Crossing: the crosser is launched at the speed it should cross at, since a hull no longer decays below top speed

845f6c3aa (aetheria-gravity:ruling:no-drag-below-top-speed) removed hull drag below a hull's top speed. The crosser was staged at the Djinni's 50 m/s cap on the premise that drag slowed it to ~25 m/s at the bow line; it now holds 50 m/s and crosses at 2.57 s, 50 m/s relative, 1.1 rad/s, outside the tuned encounter (3.6 s, 25 m/s, 0.56 rad/s) that the Brief, the pass window and CrossingHoldsAcrossTheStartWindow all describe. CrossingConditions and CrossingHoldsAcrossTheStartWindow failed on that stale tuning, not on a defect.

The encounter is restaged to reproduce its tuning under the ruled physics: launched at 25 m/s from 90 m out (probed over speed x start; constant-speed passes are dx / v seconds, 45 m ahead). The pass lands at 3.63 s, 44.7 m, 24.9 m/s relative, 0.56 rad/s. The test's launch-speed assertions now pin the scenario's 25 m/s instead of "most of the cap"; the time, distance, relative-speed and angular-rate windows are unchanged. If drag below top speed returns, the crosser decays and the pass leaves the window.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
This commit is contained in:
Nibu 2026-11-11 05:03:57 +00:00
commit 0e9b10c3ae
2 changed files with 12 additions and 10 deletions

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@ -6,8 +6,8 @@ public sealed class Crossing : Scenario
public override string Name => "Crossing";
public override string Id => "crossing";
public override string Brief => "A Lightning Projector at the starboard gun and a Cell Blaster at the port gun, an unpiloted Djinni coasting across the bow " +
"close ahead and an unpiloted one waiting at range. The crosser is launched to port at 50 m/s and only coasts: nothing steers it, " +
"its hull drag slows it to about 25 m/s at the bow line, and it does not shoot back. Make the pass coasting: give no throttle until the Djinni has crossed the bow, then fly freely " +
"close ahead and an unpiloted one waiting at range. The crosser is launched to port at 25 m/s and only coasts: nothing steers it, " +
"a hull coasts at its launch speed below its top speed, and it does not shoot back. Make the pass coasting: give no throttle until the Djinni has crossed the bow, then fly freely " +
"(thrusting from the start carries you past it). Verify: as the Djinni crosses close, FastBlast lands some and projector " +
"almost none; against the Djinni at range both land. Fly it again without the Fire Control Array: " +
"with it the small gun lands more.";
@ -16,13 +16,15 @@ public sealed class Crossing : Scenario
// Where the Djinni sit: the player is at Origin facing +z. Origin is 250 m or more from every body, where the zone's
// pull is weakest (about 1.4 u/s^2; the sum of the wells never drops to nothing, and at the old origin the player sat on the star).
// The crosser is unpiloted and placed moving at the Djinni's 50 m/s cap, so its pass is ballistic: bent by the field and slowed
// by hull drag (it reaches the bow line at about 25 m/s relative to the player, 3.6 s in), and nothing steers it.
// The crosser is unpiloted and placed moving at 25 m/s, well under the Djinni's 50 m/s top speed, so its pass is ballistic: a hull
// coasts below its top speed (aetheria-gravity:ruling:no-drag-below-top-speed) and only the field bends it, so it reaches the
// bow line at 25 m/s relative to the player, 3.6 s in, and nothing steers it. (Launched at the cap with drag slowing it to 25 m/s,
// as this scenario was first tuned, it would now hold 50 m/s and cross in 2.6 s.)
// CrosserAt is the centre of the start window in which the pass holds: shifting it by 10 m along either axis keeps the pass
// inside the test's time and distance windows (CrossingHoldsAcrossTheStartWindow).
// The waiting Djinni sits inside the Lightning Projector's arc at 80% of its Range.
public static readonly CultMath.float2 Origin = float2(724, 124);
public static readonly CultMath.float2 CrosserAt = Origin + float2(-128, 45), CrosserFacing = float2(1, 0), CrosserVelocity = float2(50, 0);
public static readonly CultMath.float2 CrosserAt = Origin + float2(-90, 45), CrosserFacing = float2(1, 0), CrosserVelocity = float2(25, 0);
// The fighter is staged at this quality, so its gear and the range below do not ride the item stream.
public const float StagedQuality = .6f;
// The Lightning Projector's Range in metres at the staged fit: 996.99 after the three seconds the test settles for