From cf83719761208cc432da08930ed478bf35f29f6c Mon Sep 17 00:00:00 2001
From: Hans Goudey <h.goudey@me.com>
Date: Tue, 16 Nov 2021 15:09:00 -0600
Subject: Geometry Nodes: Small improvements to object info node

This commit contains a few mostly-related changes to this node:
 -  Add a warning when retrieving the geometry from the modifier object.
 - Only create the output geometry when it is necessary.
 - Decompose transform matrices in a more friendly way.
 - Use default return callbacks like other newer nodes.

Differential Revision: https://developer.blender.org/D13232
---
 .../nodes/geometry/nodes/node_geo_object_info.cc   | 81 +++++++++++++---------
 1 file changed, 47 insertions(+), 34 deletions(-)

diff --git a/source/blender/nodes/geometry/nodes/node_geo_object_info.cc b/source/blender/nodes/geometry/nodes/node_geo_object_info.cc
index bd25a39fb54..bb8e5f7e29b 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_object_info.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_object_info.cc
@@ -47,51 +47,64 @@ static void geo_node_object_info_exec(GeoNodeExecParams params)
   const bool transform_space_relative = (node_storage->transform_space ==
                                          GEO_NODE_TRANSFORM_SPACE_RELATIVE);
 
-  Object *object = params.get_input<Object *>("Object");
+  auto default_transform = [&]() {
+    params.set_output("Location", float3(0));
+    params.set_output("Rotation", float3(0));
+    params.set_output("Scale", float3(0));
+  };
+  auto default_geometry = [&]() { params.set_output("Geometry", GeometrySet()); };
 
-  float3 location = {0, 0, 0};
-  float3 rotation = {0, 0, 0};
-  float3 scale = {0, 0, 0};
-  GeometrySet geometry_set;
+  Object *object = params.get_input<Object *>("Object");
 
   const Object *self_object = params.self_object();
+  if (object == nullptr) {
+    default_transform();
+    default_geometry();
+    return;
+  }
 
-  if (object != nullptr) {
-    const float4x4 transform = float4x4(self_object->imat) * float4x4(object->obmat);
+  const float4x4 &object_matrix = object->obmat;
+  const float4x4 transform = float4x4(self_object->imat) * object_matrix;
 
-    float quaternion[4];
-    if (transform_space_relative) {
-      mat4_decompose(location, quaternion, scale, transform.values);
-    }
-    else {
-      mat4_decompose(location, quaternion, scale, object->obmat);
+  if (transform_space_relative) {
+    params.set_output("Location", transform.translation());
+    params.set_output("Rotation", transform.to_euler());
+    params.set_output("Scale", transform.scale());
+  }
+  else {
+    params.set_output("Location", object_matrix.translation());
+    params.set_output("Rotation", object_matrix.to_euler());
+    params.set_output("Scale", object_matrix.scale());
+  }
+
+  if (params.output_is_required("Geometry")) {
+    if (object == self_object) {
+      params.error_message_add(NodeWarningType::Error,
+                               TIP_("Geometry cannot be retrieved from the modifier object"));
+      default_geometry();
+      return;
     }
-    quat_to_eul(rotation, quaternion);
-
-    if (object != self_object) {
-      if (params.get_input<bool>("As Instance")) {
-        InstancesComponent &instances = geometry_set.get_component_for_write<InstancesComponent>();
-        const int handle = instances.add_reference(*object);
-        if (transform_space_relative) {
-          instances.add_instance(handle, transform);
-        }
-        else {
-          instances.add_instance(handle, float4x4::identity());
-        }
+
+    GeometrySet geometry_set;
+    if (params.get_input<bool>("As Instance")) {
+      InstancesComponent &instances = geometry_set.get_component_for_write<InstancesComponent>();
+      const int handle = instances.add_reference(*object);
+      if (transform_space_relative) {
+        instances.add_instance(handle, transform);
       }
       else {
-        geometry_set = bke::object_get_evaluated_geometry_set(*object);
-        if (transform_space_relative) {
-          transform_geometry_set(geometry_set, transform, *params.depsgraph());
-        }
+        instances.add_instance(handle, float4x4::identity());
+      }
+    }
+    else {
+      geometry_set = bke::object_get_evaluated_geometry_set(*object);
+      if (transform_space_relative) {
+        transform_geometry_set(geometry_set, transform, *params.depsgraph());
       }
     }
-  }
 
-  params.set_output("Location", location);
-  params.set_output("Rotation", rotation);
-  params.set_output("Scale", scale);
-  params.set_output("Geometry", geometry_set);
+    params.set_output("Geometry", geometry_set);
+  }
 }
 
 static void geo_node_object_info_node_init(bNodeTree *UNUSED(tree), bNode *node)
-- 
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