WIP: Adding "TryFix" validation mode.

Author: vpenades

examples/Example1/Program.cs

@@ -41,7 +41,7 @@ static void Main(string[] args)
 
             var scene = new SharpGLTF.Scenes.SceneBuilder();
 
-            scene.AddMesh(mesh, Matrix4x4.Identity);
+            scene.AddRigidMesh(mesh, Matrix4x4.Identity);
 
             // save the model in different formats
 

src/Shared/_Extensions.cs

@@ -146,13 +146,28 @@ internal static bool IsValidNormal(this Vector3 normal)
             return true;
         }
 
+        internal static Vector3 SanitizeNormal(this Vector3 normal)
+        {
+            var isn = normal._IsFinite() && normal.LengthSquared() > 0;
+            return isn ? Vector3.Normalize(normal) : Vector3.UnitZ;
+        }
+
         internal static bool IsValidTangent(this Vector4 tangent)
         {
             if (tangent.W != 1 && tangent.W != -1) return false;
 
             return new Vector3(tangent.X, tangent.Y, tangent.Z).IsValidNormal();
         }
 
+        internal static Vector4 SanitizeTangent(this Vector4 tangent)
+        {
+            var n = new Vector3(tangent.X, tangent.Y, tangent.Z);
+            var s = float.IsNaN(tangent.W) ? 1 : tangent.W;
+            var isn = n._IsFinite() && n.LengthSquared() > 0;
+            n = isn ? Vector3.Normalize(n) : Vector3.UnitX;
+            return new Vector4(n, s > 0 ? 1 : -1);
+        }
+
         internal static Matrix4x4 Inverse(this Matrix4x4 src)
         {
             if (!Matrix4x4.Invert(src, out Matrix4x4 dst)) Guard.IsTrue(false, nameof(src), "Matrix cannot be inverted.");

src/SharpGLTF.Core/Schema2/gltf.Accessors.cs

@@ -456,7 +456,10 @@ internal void ValidateNormals(Validation.ValidationContext result)
 
             for (int i = 0; i < normals.Count; ++i)
             {
-                result.CheckIsUnitLength(i, normals[i]);
+                if (result.TryFixUnitLength(i, normals[i]))
+                {
+                    normals[i] = normals[i].SanitizeNormal();
+                }
             }
         }
 
@@ -473,7 +476,10 @@ internal void ValidateTangents(Validation.ValidationContext result)
 
             for (int i = 0; i < tangents.Count; ++i)
             {
-                result.CheckIsTangent(i, tangents[i]);
+                if (result.TryFixTangent(i, tangents[i]))
+                {
+                    tangents[i] = tangents[i].SanitizeTangent();
+                }
             }
         }
 

src/SharpGLTF.Core/Schema2/gltf.BufferView.cs

@@ -266,13 +266,22 @@ internal void ValidateBufferUsageGPU(Validation.ValidationContext result, Buffer
 
         internal void ValidateBufferUsageData(Validation.ValidationContext result)
         {
-            if (this.ByteStride != 0) result.AddLinkError("BufferView", "Unexpected ByteStride found. Expected 0");
+            if (this._byteStride.HasValue)
+            {
+                if (result.TryFixLink("BufferView", "Unexpected ByteStride found. Expected null"))
+                {
+                    this._byteStride = null;
+                }
+            }
 
             result = result.GetContext(this);
 
             if (!this._target.HasValue) return;
 
-            result.AddLinkError("Device Buffer Target", $"is set as {this._target.Value}. But an accessor wants to use it as a plain data buffer.");
+            if (result.TryFixLink("Device Buffer Target", $"is set as {this._target.Value}. But an accessor wants to use it as a plain data buffer."))
+            {
+                this._target = null;
+            }
         }
 
         #endregion

src/SharpGLTF.Core/Schema2/gltf.Camera.cs

@@ -91,6 +91,9 @@ public void SetPerspectiveMode(float? aspectRatio, float yfov, float znear, floa
         #endregion
     }
 
