画面を散らかす効果（肉球の足跡・爪とぎ跡）を追加

Neco/Litter.swift

@@ -0,0 +1,171 @@
+import AppKit
+
+// The mess the cat leaves behind. Neco drops paw prints while it runs and scratch
+// marks while it works its claws (grooming or clawing a wall). Marks live in global
+// screen coordinates, fade out over their lifetime, and are drawn by LitterView on a
+// full-screen overlay panel that sits just below the cat.
+
+/// One mark on the screen. Kept file-private so LitterField owns the whole lifecycle.
+private struct Mark {
+    enum Kind { case paw, scratch }
+    let kind: Kind
+    let pos: NSPoint // global screen coordinates
+    let angle: CGFloat // radians: paw points along travel, scratch is tilted
+    let birth: Int // tick when created
+}
+
+/// Accumulates and ages the cat's marks. `update(neko:)` is called once per 60fps
+/// tick; it emits new marks from the cat's motion, culls faded ones, and reports
+/// whether the set changed so the view only redraws when it needs to.
+@MainActor
+final class LitterField {
+    var pawsEnabled = false
+    var scratchEnabled = false
+
+    fileprivate private(set) var marks: [Mark] = []
+    private var tick = 0
+    private var prevPos: NSPoint?
+    private var lastPawPos: NSPoint? // nil until the first running frame seeds it
+    private var pawSide: CGFloat = 1 // flip each print for a left/right foot
+    private var lastScratch = -9999 // safely in the past; never Int.min (subtraction would overflow)
+
+    // Tunables. Times are in ticks (60 per second).
+    private let pawSpacing: CGFloat = 26 // travel distance between paw prints
+    private let scratchInterval = 9 // ~7 scratch marks per second while clawing
+    private let pawLife = 60 * 12 // 12s
+    private let scratchLife = 60 * 20 // 20s
+    private let maxMarks = 400 // hard cap: drop the oldest beyond this
+
+    private func life(of kind: Mark.Kind) -> Int {
+        kind == .paw ? pawLife : scratchLife
+    }
+
+    /// Advance one tick. Returns true if a mark was added or culled (a new/removed
+    /// mark needs an immediate redraw; ongoing fade is redrawn on a throttle).
+    @discardableResult
+    func update(neko: Neko) -> Bool {
+        tick += 1
+        let pos = neko.pos
+        defer { prevPos = pos }
+
+        let before = marks.count
+        marks.removeAll { tick - $0.birth > life(of: $0.kind) }
+        var changed = marks.count != before
+
+        if pawsEnabled, neko.isRunning {
+            if let last = lastPawPos, hypot(pos.x - last.x, pos.y - last.y) >= pawSpacing {
+                let heading = prevPos.map { atan2(pos.y - $0.y, pos.x - $0.x) } ?? 0
+                // Step sideways from the path so prints alternate like real feet.
+                let off = 6 * pawSide
+                let p = NSPoint(x: pos.x + cos(heading + .pi / 2) * off,
+                                y: pos.y + sin(heading + .pi / 2) * off)
+                add(Mark(kind: .paw, pos: p, angle: heading, birth: tick))
+                lastPawPos = pos
+                pawSide *= -1
+                changed = true
+            } else if lastPawPos == nil {
+                lastPawPos = pos // seed on the first running frame; the first step drops no print
+            }
+        } else {
+            lastPawPos = pos // measure spacing fresh from where the next run starts
+        }
+
+        if scratchEnabled, neko.isClawing, tick - lastScratch >= scratchInterval {
+            // Deterministic scatter (no RNG): derive jitter and tilt from the tick.
+            let jitter = CGFloat((tick * 37) % 18 - 9)
+            let tilt = CGFloat((tick * 53) % 50 - 25) * .pi / 180
