bind_scene.h

/*
 * Copyright 2023 Adobe. All rights reserved.
 * This file is licensed to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy
 * of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
 * OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
#pragma once
 
#include <lagrange/AttributeValueType.h>
#include <lagrange/Logger.h>
#include <lagrange/python/binding.h>
#include <lagrange/python/tensor_utils.h>
#include <lagrange/scene/Scene.h>
#include <lagrange/scene/internal/scene_string_utils.h>
#include <lagrange/scene/scene_convert.h>
#include <lagrange/scene/scene_utils.h>
#include <lagrange/utils/assert.h>
 
#include "bind_value.h"
 
namespace lagrange::python {
 
namespace nb = nanobind;
 
void bind_scene(nb::module_& m)
{
    using namespace lagrange::scene;
    using Scalar = double;
    using Index = uint32_t;
    using SceneType = Scene<Scalar, Index>;
 
    nb::bind_vector<SafeVector<ElementId>>(m, "ElementIdList");
    nb::bind_safe_vector<SafeVector<Node>>(m, "NodeList");
    nb::bind_safe_vector<SafeVector<SceneMeshInstance>>(m, "SceneMeshInstanceList");
    nb::bind_safe_vector<SafeVector<SurfaceMesh<Scalar, Index>>>(m, "SurfaceMeshList");
    nb::bind_safe_vector<SafeVector<ImageExperimental>>(m, "ImageList");
    nb::bind_safe_vector<SafeVector<Texture>>(m, "TextureList");
    nb::bind_safe_vector<SafeVector<MaterialExperimental>>(m, "MaterialList");
    nb::bind_safe_vector<SafeVector<Light>>(m, "LightList");
    nb::bind_safe_vector<SafeVector<Camera>>(m, "CameraList");
    nb::bind_safe_vector<SafeVector<Skeleton>>(m, "SkeletonList");
    nb::bind_safe_vector<SafeVector<Animation>>(m, "AnimationList");
 
    nb::class_<lagrange::scene::Extensions>(m, "Extensions")
        .def(
            "__repr__",
            [](const lagrange::scene::Extensions& self) {
                return scene::internal::to_string(self);
            })
        .def_prop_ro("size", &Extensions::size)
        .def_prop_ro("empty", &Extensions::empty)
        .def_rw(
            "data",
            &Extensions::data,
            nb::rv_policy::reference_internal,
            "Raw data stored in this extension as a dict");
 
    nb::class_<SceneMeshInstance>(
        m,
        "SceneMeshInstance",
        "Pairs a mesh with its materials (zero, one, or more)")
        .def(nb::init<>())
        .def(
            "__repr__",
            [](const SceneMeshInstance& self) { return scene::internal::to_string(self); })
        .def_prop_rw(
            "mesh",
            [](SceneMeshInstance& self) -> std::optional<ElementId> {
                if (self.mesh != invalid_element)
                    return self.mesh;
                else
                    return {};
            },
            [](SceneMeshInstance& self, ElementId mesh) { self.mesh = mesh; },
            "Mesh index. Has to be a valid index in the scene.meshes vector (None if invalid)")
        .def_rw(
            "materials",
            &SceneMeshInstance::materials,
            "Material indices in the scene.materials vector. This is typically a single material "
            "index. When a single mesh uses multiple materials, the AttributeName::material_id "
            "facet attribute should be defined.");
 
