Geometry Nodes: Add STL Import Node

This commit adds an initial STL import node, the first of the nodes from the
current Google Summer of Code Project [0]. The importer is refactored to
output a mesh pointer, and a node is added to wrap around the importer.
The node supports error messages from the importer. A new experimental
option is added to hide the nodes by default until they're ready to be exposed
generally.

0: https://devtalk.blender.org/t/gsoc-2024-geometry-nodes-file-import-nodes/34482)

Pull Request: https://projects.blender.org/blender/blender/pulls/122418

scripts/startup/bl_ui/node_add_menu_geometry.py

@@ -243,11 +243,13 @@ class NODE_MT_geometry_node_GEO_INPUT(Menu):
     bl_idname = "NODE_MT_geometry_node_GEO_INPUT"
     bl_label = "Input"
 
-    def draw(self, _context):
+    def draw(self, context):
         layout = self.layout
         layout.menu("NODE_MT_geometry_node_GEO_INPUT_CONSTANT")
         layout.menu("NODE_MT_geometry_node_GEO_INPUT_GROUP")
         layout.menu("NODE_MT_geometry_node_GEO_INPUT_SCENE")
+        if context.preferences.experimental.use_new_file_import_nodes:
+            layout.menu("NODE_MT_category_IMPORT")
         node_add_menu.draw_assets_for_catalog(layout, self.bl_label)
 
 
@@ -448,6 +450,14 @@ class NODE_MT_category_PRIMITIVES_MESH(Menu):
         node_add_menu.add_node_type(layout, "GeometryNodeMeshUVSphere")
         node_add_menu.draw_assets_for_catalog(layout, "Mesh/Primitives")
 
+class NODE_MT_category_IMPORT(Menu):
+    bl_idname = "NODE_MT_category_IMPORT"
+    bl_label = "Import"
+
+    def draw(self, _context):
+        layout = self.layout
+        node_add_menu.add_node_type(layout, "GeometryNodeImportSTL")
+        node_add_menu.draw_assets_for_catalog(layout, "Input/Import")
 
 class NODE_MT_geometry_node_mesh_topology(Menu):
     bl_idname = "NODE_MT_geometry_node_mesh_topology"
@@ -816,6 +826,7 @@ classes = (
     NODE_MT_geometry_node_GEO_MESH_OPERATIONS,
     NODE_MT_category_GEO_UV,
     NODE_MT_category_PRIMITIVES_MESH,
+    NODE_MT_category_IMPORT,
     NODE_MT_geometry_node_mesh_topology,
     NODE_MT_category_GEO_POINT,
     NODE_MT_category_simulation,

scripts/startup/bl_ui/space_userpref.py

@@ -2798,6 +2798,7 @@ class USERPREF_PT_experimental_new_features(ExperimentalPanel, Panel):
                 ({"property": "use_extended_asset_browser"},
                  ("blender/blender/projects/10", "Pipeline, Assets & IO Project Page")),
                 ({"property": "use_new_volume_nodes"}, ("blender/blender/issues/103248", "#103248")),
+                ({"property": "use_new_file_import_nodes"}, ("blender/blender/issues/122846", "#122846")),
                 ({"property": "use_shader_node_previews"}, ("blender/blender/issues/110353", "#110353")),
             ),
         )

source/blender/blenkernel/BKE_node.hh

@@ -1333,6 +1333,7 @@ void BKE_nodetree_remove_layer_n(bNodeTree *ntree, Scene *scene, int layer_index
 #define GEO_NODE_TOOL_ACTIVE_ELEMENT 2135
 #define GEO_NODE_SET_INSTANCE_TRANSFORM 2136
 #define GEO_NODE_INPUT_INSTANCE_TRANSFORM 2137
+#define GEO_NODE_IMPORT_STL 2138
 