+            let p = NSPoint(x: pos.x + jitter, y: pos.y + jitter * 0.5)
+            add(Mark(kind: .scratch, pos: p, angle: tilt, birth: tick))
+            lastScratch = tick
+            changed = true
+        }
+
+        return changed
+    }
+
+    private func add(_ mark: Mark) {
+        marks.append(mark)
+        if marks.count > maxMarks {
+            marks.removeFirst(marks.count - maxMarks)
+        }
+    }
+
+    var isEmpty: Bool {
+        marks.isEmpty
+    }
+
+    func clear() {
+        marks.removeAll()
+    }
+
+    /// Opacity for a mark: full for most of its life, then fading over the last quarter.
+    fileprivate func alpha(of mark: Mark) -> CGFloat {
+        let age = CGFloat(tick - mark.birth)
+        let life = CGFloat(life(of: mark.kind))
+        let fadeStart = life * 0.75
+        guard age > fadeStart else { return 1 }
+        return max(0, 1 - (age - fadeStart) / (life - fadeStart))
+    }
+}
+
+/// Draws every current mark onto the full-screen overlay panel. `originOffset` is the
+/// panel's origin in global coordinates, so a global mark maps to a local point by
+/// subtracting it.
+@MainActor
+final class LitterView: NSView {
+    var field: LitterField?
+    var originOffset = NSPoint.zero
+
+    override var isFlipped: Bool {
+        false
+    }
+
+    override func draw(_: NSRect) {
+        NSColor.clear.setFill()
+        bounds.fill(using: .copy)
+        guard let field, let ctx = NSGraphicsContext.current?.cgContext else { return }
+        for mark in field.marks {
+            let a = field.alpha(of: mark)
+            let p = NSPoint(x: mark.pos.x - originOffset.x, y: mark.pos.y - originOffset.y)
+            switch mark.kind {
+            case .paw: Self.drawPaw(ctx, at: p, angle: mark.angle, alpha: a)
+            case .scratch: Self.drawScratch(ctx, at: p, angle: mark.angle, alpha: a)
+            }
+        }
+    }
+
+    /// A paw print: one big pad plus four toe beans, drawn pointing +y then rotated
+    /// so it points along the direction of travel.
+    private static func drawPaw(_ ctx: CGContext, at p: NSPoint, angle: CGFloat, alpha: CGFloat) {
+        ctx.saveGState()
+        defer { ctx.restoreGState() }
+        ctx.translateBy(x: p.x, y: p.y)
+        ctx.rotate(by: angle - .pi / 2) // shape points +y; align +y with travel
+        ctx.setFillColor(NSColor(calibratedWhite: 0.12, alpha: 0.5 * alpha).cgColor)
+        let s: CGFloat = 1.2
+        ctx.fillEllipse(in: CGRect(x: -5 * s, y: -6 * s, width: 10 * s, height: 8 * s))
+        let toes = [CGPoint(x: -5, y: 3), CGPoint(x: -2, y: 6.5), CGPoint(x: 2, y: 6.5), CGPoint(x: 5, y: 3)]
+        for t in toes {
+            ctx.fillEllipse(in: CGRect(x: (t.x - 1.6) * s, y: (t.y - 1.6) * s,
+                                       width: 3.2 * s, height: 3.2 * s))
+        }
+    }
+
+    /// A scratch mark: three parallel claw streaks with a slight slant.
+    private static func drawScratch(_ ctx: CGContext, at p: NSPoint, angle: CGFloat, alpha: CGFloat) {
+        ctx.saveGState()
+        defer { ctx.restoreGState() }
+        ctx.translateBy(x: p.x, y: p.y)
+        ctx.rotate(by: angle)
+        ctx.setStrokeColor(NSColor(calibratedWhite: 0.1, alpha: 0.45 * alpha).cgColor)
+        ctx.setLineWidth(1.6)
+        ctx.setLineCap(.round)
+        let len: CGFloat = 16
+        for i in 0 ..< 3 {
+            let x = CGFloat(i - 1) * 4
+            ctx.move(to: CGPoint(x: x, y: -len / 2))
+            ctx.addLine(to: CGPoint(x: x + 1.5, y: len / 2))
+        }
+        ctx.strokePath()
+    }
+}

