scripts/startup/bl_ui/node_add_menu_geometry.py

@@ -283,6 +283,7 @@ class NODE_MT_geometry_node_GEO_INPUT_SCENE(Menu):
         layout = self.layout
         if context.space_data.geometry_nodes_type == 'TOOL':
             node_add_menu.add_node_type(layout, "GeometryNodeTool3DCursor")
+        node_add_menu.add_node_type(layout, "GeometryNodeInputActiveCamera")
         node_add_menu.add_node_type(layout, "GeometryNodeCollectionInfo")
         node_add_menu.add_node_type(layout, "GeometryNodeImageInfo")
         node_add_menu.add_node_type(layout, "GeometryNodeIsViewport")

source/blender/blenkernel/BKE_node.h

@@ -1325,6 +1325,7 @@ void BKE_nodetree_remove_layer_n(struct bNodeTree *ntree, struct Scene *scene, i
 #define GEO_NODE_SPLIT_TO_INSTANCES 2116
 #define GEO_NODE_INPUT_NAMED_LAYER_SELECTION 2117
 #define GEO_NODE_INDEX_SWITCH 2118
+#define GEO_NODE_INPUT_ACTIVE_CAMERA 2119
 
 /** \} */
 

source/blender/depsgraph/DEG_depsgraph_build.hh

@@ -120,6 +120,10 @@ void DEG_add_scene_relation(DepsNodeHandle *node_handle,
                             Scene *scene,
                             eDepsSceneComponentType component,
                             const char *description);
+void DEG_add_scene_camera_relation(DepsNodeHandle *node_handle,
+                                   Scene *scene,
+                                   eDepsObjectComponentType component,
+                                   const char *description);
 void DEG_add_object_relation(DepsNodeHandle *node_handle,
                              Object *object,
                              eDepsObjectComponentType component,

source/blender/depsgraph/intern/depsgraph_build.cc

@@ -83,6 +83,24 @@ void DEG_add_scene_relation(DepsNodeHandle *node_handle,
   deg_node_handle->builder->add_node_handle_relation(comp_key, deg_node_handle, description);
 }
 
+void DEG_add_scene_camera_relation(DepsNodeHandle *node_handle,
+                                   Scene *scene,
+                                   eDepsObjectComponentType component,
+                                   const char *description)
+{
+  if (scene->camera != nullptr) {
+    DEG_add_object_relation(node_handle, scene->camera, component, description);
+  }
+
+  /* Like DepsgraphNodeBuilder::build_scene_camera(), we also need to account for other cameras
+   * referenced by markers. */
+  LISTBASE_FOREACH (TimeMarker *, marker, &scene->markers) {
+    if (!ELEM(marker->camera, nullptr, scene->camera)) {
+      DEG_add_object_relation(node_handle, marker->camera, component, description);
+    }
+  }
+}
+
 void DEG_add_object_relation(DepsNodeHandle *node_handle,
                              Object *object,
                              eDepsObjectComponentType component,

source/blender/editors/geometry/node_group_operator.cc

@@ -249,8 +249,11 @@ static Depsgraph *build_depsgraph_from_indirect_ids(Main &bmain,
 {
   Set<ID *> ids_for_relations;
   bool needs_own_transform_relation = false;
-  nodes::find_node_tree_dependencies(
-      node_tree_orig, ids_for_relations, needs_own_transform_relation);
+  bool needs_scene_camera_relation = false;
+  nodes::find_node_tree_dependencies(node_tree_orig,
+                                     ids_for_relations,
+                                     needs_own_transform_relation,
+                                     needs_scene_camera_relation);
   IDP_foreach_property(
       &const_cast<IDProperty &>(properties),
       IDP_TYPE_FILTER_ID,

source/blender/modifiers/intern/MOD_nodes.cc

@@ -164,9 +164,11 @@ static void update_depsgraph(ModifierData *md, const ModifierUpdateDepsgraphCont
   DEG_add_node_tree_output_relation(ctx->node, nmd->node_group, "Nodes Modifier");
 
