text: // MIT License
  
  // Copyright (c) 2019 Erin Catto
  
  // 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 "test.h"
  #include "box2d/b2_distance.h"
  
  class DistanceTest : public Test
  {
  public:
    DistanceTest()
    {
      {
        m_transformA.SetIdentity();
        m_transformA.p.Set(0.0f, -0.2f);
        m_polygonA.SetAsBox(10.0f, 0.2f);
      }
  
      {
        m_positionB.Set(12.017401f, 0.13678508f);
        m_angleB = -0.0109265f;
        m_transformB.Set(m_positionB, m_angleB);
  
        m_polygonB.SetAsBox(2.0f, 0.1f);
      }
    }
  
    static Test* Create()
    {
      return new DistanceTest;
    }
  
    void Step(Settings& settings) override
    {
      Test::Step(settings);
  
      b2DistanceInput input;
      input.proxyA.Set(&m_polygonA);
      input.proxyB.Set(&m_polygonB);
      input.transformA = m_transformA;
      input.transformB = m_transformB;
      input.useRadii = true;
      b2SimplexCache cache;
      cache.count = 0;
      b2DistanceOutput output;
      b2Distance(&output, &cache, &input);
  
      g_debugDraw.DrawString(5, m_textLine, "distance = %g", output.distance);
      m_textLine += m_textIncrement;
  
      g_debugDraw.DrawString(5, m_textLine, "iterations = %d", output.iterations);
      m_textLine += m_textIncrement;
  
      {
        b2Color color(0.9f, 0.9f, 0.9f);
        b2Vec2 v[b2_maxPolygonVertices];
        for (int32 i = 0; i < m_polygonA.m_count; ++i)
        {
          v[i] = b2Mul(m_transformA, m_polygonA.m_vertices[i]);
        }
        g_debugDraw.DrawPolygon(v, m_polygonA.m_count, color);
  
        for (int32 i = 0; i < m_polygonB.m_count; ++i)
        {
          v[i] = b2Mul(m_transformB, m_polygonB.m_vertices[i]);
        }
        g_debugDraw.DrawPolygon(v, m_polygonB.m_count, color);
      }
  
      b2Vec2 x1 = output.pointA;
      b2Vec2 x2 = output.pointB;
  
      b2Color c1(1.0f, 0.0f, 0.0f);
      g_debugDraw.DrawPoint(x1, 4.0f, c1);
  
      b2Color c2(1.0f, 1.0f, 0.0f);
      g_debugDraw.DrawPoint(x2, 4.0f, c2);
    }
  
    void Keyboard(int key) override
    {
      switch (key)
      {
      case GLFW_KEY_A:
        m_positionB.x -= 0.1f;
        break;
  
      case GLFW_KEY_D:
        m_positionB.x += 0.1f;
        break;
  
      case GLFW_KEY_S:
        m_positionB.y -= 0.1f;
        break;
  
      case GLFW_KEY_W:
        m_positionB.y += 0.1f;
        break;
  
      case GLFW_KEY_Q:
        m_angleB += 0.1f * b2_pi;
        break;
  
      case GLFW_KEY_E:
        m_angleB -= 0.1f * b2_pi;
        break;
      }
  
      m_transformB.Set(m_positionB, m_angleB);
    }
  
    b2Vec2 m_positionB;
    float m_angleB;
  
    b2Transform m_transformA;
    b2Transform m_transformB;
    b2PolygonShape m_polygonA;
    b2PolygonShape m_polygonB;
  };
  
  static int testIndex = RegisterTest("Geometry", "Distance Test", DistanceTest::Create);
  