gltf

type Accessor struct {
	BufferView    uint32
	ByteOffset    uint32
	ComponentType ComponentType
	Count         uint32
	Max           []float32
	Min           []float32
	Type          DataType

	Sparse *struct {
		Count   uint32
		Indices struct {
			BufferView    uint32
			ByteOffset    uint32
			ComponentType ComponentType
		}
		Values struct {
			BufferView uint32
			ByteOffset uint32
		}
	}
}

type Animation struct {
	Channels    []AnimationChannel
	AniSamplers []AnimationSampler `json:"Samplers"`
	Name        string
}

type AnimationChannel struct {
	AniSampler uint32 `json:"Sampler"` // 指向所属Animation的Samplers, 不是数据的Sampler
	Target     AnimationTarget
}

type AnimationSampler struct {
	KeyTimes      uint32 `json:"Input"`  // glTF的Input是关键帧时间点
	KeyValues     uint32 `json:"Output"` // glTF的Output是关键帧的各参数值
	Interpolation string // "LINEAR" "STEP" "CUBICSPLINE", ""=="LINEAR"
}

type AnimationTarget struct {
	Node uint32
	Path string //    "translation"  "rotation"  "scale" "weights"
}

type Asset struct {
	Version   string
	Generator string
	Copyright string
}

type Attributes struct {
	POSITION   *uint32
	NORMAL     *uint32
	TANGENT    *uint32
	TEXCOORD_0 *uint32
	TEXCOORD_1 *uint32
	TEXCOORD_2 *uint32
	TEXCOORD_3 *uint32
	COLOR_0    *uint32
	COLOR_1    *uint32
	COLOR_2    *uint32
	COLOR_3    *uint32
	JOINTS_0   *uint32
	JOINTS_1   *uint32
	JOINTS_2   *uint32
	JOINTS_3   *uint32
	WEIGHTS_0  *uint32
	WEIGHTS_1  *uint32
	WEIGHTS_2  *uint32
	WEIGHTS_3  *uint32
}

type Buffer struct {
	URI        string
	ByteLength uint32
	Name       string
	// contains filtered or unexported fields
}

type BufferView struct {
	Buffer     uint32
	ByteLength uint32
	ByteOffset uint32  // default 0
	ByteStride *uint32 // nil or  4 to 252
	Target     *uint32 // 34962 ARRAY_BUFFER, 34963 ELEMENT_ARRAY_BUFFER
	Name       string
}

type Camera struct {
	Name        string
	Type        string
	Perspective *struct {
		AspectRatio float32
		Yfov        float32
		Zfar        float32
		Znear       float32
	}
	Orthographic *struct {
		Xmag  float32
		Ymag  float32
		Zfar  float32
		Znear float32
	}
}

type ComponentType uint32

type DataType uint32

type GLTF struct {
	Asset       Asset
	Nodes       []*Node
	Scenes      []*Scene
	Scene       *uint32
	Accessors   []*Accessor
	Meshes      []*Mesh
	Skins       []*Skin
	Textures    []*Texture
	Images      []*Image
	Samplers    []*Sampler
	Materials   []*Material
	Cameras     []*Camera
	BufferViews []*BufferView
	Buffers     []*Buffer
	Animations  []*Animation

	ExtensionsUsed     []string
	ExtensionsRequired []string

	BIN []byte `json:"-"`
}

type Image struct {
	URI        string
	BufferView *uint32
	MimeType   string
	Name       string
}

type KHR_materials_clearcoat struct {
	ClearcoatFactor           float32
	ClearcoatTexture          *TextureInfo
	ClearcoatRoughnessFactor  float32
	ClearcoatRoughnessTexture *TextureInfo
	ClearcoatNormalTexture    *NormalTextureInfo
}

type KHR_materials_pbrSpecularGlossiness struct {
	DiffuseFactor             *[4]float32
	SpecularFactor            *[3]float32
	DiffuseTexture            TextureInfo
	GlossinessFactor          *float32
	SpecularGlossinessTexture TextureInfo
}

type KHR_materials_unlit struct {
}

type Material struct {
	Name string

	PbrMetallicRoughness *struct {
		BaseColorFactor  *[4]float32 // default 1
		BaseColorTexture *TextureInfo

		MetallicFactor           *float32 // default 1
		RoughnessFactor          *float32 // default 1
		MetallicRoughnessTexture *TextureInfo
	}

	NormalTexture *NormalTextureInfo

	OcclusionTexture *OcclusionTextureInfo

	EmissiveFactor  [3]float32 // default [0 0 0]
	EmissiveTexture *TextureInfo

	AlphaMode   string
	AlphaCutoff *float32 // default 0.5
	DoubleSided bool

	Extensions struct {
		KHR_materials_pbrSpecularGlossiness *KHR_materials_pbrSpecularGlossiness
		KHR_materials_clearcoat             *KHR_materials_clearcoat
		KHR_materials_unlit                 *KHR_materials_unlit
	}
}

type Matrix [16]float32

type Mesh struct {
	Primitives []Primitive
	Weights    []float32
	Name       string
}

type MorphTarget struct {
	NORMAL   *uint32
	POSITION *uint32
	TANGENT  *uint32
}

type Node struct {
	Name        string
	Mesh        *uint32
	Skin        *uint32
	Children    []uint32
	Camera      *uint32
	Translation *Translation
	Scale       *Scale
	Rotation    *Rotation
	Matrix      *Matrix
}

type NormalTextureInfo struct {
	Index    uint32
	TexCoord uint32
	Scale    *float32 // default 1
}

type OcclusionTextureInfo struct {
	Index    uint32
	TexCoord uint32
	Strength *float32 // default 1
}

type Primitive struct {
	Attributes Attributes    // 顶点属性
	Indices    *uint32       // 顶点索引
	Material   *uint32       // 材质
	Mode       *uint32       // 图元类型 default 4 TRIANGLES
	Targets    []MorphTarget // 顶点变形动画的目标
}

type Rotation [4]float32

type Sampler struct {
	MagFilter uint32
	MinFilter uint32
	WrapS     uint32
	WrapT     uint32
}

type Scale [3]float32

type Scene struct {
	Name  string
	Nodes []uint32
}

type Skin struct {
	Name                string
	InverseBindMatrices *uint32
	Joints              []uint32

	// 骨骼的公共根节点LCA(非必填).
	// glTF文档里虽然没明确指出骨骼的范围, 我们理解为当前Skin的骨骼的LCA.
	Skeleton *uint32
}

type Texture struct {
	Name    string
	Sampler *uint32 // When undefined, a sampler with repeat wrapping and auto filtering should be used
	Source  *uint32 // When undefined, it is expected that an extension or other mechanism will supply an alternate texture source
}

type TextureInfo struct {
	Index    uint32
	TexCoord uint32
}

type Translation [3]float32