From e0e6afb76604f89ceb68582876addeb2f23e6ca3 Mon Sep 17 00:00:00 2001
From: Hans Goudey <h.goudey@me.com>
Date: Mon, 16 Jan 2023 13:14:03 -0600
Subject: [PATCH] Geometry Nodes: Parallelize mesh and curve edit hint
 transformation

Previously transforming and translating meshes (used by the object info
and transform geometry nodes) was single threaded. Now use the same
code path as other geometry types which already includes multithreading.

I observed a 5x performance improvement for a 4 million vert mesh on a
Ryzen 7950x.
---
 .../nodes/node_geo_transform_geometry.cc      | 23 ++++++++++---------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/source/blender/nodes/geometry/nodes/node_geo_transform_geometry.cc b/source/blender/nodes/geometry/nodes/node_geo_transform_geometry.cc
index 425546c3406..281ffc768ef 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_transform_geometry.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_transform_geometry.cc
@@ -55,13 +55,15 @@ static void transform_positions(MutableSpan<float3> positions, const float4x4 &m
 static void translate_mesh(Mesh &mesh, const float3 translation)
 {
   if (!math::is_zero(translation)) {
-    BKE_mesh_translate(&mesh, translation, false);
+    translate_positions(mesh.vert_positions_for_write(), translation);
+    BKE_mesh_tag_coords_changed_uniformly(&mesh);
   }
 }
 
 static void transform_mesh(Mesh &mesh, const float4x4 &transform)
 {
-  BKE_mesh_transform(&mesh, transform.values, false);
+  transform_positions(mesh.vert_positions_for_write(), transform);
+  BKE_mesh_tag_coords_changed(&mesh);
 }
 
 static void translate_pointcloud(PointCloud &pointcloud, const float3 translation)
@@ -162,16 +164,17 @@ static void translate_volume(GeoNodeExecParams &params,
 static void transform_curve_edit_hints(bke::CurvesEditHints &edit_hints, const float4x4 &transform)
 {
   if (edit_hints.positions.has_value()) {
-    for (float3 &pos : *edit_hints.positions) {
-      pos = transform * pos;
-    }
+    transform_positions(*edit_hints.positions, transform);
   }
   float3x3 deform_mat;
   copy_m3_m4(deform_mat.values, transform.values);
   if (edit_hints.deform_mats.has_value()) {
-    for (float3x3 &mat : *edit_hints.deform_mats) {
-      mat = deform_mat * mat;
-    }
+    MutableSpan<float3x3> deform_mats = *edit_hints.deform_mats;
+    threading::parallel_for(deform_mats.index_range(), 1024, [&](const IndexRange range) {
+      for (const int64_t i : range) {
+        deform_mats[i] = deform_mat * deform_mats[i];
+      }
+    });
   }
   else {
     edit_hints.deform_mats.emplace(edit_hints.curves_id_orig.geometry.point_num, deform_mat);
@@ -181,9 +184,7 @@ static void transform_curve_edit_hints(bke::CurvesEditHints &edit_hints, const f
 static void translate_curve_edit_hints(bke::CurvesEditHints &edit_hints, const float3 &translation)
 {
   if (edit_hints.positions.has_value()) {
-    for (float3 &pos : *edit_hints.positions) {
-      pos += translation;
-    }
+    translate_positions(*edit_hints.positions, translation);
   }
 }