    nb::class_<Node>(m, "Node", "Represents a node in the scene hierarchy")
        .def(nb::init<>())
        .def("__repr__", [](const Node& self) { return scene::internal::to_string(self); })
        .def_rw("name", &Node::name, "Node name. May not be unique and can be empty")
        .def_prop_rw(
            "transform",
            [](Node& node) {
                return nb::ndarray<nb::numpy, float, nb::f_contig, nb::shape<4, 4>>(
                    node.transform.data(),
                    {4, 4},
                    nb::find(node),
                    {1, 4});
            },
            [](Node& node, nb::ndarray<nb::numpy, const float, nb::shape<4, 4>> t) -> void {
                auto view = t.view<float, nb::ndim<2>>();
                // Explicit 2D indexing because the input ndarray can be either row or column major.
                for (size_t i = 0; i < 4; i++) {
                    for (size_t j = 0; j < 4; j++) {
                        node.transform.data()[i + j * 4] = view(i, j);
                    }
                }
            },
            "Transform of the node, relative to its parent")
        .def_prop_rw(
            "parent",
            [](Node& node) -> std::optional<ElementId> {
                if (node.parent != invalid_element)
                    return node.parent;
                else
                    return {};
            },
            [](Node& node, ElementId parent) { node.parent = parent; },
            "Parent index. May be invalid if the node has no parent (e.g. the root)")
        .def_rw("children", &Node::children, "Children indices. May be empty")
        .def_rw("meshes", &Node::meshes, "List of meshes contained in this node")
        .def_rw("cameras", &Node::cameras, "List of cameras contained in this node")
        .def_rw("lights", &Node::lights, "List of lights contained in this node")
        .def_rw("extensions", &Node::extensions);
 
    nb::class_<ImageBufferExperimental> image_buffer(
        m,
        "ImageBuffer",
        "Minimalistic image data structure that stores the raw image data");
    image_buffer.def(nb::init<>())
        .def(
            "__repr__",
            [](const ImageBufferExperimental& self) { return scene::internal::to_string(self); })
        .def_ro("width", &ImageBufferExperimental::width, "Image width")
        .def_ro("height", &ImageBufferExperimental::height, "Image height")
        .def_ro(
            "num_channels",
            &ImageBufferExperimental::num_channels,
            "Number of image channels (must be 1, 3, or 4)")
        .def_prop_rw(
            "data",
            [](ImageBufferExperimental& self) {
                size_t shape[3] = {self.height, self.width, self.num_channels};
                switch (self.element_type) {
                case AttributeValueType::e_int8_t:
                    return nb::cast(
                        nb::ndarray<int8_t, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<int8_t*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_uint8_t:
                    return nb::cast(
                        nb::ndarray<uint8_t, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<uint8_t*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_int16_t:
                    return nb::cast(
                        nb::ndarray<int16_t, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<int16_t*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_uint16_t:
                    return nb::cast(
                        nb::ndarray<uint16_t, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<uint16_t*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_int32_t:
                    return nb::cast(
                        nb::ndarray<int32_t, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<int32_t*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_uint32_t:
                    return nb::cast(
                        nb::ndarray<uint32_t, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<uint32_t*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_int64_t:
                    return nb::cast(
                        nb::ndarray<int64_t, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<int64_t*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_uint64_t:
                    return nb::cast(
                        nb::ndarray<uint64_t, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<uint64_t*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_float:
                    return nb::cast(
                        nb::ndarray<float, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<float*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                case AttributeValueType::e_double:
                    return nb::cast(
                        nb::ndarray<double, nb::numpy, nb::c_contig, nb::device::cpu>(
                            reinterpret_cast<double*>(self.data.data()),
                            3,
                            shape,
                            nb::find(self)),
                        nb::rv_policy::reference_internal);
                default: throw nb::type_error("Unsupported image buffer `dtype`!");
                }
            },
            [](ImageBufferExperimental& self,
               nb::ndarray<nb::numpy, nb::c_contig, nb::device::cpu> tensor) {
                la_runtime_assert(tensor.ndim() == 3);
                self.width = tensor.shape(1);
                self.height = tensor.shape(0);
                self.num_channels = tensor.shape(2);
                auto dtype = tensor.dtype();
                if (dtype == nb::dtype<int8_t>()) {
                    self.element_type = AttributeValueType::e_int8_t;
                } else if (dtype == nb::dtype<uint8_t>()) {
                    self.element_type = AttributeValueType::e_uint8_t;
                } else if (dtype == nb::dtype<int16_t>()) {
                    self.element_type = AttributeValueType::e_int16_t;
                } else if (dtype == nb::dtype<uint16_t>()) {
                    self.element_type = AttributeValueType::e_uint16_t;
                } else if (dtype == nb::dtype<int32_t>()) {
                    self.element_type = AttributeValueType::e_int32_t;
                } else if (dtype == nb::dtype<uint32_t>()) {
                    self.element_type = AttributeValueType::e_uint32_t;
                } else if (dtype == nb::dtype<int64_t>()) {
                    self.element_type = AttributeValueType::e_int64_t;
                } else if (dtype == nb::dtype<uint64_t>()) {
                    self.element_type = AttributeValueType::e_uint64_t;
                } else if (dtype == nb::dtype<float>()) {
                    self.element_type = AttributeValueType::e_float;
                } else if (dtype == nb::dtype<double>()) {
                    self.element_type = AttributeValueType::e_double;
                } else {
                    throw nb::type_error("Unsupported input tensor `dtype`!");
                }
                self.data.resize(tensor.nbytes());
                std::copy(
                    reinterpret_cast<uint8_t*>(tensor.data()),
                    reinterpret_cast<uint8_t*>(tensor.data()) + tensor.nbytes(),
                    self.data.data());
            },
            "Raw buffer of size (width * height * num_channels * num_bits_per_element / 8) bytes "
            "containing image data")
        .def_prop_ro(
            "dtype",
            [](ImageBufferExperimental& self) -> std::optional<nb::type_object> {
                auto np = nb::module_::import_("numpy");
                switch (self.element_type) {
                case AttributeValueType::e_int8_t: return np.attr("int8");
                case AttributeValueType::e_int16_t: return np.attr("int16");
                case AttributeValueType::e_int32_t: return np.attr("int32");
                case AttributeValueType::e_int64_t: return np.attr("int64");
                case AttributeValueType::e_uint8_t: return np.attr("uint8");
                case AttributeValueType::e_uint16_t: return np.attr("uint16");
                case AttributeValueType::e_uint32_t: return np.attr("uint32");
                case AttributeValueType::e_uint64_t: return np.attr("uint64");
                case AttributeValueType::e_float: return np.attr("float32");
                case AttributeValueType::e_double: return np.attr("float64");
                default: logger().warn("Image buffer has an unknown dtype."); return std::nullopt;
                }
            },
            "The scalar type of the elements in the buffer");
 
