move 3rd-party librarys into libs/ and add built-in honeysuckle

1 files changed, 1242 insertions, 0 deletions

diff --git a/libs/assimp/code/AssetLib/glTF2/glTF2Asset.h b/libs/assimp/code/AssetLib/glTF2/glTF2Asset.h
new file mode 100644
index 0000000..c597fc9
--- /dev/null
+++ b/libs/assimp/code/AssetLib/glTF2/glTF2Asset.h
@@ -0,0 +1,1242 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file glTFAsset.h
+ * Declares a glTF class to handle gltf/glb files
+ *
+ * glTF Extensions Support:
+ *   KHR_materials_pbrSpecularGlossiness full
+ *   KHR_materials_unlit full
+ *   KHR_lights_punctual full
+ *   KHR_materials_sheen full
+ *   KHR_materials_clearcoat full
+ *   KHR_materials_transmission full
+ *   KHR_materials_volume full
+ *   KHR_materials_ior full
+ */
+#ifndef GLTF2ASSET_H_INC
+#define GLTF2ASSET_H_INC
+
+#if !defined(ASSIMP_BUILD_NO_GLTF_IMPORTER) && !defined(ASSIMP_BUILD_NO_GLTF2_IMPORTER)
+
+#include <assimp/Exceptional.h>
+
+#include <algorithm>
+#include <list>
+#include <map>
+#include <set>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+// clang-format off
+#if (__GNUC__ == 8 && __GNUC_MINOR__ >= 0)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wclass-memaccess"
+#endif
+
+#include <rapidjson/document.h>
+#include <rapidjson/error/en.h>
+#include <rapidjson/rapidjson.h>
+#include <rapidjson/schema.h>
+
+#if (__GNUC__ == 8 && __GNUC_MINOR__ >= 0)
+#   pragma GCC diagnostic pop
+#endif
+
+#ifdef ASSIMP_API
+#   include <assimp/ByteSwapper.h>
+#   include <assimp/DefaultIOSystem.h>
+#   include <memory>
+#else
+#   include <memory>
+#   define AI_SWAP4(p)
+#   define ai_assert
+#endif
+
+#if _MSC_VER > 1500 || (defined __GNUC___)
+#   define ASSIMP_GLTF_USE_UNORDERED_MULTIMAP
+#else
+#   define gltf_unordered_map map
+#   define gltf_unordered_set set
+#endif
+
+#ifdef ASSIMP_GLTF_USE_UNORDERED_MULTIMAP
+#   include <unordered_map>
+#   include <unordered_set>
+#   if defined(_MSC_VER) && _MSC_VER <= 1600
+#       define gltf_unordered_map tr1::unordered_map
+#       define gltf_unordered_set tr1::unordered_set
+#   else
+#       define gltf_unordered_map unordered_map
+#       define gltf_unordered_set unordered_set
+#   endif
+#endif
+// clang-format on
+
+#include <assimp/StringUtils.h>
+#include <assimp/material.h>
+#include <assimp/GltfMaterial.h>
+
+#include "AssetLib/glTF/glTFCommon.h"
+
+namespace glTF2 {
+
+using glTFCommon::Nullable;
+using glTFCommon::Ref;
+using glTFCommon::IOStream;
+using glTFCommon::IOSystem;
+using glTFCommon::shared_ptr;
+
+using rapidjson::Document;
+using rapidjson::Value;
+
+class Asset;
+class AssetWriter;
+
+struct BufferView; // here due to cross-reference
+struct Texture;
+struct Skin;
+
+using glTFCommon::mat4;
+using glTFCommon::vec3;
+using glTFCommon::vec4;
+
+//! Magic number for GLB files
+#define AI_GLB_MAGIC_NUMBER "glTF"
+
+#ifdef ASSIMP_API
+#include <assimp/Compiler/pushpack1.h>
+#endif
+
+//! For binary .glb files
+//! 12-byte header (+ the JSON + a "body" data section)
+struct GLB_Header {
+    uint8_t magic[4]; //!< Magic number: "glTF"
+    uint32_t version; //!< Version number (always 2 as of the last update)
+    uint32_t length; //!< Total length of the Binary glTF, including header, scene, and body, in bytes
+} PACK_STRUCT;
+
+struct GLB_Chunk {
+    uint32_t chunkLength;
+    uint32_t chunkType;
+} PACK_STRUCT;
+
+#ifdef ASSIMP_API
+#include <assimp/Compiler/poppack1.h>
+#endif
+
+//! Values for the GLB_Chunk::chunkType field
+enum ChunkType {
+    ChunkType_JSON = 0x4E4F534A,
+    ChunkType_BIN = 0x004E4942
+};
+
+//! Values for the mesh primitive modes
+enum PrimitiveMode {
+    PrimitiveMode_POINTS = 0,
+    PrimitiveMode_LINES = 1,
+    PrimitiveMode_LINE_LOOP = 2,
+    PrimitiveMode_LINE_STRIP = 3,
+    PrimitiveMode_TRIANGLES = 4,
+    PrimitiveMode_TRIANGLE_STRIP = 5,
