Description

Extends the functionality of theGLTFDocument class by allowing you to run arbitrary code at various stages of glTF import or export.

To use, make a new class extending GLTFDocumentExtension, override any methods you need, make an instance of your class, and register it usingGLTFDocument.register_gltf_document_extension().

Note: Like GLTFDocument itself, all GLTFDocumentExtension classes must be stateless in order to function properly. If you need to store data, use theset_additional_data andget_additional_data methods inGLTFState orGLTFNode.

Tutorials

• Runtime file loading and saving

Methods

Method Descriptions

void_convert_scene_node(state:GLTFState, gltf_node:GLTFNode, scene_node:Node)virtual🔗

Part of the export process. This method is run after_export_preflight() and before_export_post_convert().

Runs when converting the data from a Godot scene node. This method can be used to process the Godot scene node data into a format that can be used by_export_node().

Error_export_node(state:GLTFState, gltf_node:GLTFNode, json:Dictionary, node:Node)virtual🔗

Part of the export process. This method is run after_get_saveable_image_formats() and before_export_post(). If thisGLTFDocumentExtension is used for exporting images, this runs after_serialize_texture_json().

This method can be used to modify the final JSON of each node. Data should be primarily stored ingltf_node prior to serializing the JSON, but the original GodotNode is also provided if available.node may benull if not available, such as when exporting glTF data not generated from a Godot scene.

GLTFObjectModelProperty_export_object_model_property(state:GLTFState, node_path:NodePath, godot_node:Node, gltf_node_index:int, target_object:Object, target_depth:int)virtual🔗

Part of the export process. Allows GLTFDocumentExtension classes to provide mappings for properties of nodes in the Godot scene tree, to JSON pointers to glTF properties, as defined by the glTF object model.

Returns aGLTFObjectModelProperty instance that defines how the property should be mapped. If your extension can't handle the property, returnnull or an instance without any JSON pointers (seeGLTFObjectModelProperty.has_json_pointers()). You should useGLTFObjectModelProperty.set_types() to set the types, and set the JSON pointer(s) using theGLTFObjectModelProperty.json_pointers property.

The parameters provide context for the property, including the NodePath, the Godot node, the GLTF node index, and the target object. Thetarget_object will be equal togodot_node if no sub-object can be found, otherwise it will point to a sub-object. For example, if the path is^"A/B/C/MeshInstance3D:mesh:surface_0/material:emission_intensity", it will get the node, then the mesh, and then the material, sotarget_object will be theMaterial resource, andtarget_depth will be 2 because 2 levels were traversed to get to the target.

Error_export_post(state:GLTFState)virtual🔗

Part of the export process. This method is run last, after all other parts of the export process.

This method can be used to modify the final JSON of the generated glTF file.

Error_export_post_convert(state:GLTFState, root:Node)virtual🔗

Part of the export process. This method is run after_convert_scene_node() and before_export_preserialize().

This method can be used to modify the converted node data structures before serialization with any additional data from the scene tree.

Error_export_preflight(state:GLTFState, root:Node)virtual🔗

Part of the export process. This method is run first, before all other parts of the export process.

The return value is used to determine if thisGLTFDocumentExtension instance should be used for exporting a given glTF file. If@GlobalScope.OK, the export will use thisGLTFDocumentExtension instance. If not overridden,@GlobalScope.OK is returned.

Error_export_preserialize(state:GLTFState)virtual🔗

Part of the export process. This method is run after_export_post_convert() and before_get_saveable_image_formats().

This method can be used to alter the state before performing serialization. It runs every time when generating a buffer withGLTFDocument.generate_buffer() or writing to the file system withGLTFDocument.write_to_filesystem().

Node3D_generate_scene_node(state:GLTFState, gltf_node:GLTFNode, scene_parent:Node)virtual🔗

Part of the import process. This method is run after_import_pre_generate() and before_import_node().

Runs when generating a Godot scene node from a GLTFNode. The returned node will be added to the scene tree. Multiple nodes can be generated in this step if they are added as a child of the returned node.

Note: Thescene_parent parameter may benull if this is the single root node.

String_get_image_file_extension()virtual🔗

Returns the file extension to use for saving image data into, for example,".png". If defined, when this extension is used to handle images, and the images are saved to a separate file, the image bytes will be copied to a file with this extension. If this is set, there should be aResourceImporter class able to import the file. If not defined or empty, Godot will save the image into a PNG file.

PackedStringArray_get_saveable_image_formats()virtual🔗

Part of the export process. This method is run after_convert_scene_node() and before_export_node().

Returns an array of the image formats that can be saved/exported by this extension. This extension will only be selected as the image exporter if theGLTFDocument'sGLTFDocument.image_format is in this array. If thisGLTFDocumentExtension is selected as the image exporter, one of the_save_image_at_path() or_serialize_image_to_bytes() methods will run next, otherwise_export_node() will run next. If the format name contains"Lossy", the lossy quality slider will be displayed.

PackedStringArray_get_supported_extensions()virtual🔗

Part of the import process. This method is run after_import_preflight() and before_parse_node_extensions().

Returns an array of the glTF extensions supported by this GLTFDocumentExtension class. This is used to validate if a glTF file with required extensions can be loaded.