    nb::class_<ImageExperimental> image(
        m,
        "Image",
        "Image structure that can store either image data or reference to an image file");
    image.def(nb::init<>())
        .def(
            "__repr__",
            [](const ImageExperimental& self) { return scene::internal::to_string(self); })
        .def_rw(
            "name",
            &ImageExperimental::name,
            "Image name. Not guaranteed to be unique and can be empty")
        .def_rw("image", &ImageExperimental::image, "Image data")
        .def_prop_rw(
            "uri",
            [](const ImageExperimental& self) -> std::optional<std::string> {
                if (self.uri.empty())
                    return {};
                else
                    return self.uri.string();
            },
            [](ImageExperimental& self, std::optional<std::string> uri) {
                if (uri.has_value())
                    self.uri = fs::path(uri.value());
                else
                    self.uri = fs::path();
            },
            "Image file path. This path is relative to the file that contains the scene. It is "
            "only valid if image data should be mapped to an external file")
        .def_rw("extensions", &ImageExperimental::extensions, "Image extensions");
 
    nb::class_<TextureInfo>(
        m,
        "TextureInfo",
        "Pair of texture index (which texture to use) and texture coordinate index (which set of "
        "UVs to use)")
        .def(nb::init<>())
        .def("__repr__", [](const TextureInfo& self) { return scene::internal::to_string(self); })
        .def_prop_rw(
            "index",
            [](const TextureInfo& self) -> std::optional<ElementId> {
                if (self.index != invalid_element)
                    return self.index;
                else
                    return {};
            },
            [](TextureInfo& self, std::optional<ElementId> index) {
                if (index.has_value())
                    self.index = index.value();
                else
                    self.index = invalid_element;
            },
            "Texture index. Index in scene.textures vector. `None` if not set")
        .def_rw(
            "texcoord",
            &TextureInfo::texcoord,
            "Index of UV coordinates. Usually stored in the mesh as `texcoord_x` attribute where x "
            "is this variable. This is typically 0");
 