+    PrimitiveMode_TRIANGLE_FAN = 6
+};
+
+//! Values for the Accessor::componentType field
+enum ComponentType {
+    ComponentType_BYTE = 5120,
+    ComponentType_UNSIGNED_BYTE = 5121,
+    ComponentType_SHORT = 5122,
+    ComponentType_UNSIGNED_SHORT = 5123,
+    ComponentType_UNSIGNED_INT = 5125,
+    ComponentType_FLOAT = 5126
+};
+
+inline unsigned int ComponentTypeSize(ComponentType t) {
+    switch (t) {
+    case ComponentType_SHORT:
+    case ComponentType_UNSIGNED_SHORT:
+        return 2;
+
+    case ComponentType_UNSIGNED_INT:
+    case ComponentType_FLOAT:
+        return 4;
+
+    case ComponentType_BYTE:
+    case ComponentType_UNSIGNED_BYTE:
+        return 1;
+    default:
+        throw DeadlyImportError("GLTF: Unsupported Component Type ", ai_to_string(t));
+    }
+}
+
+//! Values for the BufferView::target field
+enum BufferViewTarget {
+    BufferViewTarget_NONE = 0,
+    BufferViewTarget_ARRAY_BUFFER = 34962,
+    BufferViewTarget_ELEMENT_ARRAY_BUFFER = 34963
+};
+
+//! Values for the Sampler::magFilter field
+enum class SamplerMagFilter : unsigned int {
+    UNSET = 0,
+    SamplerMagFilter_Nearest = 9728,
+    SamplerMagFilter_Linear = 9729
+};
+
+//! Values for the Sampler::minFilter field
+enum class SamplerMinFilter : unsigned int {
+    UNSET = 0,
+    SamplerMinFilter_Nearest = 9728,
+    SamplerMinFilter_Linear = 9729,
+    SamplerMinFilter_Nearest_Mipmap_Nearest = 9984,
+    SamplerMinFilter_Linear_Mipmap_Nearest = 9985,
+    SamplerMinFilter_Nearest_Mipmap_Linear = 9986,
+    SamplerMinFilter_Linear_Mipmap_Linear = 9987
+};
+
+//! Values for the Sampler::wrapS and Sampler::wrapT field
+enum class SamplerWrap : unsigned int {
+    UNSET = 0,
+    Clamp_To_Edge = 33071,
+    Mirrored_Repeat = 33648,
+    Repeat = 10497
+};
+
+//! Values for the Texture::format and Texture::internalFormat fields
+enum TextureFormat {
+    TextureFormat_ALPHA = 6406,
+    TextureFormat_RGB = 6407,
+    TextureFormat_RGBA = 6408,
+    TextureFormat_LUMINANCE = 6409,
+    TextureFormat_LUMINANCE_ALPHA = 6410
+};
+
+//! Values for the Texture::target field
+enum TextureTarget {
+    TextureTarget_TEXTURE_2D = 3553
+};
+
+//! Values for the Texture::type field
+enum TextureType {
+    TextureType_UNSIGNED_BYTE = 5121,
+    TextureType_UNSIGNED_SHORT_5_6_5 = 33635,
+    TextureType_UNSIGNED_SHORT_4_4_4_4 = 32819,
+    TextureType_UNSIGNED_SHORT_5_5_5_1 = 32820
+};
+
+//! Values for the Animation::Target::path field
+enum AnimationPath {
+    AnimationPath_TRANSLATION,
+    AnimationPath_ROTATION,
+    AnimationPath_SCALE,
+    AnimationPath_WEIGHTS,
+};
+
+//! Values for the Animation::Sampler::interpolation field
+enum Interpolation {
+    Interpolation_LINEAR,
+    Interpolation_STEP,
+    Interpolation_CUBICSPLINE,
+};
+
+//! Values for the Accessor::type field (helper class)
+class AttribType {
+public:
+    enum Value { SCALAR,
+        VEC2,
+        VEC3,
+        VEC4,
+        MAT2,
+        MAT3,
+        MAT4 };
+
+private:
+    static const size_t NUM_VALUES = static_cast<size_t>(MAT4) + 1;
+
+    struct Info {
+        const char *name;
+        unsigned int numComponents;
+    };
+
+    template <int N>
+    struct data { static const Info infos[NUM_VALUES]; };
+
+public:
+    inline static Value FromString(const char *str) {
+        for (size_t i = 0; i < NUM_VALUES; ++i) {
+            if (strcmp(data<0>::infos[i].name, str) == 0) {
+                return static_cast<Value>(i);
+            }
+        }
+        return SCALAR;
+    }
+
+    inline static const char *ToString(Value type) {
+        return data<0>::infos[static_cast<size_t>(type)].name;
+    }
+
+    inline static unsigned int GetNumComponents(Value type) {
+        return data<0>::infos[static_cast<size_t>(type)].numComponents;
+    }
+};
+
+// must match the order of the AttribTypeTraits::Value enum!
