Function ConstructLineSegments

libs/drape_frontend/line_shape_helper.cpp:84–115

}

void ConstructLineSegments(std::vector<m2::PointD> const & path, std::vector<glsl::vec4> const & segmentsColors,
                           std::vector<LineSegment> & segments)
{
  ASSERT_LESS(1, path.size(), ());

  if (!segmentsColors.empty())
    ASSERT_EQUAL(segmentsColors.size() + 1, path.size(), ());

  m2::PointD prevPoint = path[0];
  for (size_t i = 1; i < path.size(); ++i)
  {
    m2::PointF const p1 = m2::PointF(prevPoint.x, prevPoint.y);
    m2::PointF const p2 = m2::PointF(path[i].x, path[i].y);
    if (p1.EqualDxDy(p2, 1.0E-5))
      continue;

    // Important! Do emplace_back first and fill parameters later.
    // Fill parameters first and push_back later will cause ugly bug in clang 3.6 -O3 optimization.
    segments.emplace_back(glsl::ToVec2(p1), glsl::ToVec2(p2));
    LineSegment & segment = segments.back();

    CalculateTangentAndNormals(glsl::ToVec2(p1), glsl::ToVec2(p2), segment.m_tangent, segment.m_leftBaseNormal,
                               segment.m_rightBaseNormal);

    segment.m_leftNormals[StartPoint] = segment.m_leftNormals[EndPoint] = segment.m_leftBaseNormal;
    segment.m_rightNormals[StartPoint] = segment.m_rightNormals[EndPoint] = segment.m_rightBaseNormal;
    if (!segmentsColors.empty())
      segment.m_color = segmentsColors[i - 1];

    prevPoint = path[i];
  }
}

void UpdateNormals(LineSegment * segment, LineSegment * prevSegment, LineSegment * nextSegment)
{