    nb::class_<MaterialExperimental> material(
        m,
        "Material",
        "PBR material, based on the gltf specification. This is subject to change, to support more "
        "material models");
    material.def(nb::init<>())
        .def(
            "__repr__",
            [](const MaterialExperimental& self) { return scene::internal::to_string(self); })
        .def_rw(
            "name",
            &MaterialExperimental::name,
            "Material name. May not be unique, and can be empty")
        .def_rw("base_color_value", &MaterialExperimental::base_color_value, "Base color value")
        .def_rw(
            "base_color_texture",
            &MaterialExperimental::base_color_texture,
            "Base color texture")
        .def_rw(
            "alpha_mode",
            &MaterialExperimental::alpha_mode,
            "The alpha mode specifies how to interpret the alpha value of the base color")
        .def_rw("alpha_cutoff", &MaterialExperimental::alpha_cutoff, "Alpha cutoff value")
        .def_rw("emissive_value", &MaterialExperimental::emissive_value, "Emissive color value")
        .def_rw("emissive_texture", &MaterialExperimental::emissive_texture, "Emissive texture")
        .def_rw("metallic_value", &MaterialExperimental::metallic_value, "Metallic value")
        .def_rw("roughness_value", &MaterialExperimental::roughness_value, "Roughness value")
        .def_rw(
            "metallic_roughness_texture",
            &MaterialExperimental::metallic_roughness_texture,
            "Metalness and roughness are packed together in a single texture. Green channel has "
            "roughness, blue channel has metalness")
        .def_rw("normal_texture", &MaterialExperimental::normal_texture, "Normal texture")
        .def_rw(
            "normal_scale",
            &MaterialExperimental::normal_scale,
            "Normal scaling factor. normal = normalize(<sampled tex value> * 2 - 1) * vec3(scale, "
            "scale, 1)")
        .def_rw("occlusion_texture", &MaterialExperimental::occlusion_texture, "Occlusion texture")
        .def_rw(
            "occlusion_strength",
            &MaterialExperimental::occlusion_strength,
            "Occlusion strength. color = lerp(color, color * <sampled tex value>, strength)")
        .def_rw(
            "double_sided",
            &MaterialExperimental::double_sided,
            "Whether the material is double-sided")
        .def_rw("extensions", &MaterialExperimental::extensions, "Material extensions");
 
    nb::enum_<MaterialExperimental::AlphaMode>(material, "AlphaMode", "Alpha mode")
        .value(
            "Opaque",
            MaterialExperimental::AlphaMode::Opaque,
            "Alpha is ignored, and rendered output is opaque")
        .value(
            "Mask",
            MaterialExperimental::AlphaMode::Mask,
            "Output is either opaque or transparent depending on the alpha value and the "
            "alpha_cutoff value")
        .value(
            "Blend",
            MaterialExperimental::AlphaMode::Blend,
            "Alpha value is used to composite source and destination");
 
 
    nb::class_<Texture> texture(m, "Texture", "Texture");
    texture.def(nb::init<>())
        .def("__repr__", [](const Texture& self) { return scene::internal::to_string(self); })
        .def_rw("name", &Texture::name, "Texture name")
        .def_prop_rw(
            "image",
            [](Texture& self) -> std::optional<ElementId> {
                if (self.image != invalid_element)
                    return self.image;
                else
                    return {};
            },
            [](Texture& self, ElementId img) { self.image = img; },
            "Index of image in scene.images vector (None if invalid)")
        .def_rw(
            "mag_filter",
            &Texture::mag_filter,
            "Texture magnification filter, used when texture appears larger on screen than the "
            "source image")
        .def_rw(
            "min_filter",
            &Texture::min_filter,
            "Texture minification filter, used when the texture appears smaller on screen than the "
            "source image")
        .def_rw("wrap_u", &Texture::wrap_u, "Texture wrap mode for U coordinate")
        .def_rw("wrap_v", &Texture::wrap_v, "Texture wrap mode for V coordinate")
        .def_rw("scale", &Texture::scale, "Texture scale")
        .def_rw("offset", &Texture::offset, "Texture offset")
        .def_rw("rotation", &Texture::rotation, "Texture rotation")
        .def_rw("extensions", &Texture::extensions, "Texture extensions");
 