+template <int N>
+const AttribType::Info
+        AttribType::data<N>::infos[AttribType::NUM_VALUES] = {
+            { "SCALAR", 1 }, { "VEC2", 2 }, { "VEC3", 3 }, { "VEC4", 4 }, { "MAT2", 4 }, { "MAT3", 9 }, { "MAT4", 16 }
+        };
+
+
+struct CustomExtension {
+
+    //
+    // A struct containing custom extension data added to a glTF2 file
+    // Has to contain Object, Array, String, Double, Uint64, and Int64 at a minimum
+    // String, Double, Uint64, and Int64 are stored in the Nullables
+    // Object and Array are stored in the std::vector
+    //
+    std::string name;
+
+    Nullable<std::string> mStringValue;
+    Nullable<double> mDoubleValue;
+    Nullable<uint64_t> mUint64Value;
+    Nullable<int64_t> mInt64Value;
+    Nullable<bool> mBoolValue;
+
+    // std::vector<CustomExtension> handles both Object and Array
+    Nullable<std::vector<CustomExtension>> mValues;
+
+    operator bool() const {
+        return Size() != 0;
+    }
+
+    size_t Size() const {
+        if (mValues.isPresent) {
+            return mValues.value.size();
+        } else if (mStringValue.isPresent || mDoubleValue.isPresent || mUint64Value.isPresent || mInt64Value.isPresent || mBoolValue.isPresent) {
+            return 1;
+        }
+        return 0;
+    }
+
+    CustomExtension() = default;
+
+    ~CustomExtension() = default;
+
+    CustomExtension(const CustomExtension &other) :
+            name(other.name),
+            mStringValue(other.mStringValue),
+            mDoubleValue(other.mDoubleValue),
+            mUint64Value(other.mUint64Value),
+            mInt64Value(other.mInt64Value),
+            mBoolValue(other.mBoolValue),
+            mValues(other.mValues) {
+        // empty
+    }
+};
+
+//! Base class for all glTF top-level objects
+struct Object {
+    int index; //!< The index of this object within its property container
+    int oIndex; //!< The original index of this object defined in the JSON
+    std::string id; //!< The globally unique ID used to reference this object
+    std::string name; //!< The user-defined name of this object
+
+    CustomExtension customExtensions;
+    CustomExtension extras;
+
+    //! Objects marked as special are not exported (used to emulate the binary body buffer)
+    virtual bool IsSpecial() const { return false; }
+
+    virtual ~Object() {}
+
+    //! Maps special IDs to another ID, where needed. Subclasses may override it (statically)
+    static const char *TranslateId(Asset & /*r*/, const char *id) { return id; }
+
+    inline Value *FindString(Value &val, const char *id);
+    inline Value *FindNumber(Value &val, const char *id);
+    inline Value *FindUInt(Value &val, const char *id);
+    inline Value *FindArray(Value &val, const char *id);
+    inline Value *FindObject(Value &val, const char *id);
+    inline Value *FindExtension(Value &val, const char *extensionId);
+
+    inline void ReadExtensions(Value &val);
+    inline void ReadExtras(Value &val);
+};
+
+//
+// Classes for each glTF top-level object type
+//
+
+//! A buffer points to binary geometry, animation, or skins.
+struct Buffer : public Object {
+    /********************* Types *********************/
+public:
+    enum Type {
+        Type_arraybuffer,
+        Type_text
+    };
+
+    /// \struct SEncodedRegion
+    /// Descriptor of encoded region in "bufferView".
+    struct SEncodedRegion {
+        const size_t Offset; ///< Offset from begin of "bufferView" to encoded region, in bytes.
+        const size_t EncodedData_Length; ///< Size of encoded region, in bytes.
+        uint8_t *const DecodedData; ///< Cached encoded data.
+        const size_t DecodedData_Length; ///< Size of decoded region, in bytes.
+        const std::string ID; ///< ID of the region.
+
+        /// \fn SEncodedRegion(const size_t pOffset, const size_t pEncodedData_Length, uint8_t* pDecodedData, const size_t pDecodedData_Length, const std::string pID)
+        /// Constructor.
+        /// \param [in] pOffset - offset from begin of "bufferView" to encoded region, in bytes.
+        /// \param [in] pEncodedData_Length - size of encoded region, in bytes.
+        /// \param [in] pDecodedData - pointer to decoded data array.
+        /// \param [in] pDecodedData_Length - size of encoded region, in bytes.
+        /// \param [in] pID - ID of the region.
+        SEncodedRegion(const size_t pOffset, const size_t pEncodedData_Length, uint8_t *pDecodedData, const size_t pDecodedData_Length, const std::string &pID) :
+                Offset(pOffset),
+                EncodedData_Length(pEncodedData_Length),
+                DecodedData(pDecodedData),
+                DecodedData_Length(pDecodedData_Length),
+                ID(pID) {}
+
+        /// \fn ~SEncodedRegion()
+        /// Destructor.
+        ~SEncodedRegion() { delete[] DecodedData; }
+    };
+
+    /******************* Variables *******************/
+
+    //std::string uri; //!< The uri of the buffer. Can be a filepath, a data uri, etc. (required)
+    size_t byteLength; //!< The length of the buffer in bytes. (default: 0)
+    //std::string type; //!< XMLHttpRequest responseType (default: "arraybuffer")
+    size_t capacity = 0; //!< The capacity of the buffer in bytes. (default: 0)
+
+    Type type;
+
+    /// \var EncodedRegion_Current
+    /// Pointer to currently active encoded region.
+    /// Why not decoding all regions at once and not to set one buffer with decoded data?
+    /// Yes, why not? Even "accessor" point to decoded data. I mean that fields "byteOffset", "byteStride" and "count" has values which describes decoded
+    /// data array. But only in range of mesh while is active parameters from "compressedData". For another mesh accessors point to decoded data too. But
+    /// offset is counted for another regions is encoded.
+    /// Example. You have two meshes. For every of it you have 4 bytes of data. That data compressed to 2 bytes. So, you have buffer with encoded data:
+    /// M1_E0, M1_E1, M2_E0, M2_E1.
+    /// After decoding you'll get:
+    /// M1_D0, M1_D1, M1_D2, M1_D3, M2_D0, M2_D1, M2_D2, M2_D3.
+    /// "accessors" must to use values that point to decoded data - obviously. So, you'll expect "accessors" like
+    /// "accessor_0" : { byteOffset: 0, byteLength: 4}, "accessor_1" : { byteOffset: 4, byteLength: 4}
+    /// but in real life you'll get:
+    /// "accessor_0" : { byteOffset: 0, byteLength: 4}, "accessor_1" : { byteOffset: 2, byteLength: 4}
+    /// Yes, accessor of next mesh has offset and length which mean: current mesh data is decoded, all other data is encoded.
+    /// And when before you start to read data of current mesh (with encoded data of course) you must decode region of "bufferView", after read finished
+    /// delete encoding mark. And after that you can repeat process: decode data of mesh, read, delete decoded data.