Neco/NecoApp.swift

@@ -18,6 +18,15 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
     private var paused = false
     private var lastStatusFrame = ""
 
+    // The mess overlay: a full-screen click-through panel below the cat that draws
+    // the paw prints and scratch marks the cat leaves behind.
+    private var litterPanel: NSPanel!
+    private var litterView: LitterView!
+    private let litter = LitterField()
+    private var pawsItem: NSMenuItem!
+    private var scratchItem: NSMenuItem!
+    private var tick = 0
+
     private var side: CGFloat {
         CGFloat(Sprites.width) * Tuning.scale
     }
@@ -45,15 +54,81 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
         reposition()
         panel.orderFrontRegardless()
 
+        setupLitterPanel()
         setupStatusItem()
         startTimer()
     }
 
+    /// A full-screen, click-through overlay just below the cat, for its paw prints
+    /// and scratch marks. It spans every screen so the mess follows the cat around.
+    private func setupLitterPanel() {
+        let d = UserDefaults.standard
+        litter.pawsEnabled = d.object(forKey: "pawsEnabled") as? Bool ?? false
+        litter.scratchEnabled = d.object(forKey: "scratchEnabled") as? Bool ?? false
+
+        litterView = LitterView()
+        litterView.field = litter
+
+        litterPanel = NSPanel(
+            contentRect: screensFrame(),
+            styleMask: [.borderless, .nonactivatingPanel],
+            backing: .buffered,
+            defer: false
+        )
+        litterPanel.isOpaque = false
+        litterPanel.backgroundColor = .clear
+        litterPanel.hasShadow = false
+        // One level below the cat so the cat always walks on top of its own mess.
+        litterPanel.level = NSWindow.Level(rawValue: NSWindow.Level.statusBar.rawValue - 1)
+        litterPanel.ignoresMouseEvents = true
+        litterPanel.collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary, .stationary]
+        litterPanel.contentView = litterView
+        layoutLitterPanel()
+        litterPanel.orderFrontRegardless()
+
+        NotificationCenter.default.addObserver(
+            self, selector: #selector(screensChanged),
+            name: NSApplication.didChangeScreenParametersNotification, object: nil
+        )
+    }
+
+    private func screensFrame() -> NSRect {
+        NSScreen.screens.reduce(NSRect.zero) { $0.union($1.frame) }
+    }
+
+    private func layoutLitterPanel() {
+        let frame = screensFrame()
+        litterPanel.setFrame(frame, display: false)
+        litterView.frame = NSRect(origin: .zero, size: frame.size)
+        litterView.originOffset = frame.origin
+    }
+
+    @objc private func screensChanged() {
+        layoutLitterPanel()
+        litterView.needsDisplay = true
+    }
+
     private func setupStatusItem() {
         statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)
         updateStatusImage()
 
         let menu = NSMenu()
+
+        pawsItem = NSMenuItem(title: "Paw Prints", action: #selector(togglePaws), keyEquivalent: "")
+        pawsItem.target = self
+        pawsItem.state = litter.pawsEnabled ? .on : .off
+        menu.addItem(pawsItem)
+
+        scratchItem = NSMenuItem(title: "Scratch Marks", action: #selector(toggleScratch), keyEquivalent: "")
+        scratchItem.target = self
+        scratchItem.state = litter.scratchEnabled ? .on : .off
+        menu.addItem(scratchItem)
+
+        let clear = NSMenuItem(title: "Clear Mess", action: #selector(clearMess), keyEquivalent: "")
+        clear.target = self
+        menu.addItem(clear)
+        menu.addItem(.separator())
+
         let pause = NSMenuItem(title: "Pause / Resume", action: #selector(togglePause), keyEquivalent: "p")
         pause.target = self
         menu.addItem(pause)
@@ -77,6 +152,23 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
         paused.toggle()
     }
 
