From 0dff8a6618cc3f00353dee93de4f62b0a99d661a Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Fri, 7 Aug 2020 13:06:06 +0200
Subject: [PATCH] Base: [skip ci] add class ViewOrthoProjMatrix for orthogonal
 projections in 3d

---
 src/Base/ViewProj.cpp | 38 ++++++++++++++++++++++++++++++++++++++
 src/Base/ViewProj.h   | 23 +++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/src/Base/ViewProj.cpp b/src/Base/ViewProj.cpp
index bf13085f2072..a5f485713af7 100644
--- a/src/Base/ViewProj.cpp
+++ b/src/Base/ViewProj.cpp
@@ -191,3 +191,41 @@ Vector3d ViewProjMatrix::inverse (const Vector3d& src) const
 
     return dst;
 }
+
+// ----------------------------------------------------------------------------
+
+ViewOrthoProjMatrix::ViewOrthoProjMatrix (const Matrix4D &rclMtx)
+    : _clMtx(rclMtx)
+{
+    _clMtxInv = _clMtx;
+    _clMtxInv.inverse();
+}
+
+ViewOrthoProjMatrix::~ViewOrthoProjMatrix()
+{
+}
+
+Matrix4D ViewOrthoProjMatrix::getProjectionMatrix (void) const
+{
+    return _clMtx;
+}
+
+Vector3f ViewOrthoProjMatrix::operator()(const Vector3f &rclPt) const
+{
+    return Vector3f(_clMtx * rclPt);
+}
+
+Vector3d ViewOrthoProjMatrix::operator()(const Vector3d &rclPt) const
+{
+    return Vector3d(_clMtx * rclPt);
+}
+
+Vector3f ViewOrthoProjMatrix::inverse (const Vector3f &rclPt) const
+{
+    return Vector3f(_clMtxInv * rclPt);
+}
+
+Vector3d ViewOrthoProjMatrix::inverse (const Vector3d &rclPt) const
+{
+    return Vector3d(_clMtxInv * rclPt);
+}
diff --git a/src/Base/ViewProj.h b/src/Base/ViewProj.h
index c0e5935fbda4..15faaf6374c7 100644
--- a/src/Base/ViewProj.h
+++ b/src/Base/ViewProj.h
@@ -88,6 +88,29 @@ class BaseExport ViewProjMatrix : public ViewProjMethod
     Matrix4D _clMtx, _clMtxInv;
 };
 
+/**
+ * The ViewOrthoProjMatrix class returns the result of the multiplication
+ * of the 3D vector and the transformation matrix.
+ * Unlike ViewProjMatrix this class is not supposed to project points onto
+ * a viewport but project points onto a plane in 3D.
+ */
+class BaseExport ViewOrthoProjMatrix : public ViewProjMethod
+{
+public:
+    ViewOrthoProjMatrix (const Matrix4D &rclMtx);
+    virtual ~ViewOrthoProjMatrix();
+
+    Vector3f operator()(const Vector3f &rclPt) const;
+    Vector3d operator()(const Vector3d &rclPt) const;
+    Vector3f inverse (const Vector3f &rclPt) const;
+    Vector3d inverse (const Vector3d &rclPt) const;
+
+    Matrix4D getProjectionMatrix (void) const;
+
+protected:
+    Matrix4D _clMtx, _clMtxInv;
+};
+
 } // namespace Base
 
 #endif // BASE_VIEWPROJ_H