Merge pull request #35 from B3zaleel/implement-MPEG_texture_video-ext…

…ension

Implement MPEG_texture_video Gltf extension

src/ThreeDModels/Format/Gltf/Extensions/MPEG_texture_video.cs

@@ -0,0 +1,107 @@
+using System.Text.Json;
+using ThreeDModels.Format.Gltf.Elements;
+using ThreeDModels.Format.Gltf.IO;
+using static ThreeDModels.Format.Gltf.IO.Utf8JsonReaderHelpers;
+
+namespace ThreeDModels.Format.Gltf.Extensions;
+
+/// <summary>
+/// Represents an object that specifies textures using MPEG defined formats.
+/// </summary>
+public class MPEG_texture_video : IGltfProperty
+{
+    /// <summary>
+    /// Provides the accessor's index in accessors array.
+    /// </summary>
+    public required int Accessor { get; set; }
+    /// <summary>
+    /// Provides the maximum width of the texture.
+    /// </summary>
+    public required float Width { get; set; }
+    /// <summary>
+    /// Provides the maximum height of the texture.
+    /// </summary>
+    public required float Height { get; set; }
+    /// <summary>
+    /// Indicates the format of the pixel data for this video texture.
+    /// </summary>
+    public string? Format { get; set; }
+    public Dictionary<string, object?>? Extensions { get; set; }
+    public object? Extras { get; set; }
+}
+
+public class MpegTextureVideoExtension : IGltfExtension
+{
+    public string Name => nameof(MPEG_texture_video);
+    public const string Default_Format = "RGB";
+
+    public object? Read(ref Utf8JsonReader jsonReader, GltfReaderContext context, Type parentType)
+    {
+        int? accessor = null;
+        float? width = null;
+        float? height = null;
+        string? format = null;
+        Dictionary<string, object?>? extensions = null;
+        object? extras = null;
+        if (jsonReader.TokenType == JsonTokenType.PropertyName && jsonReader.Read())
+        {
+        }
+        if (jsonReader.TokenType == JsonTokenType.Null)
+        {
+            return null;
+        }
+        else if (jsonReader.TokenType != JsonTokenType.StartObject)
+        {
+            throw new InvalidDataException("Failed to find start of property.");
+        }
+        while (jsonReader.Read())
+        {
+            if (jsonReader.TokenType == JsonTokenType.EndObject)
+            {
+                break;
+            }
+            var propertyName = jsonReader.GetString();
+            if (propertyName == nameof(accessor))
+            {
+                accessor = ReadInteger(ref jsonReader);
+            }
+            else if (propertyName == nameof(width))
+            {
+                width = ReadFloat(ref jsonReader);
+            }
+            else if (propertyName == nameof(height))
+            {
+                height = ReadFloat(ref jsonReader);
+            }
+            else if (propertyName == nameof(format))
+            {
+                format = ReadString(ref jsonReader);
+            }
+            else if (propertyName == nameof(extensions))
+            {
+                extensions = ExtensionsSerialization.Read<MPEG_texture_video>(ref jsonReader, context);
+            }
+            else if (propertyName == nameof(extras))
+            {
+                extras = JsonSerialization.Read(ref jsonReader, context);
+            }
+            else
+            {
+                throw new InvalidDataException($"Unknown property: {propertyName}");
+            }
+        }
+        if (accessor == null || width == null || height == null)
+        {
+            throw new InvalidDataException("MPEG_texture_video.accessor, MPEG_texture_video.accessor, and MPEG_texture_video.accessor are required properties.");
+        }
+        return new MPEG_texture_video()
+        {
+            Accessor = (int)accessor!,
+            Width = (float)width!,
+            Height = (float)height!,
+            Format = format ?? Default_Format,
+            Extensions = extensions,
+            Extras = extras,
+        };
+    }
+}