+    /// <summary>
+    /// Common interface for <see cref="CameraOrthographic"/> and <see cref="CameraPerspective"/>.
+    /// </summary>
     public interface ICamera
     {
         bool IsOrthographic { get; }

src/SharpGLTF.Core/Schema2/gltf.Serialization.Read.cs

@@ -5,11 +5,13 @@
 using System.Text;
 
 using Newtonsoft.Json;
+
 using BYTES = System.ArraySegment<byte>;
 
 namespace SharpGLTF.Schema2
 {
     using MODEL = ModelRoot;
+    using VALIDATIONMODE = Validation.ValidationMode;
 
     /// <summary>
     /// Callback used for loading associated files of current model.
@@ -46,7 +48,10 @@ internal ReadSettings(string filePath)
         /// </summary>
         public AssetReader FileReader { get; set; }
 
-        public Boolean SkipValidation { get; set; }
+        /// <summary>
+        /// Gets or sets a value indicating the level of validation applied when loading a file.
+        /// </summary>
+        public VALIDATIONMODE Validation { get; set; } = VALIDATIONMODE.Strict;
     }
 
     partial class ModelRoot
@@ -84,13 +89,16 @@ public static Validation.ValidationResult Validate(string filePath)
         /// Reads a <see cref="MODEL"/> instance from a path pointing to a GLB or a GLTF file
         /// </summary>
         /// <param name="filePath">A valid file path.</param>
+        /// <param name="vmode">Defines the file validation level.</param>
         /// <returns>A <see cref="MODEL"/> instance.</returns>
-        public static MODEL Load(string filePath)
+        public static MODEL Load(string filePath, VALIDATIONMODE vmode = VALIDATIONMODE.Strict)
         {
             Guard.FilePathMustExist(filePath, nameof(filePath));
 
             var settings = new ReadSettings(filePath);
 
+            settings.Validation = vmode;
+
             using (var s = File.OpenRead(filePath))
             {
                 return Read(s, settings);
@@ -182,14 +190,16 @@ public static MODEL ParseGLTF(String jsonContent, ReadSettings settings)
             return mv.Model;
         }
 
-        public static MODEL ReadFromDictionary(Dictionary<string, BYTES> files, string fileName)
+        public static MODEL ReadFromDictionary(Dictionary<string, BYTES> files, string fileName, VALIDATIONMODE vmode = VALIDATIONMODE.Strict)
         {
             Guard.NotNull(files, nameof(files));
 
             var jsonBytes = files[fileName];
 
             var settings = new ReadSettings(fn => files[fn]);
 
+            settings.Validation = vmode;
+
             using (var m = new MemoryStream(jsonBytes.Array, jsonBytes.Offset, jsonBytes.Count))
             {
                 using (var tr = new StreamReader(m))
@@ -248,11 +258,11 @@ private static (MODEL Model, Validation.ValidationResult Validation) _Read(TextR
             Guard.NotNull(textReader, nameof(textReader));
             Guard.NotNull(settings, nameof(settings));
 
+            var root = new MODEL();
+            var vcontext = new Validation.ValidationResult(root, settings.Validation);
+
             using (var reader = new JsonTextReader(textReader))
             {
-                var root = new MODEL();
-                var vcontext = new Validation.ValidationResult(root);
-
                 if (!reader.Read())
                 {
                     vcontext.AddError(new Validation.ModelException(root, "Json is empty"));
@@ -268,36 +278,36 @@ private static (MODEL Model, Validation.ValidationResult Validation) _Read(TextR
                     vcontext.AddError(new Validation.SchemaException(root, rex));
                     return (null, vcontext);
                 }
+            }
 
-                // schema validation
-
-                root.ValidateReferences(vcontext.GetContext(root));
-                var ex = vcontext.Errors.FirstOrDefault();
-                if (ex != null) return (null, vcontext);
+            // schema validation
 