+    ///
+    /// Remark. Encoding all data at once is good in world with computers which do not has RAM limitation. So, you must use step by step encoding in
+    /// exporter and importer. And, thanks to such way, there is no need to load whole file into memory.
+    SEncodedRegion *EncodedRegion_Current;
+
+private:
+    shared_ptr<uint8_t> mData; //!< Pointer to the data
+    bool mIsSpecial; //!< Set to true for special cases (e.g. the body buffer)
+
+    /// \var EncodedRegion_List
+    /// List of encoded regions.
+    std::list<SEncodedRegion *> EncodedRegion_List;
+
+    /******************* Functions *******************/
+
+public:
+    Buffer();
+    ~Buffer();
+
+    void Read(Value &obj, Asset &r);
+
+    bool LoadFromStream(IOStream &stream, size_t length = 0, size_t baseOffset = 0);
+
+    /// \fn void EncodedRegion_Mark(const size_t pOffset, const size_t pEncodedData_Length, uint8_t* pDecodedData, const size_t pDecodedData_Length, const std::string& pID)
+    /// Mark region of "bufferView" as encoded. When data is request from such region then "bufferView" use decoded data.
+    /// \param [in] pOffset - offset from begin of "bufferView" to encoded region, in bytes.
+    /// \param [in] pEncodedData_Length - size of encoded region, in bytes.
+    /// \param [in] pDecodedData - pointer to decoded data array.
+    /// \param [in] pDecodedData_Length - size of encoded region, in bytes.
+    /// \param [in] pID - ID of the region.
+    void EncodedRegion_Mark(const size_t pOffset, const size_t pEncodedData_Length, uint8_t *pDecodedData, const size_t pDecodedData_Length, const std::string &pID);
+
+    /// \fn void EncodedRegion_SetCurrent(const std::string& pID)
+    /// Select current encoded region by ID. \sa EncodedRegion_Current.
+    /// \param [in] pID - ID of the region.
+    void EncodedRegion_SetCurrent(const std::string &pID);
+
+    /// \fn bool ReplaceData(const size_t pBufferData_Offset, const size_t pBufferData_Count, const uint8_t* pReplace_Data, const size_t pReplace_Count)
+    /// Replace part of buffer data. Pay attention that function work with original array of data (\ref mData) not with encoded regions.
+    /// \param [in] pBufferData_Offset - index of first element in buffer from which new data will be placed.
+    /// \param [in] pBufferData_Count - count of bytes in buffer which will be replaced.
+    /// \param [in] pReplace_Data - pointer to array with new data for buffer.
+    /// \param [in] pReplace_Count - count of bytes in new data.
+    /// \return true - if successfully replaced, false if input arguments is out of range.
+    bool ReplaceData(const size_t pBufferData_Offset, const size_t pBufferData_Count, const uint8_t *pReplace_Data, const size_t pReplace_Count);
+    bool ReplaceData_joint(const size_t pBufferData_Offset, const size_t pBufferData_Count, const uint8_t *pReplace_Data, const size_t pReplace_Count);
+
+    size_t AppendData(uint8_t *data, size_t length);
+    void Grow(size_t amount);
+
+    uint8_t *GetPointer() { return mData.get(); }
+
+    void MarkAsSpecial() { mIsSpecial = true; }
+
+    bool IsSpecial() const override { return mIsSpecial; }
+
+    std::string GetURI() { return std::string(this->id) + ".bin"; }
+
+    static const char *TranslateId(Asset &r, const char *id);
+};
+
+//! A view into a buffer generally representing a subset of the buffer.
+struct BufferView : public Object {
+    Ref<Buffer> buffer; //! The ID of the buffer. (required)
+    size_t byteOffset; //! The offset into the buffer in bytes. (required)
+    size_t byteLength; //! The length of the bufferView in bytes. (default: 0)
+    unsigned int byteStride; //!< The stride, in bytes, between attributes referenced by this accessor. (default: 0)
+
+    BufferViewTarget target; //! The target that the WebGL buffer should be bound to.
+
+    void Read(Value &obj, Asset &r);
+    uint8_t *GetPointer(size_t accOffset);
+};
+
+//! A typed view into a BufferView. A BufferView contains raw binary data.
+//! An accessor provides a typed view into a BufferView or a subset of a BufferView
+//! similar to how WebGL's vertexAttribPointer() defines an attribute in a buffer.
+struct Accessor : public Object {
+    struct Sparse;
+
+    Ref<BufferView> bufferView; //!< The ID of the bufferView. (required)
+    size_t byteOffset; //!< The offset relative to the start of the bufferView in bytes. (required)
+    ComponentType componentType; //!< The datatype of components in the attribute. (required)
+    size_t count; //!< The number of attributes referenced by this accessor. (required)
+    AttribType::Value type; //!< Specifies if the attribute is a scalar, vector, or matrix. (required)
+    std::vector<double> max; //!< Maximum value of each component in this attribute.
+    std::vector<double> min; //!< Minimum value of each component in this attribute.
