Implement gltf loading

ThreeDModels.sln

@@ -23,6 +23,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ThreeDModels.Format.Ctm", "
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ThreeDModels.Format.Ctm.UnitTests", "tests\ThreeDModels\Format\Ctm.UnitTests\ThreeDModels.Format.Ctm.UnitTests.csproj", "{0C3E07D5-30ED-4B46-94D0-DF39D4101D95}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ThreeDModels.Format.Gltf", "src\ThreeDModels\Format\Gltf\ThreeDModels.Format.Gltf.csproj", "{568C50F8-4085-4806-B293-30C06AD8D959}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ThreeDModels.Format.Gltf.UnitTests", "tests\ThreeDModels\Format\Gltf.UnitTests\ThreeDModels.Format.Gltf.UnitTests.csproj", "{E74FFBE6-091C-4D82-8E5C-895F72A740A0}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -48,6 +52,14 @@ Global
 		{0C3E07D5-30ED-4B46-94D0-DF39D4101D95}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{0C3E07D5-30ED-4B46-94D0-DF39D4101D95}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{0C3E07D5-30ED-4B46-94D0-DF39D4101D95}.Release|Any CPU.Build.0 = Release|Any CPU
+		{568C50F8-4085-4806-B293-30C06AD8D959}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{568C50F8-4085-4806-B293-30C06AD8D959}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{568C50F8-4085-4806-B293-30C06AD8D959}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{568C50F8-4085-4806-B293-30C06AD8D959}.Release|Any CPU.Build.0 = Release|Any CPU
+		{E74FFBE6-091C-4D82-8E5C-895F72A740A0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E74FFBE6-091C-4D82-8E5C-895F72A740A0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E74FFBE6-091C-4D82-8E5C-895F72A740A0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E74FFBE6-091C-4D82-8E5C-895F72A740A0}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{A75E239E-4BB5-423D-B7E9-D60E96855389} = {7D388FB1-4C7A-410B-B186-92D5CD8819E9}
@@ -58,5 +70,7 @@ Global
 		{272082CD-8882-40F1-A232-E64F43156B1F} = {2E7AAD7B-6592-4BCD-9766-CBD16C6553BF}
 		{6F517121-325F-410D-B7B3-7B1D2FC1E420} = {9352709B-38FB-4B82-BB5B-740A7746887C}
 		{0C3E07D5-30ED-4B46-94D0-DF39D4101D95} = {2E7AAD7B-6592-4BCD-9766-CBD16C6553BF}
+		{568C50F8-4085-4806-B293-30C06AD8D959} = {9352709B-38FB-4B82-BB5B-740A7746887C}
+		{E74FFBE6-091C-4D82-8E5C-895F72A740A0} = {2E7AAD7B-6592-4BCD-9766-CBD16C6553BF}
 	EndGlobalSection
 EndGlobal

src/ThreeDModels/Format/Gltf/Elements/Accessor.cs

@@ -0,0 +1,47 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents a typed view into a buffer view that contains raw binary data.
+/// </summary>
+public class Accessor : IGltfRootProperty
+{
+    /// <summary>
+    /// The index of the bufferView.
+    /// </summary>
+    public int? BufferView { get; set; }
+    /// <summary>
+    /// The offset relative to the start of the buffer view in bytes.
+    /// </summary>
+    public int? ByteOffset { get; set; }
+    /// <summary>
+    /// The datatype of the accessor's components.
+    /// </summary>
+    public required int ComponentType { get; set; }
+    /// <summary>
+    /// Specifies whether integer data values are normalized before usage.
+    /// </summary>
+    public bool Normalized { get; set; }
+    /// <summary>
+    /// The number of elements referenced by this accessor.
+    /// </summary>
+    public required int Count { get; set; }
+    /// <summary>
+    /// Specifies if the accessor's elements are scalars, vectors, or matrices.
+    /// </summary>
+    public required string Type { get; set; } = string.Empty;
+    /// <summary>
+    /// Maximum value of each component in this accessor.
+    /// </summary>
+    public List<float> Max { get; set; } = [];
+    /// <summary>
+    /// Minimum value of each component in this accessor.
+    /// </summary>
+    public List<float> Min { get; set; } = [];
+    /// <summary>
+    /// Sparse storage of elements that deviate from their initialization value.
+    /// </summary>
+    public AccessorSparse? Sparse { get; set; }
+    public string? Name { get; set; } = string.Empty;
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/AccessorSparse.cs