   bool needs_own_transform_relation = false;
+  bool needs_scene_camera_relation = false;
   Set<ID *> used_ids;
   find_used_ids_from_settings(nmd->settings, used_ids);
-  nodes::find_node_tree_dependencies(*nmd->node_group, used_ids, needs_own_transform_relation);
+  nodes::find_node_tree_dependencies(
+      *nmd->node_group, used_ids, needs_own_transform_relation, needs_scene_camera_relation);
 
   if (ctx->object->type == OB_CURVES) {
     Curves *curves_id = static_cast<Curves *>(ctx->object->data);
@@ -203,6 +205,11 @@ static void update_depsgraph(ModifierData *md, const ModifierUpdateDepsgraphCont
   if (needs_own_transform_relation) {
     DEG_add_depends_on_transform_relation(ctx->node, "Nodes Modifier");
   }
+  if (needs_scene_camera_relation) {
+    DEG_add_scene_camera_relation(ctx->node, ctx->scene, DEG_OB_COMP_TRANSFORM, "Nodes Modifier");
+    /* Active camera is a scene parameter that can change, so we need a relation for that, too. */
+    DEG_add_scene_relation(ctx->node, ctx->scene, DEG_SCENE_COMP_PARAMETERS, "Nodes Modifier");
+  }
 }
 
 static bool check_tree_for_time_node(const bNodeTree &tree, Set<const bNodeTree *> &checked_groups)

source/blender/nodes/NOD_geometry_nodes_execute.hh

@@ -32,7 +32,8 @@ namespace blender::nodes {
 
 void find_node_tree_dependencies(const bNodeTree &tree,
                                  Set<ID *> &r_ids,
-                                 bool &r_needs_own_transform_relation);
+                                 bool &r_needs_own_transform_relation,
+                                 bool &r_needs_scene_camera_relation);
 
 StringRef input_use_attribute_suffix();
 StringRef input_attribute_name_suffix();

source/blender/nodes/NOD_static_types.h

@@ -336,6 +336,7 @@ DefNode(GeometryNode, GEO_NODE_IMAGE_TEXTURE, def_geo_image_texture, "IMAGE_TEXT
 DefNode(GeometryNode, GEO_NODE_INDEX_OF_NEAREST, 0, "INDEX_OF_NEAREST", IndexOfNearest, "Index of Nearest", "Find the nearest element in a group. Similar to the \"Sample Nearest\" node")
 DefNode(GeometryNode, GEO_NODE_INDEX_SWITCH, def_geo_index_switch, "INDEX_SWITCH", IndexSwitch, "Index Switch", "Choose between an arbitrary number of values with an index")
 DefNode(GeometryNode, GEO_NODE_IMAGE, def_geo_image, "IMAGE", InputImage, "Image", "Input image")
+DefNode(GeometryNode, GEO_NODE_INPUT_ACTIVE_CAMERA, 0, "INPUT_ACTIVE_CAMERA", InputActiveCamera, "Active Camera", "Retrieve the scene's active camera")
 DefNode(GeometryNode, GEO_NODE_INPUT_CURVE_HANDLES, 0, "INPUT_CURVE_HANDLES", InputCurveHandlePositions, "Curve Handle Positions", "Retrieve the position of each Bézier control point's handles")
 DefNode(GeometryNode, GEO_NODE_INPUT_CURVE_TILT, 0, "INPUT_CURVE_TILT", InputCurveTilt, "Curve Tilt", "Retrieve the angle at each control point used to twist the curve's normal around its tangent")
 DefNode(GeometryNode, GEO_NODE_INPUT_ID, 0, "INPUT_ID", InputID, "ID", "Retrieve a stable random identifier value from the \"id\" attribute on the point domain, or the index if the attribute does not exist")

