Unit test conversion.

Examples/SwiftGraphicsDemosApp/SwiftGraphicsDemosApp.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -1,6 +1,15 @@
 {
-  "originHash" : "f54c244080f307f895a67831835efdd7ea3298ad7e0c77a1cbe6f7f2f7312d58",
+  "originHash" : "8a583861abe86c8b50abccbc3ecadda206025716fb79d8b673b69fbc125fae4a",
   "pins" : [
+    {
+      "identity" : "approximateequality",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/schwa/ApproximateEquality",
+      "state" : {
+        "revision" : "552f716baabbb06250f6b598a88dd0a401c72857",
+        "version" : "0.4.0"
+      }
+    },
     {
       "identity" : "everything",
       "kind" : "remoteSourceControl",

Package.resolved

@@ -1,6 +1,15 @@
 {
-  "originHash" : "a4acf933b9a4f484f884225cce0313985ae1be8694da81440840f9820f35c766",
+  "originHash" : "e332d68911c15106ee5fd69a03c0cc0832ad5830cc986a521e4b5e650b8f4f4d",
   "pins" : [
+    {
+      "identity" : "approximateequality",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/schwa/ApproximateEquality",
+      "state" : {
+        "revision" : "552f716baabbb06250f6b598a88dd0a401c72857",
+        "version" : "0.4.0"
+      }
+    },
     {
       "identity" : "everything",
       "kind" : "remoteSourceControl",

Package.swift

@@ -51,6 +51,7 @@ let package = Package(
         .package(url: "https://github.com/schwa/swiftfields", from: "0.0.1"),
         .package(url: "https://github.com/schwa/swiftformats", from: "0.3.5"),
         .package(url: "https://github.com/schwa/SwiftGLTF", branch: "main"),
+        .package(url: "https://github.com/schwa/ApproximateEquality", from: "0.4.0"),
 
     ],
     targets: [
@@ -157,6 +158,7 @@ let package = Package(
                 "GaussianSplatShaders",
                 "GaussianSplatSupport",
                 "Projection",
+                "ApproximateEquality"
             ],
             resources: [
                 .copy("Resources/lastchance.splat"),

Tests/GaussianSplatTests/SplatXConversionTests.swift

@@ -0,0 +1,35 @@
+import Testing
+import GaussianSplatSupport
+import GaussianSplatShaders
+import ApproximateEquality
+
+@Test(arguments: [
+    (
+        SplatB(position: [0, 0, 0], scale: [1, 1, 1], color: [255, 255, 255, 255], rotation: [128, 128, 128, 255]),
+        SplatX(position: [0, 0, 0], u1: [3.7539063, 0.0], u2: [0.0, 3.7539063], u3: [0.0, 4.0], color: [255, 255, 255, 255]),
+        0.000_000_1
+    ),
+    (
+        SplatB(position: [5.1992097, 14.8973675, -1.0287564], scale: [0.3719001, 0.41435486, 0.22165838], color: [22, 39, 53, 255], rotation: [67, 96, 211, 59]),
+        SplatX(position: [5.1992097, 14.8973675, -1.0287564], u1: [0.6044922, -0.14904785], u2: [0.05557251, 0.25170898], u3: [-0.0061683655, 0.58154297], color: [22, 39, 53, 255]),
+        0.001
+    ),
+    (
+        SplatB(position: [0, 0, 0], scale: [1, 0.5, 0.25], color: [255, 0, 255, 255], rotation: [128, 128, 128, 255]),
+        SplatX(position: [0.0, 0.0, 0.0], u1: [3.7539063, 0.0], u2: [0.0, 0.93847656], u3: [0.0, 0.25], color: [255, 0, 255, 255]),
+        0.0001
+    ),
+])
+func testSplatXConversion(splatB: SplatB, splatX: SplatX, absoluteTolerance: Double) {
+    #expect(SplatX(splatB).isApproximatelyEqual(to: splatX, absoluteTolerance: absoluteTolerance))
+}
+
+extension SplatX: @retroactive ApproximateEquality {
+    public func isApproximatelyEqual(to other: Self, absoluteTolerance: Double.Magnitude) -> Bool {
+        return position.isApproximatelyEqual(to: other.position, absoluteTolerance: Float(absoluteTolerance)) &&
+            u1.isApproximatelyEqual(to: other.u1, absoluteTolerance: Float16(absoluteTolerance)) &&
+            u2.isApproximatelyEqual(to: other.u2, absoluteTolerance: Float16(absoluteTolerance)) &&
+            u3.isApproximatelyEqual(to: other.u3, absoluteTolerance: Float16(absoluteTolerance)) &&
+            color == other.color
+    }
+}