From a6f0f69ed664f23ddc73f4f838e199532f293092 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Sun, 13 Feb 2022 12:46:01 +0100
Subject: [PATCH] Mesh: overload MeshAlgorithm::NearestFacetOnRay to set a max.
 angle between facet and ray

---
 src/Mod/Mesh/App/Core/Algorithm.cpp | 14 +++++++++++---
 src/Mod/Mesh/App/Core/Algorithm.h   | 11 +++++++++++
 src/Mod/Mesh/App/MeshPyImp.cpp      |  5 +++--
 3 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/src/Mod/Mesh/App/Core/Algorithm.cpp b/src/Mod/Mesh/App/Core/Algorithm.cpp
index ae277455bcec..8f8f97f13631 100644
--- a/src/Mod/Mesh/App/Core/Algorithm.cpp
+++ b/src/Mod/Mesh/App/Core/Algorithm.cpp
@@ -68,6 +68,12 @@ bool MeshAlgorithm::IsVertexVisible (const Base::Vector3f &rcVertex, const Base:
 
 bool MeshAlgorithm::NearestFacetOnRay (const Base::Vector3f &rclPt, const Base::Vector3f &rclDir, Base::Vector3f &rclRes,
                                        FacetIndex &rulFacet) const
+{
+    return NearestFacetOnRay(rclPt, rclDir, Mathf::PI, rclRes, rulFacet);
+}
+
+bool MeshAlgorithm::NearestFacetOnRay (const Base::Vector3f &rclPt, const Base::Vector3f &rclDir, float fMaxAngle,
+                                       Base::Vector3f &rclRes, FacetIndex &rulFacet) const
 {
     Base::Vector3f clProj, clRes;
     bool bSol = false;
@@ -76,13 +82,15 @@ bool MeshAlgorithm::NearestFacetOnRay (const Base::Vector3f &rclPt, const Base::
     // slow execution with no grid
     MeshFacetIterator  clFIter(_rclMesh);
     for (clFIter.Init(); clFIter.More(); clFIter.Next()) {
-        if (clFIter->Foraminate( rclPt, rclDir, clRes ) == true) {
-            if (bSol == false) { // first solution
+        if (clFIter->Foraminate(rclPt, rclDir, clRes, fMaxAngle)) {
+            if (bSol == false) {
+                // first solution
                 bSol   = true;
                 clProj = clRes;
                 ulInd  = clFIter.Position();
             }
-            else {  // is closer to the point
+            else {
+                // is closer to the point
                 if ((clRes - rclPt).Length() < (clProj - rclPt).Length()) {
                     clProj = clRes;
                     ulInd  = clFIter.Position();
diff --git a/src/Mod/Mesh/App/Core/Algorithm.h b/src/Mod/Mesh/App/Core/Algorithm.h
index 0c35235f0b30..4ab6700ac83b 100644
--- a/src/Mod/Mesh/App/Core/Algorithm.h
+++ b/src/Mod/Mesh/App/Core/Algorithm.h
@@ -71,6 +71,17 @@ class MeshExport MeshAlgorithm
    */
   bool NearestFacetOnRay (const Base::Vector3f &rclPt, const Base::Vector3f &rclDir, Base::Vector3f &rclRes,
                           FacetIndex &rulFacet) const;
+  /**
+   * Searches for the nearest facet to the ray defined by
+   * (\a rclPt, \a rclDir).
+   * The point \a rclRes holds the intersection point with the ray and the
+   * nearest facet with index \a rulFacet. The angle between the ray and the normal of the triangle
+   * must be less than or equal to \a fMaxAngle.
+   * \note This method tests all facets so it should only be used
+   * occasionally.
+   */
+  bool NearestFacetOnRay (const Base::Vector3f &rclPt, const Base::Vector3f &rclDir, float fMaxAngle, Base::Vector3f &rclRes,
+                          FacetIndex &rulFacet) const;
   /**
    * Searches for the nearest facet to the ray defined by
    * (\a rclPt, \a rclDir).
diff --git a/src/Mod/Mesh/App/MeshPyImp.cpp b/src/Mod/Mesh/App/MeshPyImp.cpp
index a6c4f6f39404..5b48dbc043f2 100644
--- a/src/Mod/Mesh/App/MeshPyImp.cpp
+++ b/src/Mod/Mesh/App/MeshPyImp.cpp
@@ -1830,7 +1830,8 @@ PyObject* MeshPy::nearestFacetOnRay(PyObject *args)
 {
     PyObject* pnt_p;
     PyObject* dir_p;
-    if (!PyArg_ParseTuple(args, "OO", &pnt_p, &dir_p))
+    double maxAngle = MeshCore::Mathd::PI;
+    if (!PyArg_ParseTuple(args, "OO|d", &pnt_p, &dir_p, &maxAngle))
         return nullptr;
 
     try {
@@ -1854,7 +1855,7 @@ PyObject* MeshPy::nearestFacetOnRay(PyObject *args)
         if (alg.NearestFacetOnRay(pnt,  dir, grid, res, index) ||
             alg.NearestFacetOnRay(pnt, -dir, grid, res, index)) {
 #else
-        if (alg.NearestFacetOnRay(pnt, dir, res, index)) {
+        if (alg.NearestFacetOnRay(pnt, dir, static_cast<float>(maxAngle), res, index)) {
 #endif
             Py::Tuple tuple(3);
             tuple.setItem(0, Py::Float(res.x));