From b208cd8cae138bfc84809704093c715e4d7bc506 Mon Sep 17 00:00:00 2001
From: phkahler <14852918+phkahler@users.noreply.github.com>
Date: Sun, 6 Sep 2020 10:39:37 -0400
Subject: [PATCH] NFC, Performance: Use OpenMP for boolean function
 MakeItersectionCurvesAgainst.

This is the last long-running single-threaded part of the boolean code. On one test model this took Regenerate form 27 seconds down to 18s. The critical sections needed a name (into) because that object must not be modified while in use in different places.
---
 src/srf/boolean.cpp   |  6 ++++--
 src/srf/surfinter.cpp | 35 ++++++++++++++++++++++-------------
 2 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/src/srf/boolean.cpp b/src/srf/boolean.cpp
index 6c2443e1..b0b175da 100644
--- a/src/srf/boolean.cpp
+++ b/src/srf/boolean.cpp
@@ -640,8 +640,10 @@ void SShell::CopySurfacesTrimAgainst(SShell *sha, SShell *shb, SShell *into, SSu
 }
 
 void SShell::MakeIntersectionCurvesAgainst(SShell *agnst, SShell *into) {
-    SSurface *sa;
-    for(sa = surface.First(); sa; sa = surface.NextAfter(sa)) {
+#pragma omp parallel for
+    for(int i = 0; i< surface.n; i++) {
+        SSurface *sa = &surface[i];
+
         SSurface *sb;
         for(sb = agnst->surface.First(); sb; sb = agnst->surface.NextAfter(sb)){
             // Intersect every surface from our shell against every surface
diff --git a/src/srf/surfinter.cpp b/src/srf/surfinter.cpp
index 0a2f09c0..ddcbad23 100644
--- a/src/srf/surfinter.cpp
+++ b/src/srf/surfinter.cpp
@@ -27,19 +27,22 @@ void SSurface::AddExactIntersectionCurve(SBezier *sb, SSurface *srfB,
     SBezier sbrev = *sb;
     sbrev.Reverse();
     bool backwards = false;
-    for(se = into->curve.First(); se; se = into->curve.NextAfter(se)) {
-        if(se->isExact) {
-            if(sb->Equals(&(se->exact))) {
-                existing = se;
-                break;
-            }
-            if(sbrev.Equals(&(se->exact))) {
-                existing = se;
-                backwards = true;
-                break;
+#pragma omp critical(into)
+    {
+        for(se = into->curve.First(); se; se = into->curve.NextAfter(se)) {
+            if(se->isExact) {
+                if(sb->Equals(&(se->exact))) {
+                    existing = se;
+                    break;
+                }
+                if(sbrev.Equals(&(se->exact))) {
+                    existing = se;
+                    backwards = true;
+                    break;
+                }
             }
         }
-    }
+    }// end omp critical
     if(existing) {
         SCurvePt *v;
         for(v = existing->pts.First(); v; v = existing->pts.NextAfter(v)) {
@@ -101,7 +104,10 @@ void SSurface::AddExactIntersectionCurve(SBezier *sb, SSurface *srfB,
              "Unexpected zero-length edge");
 
     split.source = SCurve::Source::INTERSECTION;
-    into->curve.AddAndAssignId(&split);
+#pragma omp critical(into)
+    {
+        into->curve.AddAndAssignId(&split);
+    }
 }
 
 void SSurface::IntersectAgainst(SSurface *b, SShell *agnstA, SShell *agnstB,
@@ -456,7 +462,10 @@ void SSurface::IntersectAgainst(SSurface *b, SShell *agnstA, SShell *agnstB,
             // And now we split and insert the curve
             SCurve split = sc.MakeCopySplitAgainst(agnstA, agnstB, this, b);
             sc.Clear();
-            into->curve.AddAndAssignId(&split);
+#pragma omp critical(into)
+            {
+                into->curve.AddAndAssignId(&split);
+            }
         }
         spl.Clear();
     }