Improved displacement algorithm and overlays rendering

2 files changed, 14 insertions, 0 deletions

diff --git a/geometry/screenbase.cpp b/geometry/screenbase.cpp
index c00f882b86..b46a6da78c 100644
--- a/geometry/screenbase.cpp
+++ b/geometry/screenbase.cpp
@@ -411,3 +411,15 @@ m2::PointD ScreenBase::P3dtoP(m2::PointD const & pt) const
 
   return pixelPointOriginal;
 }
+
+bool ScreenBase::IsReverseProjection3d(m2::PointD const & pt) const
+{
+  if (!m_isPerspective)
+    return false;
+
+  Vector3dT const normalizedPoint{float(2.0 * pt.x / m_PixelRect.SizeX() - 1.0),
+                                  -float(2.0 * pt.y / m_PixelRect.SizeY() - 1.0), 0.0, 1.0};
+
+  Vector3dT const perspectivePoint = normalizedPoint * m_Pto3d;
+  return perspectivePoint(0, 3) < 0.0;
+}
diff --git a/geometry/screenbase.hpp b/geometry/screenbase.hpp
index 016feab973..93959d9998 100644
--- a/geometry/screenbase.hpp
+++ b/geometry/screenbase.hpp
@@ -139,6 +139,8 @@ public:
   Matrix3dT const & Pto3dMatrix() const { return m_Pto3d; }
   bool isPerspective() const { return m_isPerspective; }
 
+  bool IsReverseProjection3d(m2::PointD const & pt) const;
+
   m2::PointD PtoP3d(m2::PointD const & pt) const;
   m2::PointD PtoP3d(m2::PointD const & pt, double ptZ) const;