-                // resolve external references
+            root.ValidateReferences(vcontext.GetContext(root));
+            var ex = vcontext.Errors.FirstOrDefault();
+            if (ex != null) return (null, vcontext);
 
-                foreach (var buffer in root._buffers)
-                {
-                    buffer._ResolveUri(settings.FileReader);
-                }
+            // resolve external references
 
-                foreach (var image in root._images)
-                {
-                    image._ResolveUri(settings.FileReader);
-                }
+            foreach (var buffer in root._buffers)
+            {
+                buffer._ResolveUri(settings.FileReader);
+            }
 
-                // full validation
+            foreach (var image in root._images)
+            {
+                image._ResolveUri(settings.FileReader);
+            }
 
-                if (!settings.SkipValidation)
-                {
-                    root.Validate(vcontext.GetContext(root));
-                    ex = vcontext.Errors.FirstOrDefault();
-                    if (ex != null) return (null, vcontext);
-                }
+            // full validation
 
-                return (root, vcontext);
+            if (settings.Validation != VALIDATIONMODE.Skip)
+            {
+                root.Validate(vcontext.GetContext(root));
+                ex = vcontext.Errors.FirstOrDefault();
+                if (ex != null) return (null, vcontext);
             }
+
+            return (root, vcontext);
         }
 
         #endregion

src/SharpGLTF.Core/Validation/ValidationContext.cs

@@ -36,6 +36,8 @@ public ValidationContext(ValidationResult result, TARGET target)
 
         public ValidationResult Result => _Result;
 
+        public bool TryFix => Result.Mode == Validation.ValidationMode.TryFix;
+
         #endregion
 
         #region API
@@ -44,12 +46,30 @@ public ValidationContext(ValidationResult result, TARGET target)
 
         public void AddSchemaError(ValueLocation location, string message) { AddSchemaError(location.ToString(_Target, message)); }
 
+        public bool TryFixLink(ValueLocation location, string message)
+        {
+            if (TryFix) AddLinkWarning(location.ToString(_Target, message));
+            else AddLinkError(location.ToString(_Target, message));
+
+            return TryFix;
+        }
+
+        public bool TryFixData(ValueLocation location, string message)
+        {
+            if (TryFix) AddDataWarning(location.ToString(_Target, message));
+            else AddDataError(location.ToString(_Target, message));
+
+            return TryFix;
+        }
+
         public void AddLinkError(ValueLocation location, string message) { AddLinkError(location.ToString(_Target, message)); }
 
         public void AddLinkWarning(String format, params object[] args) { AddLinkWarning(String.Format(format, args)); }
 
         public void AddDataError(ValueLocation location, string message) { AddDataError(location.ToString(_Target, message)); }
 
+        public void AddDataWarning(ValueLocation location, string message) { AddDataWarning(location.ToString(_Target, message)); }
+
         public void AddSemanticWarning(String format, params object[] args) { AddSemanticWarning(String.Format(format, args)); }
 
         public void AddSemanticError(String format, params object[] args) { AddSemanticError(String.Format(format, args)); }
@@ -75,6 +95,12 @@ public void AddSchemaError(string message)
             _Result.AddError(ex);
         }
 
+        public void AddDataWarning(string message)
+        {
+            var ex = new DataException(_Target, message);
+            _Result.AddWarning(ex);
+        }
+
         public void AddDataError(string message)
         {
             var ex = new DataException(_Target, message);
@@ -221,21 +247,22 @@ public bool CheckIsFinite(ValueLocation location, System.Numerics.Quaternion? va
             return false;
         }
 