+    @objc private func togglePaws() {
+        litter.pawsEnabled.toggle()
+        pawsItem.state = litter.pawsEnabled ? .on : .off
+        UserDefaults.standard.set(litter.pawsEnabled, forKey: "pawsEnabled")
+    }
+
+    @objc private func toggleScratch() {
+        litter.scratchEnabled.toggle()
+        scratchItem.state = litter.scratchEnabled ? .on : .off
+        UserDefaults.standard.set(litter.scratchEnabled, forKey: "scratchEnabled")
+    }
+
+    @objc private func clearMess() {
+        litter.clear()
+        litterView.needsDisplay = true
+    }
+
     private func startTimer() {
         // Target/selector Timer: it fires on the run loop it is scheduled on (main),
         // so tick stays on the MainActor without an unchecked assumeIsolated.
@@ -88,10 +180,18 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
 
     @objc private func onTick() {
         guard !paused else { return }
+        tick += 1
         neko.update(mouse: NSEvent.mouseLocation)
         reposition()
         view.needsDisplay = true
         updateStatusImage()
+
+        // Redraw the mess when a mark appears or vanishes; otherwise refresh at ~10fps
+        // so fading marks dim smoothly without a full-screen repaint every frame.
+        let changed = litter.update(neko: neko)
+        if changed || (!litter.isEmpty && tick % 6 == 0) {
+            litterView.needsDisplay = true
+        }
     }
 
     private func reposition() {

Neco/Neko.swift

@@ -10,6 +10,7 @@ enum Tuning {
     static let stopDistance: CGFloat = 24 // "caught the cursor" threshold
     static let wakeDistance: CGFloat = 40 // cursor must move this far to wake a sleeping cat
     static let edgeMargin: CGFloat = 24 // how close to a screen edge counts as "at the wall"
+    static let togiChance = 0.5 // when not at a wall, chance of scratching claws (togi) instead of pawing (jare) on stop
 
     // Idle-chain durations, in seconds. Mirror oneko.h (there 1 tick ~= 0.125s):
     // STOP 4, JARE 10, KAKI 4, AKUBI 6, AWAKE 3, TOGI 10.
@@ -47,6 +48,24 @@ final class Neko {
         Double(tick - stateStart) / 60.0
     }
 
+    /// The cat is on the move; drops paw prints behind it (see LitterField).
+    var isRunning: Bool {
+        if case .running = motion {
+            true
+        } else {
+            false
+        }
+    }
+
+    /// The cat is sharpening its claws (togi): at a screen edge, or — per
+    /// Tuning.togiChance — at a random stop anywhere. Scratch marks drop in this state.
+    var isClawing: Bool {
+        switch motion {
+        case .togi: true
+        default: false
+        }
+    }
+
     private func setState(_ m: Motion) {
         motion = m
         stateStart = tick
@@ -119,7 +138,8 @@ final class Neko {
         }
     }
 
-    /// Leaving STOP: groom if the cat has run up against a screen edge, else paw.
+    /// Leaving STOP: groom if the cat has run up against a screen edge. Otherwise, at
+    /// random, sharpen claws (togi) facing a random way, else paw (jare).
     private func chooseAfterStop() {
         let screen = NSScreen.screens.first { $0.frame.contains(pos) } ?? NSScreen.main
         if let f = screen?.frame {
@@ -137,7 +157,12 @@ final class Neko {
                 togiDir = "d"; return setState(.togi)
             }
         }
-        setState(.jare)
+        if Double.random(in: 0 ..< 1) < Tuning.togiChance {
+            togiDir = ["u", "d", "l", "r"].randomElement() ?? "d"
+            setState(.togi)
+        } else {
+            setState(.jare)
+        }
     }
 
     /// Which sprite to show right now.