    nb::enum_<Texture::WrapMode>(texture, "WrapMode", "Texture wrap mode")
        .value("Wrap", Texture::WrapMode::Wrap, "u|v becomes u%1|v%1")
        .value(
            "Clamp",
            Texture::WrapMode::Clamp,
            "Coordinates outside [0, 1] are clamped to the nearest value")
        .value(
            "Decal",
            Texture::WrapMode::Decal,
            "If the texture coordinates for a pixel are outside [0, 1], the texture is not applied")
        .value("Mirror", Texture::WrapMode::Mirror, "Mirror wrap mode");
    nb::enum_<Texture::TextureFilter>(texture, "TextureFilter", "Texture filter mode")
        .value("Undefined", Texture::TextureFilter::Undefined, "Undefined filter")
        .value("Nearest", Texture::TextureFilter::Nearest, "Nearest neighbor filtering")
        .value("Linear", Texture::TextureFilter::Linear, "Linear filtering")
        .value(
            "NearestMipmapNearest",
            Texture::TextureFilter::NearestMipmapNearest,
            "Nearest mipmap nearest filtering")
        .value(
            "LinearMipmapNearest",
            Texture::TextureFilter::LinearMipmapNearest,
            "Linear mipmap nearest filtering")
        .value(
            "NearestMipmapLinear",
            Texture::TextureFilter::NearestMipmapLinear,
            "Nearest mipmap linear filtering")
        .value(
            "LinearMipmapLinear",
            Texture::TextureFilter::LinearMipmapLinear,
            "Linear mipmap linear filtering");
 
    nb::class_<Light> light(m, "Light", "Light");
    light.def(nb::init<>())
        .def("__repr__", [](const Light& self) { return scene::internal::to_string(self); })
        .def_rw("name", &Light::name, "Light name")
        .def_rw("type", &Light::type, "Light type")
        .def_rw(
            "position",
            &Light::position,
            "Light position. Note that the light is part of the scene graph, and has an associated "
            "transform in its node. This value is relative to the coordinate system defined by the "
            "node")
        .def_rw("direction", &Light::direction, "Light direction")
        .def_rw("up", &Light::up, "Light up vector")
        .def_rw("intensity", &Light::intensity, "Light intensity")
        .def_rw(
            "attenuation_constant",
            &Light::attenuation_constant,
            "Attenuation constant. Intensity of light at a given distance 'd' is: intensity / "
            "(attenuation_constant + attenuation_linear * d + attenuation_quadratic * d * d + "
            "attenuation_cubic * d * d * d)")
        .def_rw("attenuation_linear", &Light::attenuation_linear, "Linear attenuation factor")
        .def_rw(
            "attenuation_quadratic",
            &Light::attenuation_quadratic,
            "Quadratic attenuation factor")
        .def_rw("attenuation_cubic", &Light::attenuation_cubic, "Cubic attenuation factor")
        .def_rw(
            "range",
            &Light::range,
            "Range is defined for point and spot lights. It defines a distance cutoff at which the "
            "light intensity is to be considered zero. When the value is 0, range is assumed to be "
            "infinite")
        .def_rw("color_diffuse", &Light::color_diffuse, "Diffuse color")
        .def_rw("color_specular", &Light::color_specular, "Specular color")
        .def_rw("color_ambient", &Light::color_ambient, "Ambient color")
        .def_rw(
            "angle_inner_cone",
            &Light::angle_inner_cone,
            "Inner angle of a spot light's light cone. 2PI for point lights, undefined for "
            "directional lights")
        .def_rw(
            "angle_outer_cone",
            &Light::angle_outer_cone,
            "Outer angle of a spot light's light cone. 2PI for point lights, undefined for "
            "directional lights")
        .def_rw("size", &Light::size, "Size of area light source")
        .def_rw("extensions", &Light::extensions, "Light extensions");
 
    nb::enum_<Light::Type>(light, "Type", "Light type")
        .value("Undefined", Light::Type::Undefined, "Undefined light type")
        .value("Directional", Light::Type::Directional, "Directional light")
        .value("Point", Light::Type::Point, "Point light")
        .value("Spot", Light::Type::Spot, "Spot light")
        .value("Ambient", Light::Type::Ambient, "Ambient light")
        .value("Area", Light::Type::Area, "Area light");
 
