From 46d746c9daeb413d4b673258c2efeeb0bd8f704b Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Tue, 1 Jun 2021 22:07:52 +0100
Subject: [PATCH] Performance optimizations.

---
 libs/kimath/include/geometry/seg.h            |  5 ++
 libs/kimath/src/geometry/seg.cpp              | 69 ++++++++++++-------
 libs/kimath/src/geometry/shape_line_chain.cpp |  2 +-
 3 files changed, 49 insertions(+), 27 deletions(-)

diff --git a/libs/kimath/include/geometry/seg.h b/libs/kimath/include/geometry/seg.h
index ef74bfeed3..323b198546 100644
--- a/libs/kimath/include/geometry/seg.h
+++ b/libs/kimath/include/geometry/seg.h
@@ -199,6 +199,8 @@ public:
     OPT_VECTOR2I Intersect( const SEG& aSeg, bool aIgnoreEndpoints = false,
                             bool aLines = false ) const;
 
+    bool Intersects( const SEG& aSeg ) const;
+
     /**
      * Compute the intersection point of lines passing through ends of (this) and \a aSeg.
      *
@@ -396,6 +398,9 @@ public:
 private:
     bool ccw( const VECTOR2I& aA, const VECTOR2I& aB, const VECTOR2I &aC ) const;
 
+    bool intersects( const SEG& aSeg, bool aIgnoreEndpoints = false, bool aLines = false,
+                     VECTOR2I* aPt = nullptr ) const;
+
 private:
     ///< index withing the parent shape (used when m_is_local == false)
     int m_index;
diff --git a/libs/kimath/src/geometry/seg.cpp b/libs/kimath/src/geometry/seg.cpp
index 3b0acef60a..f875b70fdc 100644
--- a/libs/kimath/src/geometry/seg.cpp
+++ b/libs/kimath/src/geometry/seg.cpp
@@ -38,8 +38,7 @@ int sgn( T aVal )
 
 SEG::ecoord SEG::SquaredDistance( const SEG& aSeg ) const
 {
-    // fixme: rather inefficient....
-    if( Intersect( aSeg ) )
+    if( Intersects( aSeg ) )
         return 0;
 
     const VECTOR2I pts[4] =
@@ -53,9 +52,7 @@ SEG::ecoord SEG::SquaredDistance( const SEG& aSeg ) const
     ecoord m = VECTOR2I::ECOORD_MAX;
 
     for( int i = 0; i < 4; i++ )
-    {
         m = std::min( m, pts[i].SquaredEuclideanNorm() );
-    }
 
     return m;
 }
@@ -81,27 +78,27 @@ const VECTOR2I SEG::NearestPoint( const SEG& aSeg ) const
 
     const VECTOR2I pts_origin[4] =
     {
-            aSeg.NearestPoint( A ),
-            aSeg.NearestPoint( B ),
-            NearestPoint( aSeg.A ),
-            NearestPoint( aSeg.B )
+        aSeg.NearestPoint( A ),
+        aSeg.NearestPoint( B ),
+        NearestPoint( aSeg.A ),
+        NearestPoint( aSeg.B )
     };
 
 
     const VECTOR2I* pts_out[4] =
     {
-            &A,
-            &B,
-            &pts_origin[2],
-            &pts_origin[3]
+        &A,
+        &B,
+        &pts_origin[2],
+        &pts_origin[3]
     };
 
     const ecoord pts_dist[4] =
     {
-            ( pts_origin[0] - A ).SquaredEuclideanNorm(),
-            ( pts_origin[1] - B ).SquaredEuclideanNorm(),
-            ( pts_origin[2] - aSeg.A ).SquaredEuclideanNorm(),
-            ( pts_origin[3] - aSeg.B ).SquaredEuclideanNorm()
+        ( pts_origin[0] - A ).SquaredEuclideanNorm(),
+        ( pts_origin[1] - B ).SquaredEuclideanNorm(),
+        ( pts_origin[2] - aSeg.A ).SquaredEuclideanNorm(),
+        ( pts_origin[3] - aSeg.B ).SquaredEuclideanNorm()
     };
 
     int min_i = 0;
@@ -116,7 +113,7 @@ const VECTOR2I SEG::NearestPoint( const SEG& aSeg ) const
 }
 
 
-OPT_VECTOR2I SEG::Intersect( const SEG& aSeg, bool aIgnoreEndpoints, bool aLines ) const
+bool SEG::intersects( const SEG& aSeg, bool aIgnoreEndpoints, bool aLines, VECTOR2I* aPt ) const
 {
     const VECTOR2I  e( B - A );
     const VECTOR2I  f( aSeg.B - aSeg.A );
@@ -127,21 +124,41 @@ OPT_VECTOR2I SEG::Intersect( const SEG& aSeg, bool aIgnoreEndpoints, bool aLines
     ecoord q = e.Cross( ac );
 
     if( d == 0 )
-        return OPT_VECTOR2I();
+        return false;
 
     if( !aLines && d > 0 && ( q < 0 || q > d || p < 0 || p > d ) )
-        return OPT_VECTOR2I();
+        return false;
 
     if( !aLines && d < 0 && ( q < d || p < d || p > 0 || q > 0 ) )
-        return OPT_VECTOR2I();
+        return false;
 
     if( !aLines && aIgnoreEndpoints && ( q == 0 || q == d ) && ( p == 0 || p == d ) )
+        return false;
+
+    if( aPt )
+    {
+        *aPt = VECTOR2I( aSeg.A.x + rescale( q, (ecoord) f.x, d ),
+                         aSeg.A.y + rescale( q, (ecoord) f.y, d ) );
+    }
+
+    return true;
+}
+
+
+bool SEG::Intersects( const SEG& aSeg ) const
+{
+    return intersects( aSeg );
+}
+
+
+OPT_VECTOR2I SEG::Intersect( const SEG& aSeg, bool aIgnoreEndpoints, bool aLines ) const
+{
+    VECTOR2I ip;
+
+    if( intersects( aSeg, aIgnoreEndpoints, aLines, &ip ) )
+        return ip;
+    else
         return OPT_VECTOR2I();
-
-    VECTOR2I ip( aSeg.A.x + rescale( q, (ecoord) f.x, d ),
-                 aSeg.A.y + rescale( q, (ecoord) f.y, d ) );
-
-     return ip;
 }
 
 
@@ -203,5 +220,5 @@ bool SEG::Collide( const SEG& aSeg, int aClearance, int* aActual ) const
 
 bool SEG::Contains( const VECTOR2I& aP ) const
 {
-    return Distance( aP ) <= 1;       // 1 * 1 to be pedantic
+    return Distance( aP ) <= 1;
 }
diff --git a/libs/kimath/src/geometry/shape_line_chain.cpp b/libs/kimath/src/geometry/shape_line_chain.cpp
index 1b96e444a3..a6e43a6e86 100644
--- a/libs/kimath/src/geometry/shape_line_chain.cpp
+++ b/libs/kimath/src/geometry/shape_line_chain.cpp
@@ -173,7 +173,7 @@ bool SHAPE_LINE_CHAIN_BASE::Collide( const SEG& aSeg, int aClearance, int* aActu
     for( size_t i = 0; i < GetSegmentCount(); i++ )
     {
         const SEG& s = GetSegment( i );
-        SEG::ecoord dist_sq =s.SquaredDistance( aSeg );
+        SEG::ecoord dist_sq = s.SquaredDistance( aSeg );
 
         if( dist_sq < closest_dist_sq )
         {