 /** \} */
 

source/blender/io/stl/IO_stl.cc

@@ -23,3 +23,8 @@ void STL_export(bContext *C, const STLExportParams *export_params)
   SCOPED_TIMER("STL Export");
   blender::io::stl::exporter_main(C, *export_params);
 }
+
+Mesh *STL_import_mesh(const STLImportParams *import_params)
+{
+  return blender::io::stl::read_stl_file(*import_params);
+}

source/blender/io/stl/IO_stl.hh

@@ -14,6 +14,7 @@
 
 #include "IO_orientation.hh"
 
+struct Mesh;
 struct bContext;
 struct ReportList;
 
@@ -48,3 +49,5 @@ struct STLExportParams {
 
 void STL_import(bContext *C, const STLImportParams *import_params);
 void STL_export(bContext *C, const STLExportParams *export_params);
+
+Mesh *STL_import_mesh(const STLImportParams *import_params);

source/blender/io/stl/importer/stl_import.cc

@@ -47,18 +47,7 @@ void stl_import_report_error(FILE *file)
   }
 }
 
-void importer_main(const bContext *C, const STLImportParams &import_params)
-{
-  Main *bmain = CTX_data_main(C);
-  Scene *scene = CTX_data_scene(C);
-  ViewLayer *view_layer = CTX_data_view_layer(C);
-  importer_main(bmain, scene, view_layer, import_params);
-}
-
-void importer_main(Main *bmain,
-                   Scene *scene,
-                   ViewLayer *view_layer,
-                   const STLImportParams &import_params)
+Mesh *read_stl_file(const STLImportParams &import_params)
 {
   FILE *file = BLI_fopen(import_params.filepath, "rb");
   if (!file) {
@@ -67,7 +56,7 @@ void importer_main(Main *bmain,
                 RPT_ERROR,
                 "STL Import: Cannot open file '%s'",
                 import_params.filepath);
-    return;
+    return nullptr;
   }
   BLI_SCOPED_DEFER([&]() { fclose(file); });
 
@@ -84,15 +73,10 @@ void importer_main(Main *bmain,
                 RPT_ERROR,
                 "STL Import: Failed to read file '%s'",
                 import_params.filepath);
-    return;
+    return nullptr;
   }
   bool is_ascii_stl = (file_size != (BINARY_HEADER_SIZE + 4 + BINARY_STRIDE * num_tri));
 
-  /* Name used for both mesh and object. */
-  char ob_name[FILE_MAX];
-  STRNCPY(ob_name, BLI_path_basename(import_params.filepath));
-  BLI_path_extension_strip(ob_name);
-
   Mesh *mesh = is_ascii_stl ?
                    read_stl_ascii(import_params.filepath, import_params.use_facet_normal) :
                    read_stl_binary(file, import_params.use_facet_normal);
@@ -103,7 +87,7 @@ void importer_main(Main *bmain,
                 RPT_ERROR,
                 "STL Import: Failed to import mesh from file '%s'",
                 import_params.filepath);
-    return;
+    return nullptr;
   }
 
   if (import_params.use_mesh_validate) {
@@ -114,6 +98,29 @@ void importer_main(Main *bmain,
     BKE_mesh_validate(mesh, verbose_validate, false);
   }
 
+  return mesh;
+}
+
+void importer_main(const bContext *C, const STLImportParams &import_params)
+{
+  Main *bmain = CTX_data_main(C);
+  Scene *scene = CTX_data_scene(C);
+  ViewLayer *view_layer = CTX_data_view_layer(C);
+  importer_main(bmain, scene, view_layer, import_params);
+}
+
+void importer_main(Main *bmain,
+                   Scene *scene,
+                   ViewLayer *view_layer,
+                   const STLImportParams &import_params)
+{
+  /* Name used for both mesh and object. */
+  char ob_name[FILE_MAX];
+  STRNCPY(ob_name, BLI_path_basename(import_params.filepath));
+  BLI_path_extension_strip(ob_name);
+
+  Mesh *mesh = read_stl_file(import_params);
+
   Mesh *mesh_in_main = BKE_mesh_add(bmain, ob_name);
   BKE_mesh_nomain_to_mesh(mesh, mesh_in_main, nullptr);
   BKE_view_layer_base_deselect_all(scene, view_layer);

source/blender/io/stl/importer/stl_import.hh

@@ -12,6 +12,7 @@
 
 struct bContext;
 struct Main;
+struct Mesh;
 struct Scene;
 struct ViewLayer;
 
