[UUM-148935] Make VectorHash quantization runtime-independent

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Fixed
 
 - [UUM-149791] Fixed the First Vertex pivot ending up offset from the shape after resizing an existing shape or shift-duplicating one with the Shape tool.
+- [UUM-148935] Fixed `VectorHash`/`IntVec2`/`IntVec3`/`IntVec4` producing different hash codes on different runtimes and architectures (e.g. Mono vs CoreCLR), and fixed a `GetHashCode` contract violation where positions considered equal by `IntVec3.Equals` could still hash differently, silently breaking vertex welding.
 - [UUM-150702] Fixed the ProBuilderDefault and Checker materials referencing a stale shader ID, causing ProBuilder meshes to render magenta when a scene was opened.
 - [UUM-148237] Fixed the "Lightmap UVs Settings" foldout in ProBuilder Preferences not opening when clicking its title.
 - [UUM-133528] Fixed an issue where using some UV Editor actions would clear a mesh's Lightmap UVs without regenerating them.

Runtime/Core/IntVec2.cs

@@ -57,7 +57,7 @@ public override int GetHashCode()
 
 		private static int round(float v)
 		{
-			return System.Convert.ToInt32(v * VectorHash.FltCompareResolution);
+			return VectorHash.RoundToInt(v);
 		}
 
 		public static implicit operator Vector2(IntVec2 p)

Runtime/Core/IntVec3.cs

@@ -60,7 +60,7 @@ public override int GetHashCode()
 
         private static int round(float v)
         {
-            return System.Convert.ToInt32(v * VectorHash.FltCompareResolution);
+            return VectorHash.RoundToInt(v);
         }
 
         public static implicit operator Vector3(IntVec3 p)

Runtime/Core/IntVec4.cs

@@ -63,7 +63,7 @@ public override int GetHashCode()
 
 		private static int round(float v)
 		{
-			return System.Convert.ToInt32(v * VectorHash.FltCompareResolution);
+			return VectorHash.RoundToInt(v);
 		}
 
 		public static implicit operator Vector4(IntVec4 p)

Runtime/Core/VectorHash.cs

@@ -11,10 +11,28 @@ static class VectorHash
     {
         public const float FltCompareResolution = 1000f;
 
-        static int HashFloat(float f)
+        /// <summary>
+        /// Quantize a float to FltCompareResolution. Shared by IntVec2/IntVec3/IntVec4 equality and
+        /// by the hash functions below, so that values which compare equal always hash equally.
+        /// </summary>
+        internal static int RoundToInt(float f)
         {
-            ulong u = (ulong)(f * FltCompareResolution);
-            return (int)(u % int.MaxValue);
+            if (float.IsNaN(f))
+                return 0;
+
+            float scaled = f * FltCompareResolution;
+
+            // Casting an out-of-range float to an integer type is unspecified in ECMA-335 - Mono on
+            // x64 wraps around while CoreCLR and Mono on Arm64 saturate, which also collapses every
+            // negative component to 0 - so clamp explicitly (UUM-148935, UUM-111993).
+            if (scaled <= int.MinValue)
+                return int.MinValue;
+
+            if (scaled >= int.MaxValue)
+                return int.MaxValue;
+
+            // System.Math, not UnityEngine.ProBuilder.Math
+            return (int)System.Math.Round(scaled, MidpointRounding.ToEven);
         }
 
         /// <summary>
@@ -29,8 +47,8 @@ public static int GetHashCode(Vector2 v)
 
             unchecked
             {
-                hash = hash * 29 + HashFloat(v.x);
-                hash = hash * 29 + HashFloat(v.y);
+                hash = hash * 29 + RoundToInt(v.x);
+                hash = hash * 29 + RoundToInt(v.y);
             }
 
             return hash;
@@ -48,9 +66,9 @@ public static int GetHashCode(Vector3 v)
 
             unchecked
             {
-                hash = hash * 29 + HashFloat(v.x);
-                hash = hash * 29 + HashFloat(v.y);
-                hash = hash * 29 + HashFloat(v.z);
+                hash = hash * 29 + RoundToInt(v.x);
+                hash = hash * 29 + RoundToInt(v.y);
+                hash = hash * 29 + RoundToInt(v.z);
             }
 
             return hash;
@@ -68,10 +86,10 @@ public static int GetHashCode(Vector4 v)
 
             unchecked
             {
-                hash = hash * 29 + HashFloat(v.x);
-                hash = hash * 29 + HashFloat(v.y);
-                hash = hash * 29 + HashFloat(v.z);
-                hash = hash * 29 + HashFloat(v.w);
+                hash = hash * 29 + RoundToInt(v.x);
+                hash = hash * 29 + RoundToInt(v.y);
+                hash = hash * 29 + RoundToInt(v.z);
+                hash = hash * 29 + RoundToInt(v.w);
             }
 
             return hash;

Tests/Runtime/Type/VertexTests.cs

@@ -4,9 +4,6 @@
 using System.Linq;
 using System;
 using UnityEngine.ProBuilder;
-#if UNITY_6000_7_OR_NEWER
-using UnityEngine.TestTools;
-#endif
 
 static class TestHashUtility
 {
@@ -44,6 +41,11 @@ static float RandFlt()
         return UnityEngine.Random.Range(0f, 100f) * .001f;
     }
 