+    std::unique_ptr<Sparse> sparse;
+    std::unique_ptr<Buffer> decodedBuffer; // Packed decoded data, returned instead of original bufferView if present
+
+    unsigned int GetNumComponents();
+    unsigned int GetBytesPerComponent();
+    unsigned int GetElementSize();
+
+    inline uint8_t *GetPointer();
+    inline size_t GetStride();
+    inline size_t GetMaxByteSize();
+
+    template <class T>
+    void ExtractData(T *&outData);
+
+    void WriteData(size_t count, const void *src_buffer, size_t src_stride);
+    void WriteSparseValues(size_t count, const void *src_data, size_t src_dataStride);
+    void WriteSparseIndices(size_t count, const void *src_idx, size_t src_idxStride);
+
+    //! Helper class to iterate the data
+    class Indexer {
+        friend struct Accessor;
+
+        // This field is reported as not used, making it protectd is the easiest way to work around it without going to the bottom of what the problem is:
+        // ../code/glTF2/glTF2Asset.h:392:19: error: private field 'accessor' is not used [-Werror,-Wunused-private-field]
+    protected:
+        Accessor &accessor;
+
+    private:
+        uint8_t *data;
+        size_t elemSize, stride;
+
+        Indexer(Accessor &acc);
+
+    public:
+        //! Accesses the i-th value as defined by the accessor
+        template <class T>
+        T GetValue(int i);
+
+        //! Accesses the i-th value as defined by the accessor
+        inline unsigned int GetUInt(int i) {
+            return GetValue<unsigned int>(i);
+        }
+
+        inline bool IsValid() const {
+            return data != nullptr;
+        }
+    };
+
+    inline Indexer GetIndexer() {
+        return Indexer(*this);
+    }
+
+    Accessor() {}
+    void Read(Value &obj, Asset &r);
+
+    //sparse
+    struct Sparse {
+        size_t count;
+        ComponentType indicesType;
+        Ref<BufferView> indices;
+        size_t indicesByteOffset;
+        Ref<BufferView> values;
+        size_t valuesByteOffset;
+
+        std::vector<uint8_t> data; //!< Actual data, which may be defaulted to an array of zeros or the original data, with the sparse buffer view applied on top of it.
+
+        void PopulateData(size_t numBytes, uint8_t *bytes);
+        void PatchData(unsigned int elementSize);
+    };
+};
+
+struct Camera : public Object {
+    enum Type {
+        Perspective,
+        Orthographic
+    };
+
+    Type type;
+
+    union {
+        struct {
+            float aspectRatio; //!<The floating - point aspect ratio of the field of view. (0 = undefined = use the canvas one)
+            float yfov; //!<The floating - point vertical field of view in radians. (required)
+            float zfar; //!<The floating - point distance to the far clipping plane. (required)
+            float znear; //!< The floating - point distance to the near clipping plane. (required)
+        } perspective;
+
+        struct {
+            float xmag; //! The floating-point horizontal magnification of the view. (required)
+            float ymag; //! The floating-point vertical magnification of the view. (required)
+            float zfar; //! The floating-point distance to the far clipping plane. (required)
+            float znear; //! The floating-point distance to the near clipping plane. (required)
+        } ortographic;
+    } cameraProperties;
+
+    Camera() :
+            type(Perspective),
+            cameraProperties() {
+        // empty
+    }
+    void Read(Value &obj, Asset &r);
+};
+
+//! A light (from KHR_lights_punctual extension)
+struct Light : public Object {
+    enum Type {
+        Directional,
+        Point,
+        Spot
+    };
+
+    Type type;
+
+    vec3 color;
+    float intensity;
+    Nullable<float> range;
+
+    float innerConeAngle;
+    float outerConeAngle;
+
+    Light() {}
+    void Read(Value &obj, Asset &r);
+};
+
+//! Image data used to create a texture.
+struct Image : public Object {
+    std::string uri; //! The uri of the image, that can be a file path, a data URI, etc.. (required)
+
+    Ref<BufferView> bufferView;
+
+    std::string mimeType;
+
+    int width, height;
+
+private:
+    std::unique_ptr<uint8_t[]> mData;
+    size_t mDataLength;
+
+public:
+    Image();
+    void Read(Value &obj, Asset &r);
+
+    inline bool HasData() const { return mDataLength > 0; }
+
+    inline size_t GetDataLength() const { return mDataLength; }
+
+    inline const uint8_t *GetData() const { return mData.get(); }
+
+    inline uint8_t *StealData();
+
+    inline void SetData(uint8_t *data, size_t length, Asset &r);
+};
+
+const vec4 defaultBaseColor = { 1, 1, 1, 1 };
+const vec3 defaultEmissiveFactor = { 0, 0, 0 };
+const vec4 defaultDiffuseFactor = { 1, 1, 1, 1 };
+const vec3 defaultSpecularFactor = { 1, 1, 1 };
+const vec3 defaultSheenFactor = { 0, 0, 0 };
+const vec3 defaultAttenuationColor = { 1, 1, 1 };
+
+struct TextureInfo {
+    Ref<Texture> texture;
+    unsigned int index;
+    unsigned int texCoord = 0;
+
+    bool textureTransformSupported = false;
+    struct TextureTransformExt {
+        float offset[2];
+        float rotation;
+        float scale[2];
+    } TextureTransformExt_t;
+};
+
+struct NormalTextureInfo : TextureInfo {
+    float scale = 1;
+};
+
+struct OcclusionTextureInfo : TextureInfo {
+    float strength = 1;
+};
+
+struct PbrMetallicRoughness {
+    vec4 baseColorFactor;
+    TextureInfo baseColorTexture;
+    TextureInfo metallicRoughnessTexture;
+    float metallicFactor;
+    float roughnessFactor;
+};
+
+struct PbrSpecularGlossiness {
+    vec4 diffuseFactor;
+    vec3 specularFactor;
+    float glossinessFactor;
+    TextureInfo diffuseTexture;
+    TextureInfo specularGlossinessTexture;
+
+    PbrSpecularGlossiness() { SetDefaults(); }
+    void SetDefaults();
+};
+
+struct MaterialSheen {
+    vec3 sheenColorFactor;
+    float sheenRoughnessFactor;
+    TextureInfo sheenColorTexture;
+    TextureInfo sheenRoughnessTexture;
+
+    MaterialSheen() { SetDefaults(); }
+    void SetDefaults();
+};
+
+struct MaterialClearcoat {
+    float clearcoatFactor = 0.f;
+    float clearcoatRoughnessFactor = 0.f;
+    TextureInfo clearcoatTexture;
+    TextureInfo clearcoatRoughnessTexture;
+    NormalTextureInfo clearcoatNormalTexture;
+};
+
+struct MaterialTransmission {
+    TextureInfo transmissionTexture;
+    float transmissionFactor = 0.f;
+};
+
+struct MaterialVolume {
+    float thicknessFactor = 0.f;
+    TextureInfo thicknessTexture;
+    float attenuationDistance = 0.f;
+    vec3 attenuationColor;
+
+    MaterialVolume() { SetDefaults(); }
+    void SetDefaults();
+};
+
+struct MaterialIOR {
+    float ior = 0.f;
+
+    MaterialIOR() { SetDefaults(); }
+    void SetDefaults();
+};
+
+//! The material appearance of a primitive.
