Tracking de l'application VApp (IHM du jeu)

VApp/node_modules/vuetify/lib/composables/touch.mjs

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+// Utilities
+import { CircularBuffer } from "../util/index.mjs";
+const HORIZON = 100; // ms
+const HISTORY = 20; // number of samples to keep
+
+/** @see https://android.googlesource.com/platform/frameworks/native/+/master/libs/input/VelocityTracker.cpp */
+function kineticEnergyToVelocity(work) {
+  const sqrt2 = 1.41421356237;
+  return (work < 0 ? -1.0 : 1.0) * Math.sqrt(Math.abs(work)) * sqrt2;
+}
+
+/**
+ * Returns pointer velocity in px/s
+ */
+export function calculateImpulseVelocity(samples) {
+  // The input should be in reversed time order (most recent sample at index i=0)
+  if (samples.length < 2) {
+    // if 0 or 1 points, velocity is zero
+    return 0;
+  }
+  // if (samples[1].t > samples[0].t) {
+  //   // Algorithm will still work, but not perfectly
+  //   consoleWarn('Samples provided to calculateImpulseVelocity in the wrong order')
+  // }
+  if (samples.length === 2) {
+    // if 2 points, basic linear calculation
+    if (samples[1].t === samples[0].t) {
+      // consoleWarn(`Events have identical time stamps t=${samples[0].t}, setting velocity = 0`)
+      return 0;
+    }
+    return (samples[1].d - samples[0].d) / (samples[1].t - samples[0].t);
+  }
+  // Guaranteed to have at least 3 points here
+  // start with the oldest sample and go forward in time
+  let work = 0;
+  for (let i = samples.length - 1; i > 0; i--) {
+    if (samples[i].t === samples[i - 1].t) {
+      // consoleWarn(`Events have identical time stamps t=${samples[i].t}, skipping sample`)
+      continue;
+    }
+    const vprev = kineticEnergyToVelocity(work); // v[i-1]
+    const vcurr = (samples[i].d - samples[i - 1].d) / (samples[i].t - samples[i - 1].t); // v[i]
+    work += (vcurr - vprev) * Math.abs(vcurr);
+    if (i === samples.length - 1) {
+      work *= 0.5;
+    }
+  }
+  return kineticEnergyToVelocity(work) * 1000;
+}
+export function useVelocity() {
+  const touches = {};
+  function addMovement(e) {
+    Array.from(e.changedTouches).forEach(touch => {
+      const samples = touches[touch.identifier] ?? (touches[touch.identifier] = new CircularBuffer(HISTORY));
+      samples.push([e.timeStamp, touch]);
+    });
+  }
+  function endTouch(e) {
+    Array.from(e.changedTouches).forEach(touch => {
+      delete touches[touch.identifier];
+    });
+  }
+  function getVelocity(id) {
+    const samples = touches[id]?.values().reverse();
+    if (!samples) {
+      throw new Error(`No samples for touch id ${id}`);
+    }
+    const newest = samples[0];
+    const x = [];
+    const y = [];
+    for (const val of samples) {
+      if (newest[0] - val[0] > HORIZON) break;
+      x.push({
+        t: val[0],
+        d: val[1].clientX
+      });
+      y.push({
+        t: val[0],
+        d: val[1].clientY
+      });
+    }
+    return {
+      x: calculateImpulseVelocity(x),
+      y: calculateImpulseVelocity(y),
+      get direction() {
+        const {
+          x,
+          y
+        } = this;
+        const [absX, absY] = [Math.abs(x), Math.abs(y)];
+        return absX > absY && x >= 0 ? 'right' : absX > absY && x <= 0 ? 'left' : absY > absX && y >= 0 ? 'down' : absY > absX && y <= 0 ? 'up' : oops();
+      }
+    };
+  }
+  return {
+    addMovement,
+    endTouch,
+    getVelocity
+  };
+}
+function oops() {
+  throw new Error();
+}
+//# sourceMappingURL=touch.mjs.map