-        public void CheckIsUnitLength(ValueLocation location, System.Numerics.Vector3? value)
+        public bool TryFixUnitLength(ValueLocation location, System.Numerics.Vector3? value)
         {
-            if (!value.HasValue) return;
-            if (!CheckIsFinite(location, value)) return;
-            if (value.Value.IsValidNormal()) return;
-            AddDataError(location, $"is not of unit length: {value.Value.Length()}.");
+            if (!value.HasValue) return false;
+            if (!CheckIsFinite(location, value)) return false;
+            if (value.Value.IsValidNormal()) return false;
+
+            return TryFixData(location, $"is not of unit length: {value.Value.Length()}.");
         }
 
-        public void CheckIsTangent(ValueLocation location, System.Numerics.Vector4 tangent)
+        public bool TryFixTangent(ValueLocation location, System.Numerics.Vector4 tangent)
         {
-            CheckIsUnitLength(location, new System.Numerics.Vector3(tangent.X, tangent.Y, tangent.Z));
+            if (TryFixUnitLength(location, new System.Numerics.Vector3(tangent.X, tangent.Y, tangent.Z))) return true;
 
-            if (tangent.W == 1 || tangent.W == -1) return;
+            if (tangent.W == 1 || tangent.W == -1) return false;
 
-            AddDataError(location, $"has invalid value: {tangent.W}. Must be 1.0 or -1.0.");
+            return TryFixData(location, $"has invalid value: {tangent.W}. Must be 1.0 or -1.0.");
         }
 
         public void CheckIsInRange(ValueLocation location, System.Numerics.Vector4 v, float minInclusive, float maxInclusive)

src/SharpGLTF.Core/Validation/ValidationMode.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace SharpGLTF.Validation
+{
+    /// <summary>
+    /// Defines validation modes for reading files.
+    /// </summary>
+    public enum ValidationMode
+    {
+        /// <summary>
+        /// Skip validation completely.
+        /// </summary>
+        Skip,
+
+        /// <summary>
+        /// In some specific cases, the file can be fixed, at which point the errors successfully fixed will be reported as warnings.
+        /// </summary>
+        TryFix,
+
+        /// <summary>
+        /// Full validation, any error throws an exception.
+        /// </summary>
+        Strict
+    }
+}

src/SharpGLTF.Core/Validation/ValidationResult.cs

@@ -11,9 +11,10 @@ public sealed class ValidationResult
     {
         #region lifecycle
 
-        public ValidationResult(Schema2.ModelRoot root, bool instantThrow = false)
+        public ValidationResult(Schema2.ModelRoot root, ValidationMode mode, bool instantThrow = false)
         {
             _Root = root;
+            _Mode = mode;
             _InstantThrow = instantThrow;
         }
 
@@ -22,6 +23,7 @@ public ValidationResult(Schema2.ModelRoot root, bool instantThrow = false)
         #region data
 
         private readonly Schema2.ModelRoot _Root;
+        private readonly ValidationMode _Mode;
         private readonly bool _InstantThrow;
 
         private readonly List<Exception> _Errors = new List<Exception>();
@@ -33,6 +35,8 @@ public ValidationResult(Schema2.ModelRoot root, bool instantThrow = false)
 
         public Schema2.ModelRoot Root => _Root;
 
+        public ValidationMode Mode => _Mode;
+
         public IEnumerable<Exception> Errors => _Errors;
 
         public bool HasErrors => _Errors.Count > 0;

src/SharpGLTF.Toolkit/Geometry/MeshBuilderToolkit.cs

@@ -86,7 +86,7 @@ public static IReadOnlyDictionary<Vector3, Vector3> CalculateSmoothNormals<TMate
         {
             var posnrm = new Dictionary<Vector3, Vector3>();
 
-            void addDirection(Dictionary<Vector3, Vector3> dict, Vector3 pos, Vector3 dir)
+            static void addDirection(Dictionary<Vector3, Vector3> dict, Vector3 pos, Vector3 dir)
             {
                 if (!dir._IsFinite()) return;
                 if (!dict.TryGetValue(pos, out Vector3 n)) n = Vector3.Zero;