+struct Material : public Object {
+    //PBR metallic roughness properties
+    PbrMetallicRoughness pbrMetallicRoughness;
+
+    //other basic material properties
+    NormalTextureInfo normalTexture;
+    OcclusionTextureInfo occlusionTexture;
+    TextureInfo emissiveTexture;
+    vec3 emissiveFactor;
+    std::string alphaMode;
+    float alphaCutoff;
+    bool doubleSided;
+
+    //extension: KHR_materials_pbrSpecularGlossiness
+    Nullable<PbrSpecularGlossiness> pbrSpecularGlossiness;
+
+    //extension: KHR_materials_sheen
+    Nullable<MaterialSheen> materialSheen;
+
+    //extension: KHR_materials_clearcoat
+    Nullable<MaterialClearcoat> materialClearcoat;
+
+    //extension: KHR_materials_transmission
+    Nullable<MaterialTransmission> materialTransmission;
+
+    //extension: KHR_materials_volume
+    Nullable<MaterialVolume> materialVolume;
+
+    //extension: KHR_materials_ior
+    Nullable<MaterialIOR> materialIOR;
+    
+    //extension: KHR_materials_unlit
+    bool unlit;
+
+    Material() { SetDefaults(); }
+    void Read(Value &obj, Asset &r);
+    void SetDefaults();
+
+    inline void SetTextureProperties(Asset &r, Value *prop, TextureInfo &out);
+    inline void ReadTextureProperty(Asset &r, Value &vals, const char *propName, TextureInfo &out);
+    inline void ReadTextureProperty(Asset &r, Value &vals, const char *propName, NormalTextureInfo &out);
+    inline void ReadTextureProperty(Asset &r, Value &vals, const char *propName, OcclusionTextureInfo &out);
+};
+
+//! A set of primitives to be rendered. A node can contain one or more meshes. A node's transform places the mesh in the scene.
+struct Mesh : public Object {
+    using AccessorList = std::vector<Ref<Accessor>>;
+
+    struct Primitive {
+        PrimitiveMode mode;
+
+        struct Attributes {
+            AccessorList position, normal, tangent, texcoord, color, joint, jointmatrix, weight;
+        } attributes;
+
+        Ref<Accessor> indices;
+
+        Ref<Material> material;
+
+        struct Target {
+            AccessorList position, normal, tangent;
+        };
+        std::vector<Target> targets;
+
+        // extension: FB_ngon_encoding
+        bool ngonEncoded;
+
+        Primitive(): ngonEncoded(false) {}
+    };
+
+    std::vector<Primitive> primitives;
+
+    std::vector<float> weights;
+    std::vector<std::string> targetNames;
+
+    Mesh() {}
+
+    /// Get mesh data from JSON-object and place them to root asset.
+    /// \param [in] pJSON_Object - reference to pJSON-object from which data are read.
+    /// \param [out] pAsset_Root - reference to root asset where data will be stored.
+    void Read(Value &pJSON_Object, Asset &pAsset_Root);
+};
+
+struct Node : public Object {
+    std::vector<Ref<Node>> children;
+    std::vector<Ref<Mesh>> meshes;
+
+    Nullable<mat4> matrix;
+    Nullable<vec3> translation;
+    Nullable<vec4> rotation;
+    Nullable<vec3> scale;
+
+    Ref<Camera> camera;
+    Ref<Light> light;
+
+    std::vector<Ref<Node>> skeletons; //!< The ID of skeleton nodes. Each of which is the root of a node hierarchy.
+    Ref<Skin> skin; //!< The ID of the skin referenced by this node.
+    std::string jointName; //!< Name used when this node is a joint in a skin.
+
+    Ref<Node> parent; //!< This is not part of the glTF specification. Used as a helper.
+
+    Node() {}
+    void Read(Value &obj, Asset &r);
+};
+
+struct Program : public Object {
+    Program() {}
+    void Read(Value &obj, Asset &r);
+};
+
+struct Sampler : public Object {
+    SamplerMagFilter magFilter; //!< The texture magnification filter.
+    SamplerMinFilter minFilter; //!< The texture minification filter.
+    SamplerWrap wrapS; //!< The texture wrapping in the S direction.
+    SamplerWrap wrapT; //!< The texture wrapping in the T direction.
+
+    Sampler() { SetDefaults(); }
+    void Read(Value &obj, Asset &r);
+    void SetDefaults();
+};
+
+struct Scene : public Object {
+    std::string name;
+    std::vector<Ref<Node>> nodes;
+
+    Scene() {}
+    void Read(Value &obj, Asset &r);
+};
+
+struct Shader : public Object {
+    Shader() {}
+    void Read(Value &obj, Asset &r);
+};
+
+struct Skin : public Object {
+    Nullable<mat4> bindShapeMatrix; //!< Floating-point 4x4 transformation matrix stored in column-major order.
