Replace bogus normals with (1,0,0) which is bogus but well-formed

Fixes #10
kythyria · Mar 14, 2020 · d9b5160 · d9b5160
1 parent 944d044
commit d9b5160
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Showing 2 changed files with 33 additions and 2 deletions.
diff --git a/PD2ModelParser/Exporters/GltfExporter.cs b/PD2ModelParser/Exporters/GltfExporter.cs
@@ -254,9 +254,20 @@ GLTF.Mesh GetMeshForModel(Model model)
 
             if (geometry.normals.Count > 0)
             {
-                Vector3 MakeNormal(Nexus.Vector3D norm)
+                Vector3 MakeNormal(Nexus.Vector3D norm, int idx)
                 {
-                    return Vector3.Normalize(norm.ToVector3());
+                    var normalized = Vector3.Normalize(norm.ToVector3());
+                    if(!normalized.IsFinite())
+                    {
+                        Log.Default.Warn("Vertex {0} of geometry {1}|{2} is bogus ({3})", idx, geometry.SectionId, geometry.hashname, norm);
+                        return new Vector3(1, 0, 0);
+                    }
+                    if(!normalized.IsUnitLength())
+                    {
+                        Log.Default.Warn("Vertex {0} of geometry {1}|{2} is bogus length {4} ({3})", idx, geometry.SectionId, geometry.hashname, norm, norm.Length());
+                        return new Vector3(1, 0, 0);
+                    }
+                    return normalized;
                 }
                 var a_norm = MakeVertexAttributeAccessor("vnorm", geometry.normals, 12, GLTF.DimensionType.VEC3, MakeNormal, ma => ma.AsVector3Array());
                 result.Add(("NORMAL", a_norm));

diff --git a/PD2ModelParser/Utils.cs b/PD2ModelParser/Utils.cs
@@ -169,6 +169,26 @@ public static byte ClampFloatToByte(double input)
             var rounded = Math.Round(scaled);
             return (byte)rounded;
         }
+
+        public static Boolean IsFinite(this System.Numerics.Vector3 vec)
+        {
+            return !(
+                float.IsInfinity(vec.X)
+                || float.IsInfinity(vec.Y)
+                || float.IsInfinity(vec.Z)
+                || float.IsNaN(vec.X)
+                || float.IsNaN(vec.Y)
+                || float.IsNaN(vec.Z)
+            );
+        }
+
+        // From https://github.com/KhronosGroup/glTF-Validator/blob/master/lib/src/errors.dart
+        // which says, "these values are slightly greater than the maximum error from signed 8-bit quantization"
+        const float UnitLengthThresholdVec3 = 0.00674f;
+        const float UnitLengthThresholdVec4 = 0.00769f;
+
+        public static Boolean IsUnitLength(this System.Numerics.Vector3 vec) =>
+            Math.Abs(vec.Length() - 1) <= UnitLengthThresholdVec3;
     }
 
     public static class MatrixExtensions