@@ -0,0 +1,22 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents a sparse storage of accessor values that deviate from their initialization value.
+/// </summary>
+public class AccessorSparse : IGltfProperty
+{
+    /// <summary>
+    /// Number of deviating accessor values stored in the sparse array.
+    /// </summary>
+    public required int Count { get; set; }
+    /// <summary>
+    /// An object pointing to a buffer view containing the indices of deviating accessor values.
+    /// </summary>
+    public required AccessorSparseIndices Indices { get; set; }
+    /// <summary>
+    /// An object pointing to a buffer view containing the deviating accessor values.
+    /// </summary>
+    public required AccessorSparseValues Values { get; set; }
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/AccessorSparseIndices..cs

@@ -0,0 +1,22 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents an object pointing to a buffer view containing the indices of deviating accessor values.
+/// </summary>
+public class AccessorSparseIndices : IGltfProperty
+{
+    /// <summary>
+    /// The index of the buffer view with sparse indices.
+    /// </summary>
+    public required int BufferView { get; set; }
+    /// <summary>
+    /// The offset relative to the start of the buffer view in bytes.
+    /// </summary>
+    public int ByteOffset { get; set; } = 0;
+    /// <summary>
+    /// The indices data type.
+    /// </summary>
+    public required int ComponentType { get; set; }
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/AccessorSparseValues.cs

@@ -0,0 +1,18 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents an object pointing to a buffer view containing the deviating accessor values.
+/// </summary>
+public class AccessorSparseValues : IGltfProperty
+{
+    /// <summary>
+    /// The index of the bufferView with sparse values.
+    /// </summary>
+    public required int BufferView { get; set; }
+    /// <summary>
+    /// The offset relative to the start of the bufferView in bytes.
+    /// </summary>
+    public int ByteOffset { get; set; } = 0;
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/Animation.cs

@@ -0,0 +1,19 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents a keyframe animation.
+/// </summary>
+public class Animation : IGltfRootProperty
+{
+    /// <summary>
+    /// An array of animation channels.
+    /// </summary>
+    public required List<AnimationChannel> Channels { get; set; } = [];
+    /// <summary>
+    /// An array of animation samplers.
+    /// </summary>
+    public required List<AnimationSampler> Samplers { get; set; } = [];
+    public string? Name { get; set; } = string.Empty;
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/AnimationChannel.cs

@@ -0,0 +1,18 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents a combination of an animation sampler with a target property being animated.
+/// </summary>
+public class AnimationChannel : IGltfProperty
+{
+    /// <summary>
+    /// The index of a sampler in this animation used to compute the value for the target.
+    /// </summary>
+    public required int Sampler { get; set; }
+    /// <summary>
+    /// The descriptor of the animated property.
+    /// </summary>
+    public required AnimationChannelTarget Target { get; set; }
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/AnimationChannelTarget.cs

@@ -0,0 +1,24 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents the descriptor of the animated property.
+/// </summary>
+public class AnimationChannelTarget : IGltfProperty
+{
+    /// <summary>
+    /// The index of the node to animate.
+    /// </summary>
+    public int? Node { get; set; }
+    /// <summary>
+    /// The name of the node's TRS property to animate, or the `weights` of the Morph Targets it instantiates. 
+    /// <para/>
+    /// For the `translation` property, the values that are provided by the sampler are the translation along the X, Y, and Z axes.
+    /// <para/>
+    /// For the `rotation` property, the values are a quaternion in the order (x, y, z, w), where w is the scalar. 
+    /// <para/>
+    /// For the `scale` property, the values are the scaling factors along the X, Y, and Z axes.
+    /// </summary>
+    public required string Path { get; set; }
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/AnimationSampler.cs

@@ -0,0 +1,24 @@
+using ThreeDModels.Format.Gltf.IO;
+
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents a combination of timestamps with a sequence of output values and defines an interpolation algorithm.
+/// </summary>
+public class AnimationSampler : IGltfProperty
+{
+    /// <summary>
+    /// The index of an accessor containing keyframe timestamps.
+    /// </summary>
+    public required int Input { get; set; }
+    /// <summary>
+    /// Interpolation algorithm.
+    /// </summary>
+    public string Interpolation { get; set; } = Default.InterpolationAlgorithm;
+    /// <summary>
+    /// The index of an accessor, containing keyframe output values.
+    /// </summary>
+    public required int Output { get; set; }
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/Asset.cs