+    Ref<Accessor> inverseBindMatrices; //!< The ID of the accessor containing the floating-point 4x4 inverse-bind matrices.
+    std::vector<Ref<Node>> jointNames; //!< Joint names of the joints (nodes with a jointName property) in this skin.
+    std::string name; //!< The user-defined name of this object.
+
+    Skin() {}
+    void Read(Value &obj, Asset &r);
+};
+
+//! A texture and its sampler.
+struct Texture : public Object {
+    Ref<Sampler> sampler; //!< The ID of the sampler used by this texture. (required)
+    Ref<Image> source; //!< The ID of the image used by this texture. (required)
+
+    //TextureFormat format; //!< The texture's format. (default: TextureFormat_RGBA)
+    //TextureFormat internalFormat; //!< The texture's internal format. (default: TextureFormat_RGBA)
+
+    //TextureTarget target; //!< The target that the WebGL texture should be bound to. (default: TextureTarget_TEXTURE_2D)
+    //TextureType type; //!< Texel datatype. (default: TextureType_UNSIGNED_BYTE)
+
+    Texture() {}
+    void Read(Value &obj, Asset &r);
+};
+
+struct Animation : public Object {
+    struct Sampler {
+        Sampler() :
+                interpolation(Interpolation_LINEAR) {}
+
+        Ref<Accessor> input; //!< Accessor reference to the buffer storing the key-frame times.
+        Ref<Accessor> output; //!< Accessor reference to the buffer storing the key-frame values.
+        Interpolation interpolation; //!< Type of interpolation algorithm to use between key-frames.
+    };
+
+    struct Target {
+        Target() :
+                path(AnimationPath_TRANSLATION) {}
+
+        Ref<Node> node; //!< The node to animate.
+        AnimationPath path; //!< The property of the node to animate.
+    };
+
+    struct Channel {
+        Channel() :
+                sampler(-1) {}
+
+        int sampler; //!< The sampler index containing the animation data.
+        Target target; //!< The node and property to animate.
+    };
+
+    std::vector<Sampler> samplers; //!< All the key-frame data for this animation.
+    std::vector<Channel> channels; //!< Data to connect nodes to key-frames.
+
+    Animation() {}
+    void Read(Value &obj, Asset &r);
+};
+
+//! Base class for LazyDict that acts as an interface
+class LazyDictBase {
+public:
+    virtual ~LazyDictBase() {}
+
+    virtual void AttachToDocument(Document &doc) = 0;
+    virtual void DetachFromDocument() = 0;
+
+#if !defined(ASSIMP_BUILD_NO_EXPORT)
+    virtual void WriteObjects(AssetWriter &writer) = 0;
+#endif
+};
+
+template <class T>
+class LazyDict;
+
+//! (Implemented in glTFAssetWriter.h)
+template <class T>
+void WriteLazyDict(LazyDict<T> &d, AssetWriter &w);
+
+//! Manages lazy loading of the glTF top-level objects, and keeps a reference to them by ID
+//! It is the owner the loaded objects, so when it is destroyed it also deletes them
+template <class T>
+class LazyDict : public LazyDictBase {
+    friend class Asset;
+    friend class AssetWriter;
+
+    using Dict = typename std::gltf_unordered_map<unsigned int, unsigned int>;
+    using IdDict = typename std::gltf_unordered_map<std::string, unsigned int>;
+
+    std::vector<T *> mObjs; //! The read objects
+    Dict mObjsByOIndex; //! The read objects accessible by original index
+    IdDict mObjsById; //! The read objects accessible by id
+    const char *mDictId; //! ID of the dictionary object
+    const char *mExtId; //! ID of the extension defining the dictionary
+    Value *mDict; //! JSON dictionary object
+    Asset &mAsset; //! The asset instance
+
+    std::gltf_unordered_set<unsigned int> mRecursiveReferenceCheck; //! Used by Retrieve to prevent recursive lookups
+
+    void AttachToDocument(Document &doc);
+    void DetachFromDocument();
+
+#if !defined(ASSIMP_BUILD_NO_EXPORT)
+    void WriteObjects(AssetWriter &writer) { WriteLazyDict<T>(*this, writer); }
+#endif
+
+    Ref<T> Add(T *obj);
+
+public:
+    LazyDict(Asset &asset, const char *dictId, const char *extId = 0);
+    ~LazyDict();
+
+    Ref<T> Retrieve(unsigned int i);
+
+    Ref<T> Get(unsigned int i);
+    Ref<T> Get(const char *id);
+
+    Ref<T> Create(const char *id);
+    Ref<T> Create(const std::string &id) { return Create(id.c_str()); }
+
+    unsigned int Remove(const char *id);
+
+    inline unsigned int Size() const { return unsigned(mObjs.size()); }
+
+    inline T &operator[](size_t i) { return *mObjs[i]; }
+};
+
+struct AssetMetadata {
+    std::string copyright; //!< A copyright message suitable for display to credit the content creator.
+    std::string generator; //!< Tool that generated this glTF model.Useful for debugging.
