Splatter: chevrons in perspective, and a smash that actually flies

The chevrons were stepped along the SCREEN line at a fixed size, so they read as
a flat sticker over a 3D court. They now step through world space and take their
size from their own projection scale — near ones roughly twice the far ones —
and they fade IN toward the target so the eye is walked up the lane instead of
being handed a uniform stripe. The arrowhead scales with the target's own depth
too. (proj is a true projective map, so the screen direction stays constant
along the line; only size and alpha needed to vary.)

Hard shots now fly hard: serve pace is weighted onto quality (19 base + 22×q,
so 21 -> 41 m/s) instead of 21 -> 28. Two things had to give way for it.

Serve topspin was a fixed 1 + 0.35q, which meant a fast flat ball could not
both clear the tape and land on a target, so the net-loft loop throttled every
smash back to walking pace — measured 21.8 m/s whether you drew 60px or 95px.
TUNE.serveSpin 1.3 lets it leave flat and DIVE, which is what a smash is.

And the loft loop's margin was doHit's quality cushion, which taxed exactly the
shots meant to hurt. It's now sized to the real error it exists to cover: the
sim samples the net plane once a frame, so a diving ball can test below the tape
when the closed form clears it. Margin = descent rate × the dt clamp. A flat
drive pays almost nothing, a lob pays what it must.

Measured, target 20m out: 24.7 / 32.2 / 41 m/s for weak / mid / full draw. At
the net it's 9.6 / 11.2 / 11.6 — still the slow floaty lob, as it should be.

Ball-vs-shambler contact gets a crude sweep (radius + half a frame's travel),
because a 41 m/s ball steps 0.7m per frame at 60fps and 1.6m at main.js's dt
clamp, both wider than a shambler. Verified the full smash connects at both.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

gameplay.js

@@ -151,17 +151,21 @@ function hitServe(sv, quality, aim = null) {
     const boxZ = toFar ? COURT.svcFar + 1.6 : COURT.svcNear - 1.6;
     tzs = boxZ + (Math.random() * 2 - 1) * (1 - quality) * 1.5;
   }
-  const g = TUNE.gravity * (1 + quality * 0.35); // kick serves dip a little too
+  const g = TUNE.gravity * (1 + quality * TUNE.serveSpin); // the harder you hit it, the harder it dips
   // CLEAR THE NET. A shambler standing just the other side of the tape is only reachable on a
   // loft, so trade pace for arc until the ball actually gets over. doHit has done this since
   // forever; the serve never did, which is why every shot at a net-hugger died in the tape.
   // The trade is real: the loftier it goes the slower it arrives, and the walk-lead below was
   // computed for the original pace — a lob is a genuinely less reliable shot.
   let v = solveShot(ball.x, ball.y, ball.z, boxX, tzs, s, g);
-  const margin = 0.06 + 0.22 * quality;
   for (let i = 0; i < NET_LOFT_TRIES; i++) {
     const tN = (COURT.netZ - ball.z) / v.vz;
     const yN = ball.y + v.vy * tN - 0.5 * g * tN * tN;
+    // The sim only samples the net plane once a frame, so a steeply DIVING ball can test below
+    // the tape even when the closed form clears it. Charge margin for exactly that sampling
+    // error (descent rate × the worst frame step) instead of doHit's flat quality cushion —
+    // that cushion is paid for in pace, and it was taxing precisely the shots meant to hurt.
+    const margin = 0.06 + Math.abs(v.vy - g * tN) * 0.04; // 0.04 s = main.js's dt clamp
     if (tN <= 0 || yN >= COURT.netH + margin) break;
     s *= 0.9; v = solveShot(ball.x, ball.y, ball.z, boxX, tzs, s, g);
   }