Speedup exact boolean by avoiding some mallocs and frees.

This is from patch D11432 from Erik Abrahamsson. He found that
in some mpq3 functions called frequently from loops, passing in
buffers for termporary mpq3 values can save substantial time.
On my machine, his example in that patch went from 9.48s to 7.50s
for the boolean part of the calculation. On his machine, a running
time went from 17s to 10.3s.

1 files changed, 16 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_mpq3.hh b/source/blender/blenlib/BLI_mpq3.hh
index fb5e2b61cdb..b9eda2ad7e1 100644
--- a/source/blender/blenlib/BLI_mpq3.hh
+++ b/source/blender/blenlib/BLI_mpq3.hh
@@ -218,6 +218,15 @@ struct mpq3 {
     return a.x * b.x + a.y * b.y + a.z * b.z;
   }
 
+  static mpq_class dot_with_buffer(const mpq3 &a, const mpq3 &b, mpq3 &buffer)
+  {
+    buffer = a;
+    buffer *= b;
+    buffer.x += buffer.y;
+    buffer.x += buffer.z;
+    return buffer.x;
+  }
+
   static mpq3 cross(const mpq3 &a, const mpq3 &b)
   {
     return mpq3(a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0]);
@@ -246,6 +255,13 @@ struct mpq3 {
     return mpq3::dot(diff, diff);
   }
 
+  static mpq_class distance_squared_with_buffer(const mpq3 &a, const mpq3 &b, mpq3 &buffer)
+  {
+    buffer = a;
+    buffer -= b;
+    return mpq3::dot(buffer, buffer);
+  }
+
   static mpq3 interpolate(const mpq3 &a, const mpq3 &b, mpq_class t)
   {
     mpq_class s = 1 - t;