@@ -19,6 +20,9 @@ namespace blender::io::stl {
 
 void stl_import_report_error(FILE *file);
 
+/* Used from Geo nodes import for Mesh* access */
+Mesh *read_stl_file(const STLImportParams &import_params);
+
 /* Main import function used from within Blender. */
 void importer_main(const bContext *C, const STLImportParams &import_params);
 
@@ -27,5 +31,4 @@ void importer_main(Main *bmain,
                    Scene *scene,
                    ViewLayer *view_layer,
                    const STLImportParams &import_params);
-
 }  // namespace blender::io::stl

source/blender/makesdna/DNA_userdef_types.h

@@ -752,10 +752,11 @@ typedef struct UserDef_Experimental {
   char use_grease_pencil_version3;
   char enable_overlay_next;
   char use_new_volume_nodes;
+  char use_new_file_import_nodes;
   char use_shader_node_previews;
   char use_grease_pencil_version3_convert_on_load;
   char use_animation_baklava;
-  char _pad[3];
+  char _pad[2];
   /** `makesdna` does not allow empty structs. */
 } UserDef_Experimental;
 

source/blender/makesrna/intern/rna_userdef.cc

@@ -7401,6 +7401,10 @@ static void rna_def_userdef_experimental(BlenderRNA *brna)
   RNA_def_property_ui_text(
       prop, "New Volume Nodes", "Enables visibility of the new Volume nodes in the UI");
 
+  prop = RNA_def_property(srna, "use_new_file_import_nodes", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_ui_text(
+      prop, "New File Import Nodes", "Enables visibility of the new File Import nodes in the UI");
+
   prop = RNA_def_property(srna, "use_shader_node_previews", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_ui_text(
       prop, "Shader Node Previews", "Enables previews in the shader node editor");

source/blender/nodes/NOD_static_types.h

@@ -353,6 +353,7 @@ DefNode(GeometryNode, GEO_NODE_GRID_TO_MESH, 0, "GRID_TO_MESH", GridToMesh, "Gri
 DefNode(GeometryNode, GEO_NODE_IMAGE_INFO, 0, "IMAGE_INFO", ImageInfo, "Image Info", "Retrieve information about an image")
 DefNode(GeometryNode, GEO_NODE_IMAGE_TEXTURE, def_geo_image_texture, "IMAGE_TEXTURE", ImageTexture, "Image Texture", "Sample values from an image texture")
 DefNode(GeometryNode, GEO_NODE_IMAGE, def_geo_image, "IMAGE", InputImage, "Image", "Input image")
+DefNode(GeometryNode, GEO_NODE_IMPORT_STL, 0, "IMPORT_STL", ImportSTL, "Import STL", "Import a mesh from an STL file")
 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_INPUT_ACTIVE_CAMERA, 0, "INPUT_ACTIVE_CAMERA", InputActiveCamera, "Active Camera", "Retrieve the scene's active camera")

source/blender/nodes/geometry/CMakeLists.txt

@@ -20,6 +20,8 @@ set(INC
   ../../modifiers
   ../../render
   ../../windowmanager
+  ../../io/common
+  ../../io/stl
   # RNA_prototypes.h
   ${CMAKE_BINARY_DIR}/source/blender/makesrna
 )
@@ -85,6 +87,7 @@ set(SRC
   nodes/node_geo_image.cc
   nodes/node_geo_image_info.cc
   nodes/node_geo_image_texture.cc
+  nodes/node_geo_import_stl.cc
   nodes/node_geo_index_of_nearest.cc
   nodes/node_geo_index_switch.cc
   nodes/node_geo_input_active_camera.cc
@@ -237,6 +240,8 @@ set(LIB
   bf_nodes
   PRIVATE bf::intern::atomic
   PRIVATE bf::extern::fmtlib
+  PRIVATE bf_io_common
+  PRIVATE bf_io_stl
 )
 
 if(WITH_BULLET)

source/blender/nodes/geometry/node_geometry_util.cc

@@ -41,6 +41,13 @@ void search_link_ops_for_volume_grid_node(GatherLinkSearchOpParams &params)
   }
 }
 