source/blender/nodes/geometry/CMakeLists.txt

@@ -82,6 +82,7 @@ set(SRC
   nodes/node_geo_image_texture.cc
   nodes/node_geo_index_of_nearest.cc
   nodes/node_geo_index_switch.cc
+  nodes/node_geo_input_active_camera.cc
   nodes/node_geo_input_curve_handles.cc
   nodes/node_geo_input_curve_tilt.cc
   nodes/node_geo_input_edge_smooth.cc

source/blender/nodes/geometry/nodes/node_geo_input_active_camera.cc

@@ -0,0 +1,36 @@
+/* SPDX-FileCopyrightText: 2023 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BKE_scene.h"
+
+#include "DEG_depsgraph_query.hh"
+
+#include "node_geometry_util.hh"
+
+namespace blender::nodes::node_geo_input_active_camera_cc {
+
+static void node_declare(NodeDeclarationBuilder &b)
+{
+  b.add_output<decl::Object>("Active Camera")
+      .description("The camera used for rendering the scene");
+}
+
+static void node_exec(GeoNodeExecParams params)
+{
+  const Scene *scene = DEG_get_evaluated_scene(params.depsgraph());
+  Object *camera = DEG_get_evaluated_object(params.depsgraph(), scene->camera);
+  params.set_output("Active Camera", camera);
+}
+
+static void node_register()
+{
+  static bNodeType ntype;
+  geo_node_type_base(&ntype, GEO_NODE_INPUT_ACTIVE_CAMERA, "Active Camera", NODE_CLASS_INPUT);
+  ntype.geometry_node_execute = node_exec;
+  ntype.declare = node_declare;
+  nodeRegisterType(&ntype);
+}
+NOD_REGISTER_NODE(node_register)
+
+}  // namespace blender::nodes::node_geo_input_active_camera_cc

source/blender/nodes/intern/geometry_nodes_execute.cc

@@ -104,6 +104,7 @@ static bool node_needs_own_transform_relation(const bNode &node)
 static void process_nodes_for_depsgraph(const bNodeTree &tree,
                                         Set<ID *> &ids,
                                         bool &r_needs_own_transform_relation,
+                                        bool &r_needs_scene_camera_relation,
                                         Set<const bNodeTree *> &checked_groups)
 {
   if (!checked_groups.add(&tree)) {
@@ -115,21 +116,28 @@ static void process_nodes_for_depsgraph(const bNodeTree &tree,
     add_used_ids_from_sockets(node->inputs, ids);
     add_used_ids_from_sockets(node->outputs, ids);
     r_needs_own_transform_relation |= node_needs_own_transform_relation(*node);
+    r_needs_scene_camera_relation |= (node->type == GEO_NODE_INPUT_ACTIVE_CAMERA);
   }
 
   for (const bNode *node : tree.group_nodes()) {
     if (const bNodeTree *sub_tree = reinterpret_cast<const bNodeTree *>(node->id)) {
-      process_nodes_for_depsgraph(*sub_tree, ids, r_needs_own_transform_relation, checked_groups);
+      process_nodes_for_depsgraph(*sub_tree,
+                                  ids,
+                                  r_needs_own_transform_relation,
+                                  r_needs_scene_camera_relation,
+                                  checked_groups);
     }
   }
 }
 
 void find_node_tree_dependencies(const bNodeTree &tree,
                                  Set<ID *> &r_ids,
-                                 bool &r_needs_own_transform_relation)
+                                 bool &r_needs_own_transform_relation,
+                                 bool &r_needs_scene_camera_relation)
 {
   Set<const bNodeTree *> checked_groups;
-  process_nodes_for_depsgraph(tree, r_ids, r_needs_own_transform_relation, checked_groups);
+  process_nodes_for_depsgraph(
+      tree, r_ids, r_needs_own_transform_relation, r_needs_scene_camera_relation, checked_groups);
 }
 
 StringRef input_use_attribute_suffix()