From ff7f8a1542c8291fc8f67de6241c5c802e39bc2e Mon Sep 17 00:00:00 2001
From: Eric Wasylishen <ewasylishen@gmail.com>
Date: Mon, 23 Aug 2021 00:10:11 -0600
Subject: [PATCH] qbsp: add -nothreads debug option

---
 include/qbsp/qbsp.hh |  4 +++-
 qbsp/qbsp.cc         | 12 ++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/qbsp/qbsp.hh b/include/qbsp/qbsp.hh
index eff7c070..502b25c4 100644
--- a/include/qbsp/qbsp.hh
+++ b/include/qbsp/qbsp.hh
@@ -391,6 +391,7 @@ public:
     bool fLeakTest;
     bool fContentHack;
     vec_t worldExtent;
+    bool fNoThreads;
 
     options_t() :
     fNofill(false),
@@ -432,7 +433,8 @@ public:
     fTestExpand(false),
     fLeakTest(false),
     fContentHack(false),
-    worldExtent(65536.0f) {}
+    worldExtent(65536.0f),
+    fNoThreads(false) {}
 };
 
 extern options_t options;
diff --git a/qbsp/qbsp.cc b/qbsp/qbsp.cc
index 875968f9..33abd4cd 100644
--- a/qbsp/qbsp.cc
+++ b/qbsp/qbsp.cc
@@ -19,12 +19,15 @@
     See file, 'COPYING', for details.
 */
 
+#include <memory>
 #include <string.h>
 
 #include <common/log.hh>
 #include <qbsp/qbsp.hh>
 #include <qbsp/wad.hh>
 
+#include "tbb/global_control.h"
+
 static const char *IntroString =
     "---- qbsp / ericw-tools " stringify(ERICWTOOLS_VERSION) " ----\n";
 
@@ -714,6 +717,7 @@ PrintOptions(void)
            "   -expand         Write hull 1 expanded brushes to expanded.map for debugging\n"
            "   -leaktest       Make compilation fail if the map leaks\n"
            "   -contenthack    Hack to fix leaks through solids. Causes missing faces in some cases so disabled by default.\n"
+           "   -nothreads      Disable multithreading\n"
            "   sourcefile      .MAP file to process\n"
            "   destfile        .BSP file to output\n");
 
@@ -944,6 +948,8 @@ ParseOptions(char *szOptions)
                 options.fLeakTest = true;
             } else if (!Q_strcasecmp(szTok, "contenthack")) {
                 options.fContentHack = true;
+            } else if (!Q_strcasecmp(szTok, "nothreads")) {
+                options.fNoThreads = true;
             } else if (!Q_strcasecmp(szTok, "?") || !Q_strcasecmp(szTok, "help"))
                 PrintOptions();
             else
@@ -1064,6 +1070,12 @@ int qbsp_main(int argc, const char **argv)
 
     InitQBSP(argc, argv);
 
+    // disable TBB if requested
+    auto tbbOptions = std::unique_ptr<tbb::global_control>();
+    if (options.fNoThreads) {
+        tbbOptions = std::make_unique<tbb::global_control>(tbb::global_control::max_allowed_parallelism, 1);
+    }
+
     // do it!
     start = I_FloatTime();
     ProcessFile();