Convert the vector socket from four nodes to a rotation socket, adding
versioning to insert the conversion nodes and change the default values
where necessary.
- Distribute Points on Faces
- Instance on Points
- Rotate Instances
- Transform Geometry

Using rotation sockets disallows implicit conversions from vectors,
which helps avoid some common mistakes. It can also be faster,
since converting to and from Euler rotations is slow. For best
performance, the automatically added nodes should be removed.

Note that this change is not forward compatible with 3.6.

@@ -423,0 +427,4 @@
+  socket.type = SOCK_ROTATION;
+  STRNCPY(socket.idname, "NodeSocketRotation");
+  auto *old_value = static_cast<bNodeSocketValueVector *>(socket.default_value);
+  auto *new_value = MEM_new<bNodeSocketValueRotation>(__func__);

@@ -426,2 +438,4 @@
   add_implicit_conversion<ColorGeometry4b, ColorGeometry4f, byte_color_to_color>(conversions);
 
+  add_implicit_conversion<float, math::Quaternion, float_to_quaternion>(conversions);
+  add_implicit_conversion<float3, math::Quaternion, float3_to_quaternion>(conversions);

@@ -836,0 +855,4 @@
+      /* Make versioning idempotent. */
+      continue;
+    }
+    bNode *convert = nodeAddNode(nullptr, &ntree, "FunctionNodeEulerToRotation");

@@ -33,2 +32,3 @@
+static bool use_translate(const math::Quaternion &rotation, const float3 scale)
 {
-  if (compare_ff(math::length_squared(rotation), 0.0f, 1e-9f) != 1) {
+  if (math::angle_between(rotation, math::Quaternion::identity()).radian() > 1e-7f) {

@@ -836,0 +853,4 @@
+    }
+    if (ELEM(link->fromsock->type, SOCK_VECTOR, SOCK_FLOAT) &&
+        link->fromnode->type != NODE_REROUTE) {
+      /* No need to add the conversion node when impicit conversions will work. */