feat: add instrument logic (VU scale, needle spring, segment glyphs, LED bar)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
2026-10-01 15:21:10 +02:00
parent bd6bc3b890
commit 9a0effa881
2 changed files with 218 additions and 0 deletions
@@ -0,0 +1,108 @@
+import CoreGraphics
+import Testing
+@testable import SstUI
+
+struct VUScaleTests {
+    @Test func zeroVUIsMinusTwentyDbfs() {
+        #expect(VUScale.vu(fromDbfs: -20) == 0)
+        #expect(VUScale.vu(fromDbfs: -40) == -20)
+    }
+
+    @Test func fractionSpansTheScale() {
+        #expect(VUScale.fraction(forVU: -20) == 0)
+        #expect(abs(VUScale.fraction(forVU: 3) - 1) < 1e-9)
+        #expect(abs(VUScale.fraction(forVU: 0) - 20.0 / 23.0) < 1e-9)
+    }
+
+    @Test func fractionIsClampedAtBothEnds() {
+        #expect(VUScale.fraction(forVU: -60) == 0)
+        #expect(VUScale.fraction(forVU: 30) == 1.03)
+        #expect(VUScale.fraction(forDbfs: -120) == 0)
+    }
+
+    @Test func angleIsSymmetricAroundVertical() {
+        #expect(abs(VUScale.angle(forFraction: 0) + VUScale.angle(forFraction: 1)) < 1e-9)
+        #expect(abs(VUScale.angle(forFraction: 0.5)) < 1e-9)
+        #expect(abs(VUScale.angle(forFraction: 1) - 45 * .pi / 180) < 1e-9)
+    }
+}
+
+struct NeedleSpringTests {
+    func simulate(_ spring: NeedleSpring, seconds: Double, target: Double = 1) -> (final: Double, peak: Double) {
+        var spring = spring
+        var peak = 0.0
+        let dt = 1.0 / 240
+        for _ in 0..<Int(seconds / dt) { peak = max(peak, spring.step(target: target, dt: dt)) }
+        return (spring.position, peak)
+    }
+
+    @Test func reachesTheTargetWithinTheResponseTime() {
+        let result = simulate(NeedleSpring(), seconds: Motion.needleResponse)
+        #expect(abs(result.final - 1) < 0.02)
+    }
+
+    @Test func overshootsSlightlyWithTheTokenDamping() {
+        let result = simulate(NeedleSpring(), seconds: 1)
+        #expect(result.peak > 1.003)
+        #expect(result.peak < 1.03)
+        #expect(abs(result.final - 1) < 0.001)
+    }
+
+    @Test func criticalDampingNeverOvershoots() {
+        let result = simulate(NeedleSpring(damping: 1), seconds: 1)
+        #expect(result.peak <= 1.000001)
+    }
+
+    @Test func largeFrameStepsStayStable() {
+        var spring = NeedleSpring()
+        for _ in 0..<40 { spring.step(target: 1, dt: 0.05) }
+        #expect(abs(spring.position - 1) < 0.001)
+    }
+
+    @Test func restsAtTheStartWithoutATarget() {
+        var spring = NeedleSpring()
+        for _ in 0..<60 { spring.step(target: 0, dt: 1.0 / 60) }
+        #expect(spring.position == 0)
+    }
+}
+
+struct SegmentGlyphTests {
+    @Test func everyDigitHasASegmentPattern() {
+        for digit in "0123456789" { #expect(!SegmentGlyph.lit(for: digit).isEmpty) }
+        #expect(SegmentGlyph.lit(for: "8").count == 7)
+        #expect(SegmentGlyph.lit(for: "1") == [.b, .c])
+        #expect(SegmentGlyph.lit(for: ":").isEmpty)
+    }
+
+    @Test func polygonsStayInsideTheDigitBoxAndDiffer() {
+        var seen: [[CGPoint]] = []
+        for id in SegmentID.allCases {
+            let polygon = SegmentGlyph.polygon(id)
+            #expect(polygon.count == 6)
+            for point in polygon {
+                #expect(point.x >= 0 && point.x <= Segment.digitWidth)
+                #expect(point.y >= 0 && point.y <= Segment.digitHeight)
+            }
+            #expect(!seen.contains(polygon))
+            seen.append(polygon)
+        }
+        #expect(seen.count == 7)
+    }
+}
+
+struct LEDBarTests {
+    @Test func tonesFollowTheEightThreeOneSplit() {
+        let tones = (0..<12).map { LEDBar.tone(forSegment: $0) }
+        #expect(tones.prefix(8).allSatisfy { $0 == .green })
+        #expect(tones[8...10].allSatisfy { $0 == .amber })
+        #expect(tones[11] == .red)
+    }
+
+    @Test func litCountScalesAndClamps() {
+        #expect(LEDBar.litCount(forFraction: 0) == 0)
+        #expect(LEDBar.litCount(forFraction: 0.5) == 6)
+        #expect(LEDBar.litCount(forFraction: 1) == 12)
+        #expect(LEDBar.litCount(forFraction: 1.03) == 12)
+        #expect(LEDBar.litCount(forFraction: -1) == 0)
+    }
+}