add mouse support

Sources/Voxelotl/Input/Mouse.swift

@@ -0,0 +1,81 @@
+import SDL3
+
+public class Mouse {
+  public struct Buttons: OptionSet {
+    public let rawValue: UInt32
+    public init(rawValue: UInt32) { self.rawValue = rawValue }
+
+    static let left    = Self(rawValue: UInt32(SDL_BUTTON_LEFT).buttonMask)
+    static let middle  = Self(rawValue: UInt32(SDL_BUTTON_MIDDLE).buttonMask)
+    static let right   = Self(rawValue: UInt32(SDL_BUTTON_RIGHT).buttonMask)
+    static let button4 = Self(rawValue: UInt32(SDL_BUTTON_X1).buttonMask)
+    static let button5 = Self(rawValue: UInt32(SDL_BUTTON_X2).buttonMask)
+  }
+
+  public static var capture: Bool {
+    get { self._instance.getCapture() }
+    set { self._instance.setCapture(newValue) }
+  }
+
+  public static var position: SIMD2<Float> { self._instance.getAbsolute() }
+  public static var relative: SIMD2<Float> { self._instance.getDelta() }
+
+  public static func down(_ btn: Buttons) -> Bool {
+    btn.isSubset(of: self._instance._btns)
+  }
+  public static func pressed(_ btn: Buttons) -> Bool {
+    btn.isSubset(of: self._instance._btns.intersection(self._instance._btnImpulse))
+  }
+  public static func released(_ btn: Buttons) -> Bool {
+    btn.isSubset(of: self._instance._btnImpulse.subtracting(self._instance._btns))
+  }
+
+  //MARK: - Private
+
+  private static let _instance = Mouse()
+  public static var instance: Mouse { self._instance }
+
+  private var _window: OpaquePointer!
+  private var _captured: Bool = false
+  private var _abs: SIMD2<Float> = .zero, _delta: SIMD2<Float> = .zero
+  private var _btns: Buttons = [], _btnImpulse: Buttons = []
+
+  private func getCapture() -> Bool { self._captured }
+  private func setCapture(_ toggle: Bool) {
+    let sdlBool = toggle ? SDL_TRUE : SDL_FALSE
+    if SDL_SetRelativeMouseMode(sdlBool) >= 0 && SDL_SetWindowMouseGrab(self._window, sdlBool) >= 0 {
+      self._captured = toggle
+    }
+  }
+
+  private func getAbsolute() -> SIMD2<Float> { self._abs }
+  private func getDelta() -> SIMD2<Float> { self._delta }
+
+  internal func buttonEvent(btn: UInt32, state: UInt8) {
+    if state == SDL_PRESSED {
+      self._btns.formUnion(.init(rawValue: btn.buttonMask))
+    } else {
+      self._btns.subtract(.init(rawValue: btn.buttonMask))
+    }
+    self._btnImpulse.formUnion(.init(rawValue: btn.buttonMask))
+  }
+
+  internal func motionEvent(absolute: SIMD2<Float>, relative: SIMD2<Float>) {
+    self._abs = absolute
+    self._delta += relative
+  }
+
+  internal func newFrame(_ window: OpaquePointer) {
+    self._window = window
+
+    let grabbedFlag = SDL_WindowFlags(SDL_WINDOW_MOUSE_GRABBED)
+    self._captured = (SDL_GetWindowFlags(window) & grabbedFlag) == grabbedFlag
+
+    self._delta = .zero
+    self._btnImpulse = []
+  }
+}
+
+fileprivate extension UInt32 {
+  var buttonMask: UInt32 { 1 &<< (self &- 1) }
+}