Error_import_node(state:GLTFState, gltf_node:GLTFNode, json:Dictionary, node:Node)virtual🔗

Part of the import process. This method is run after_generate_scene_node() and before_import_post().

This method can be used to make modifications to each of the generated Godot scene nodes.

GLTFObjectModelProperty_import_object_model_property(state:GLTFState, split_json_pointer:PackedStringArray, partial_paths:Array[NodePath])virtual🔗

Part of the import process. Allows GLTFDocumentExtension classes to provide mappings for JSON pointers to glTF properties, as defined by the glTF object model, to properties of nodes in the Godot scene tree.

Returns aGLTFObjectModelProperty instance that defines how the property should be mapped. If your extension can't handle the property, returnnull or an instance without any NodePaths (seeGLTFObjectModelProperty.has_node_paths()). You should useGLTFObjectModelProperty.set_types() to set the types, andGLTFObjectModelProperty.append_path_to_property() function is useful for most simple cases.

In many cases,partial_paths will contain the start of a path, allowing the extension to complete the path. For example, for/nodes/3/extensions/MY_ext/prop, Godot will pass you a NodePath that leads to node 3, so the GLTFDocumentExtension class only needs to resolve the lastMY_ext/prop part of the path. In this example, the extension should checksplit.size()>4andsplit[0]=="nodes"andsplit[2]=="extensions"andsplit[3]=="MY_ext" at the start of the function to check if this JSON pointer applies to it, then it can usepartial_paths and handlesplit[4].

Error_import_post(state:GLTFState, root:Node)virtual🔗

Part of the import process. This method is run last, after all other parts of the import process.

This method can be used to modify the final Godot scene generated by the import process.

Error_import_post_parse(state:GLTFState)virtual🔗

Part of the import process. This method is run after_parse_node_extensions() and before_import_pre_generate().

This method can be used to modify any of the data imported so far after parsing each node, but before generating the scene or any of its nodes.

Error_import_pre_generate(state:GLTFState)virtual🔗

Part of the import process. This method is run after_import_post_parse() and before_generate_scene_node().

This method can be used to modify or read from any of the processed data structures, before generating the nodes and then running the final per-node import step.

Error_import_preflight(state:GLTFState, extensions:PackedStringArray)virtual🔗

Part of the import process. This method is run first, before all other parts of the import process.

The return value is used to determine if thisGLTFDocumentExtension instance should be used for importing a given glTF file. If@GlobalScope.OK, the import will use thisGLTFDocumentExtension instance. If not overridden,@GlobalScope.OK is returned.

Error_parse_image_data(state:GLTFState, image_data:PackedByteArray, mime_type:String, ret_image:Image)virtual🔗

Part of the import process. This method is run after_parse_node_extensions() and before_parse_texture_json().

Runs when parsing image data from a glTF file. The data could be sourced from a separate file, a URI, or a buffer, and then is passed as a byte array.

Error_parse_node_extensions(state:GLTFState, gltf_node:GLTFNode, extensions:Dictionary)virtual🔗

Part of the import process. This method is run after_get_supported_extensions() and before_import_post_parse().

Runs when parsing the node extensions of a GLTFNode. This method can be used to process the extension JSON data into a format that can be used by_generate_scene_node(). The return value should be a member of theError enum.

Error_parse_texture_json(state:GLTFState, texture_json:Dictionary, ret_gltf_texture:GLTFTexture)virtual🔗

Part of the import process. This method is run after_parse_image_data() and before_generate_scene_node().

Runs when parsing the texture JSON from the glTF textures array. This can be used to set the source image index to use as the texture.

Error_save_image_at_path(state:GLTFState, image:Image, file_path:String, image_format:String, lossy_quality:float)virtual🔗

Part of the export process. This method is run after_get_saveable_image_formats() and before_serialize_texture_json().

This method is run when saving images separately from the glTF file. When images are embedded,_serialize_image_to_bytes() runs instead. Note that these methods only run when thisGLTFDocumentExtension is selected as the image exporter.

PackedByteArray_serialize_image_to_bytes(state:GLTFState, image:Image, image_dict:Dictionary, image_format:String, lossy_quality:float)virtual🔗

Part of the export process. This method is run after_get_saveable_image_formats() and before_serialize_texture_json().

This method is run when embedding images in the glTF file. When images are saved separately,_save_image_at_path() runs instead. Note that these methods only run when thisGLTFDocumentExtension is selected as the image exporter.

This method must set the image MIME type in theimage_dict with the"mimeType" key. For example, for a PNG image, it would be set to"image/png". The return value must be aPackedByteArray containing the image data.

Error_serialize_texture_json(state:GLTFState, texture_json:Dictionary, gltf_texture:GLTFTexture, image_format:String)virtual🔗

Part of the export process. This method is run after_save_image_at_path() or_serialize_image_to_bytes(), and before_export_node(). Note that this method only runs when thisGLTFDocumentExtension is selected as the image exporter.

This method can be used to set up the extensions for the texture JSON by editingtexture_json. The extension must also be added as used extension withGLTFState.add_used_extension(), be sure to setrequired totrue if you are not providing a fallback.