    nb::class_<Camera> camera(m, "Camera", "Camera");
    camera.def(nb::init<>())
        .def("__repr__", [](const Camera& self) { return scene::internal::to_string(self); })
        .def_rw("name", &Camera::name, "Camera name")
        .def_rw(
            "position",
            &Camera::position,
            "Camera position. Note that the camera is part of the scene graph, and has an "
            "associated transform in its node. This value is relative to the coordinate system "
            "defined by the node")
        .def_rw("up", &Camera::up, "Camera up vector")
        .def_rw("look_at", &Camera::look_at, "Camera look-at point")
        .def_rw(
            "near_plane",
            &Camera::near_plane,
            "Distance of the near clipping plane. This value cannot be 0")
        .def_rw("far_plane", &Camera::far_plane, "Distance of the far clipping plane")
        .def_rw("type", &Camera::type, "Camera type")
        .def_rw(
            "aspect_ratio",
            &Camera::aspect_ratio,
            "Screen aspect ratio. This is the value of width / height of the screen. aspect_ratio "
            "= tan(horizontal_fov / 2) / tan(vertical_fov / 2)")
        .def_rw(
            "horizontal_fov",
            &Camera::horizontal_fov,
            "Horizontal field of view angle, in radians. This is the angle between the left and "
            "right borders of the viewport. It should not be greater than Pi. fov is only defined "
            "when the camera type is perspective, otherwise it should be 0")
        .def_rw(
            "orthographic_width",
            &Camera::orthographic_width,
            "Half width of the orthographic view box. Or horizontal magnification. This is only "
            "defined when the camera type is orthographic, otherwise it should be 0")
        .def_prop_ro(
            "get_vertical_fov",
            &Camera::get_vertical_fov,
            "Get the vertical field of view. Make sure aspect_ratio is set before calling this")
        .def(
            "set_horizontal_fov_from_vertical_fov",
            &Camera::set_horizontal_fov_from_vertical_fov,
            "vfov"_a,
            "Set horizontal fov from vertical fov. Make sure aspect_ratio is set before calling "
            "this")
        .def_rw("extensions", &Camera::extensions, "Camera extensions");
 
    nb::enum_<Camera::Type>(camera, "Type", "Camera type")
        .value("Perspective", Camera::Type::Perspective, "Perspective projection")
        .value("Orthographic", Camera::Type::Orthographic, "Orthographic projection");
 
    nb::class_<Animation>(m, "Animation", "Animation")
        .def(nb::init<>())
        .def("__repr__", [](const Animation& self) { return scene::internal::to_string(self); })
        .def_rw("name", &Animation::name, "Animation name")
        .def_rw("extensions", &Animation::extensions, "Animation extensions");
 
 
    nb::class_<Skeleton>(m, "Skeleton", "Skeleton")
        .def(nb::init<>())
        .def("__repr__", [](const Skeleton& self) { return scene::internal::to_string(self); })
        .def_rw(
            "meshes",
            &Skeleton::meshes,
            "This skeleton is used to deform those meshes. This will typically contain one value, "
            "but can have zero or multiple meshes. The value is the index in the scene meshes")
        .def_rw("extensions", &Skeleton::extensions, "Skeleton extensions");
 
