From 6323e27cdca4d3fabc2ee22d78dd7efb23adcadb Mon Sep 17 00:00:00 2001
From: tamasmeszaros <meszaros.q@gmail.com>
Date: Thu, 15 Dec 2022 13:05:02 +0100
Subject: [PATCH] csg voxelization speedup with additional parallelism

---
 src/libslic3r/CSGMesh/VoxelizeCSGMesh.hpp | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/libslic3r/CSGMesh/VoxelizeCSGMesh.hpp b/src/libslic3r/CSGMesh/VoxelizeCSGMesh.hpp
index f1fd73981..0f2e8c898 100644
--- a/src/libslic3r/CSGMesh/VoxelizeCSGMesh.hpp
+++ b/src/libslic3r/CSGMesh/VoxelizeCSGMesh.hpp
@@ -5,6 +5,7 @@
 
 #include "CSGMesh.hpp"
 #include "libslic3r/OpenVDBUtils.hpp"
+#include "libslic3r/Execution/ExecutionTBB.hpp"
 
 namespace Slic3r { namespace csg {
 
@@ -32,11 +33,24 @@ VoxelGridPtr voxelize_csgmesh(const Range<It>      &csgrange,
 {
     VoxelGridPtr ret;
 
+    std::vector<VoxelGridPtr> grids (csgrange.size());
+
+    execution::for_each(ex_tbb, size_t(0), csgrange.size(), [&](size_t csgidx) {
+        if (params.statusfn() && params.statusfn()(-1))
+            return;
+
+        auto it = csgrange.begin();
+        std::advance(it, csgidx);
+        auto &csgpart = *it;
+        grids[csgidx] = get_voxelgrid(csgpart, params);
+    }, execution::max_concurrency(ex_tbb));
+
+    size_t csgidx = 0;
     for (auto &csgpart : csgrange) {
         if (params.statusfn() && params.statusfn()(-1))
             break;
 
-        VoxelGridPtr partgrid = get_voxelgrid(csgpart, params);
+        auto &partgrid = grids[csgidx++];
 
         if (!ret && get_operation(csgpart) == CSGType::Union) {
             ret = std::move(partgrid);