animations

test/skaterSim.mjs

@@ -183,6 +183,113 @@ section('turning is harder at speed than at rest');
   );
 }
 
+section('LT does not spin the body around');
+{
+  // Facing +X, stick pulled toward −X under LT — should retreat heels-first
+  // without yaw flipping to face the stick.
+  const s = createSkaterState(0, { x: 0, z: 0, yaw: Math.PI / 2 });
+  const startYaw = s.yaw;
+  run(s, 2.5, (st) => {
+    st.ix = -1;
+    st.iz = 0;
+    st.backskate = true;
+  });
+  const yawDrift = Math.abs(wrap(s.yaw - startYaw));
+  ok(yawDrift < 0.45, `facing holds under LT (yaw drift ${yawDrift.toFixed(2)} rad)`);
+  ok(s.bladeSpeed < -1.2, `stick back drives reverse (${s.bladeSpeed.toFixed(2)} m/s)`);
+  ok(s.x < -1.5, `and the body retreats (x ${s.x.toFixed(2)})`);
+}
+
+section('LT with stick forward is a crawl, not a rush');
+{
+  const free = createSkaterState(0, START);
+  run(free, 5, forward);
+  const contain = createSkaterState(1, START);
+  run(contain, 5, (st) => {
+    forward(st);
+    st.backskate = true;
+  });
+  ok(
+    speedOf(free) > speedOf(contain) + 1.2,
+    `contain is much slower than free skate (${speedOf(contain).toFixed(2)} vs ${speedOf(free).toFixed(2)})`,
+  );
+  ok(speedOf(contain) <= SKATE.containForwardSpeed + 0.25, 'under the forward-contain ceiling');
+  ok(contain.bladeSpeed > 0, 'still facing the stick way, not flipped reverse');
+}
+
+section('LT reverse and lateral accelerate quickly for gap control');
+{
+  // Reverse from a standstill under LT should get moving fast.
+  const back = createSkaterState(0, { x: 0, z: 0, yaw: Math.PI / 2 });
+  run(back, 0.45, (st) => {
+    st.ix = -1;
+    st.iz = 0;
+    st.backskate = true;
+  });
+  ok(back.bladeSpeed < -2.5, `quick reverse accel (${back.bladeSpeed.toFixed(2)} m/s in 0.45s)`);
+  ok(Math.abs(back.x) > 0.6, 'and covers ground retreating');
+
+  // Lateral shuffle under LT.
+  const side = createSkaterState(1, { x: 0, z: 0, yaw: Math.PI / 2 });
+  run(side, 0.45, (st) => {
+    st.ix = 0;
+    st.iz = 1; // body right when facing +X
+    st.backskate = true;
+  });
+  ok(Math.abs(side.z) > 0.7, `quick lateral under LT (z ${side.z.toFixed(2)})`);
+  ok(Math.abs(side.x) < Math.abs(side.z), 'mostly sideways relative to facing (+X)');
+
+  // Flip reverse → forward under LT (offense ↔ defense switch).
+  const flip = createSkaterState(2, { x: 0, z: 0, yaw: Math.PI / 2 });
+  run(flip, 0.8, (st) => {
+    st.ix = -1;
+    st.iz = 0;
+    st.backskate = true;
+  });
+  const rev = flip.bladeSpeed;
+  ok(rev < -2, 'was reverse');
+  run(flip, 0.35, (st) => {
+    st.ix = 1;
+    st.iz = 0;
+    st.backskate = true;
+  });
+  ok(flip.bladeSpeed > rev + 2.5, `snaps out of reverse toward forward (${flip.bladeSpeed.toFixed(2)} from ${rev.toFixed(2)})`);
+}
+
+section('LT stick neutral bleeds a rush toward neutral');
+{
+  const s = createSkaterState(0, START);
+  run(s, 5, forward);
+  const entry = speedOf(s);
+  ok(entry > 3.5, 'at cruise');
+  // Hold LT, stick centred — sit in the gap instead of flying.
+  run(s, 1.2, (st) => {
+    st.ix = 0;
+    st.iz = 0;
+    st.backskate = true;
+  });
+  ok(speedOf(s) < entry * 0.55, `bled speed under LT (${speedOf(s).toFixed(2)} of ${entry.toFixed(2)})`);
+  ok(speedOf(s) > 0.15, 'but not a hard snowplow to zero');
+  const yawStill = Math.abs(wrap(s.yaw - Math.PI / 2));
+  ok(yawStill < 0.3, 'and did not spin to face the other way');
+}
+
+section('applyIntent accepts backskate');
+{
+  const s = createSkaterState(0, START);
+  applyIntent(s, { ix: 0, iz: 1, backskate: 1 });
+  ok(s.backskate === true, 'backskate flag is boolean true');
+  applyIntent(s, { ix: 0, iz: 1, backskate: 0 });
+  ok(s.backskate === false, 'and clears');
+}
+
+function wrap(a) {
+  let x = a;
+  while (x > Math.PI) x -= Math.PI * 2;
+  while (x <= -Math.PI) x += Math.PI * 2;
+  return x;
+}
+
 section('nothing leaves the rink');
 {
   // Point skaters at the boards from centre ice and hold it for ten seconds.