 
    nb::class_<SceneType>(m, "Scene", "A 3D scene")
        .def(nb::init<>())
        .def("__repr__", [](const SceneType& self) { return scene::internal::to_string(self); })
        .def_rw("name", &SceneType::name, "Name of the scene")
        .def_rw(
            "nodes",
            &SceneType::nodes,
            "Scene nodes. This is a list of nodes, the hierarchy information is contained by each "
            "node having a list of children as indices to this vector")
        .def_rw(
            "root_nodes",
            &SceneType::root_nodes,
            "Root nodes. This is typically one. Must be at least one")
        .def_rw("meshes", &SceneType::meshes, "Scene meshes")
        .def_rw("images", &SceneType::images, "Images")
        .def_rw("textures", &SceneType::textures, "Textures. They can reference images")
        .def_rw("materials", &SceneType::materials, "Materials. They can reference textures")
        .def_rw("lights", &SceneType::lights, "Lights in the scene")
        .def_rw(
            "cameras",
            &SceneType::cameras,
            "Cameras. The first camera (if any) is the default camera view")
        .def_rw("skeletons", &SceneType::skeletons, "Scene skeletons")
        .def_rw("animations", &SceneType::animations, "Animations (unused for now)")
        .def_rw("extensions", &SceneType::extensions, "Scene extensions")
        .def(
            "add",
            [](SceneType& self,
               std::variant<
                   Node,
                   SceneType::MeshType,
                   ImageExperimental,
                   Texture,
                   MaterialExperimental,
                   Light,
                   Camera,
                   Skeleton,
                   Animation> element) {
                return std::visit(
                    [&](auto&& value) {
                        using T = std::decay_t<decltype(value)>;
                        return self.add(std::forward<T>(value));
                    },
                    element);
            },
            "element"_a,
            R"(Add an element to the scene.
 
:param element: The element to add to the scene. E.g. node, mesh, image, texture, material, light, camera, skeleton, or animation.
 
:returns: The id of the added element.)")
        .def(
            "add_child",
            &SceneType::add_child,
            "parent_id"_a,
            "child_id"_a,
            R"(Add a child node to a parent node. The parent-child relationship will be updated for both nodes.
 
:param parent_id: The parent node id.
:param child_id: The child node id.
 
:returns: The id of the added child node.)");
 
    m.def(
        "compute_global_node_transform",
        [](const SceneType& scene, size_t node_idx) {
            auto t = utils::compute_global_node_transform<Scalar, Index>(scene, node_idx);
            return nb::ndarray<nb::numpy, float, nb::f_contig, nb::shape<4, 4>>(
                t.data(),
                {4, 4},
                nb::handle(), // owner
                {1, 4});
        },
        nb::rv_policy::copy,
        "scene"_a,
        "node_idx"_a,
        R"(Compute the global transform associated with a node.
 
:param scene: The input scene.
:param node_idx: The index of the target node.
 
:returns: The global transform of the target node, which is the combination of transforms from this node all the way to the root.
    )");
 
    m.def(
        "scene_to_mesh",
        [](const SceneType& scene,
           bool normalize_normals,
           bool normalize_tangents_bitangents,
           bool preserve_attributes) {
            TransformOptions transform_options;
            transform_options.normalize_normals = normalize_normals;
            transform_options.normalize_tangents_bitangents = normalize_tangents_bitangents;
            return scene::scene_to_mesh(scene, transform_options, preserve_attributes);
        },
        "scene"_a,
        "normalize_normals"_a = TransformOptions{}.normalize_normals,
        "normalize_tangents_bitangents"_a = TransformOptions{}.normalize_tangents_bitangents,
        "preserve_attributes"_a = true,
        R"(Converts a scene into a concatenated mesh with all the transforms applied.
 
:param scene: Scene to convert.
:param normalize_normals: If enabled, normals are normalized after transformation.
:param normalize_tangents_bitangents: If enabled, tangents and bitangents are normalized after transformation.
:param preserve_attributes: Preserve shared attributes and map them to the output mesh.
 
:return: Concatenated mesh.)");
 
    m.def(
        "mesh_to_scene",
        [](const SceneType::MeshType& mesh) { return scene::mesh_to_scene(mesh); },
        "mesh"_a,
        R"(Converts a single mesh into a scene with a single identity instance of the input mesh.
 
:param mesh: Input mesh to convert.
 
:return: Scene containing the input mesh.)");
 
    m.def(
        "meshes_to_scene",
        [](std::vector<SceneType::MeshType> meshes) {
            return scene::meshes_to_scene(std::move(meshes));
        },
        "meshes"_a,
        R"(Converts a list of meshes into a scene with a single identity instance of each input mesh.
 
:param meshes: Input meshes to convert.
 
:return: Scene containing the input meshes.)");
}
 
} // namespace lagrange::python