Review fixes.

Conflicts:
	drape/overlay_handle.cpp
	drape/overlay_handle.hpp
	drape/overlay_tree.cpp
	drape/shaders/text_billboard_vertex_shader.vsh
	drape_frontend/gui/shape.cpp
	drape_frontend/path_text_shape.cpp

2 files changed, 41 insertions, 20 deletions

diff --git a/geometry/screenbase.cpp b/geometry/screenbase.cpp
index f9d928149e..7b1cad54d6 100644
--- a/geometry/screenbase.cpp
+++ b/geometry/screenbase.cpp
@@ -250,41 +250,46 @@ void ScreenBase::ExtractGtoPParams(MatrixT const & m,
   dy = m(2, 1);
 }
 
-void ScreenBase::ApplyPerspective(double angleX, double fov)
+// Place the camera at the distance, where it gives the same view of plane as the
+// orthogonal projection does and rotate the map plane around its near horizontal side.
+// Calculate expanded area of visible map plane.
+void ScreenBase::ApplyPerspective(double rotationAngle, double angleFOV)
 {
   m_isPerspective = true;
 
-  m_3dAngleX = -angleX;
-  m_3dFOV = fov;
+  m_3dAngleX = rotationAngle;
+  m_3dFOV = angleFOV;
 
-  double halfFOV = m_3dFOV / 2.0;
-  double cameraZ = 1.0 / tan(halfFOV);
+  double const halfFOV = m_3dFOV / 2.0;
+  double const cameraZ = 1.0 / tan(halfFOV);
 
+  // Ratio of the expanded plane's size to the original size.
   m_3dScaleY = cos(m_3dAngleX) + sin(m_3dAngleX) * tan(halfFOV + m_3dAngleX);
   m_3dScaleX = 1.0 + 2 * sin(m_3dAngleX) * cos(halfFOV) / (cameraZ * cos(halfFOV + m_3dAngleX));
 
   m_3dScaleX = m_3dScaleY = max(m_3dScaleX, m_3dScaleY);
 
-  double offsetZ = cameraZ + sin(m_3dAngleX) * m_3dScaleY;
-  double offsetY = cos(m_3dAngleX) * m_3dScaleX - 1.0;
+  double const offsetZ = cameraZ + sin(m_3dAngleX) * m_3dScaleY;
+  double const offsetY = cos(m_3dAngleX) * m_3dScaleX - 1.0;
 
   Matrix3dT scaleM = math::Identity<double, 4>();
   scaleM(0, 0) = m_3dScaleX;
   scaleM(1, 1) = m_3dScaleY;
 
   Matrix3dT rotateM = math::Identity<double, 4>();
-  rotateM(1, 1) = cos(angleX);
-  rotateM(1, 2) = -sin(angleX);
-  rotateM(2, 1) = sin(angleX);
-  rotateM(2, 2) = cos(angleX);
+  rotateM(1, 1) = cos(m_3dAngleX);
+  rotateM(1, 2) = sin(m_3dAngleX);
+  rotateM(2, 1) = -sin(m_3dAngleX);
+  rotateM(2, 2) = cos(m_3dAngleX);
 
   Matrix3dT translateM = math::Identity<double, 4>();
   translateM(3, 1) = offsetY;
   translateM(3, 2) = offsetZ;
 
   Matrix3dT projectionM = math::Zero<double, 4>();
-  double near = 0.1;
-  double far = 100.0;
+  // TODO: Calculate near and far values.
+  double const near = 0.1;
+  double const far = 100.0;
   projectionM(0, 0) = projectionM(1, 1) = cameraZ;
   projectionM(2, 2) = (far + near) / (far - near);
   projectionM(2, 3) = 1.0;
@@ -292,7 +297,7 @@ void ScreenBase::ApplyPerspective(double angleX, double fov)
 
   m_Pto3d = scaleM * rotateM * translateM * projectionM;
 
-  double dyG = m_GlobalRect.GetLocalRect().SizeY() * (m_3dScaleX - 1.0);
+  double const dyG = m_GlobalRect.GetLocalRect().SizeY() * (m_3dScaleX - 1.0);
   Scale(1.0 / m_3dScaleX);
 
   MoveG(m2::PointD(0, -dyG / 2.0));
@@ -306,7 +311,7 @@ void ScreenBase::ResetPerspective()
 {
   m_isPerspective = false;
 
-  double dyG = m_GlobalRect.GetLocalRect().SizeY() * (1.0 - 1.0 / m_3dScaleX);
+  double const dyG = m_GlobalRect.GetLocalRect().SizeY() * (1.0 - 1.0 / m_3dScaleX);
   Scale(m_3dScaleX);
 
   MoveG(m2::PointD(0, dyG / 2.0));
@@ -315,3 +320,17 @@ void ScreenBase::ResetPerspective()
 
   Scale(1.0 / m_3dScaleX);
 }
+
+m2::PointD ScreenBase::PtoP3d(m2::PointD const & pt) const
+{
+  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;
+
+  m2::RectD const viewport = PixelRectIn3d();
+  m2::PointD const pixelPointPerspective(
+      (perspectivePoint(0, 0) / perspectivePoint(0, 3) + 1.0) * viewport.SizeX() / 2.0,
+      (perspectivePoint(0, 1) / perspectivePoint(0, 3) + 1.0) * viewport.SizeY() / 2.0);
+
+  return pixelPointPerspective;
+}
diff --git a/geometry/screenbase.hpp b/geometry/screenbase.hpp
index d666c25922..49a9462206 100644
--- a/geometry/screenbase.hpp
+++ b/geometry/screenbase.hpp
@@ -10,8 +10,9 @@
 class ScreenBase
 {
 public:
-  typedef math::Matrix<double, 3, 3> MatrixT;
-  typedef math::Matrix<double, 4, 4> Matrix3dT;
+  using MatrixT = math::Matrix<double, 3, 3>;
+  using Matrix3dT = math::Matrix<double, 4, 4>;
+  using Vector3dT = math::Matrix<double, 1, 4>;
 
 private:
   m2::RectD m_PixelRect;
@@ -121,14 +122,15 @@ public:
   m2::AnyRectD const & GlobalRect() const { return m_GlobalRect; }
   m2::RectD const & ClipRect() const { return m_ClipRect; }
 
-  void ApplyPerspective(double angleX, double fov);
+  void ApplyPerspective(double rotationAngle, double angleFOV);
   void ResetPerspective();
 
   Matrix3dT const & PTo3dMatrix() const { return m_Pto3d; }
   bool isPerspective() const { return m_isPerspective; }
 
-  // TODO: temporary function
-  m2::RectD PixelRect3d() const
+  m2::PointD PtoP3d(m2::PointD const & pt) const;
+
+  m2::RectD PixelRectIn3d() const
   {
     return m2::RectD(0.0, 0.0, m_PixelRect.maxX() / m_3dScaleX, m_PixelRect.maxY() / m_3dScaleY);
   }