@@ -0,0 +1,26 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents an object that contains metadata about the glTF asset.
+/// </summary>
+public class Asset : IGltfProperty
+{
+    /// <summary>
+    /// A copyright message suitable for display to credit the content creator.
+    /// </summary>
+    public string? Copyright { get; set; } = string.Empty;
+    /// <summary>
+    /// Tool that generated this glTF model.  Useful for debugging.
+    /// </summary>
+    public string? Generator { get; set; } = string.Empty;
+    /// <summary>
+    /// The glTF version in the form of `<major>.<minor>` that this asset targets.
+    /// </summary>
+    public required string Version { get; set; }
+    /// <summary>
+    /// The minimum glTF version in the form of `<major>.<minor>` that this asset targets.
+    /// </summary>
+    public string? MinVersion { get; set; } = string.Empty;
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/Buffer.cs

@@ -0,0 +1,19 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents data that points to binary geometry, animation, or skins.
+/// </summary>
+public class Buffer : IGltfRootProperty
+{
+    /// <summary>
+    /// The URI (or IRI) of the buffer.
+    /// </summary>
+    public string? Uri { get; set; } = string.Empty;
+    /// <summary>
+    /// The length of the buffer in bytes.
+    /// </summary>
+    public required int ByteLength { get; set; }
+    public string? Name { get; set; } = string.Empty;
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/BufferView.cs

@@ -0,0 +1,33 @@
+using ThreeDModels.Format.Gltf.IO;
+
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents a subset of a buffer.
+/// </summary>
+public class BufferView : IGltfRootProperty
+{
+    /// <summary>
+    /// The index of the buffer.
+    /// </summary>
+    public required int Buffer { get; set; }
+    /// <summary>
+    /// The offset into the buffer in bytes.
+    /// </summary>
+    public int ByteOffset { get; set; } = Default.ByteOffset;
+    /// <summary>
+    /// The length of the bufferView in bytes.
+    /// </summary>
+    public required int ByteLength { get; set; }
+    /// <summary>
+    /// The stride, in bytes.
+    /// </summary>
+    public int? ByteStride { get; set; }
+    /// <summary>
+    /// The hint representing the intended GPU buffer type to use with this buffer view.
+    /// </summary>
+    public int? Target { get; set; }
+    public string? Name { get; set; } = string.Empty;
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/Camera.cs

@@ -0,0 +1,23 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents a camera's projection.
+/// </summary>
+public class Camera : IGltfRootProperty
+{
+    /// <summary>
+    /// An orthographic camera containing properties to create an orthographic projection matrix.
+    /// </summary>
+    public CameraOrthographic? Orthographic { get; set; }
+    /// <summary>
+    /// A perspective camera containing properties to create a perspective projection matrix.
+    /// </summary>
+    public CameraPerspective? Perspective { get; set; }
+    /// <summary>
+    /// Specifies if the camera uses a perspective or orthographic projection.
+    /// </summary>
+    public required string Type { get; set; }
+    public string? Name { get; set; } = string.Empty;
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/CameraOrthographic.cs

@@ -0,0 +1,26 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// An orthographic camera containing properties to create an orthographic projection matrix.
+/// </summary>
+public class CameraOrthographic : IGltfProperty
+{
+    /// <summary>
+    /// The floating-point horizontal magnification of the view.
+    /// </summary>
+    public required float XMag { get; set; }
+    /// <summary>
+    /// The floating-point vertical magnification of the view.
+    /// </summary>
+    public required float YMag { get; set; }
+    /// <summary>
+    /// The floating-point distance to the far clipping plane.
+    /// </summary>
+    public required float ZFar { get; set; }
+    /// <summary>
+    /// The floating-point distance to the near clipping plane.
+    /// </summary>
+    public required float ZNear { get; set; }
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}

src/ThreeDModels/Format/Gltf/Elements/CameraPerspective.cs

@@ -0,0 +1,26 @@
+namespace ThreeDModels.Format.Gltf.Elements;
+
+/// <summary>
+/// Represents a perspective camera containing properties to create a perspective projection matrix.
+/// </summary>
+public class CameraPerspective : IGltfProperty
+{
+    /// <summary>
+    /// The floating-point aspect ratio of the field of view.
+    /// </summary>
+    public float? AspectRatio { get; set; }
+    /// <summary>
+    /// The floating-point vertical field of view in radians.
+    /// </summary>
+    public required float YFov { get; set; }
+    /// <summary>
+    /// The floating-point distance to the far clipping plane.
+    /// </summary>
+    public float? ZFar { get; set; }
+    /// <summary>
+    /// The floating-point distance to the near clipping plane.
+    /// </summary>
+    public required float ZNear { get; set; }
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}