Add README

Author: tomasf

README.md

@@ -0,0 +1,51 @@
+# Manifold-Swift
+
+A Swift interface to the [Manifold geometry library](https://github.com/elalish/manifold), for manipulation of solid 3D meshes. 
+
+This SPM package includes Manifold, as well as its dependencies Clipper2 and oneTBB as Git submodules, so no additional dependencies are needed beyond the C++ standard library. Manifold-Swift works on macOS, Linux and Windows. The library covers most of the Manifold API, and naming is similar but using Swift conventions.
+
+Due to a bug in Swift that isn't fixed in the latest release (as of 2025-01-13, version 6.0.3), the library requires a development snapshot of Swift to build on Windows. Because the library interfaces with C++, you need to enable C++ interoperability when using Manifold-Swift:
+
+```swift
+let package = Package(
+    name: "manifold-swift-example",
+    dependencies: [
+        .package(url: "https://github.com/tomasf/manifold-swift.git", .upToNextMinor(from: "0.1.0"))
+    ],
+    targets: [
+        .executableTarget(
+            name: "manifold-swift-example",
+            dependencies: [.product(name: "Manifold", package: "manifold-swift")],
+            swiftSettings: [.interoperabilityMode(.Cxx)]
+        )
+    ]
+)
+```
+
+## Usage
+
+The library uses protocols for vectors and matrices, so you can add conformance to your own types and send them in without conversion.
+
+```swift
+import Manifold3D
+
+struct V: Vector3 {
+    let x: Double
+    let y: Double
+    let z: Double
+}
+
+let sphere = Manifold.sphere(radius: 10, segmentCount: 25)
+let box = Manifold.cube(size: V(x: 12, y: 20, z: 20))
+    .rotate(V(x: 20, y: 25, z: 0))
+let difference = sphere.boolean(.difference, with: box)
+
+let meshGL = difference.meshGL()
+// Render or save meshGL.vertices, meshGL.triangles, etc.
+```
+
+Read the [Manifold documentation](https://manifoldcad.org/docs/html) for more information.
+
+## Contributions
+
+Contributions are welcome! Submit pull requests or open issues to discuss improvements or report bugs.