+void search_link_ops_for_import_node(GatherLinkSearchOpParams &params)
+{
+  if (U.experimental.use_new_file_import_nodes) {
+    nodes::search_link_ops_for_basic_node(params);
+  }
+}
+
 namespace enums {
 
 const EnumPropertyItem *attribute_type_type_with_socket_fn(bContext * /*C*/,

source/blender/nodes/geometry/node_geometry_util.hh

@@ -33,6 +33,7 @@ namespace blender::nodes {
 bool check_tool_context_and_error(GeoNodeExecParams &params);
 void search_link_ops_for_tool_node(GatherLinkSearchOpParams &params);
 void search_link_ops_for_volume_grid_node(GatherLinkSearchOpParams &params);
+void search_link_ops_for_import_node(GatherLinkSearchOpParams &params);
 
 void get_closest_in_bvhtree(BVHTreeFromMesh &tree_data,
                             const VArray<float3> &positions,

source/blender/nodes/geometry/nodes/node_geo_import_stl.cc

@@ -0,0 +1,90 @@
+/* SPDX-FileCopyrightText: 2023 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "node_geometry_util.hh"
+
+#include "BKE_mesh.hh"
+
+#include "BKE_report.hh"
+#include "BLI_string.h"
+
+#include "IO_stl.hh"
+
+#include "node_geometry_util.hh"
+
+namespace blender::nodes::node_geo_import_stl {
+
+static void node_declare(NodeDeclarationBuilder &b)
+{
+  b.add_input<decl::String>("Path").default_value("").description("Path to a STL file");
+
+  b.add_output<decl::Geometry>("Mesh");
+}
+
+static void node_geo_exec(GeoNodeExecParams params)
+{
+  const std::string path = params.extract_input<std::string>("Path");
+
+  if (path.empty()) {
+    params.set_default_remaining_outputs();
+    return;
+  }
+
+  STLImportParams import_params;
+
+  STRNCPY(import_params.filepath, path.c_str());
+
+  import_params.forward_axis = IO_AXIS_NEGATIVE_Z;
+  import_params.up_axis = IO_AXIS_Y;
+  import_params.use_facet_normal = false;
+  import_params.use_scene_unit = false;
+  import_params.global_scale = 1.0f;
+  import_params.use_mesh_validate = true;
+
+  ReportList reports;
+  BKE_reports_init(&reports, RPT_STORE);
+  import_params.reports = &reports;
+
+  Mesh *mesh = STL_import_mesh(&import_params);
+
+  LISTBASE_FOREACH (Report *, report, &(import_params.reports)->list) {
+    NodeWarningType type;
+
+    switch (report->type) {
+      case RPT_ERROR:
+        type = NodeWarningType::Error;
+        break;
+      default:
+        type = NodeWarningType::Info;
+        break;
+    }
+
+    params.error_message_add(type, TIP_(report->message));
+  }
+
+  BKE_reports_free(&reports);
+
+  if (mesh != nullptr) {
+    params.set_output("Mesh", GeometrySet::from_mesh(mesh));
+  }
+  else {
+    params.set_default_remaining_outputs();
+  }
+}
+
+static void node_register()
+{
+  static blender::bke::bNodeType ntype;
+
+  geo_node_type_base(&ntype, GEO_NODE_IMPORT_STL, "Import STL", NODE_CLASS_INPUT);
+
+  ntype.geometry_node_execute = node_geo_exec;
+  ntype.declare = node_declare;
+  ntype.gather_link_search_ops = search_link_ops_for_import_node;
+
+  blender::bke::nodeRegisterType(&ntype);
+}
+NOD_REGISTER_NODE(node_register)
+
+}  // namespace blender::nodes::node_geo_import_stl