+
+    struct {
+        std::string api; //!< Specifies the target rendering API (default: "WebGL")
+        std::string version; //!< Specifies the target rendering API (default: "1.0.3")
+    } profile; //!< Specifies the target rendering API and version, e.g., WebGL 1.0.3. (default: {})
+
+    std::string version; //!< The glTF format version
+
+    void Read(Document &doc);
+
+    AssetMetadata() :
+            version() {}
+};
+
+//
+// glTF Asset class
+//
+
+//! Root object for a glTF asset
+class Asset {
+    using IdMap = std::gltf_unordered_map<std::string, int>;
+
+    template <class T>
+    friend class LazyDict;
+    friend struct Buffer; // To access OpenFile
+    friend class AssetWriter;
+
+    std::vector<LazyDictBase *> mDicts;
+
+public:
+    //! Keeps info about the enabled extensions
+    struct Extensions {
+        bool KHR_materials_pbrSpecularGlossiness;
+        bool KHR_materials_unlit;
+        bool KHR_lights_punctual;
+        bool KHR_texture_transform;
+        bool KHR_materials_sheen;
+        bool KHR_materials_clearcoat;
+        bool KHR_materials_transmission;
+        bool KHR_materials_volume;
+        bool KHR_materials_ior;
+        bool KHR_draco_mesh_compression;
+        bool FB_ngon_encoding;
+        bool KHR_texture_basisu;
+
+        Extensions() :
+                KHR_materials_pbrSpecularGlossiness(false), 
+                KHR_materials_unlit(false), 
+                KHR_lights_punctual(false), 
+                KHR_texture_transform(false), 
+                KHR_materials_sheen(false), 
+                KHR_materials_clearcoat(false), 
+                KHR_materials_transmission(false), 
+                KHR_materials_volume(false),
+                KHR_materials_ior(false),
+                KHR_draco_mesh_compression(false),
+                FB_ngon_encoding(false),
+                KHR_texture_basisu(false) {
+            // empty
+        }
+    } extensionsUsed;
+
+    //! Keeps info about the required extensions
+    struct RequiredExtensions {
+        bool KHR_draco_mesh_compression;
+        bool KHR_texture_basisu;
+
+        RequiredExtensions() : KHR_draco_mesh_compression(false), KHR_texture_basisu(false) {
+            // empty
+        }
+    } extensionsRequired;
+
+    AssetMetadata asset;
+    Value *extras;
+
+    // Dictionaries for each type of object
+
+    LazyDict<Accessor> accessors;
+    LazyDict<Animation> animations;
+    LazyDict<Buffer> buffers;
+    LazyDict<BufferView> bufferViews;
+    LazyDict<Camera> cameras;
+    LazyDict<Light> lights;
+    LazyDict<Image> images;
+    LazyDict<Material> materials;
+    LazyDict<Mesh> meshes;
+    LazyDict<Node> nodes;
+    LazyDict<Sampler> samplers;
+    LazyDict<Scene> scenes;
+    LazyDict<Skin> skins;
+    LazyDict<Texture> textures;
+
+    Ref<Scene> scene;
+
+public:
+    Asset(IOSystem *io = nullptr, rapidjson::IRemoteSchemaDocumentProvider *schemaDocumentProvider = nullptr) :
+            mDicts(),
+            extensionsUsed(),
+            extensionsRequired(),
+            asset(),
+            extras(nullptr),
+            accessors(*this, "accessors"),
+            animations(*this, "animations"),
+            buffers(*this, "buffers"),
+            bufferViews(*this, "bufferViews"),
+            cameras(*this, "cameras"),
+            lights(*this, "lights", "KHR_lights_punctual"),
+            images(*this, "images"),
+            materials(*this, "materials"),
+            meshes(*this, "meshes"),
+            nodes(*this, "nodes"),
+            samplers(*this, "samplers"),
+            scenes(*this, "scenes"),
+            skins(*this, "skins"),
+            textures(*this, "textures") ,
+            mIOSystem(io),
+            mSchemaDocumentProvider(schemaDocumentProvider) {
+        // empty
+    }
+
+    //! Main function
+    void Load(const std::string &file, bool isBinary = false);
+
+    //! Parse the AssetMetadata and check that the version is 2.
+    bool CanRead(const std::string &pFile, bool isBinary = false);
+
+    //! Enables binary encoding on the asset
+    void SetAsBinary();
+
+    //! Search for an available name, starting from the given strings
+    std::string FindUniqueID(const std::string &str, const char *suffix);
+
+    Ref<Buffer> GetBodyBuffer() { return mBodyBuffer; }
+
+    Asset(Asset &) = delete;
+    Asset &operator=(const Asset &) = delete;
+
+private:
+    void ReadBinaryHeader(IOStream &stream, std::vector<char> &sceneData);
+
+    /// Obtain a JSON document from the stream.
+    /// \param second argument is a buffer used by the document. It must be kept
+    /// alive while the document is in use.
+    Document ReadDocument(IOStream& stream, bool isBinary, std::vector<char>& sceneData);
+
+    void ReadExtensionsUsed(Document &doc);
+    void ReadExtensionsRequired(Document &doc);
+
+    IOStream *OpenFile(const std::string &path, const char *mode, bool absolute = false);
+
+private:
+    IOSystem *mIOSystem;
+    rapidjson::IRemoteSchemaDocumentProvider *mSchemaDocumentProvider;
+    std::string mCurrentAssetDir;
+    size_t mSceneLength;
+    size_t mBodyOffset;
+    size_t mBodyLength;
+    IdMap mUsedIds;
+    Ref<Buffer> mBodyBuffer;
+};
+
+inline std::string getContextForErrorMessages(const std::string &id, const std::string &name) {
+    std::string context = id;
+    if (!name.empty()) {
+        context += " (\"" + name + "\")";
+    }
+    return context;
+}
+
+} // namespace glTF2
+
+// Include the implementation of the methods
+#include "glTF2Asset.inl"
+
+#endif // ASSIMP_BUILD_NO_GLTF_IMPORTER
+
+#endif // GLTF2ASSET_H_INC