vertices_[index] = vertex;
  
      if (index == vertices_.Size() - 1)
      {
          MarkNetworkUpdate();
          RecreateFixture();
      }
  }
  
  void CollisionChain2D::SetVertices(const PODVector<Vector2>& vertices)
  {
      vertices_ = vertices;
  
      MarkNetworkUpdate();
      RecreateFixture();
  }
  
  void CollisionChain2D::SetVerticesAttr(const PODVector<unsigned char>& value)
  {
      if (value.Empty())
          return;
  
      PODVector<Vector2> vertices;
  
      MemoryBuffer buffer(value);
      while (!buffer.IsEof())
          vertices.Push(buffer.ReadVector2());
  
      SetVertices(vertices);
  }
  
  PODVector<unsigned char> CollisionChain2D::GetVerticesAttr() const
  {
      VectorBuffer ret;
  
      for (unsigned i = 0; i < vertices_.Size(); ++i)
          ret.WriteVector2(vertices_[i]);
  
      return ret.GetBuffer();
  }
  
  void CollisionChain2D::ApplyNodeWorldScale()
  {
      RecreateFixture();
  }
  
  void CollisionChain2D::RecreateFixture()
  {
      ReleaseFixture();
  
      PODVector<b2Vec2> b2Vertices;
      unsigned count = vertices_.Size();
      b2Vertices.Resize(count);
  
      Vector2 worldScale(cachedWorldScale_.x_, cachedWorldScale_.y_);
      for (unsigned i = 0; i < count; ++i)
          b2Vertices[i] = ToB2Vec2(vertices_[i] * worldScale);
  
      chainShape_.Clear();
      
      if (loop_)
      {
          if (count < 2)
              return;
  
          chainShape_.CreateLoop(&b2Vertices[0], count);
      }
      else
      {
          if (count < 4)
              return;
  
          chainShape_.CreateChain(&b2Vertices[1], count - 2, b2Vertices[0], b2Vertices[count - 1]);
      }
  
      CreateFixture();
  }
  
  }
  