+    static float RandJitter()
+    {
+        return UnityEngine.Random.Range(-.001f, .001f);
+    }
+
     static Vertex RandVertex()
     {
         Vertex v = new Vertex();
@@ -59,54 +61,33 @@ static Vertex RandVertex()
     }
 
     [Test]
-#if UNITY_6000_7_OR_NEWER
-    [UnityCoreClrExplicitDisabled("https://jira.unity3d.com/browse/UUM-148935", "ProBuilder IntVec3/VectorHash float hashing produces different values on CoreCLR")]
-#endif
     public static void TestHashCollisions_IVEC3()
     {
-#if UNITY_EDITOR_OSX
-        if (System.Runtime.InteropServices.RuntimeInformation.OSArchitecture == System.Runtime.InteropServices.Architecture.Arm64)
-            Assert.Ignore("Fails on macOS13 Arm64 https://jira.unity3d.com/browse/UUM-111993");
-#endif
-
         IntVec3[] ivec3 = ArrayUtility.Fill<IntVec3>(TestIterationCount, (i) => { return (IntVec3)RandVec3(); });
         Assert.IsTrue(TestHashUtility.GetCollisionsCount(ivec3) < TestIterationCount * .05f);
     }
 
     [Test]
-#if UNITY_6000_7_OR_NEWER
-    [UnityCoreClrExplicitDisabled("https://jira.unity3d.com/browse/UUM-148935", "ProBuilder IntVec3/VectorHash float hashing produces different values on CoreCLR")]
-#endif
     public static void TestVectorHashOverflow()
     {
-#if UNITY_EDITOR_OSX
-        if (System.Runtime.InteropServices.RuntimeInformation.OSArchitecture == System.Runtime.InteropServices.Architecture.Arm64)
-            Assert.Ignore("Fails on macOS13 Arm64 https://jira.unity3d.com/browse/UUM-111993");
-#endif
-
         Vector3 over = new Vector3(((float)int.MaxValue) + 10f, 0f, 0f);
         Vector3 under = new Vector3(((float)-int.MaxValue) - 10f, 0f, 0f);
         Vector3 inf = new Vector3(Mathf.Infinity, 0f, 0f);
+        Vector3 negInf = new Vector3(Mathf.NegativeInfinity, 0f, 0f);
         Vector3 nan = new Vector3(float.NaN, 0f, 0f);
 
-        // mostly checking that GetHashCode doesn't throw an error when converting bad float values
-        Assert.AreEqual(VectorHash.GetHashCode(over), 1499503, "Over");
-        Assert.AreEqual(VectorHash.GetHashCode(under), 2147303674, "Under");
-        Assert.AreNotEqual(VectorHash.GetHashCode(inf), 0, "Inf");
-        Assert.AreNotEqual(VectorHash.GetHashCode(nan), 0, "NaN");
+        // Out-of-range components saturate and NaN quantizes to zero, so these hash codes are
+        // identical on every runtime and architecture. See UUM-148935.
+        Assert.AreEqual(-2146825986, VectorHash.GetHashCode(over), "Over");
+        Assert.AreEqual(-2146825145, VectorHash.GetHashCode(under), "Under");
+        Assert.AreEqual(-2146825986, VectorHash.GetHashCode(inf), "Inf");
+        Assert.AreEqual(-2146825145, VectorHash.GetHashCode(negInf), "NegInf");
+        Assert.AreEqual(VectorHash.GetHashCode(Vector3.zero), VectorHash.GetHashCode(nan), "NaN");
     }
 
     [Test]
-#if UNITY_6000_7_OR_NEWER
-    [UnityCoreClrExplicitDisabled("https://jira.unity3d.com/browse/UUM-148935", "ProBuilder IntVec3/VectorHash float hashing produces different values on CoreCLR")]
-#endif
     public static void TestComparison_IVEC3()
     {
-#if UNITY_EDITOR_OSX
-        if (System.Runtime.InteropServices.RuntimeInformation.OSArchitecture == System.Runtime.InteropServices.Architecture.Arm64)
-            Assert.Ignore("Fails on macOS13 Arm64 https://jira.unity3d.com/browse/UUM-111993");
-#endif
-
         IntVec3 a = (IntVec3)RandVec3();
         IntVec3 b = (IntVec3)(a.value * 2.3f);
         IntVec3 c = (IntVec3) new Vector3(a.x, a.y + .001f, a.z);
@@ -123,6 +104,21 @@ public static void TestComparison_IVEC3()
         Assert.AreEqual(13, arr.Distinct().Count());
     }
 
+    [Test]
+    public static void TestEqualIntVec3SharesHashCode()
+    {
+        // IntVec3.Equals and VectorHash must quantize identically, otherwise positions that
+        // ProBuilder considers coincident land in different dictionary buckets and never weld.
+        for (int i = 0; i < TestIterationCount; ++i)
+        {
+            IntVec3 a = (IntVec3)RandVec3();
+            IntVec3 b = (IntVec3)(a.value + new Vector3(RandJitter(), RandJitter(), RandJitter()));
+
+            if (a == b)
+                Assert.AreEqual(a.GetHashCode(), b.GetHashCode(), a + " == " + b);
+        }
+    }
+
     [Test]
     public static void TestComparison_VERTEX()
     {