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hud.cpp: byte-ground the HudSimulation constants -- all five were stand-ins under guessed names

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Found chasing the Thor "no range finder" report: _DAT_004b7ec4 was documented
as two incompatible things -- the 0.75 LOCK damage threshold (mech4.cpp:6325)
and a "heat threshold for HUD page visibility" valued 0.0f (hud.cpp:59).

The .rdata settles it (reference/decomp/section_dump.txt):

     4b7ec0  8be55dc3 0000403f 0000803f 0000c842
     4b7ed0  00000000

  _DAT_004b7ec4 = 0.75f    _DAT_004b7ec8 = 1.0f
  _DAT_004b7ecc = 100.0f   _DAT_004b7ed0 = 0.0f    _DAT_004b7f90 = 0.0f

mech4.cpp was right on both thresholds.  hud.cpp's whole tuning block was
wrong -- every entry a 0.0f/500.0f stand-in, and three of five names named the
wrong mechanism:

  * ec4/ec8 are the fire-control LOCK limits (own HUD host zone < 0.75 damage,
    targeted zone < 1.0), NOT heat/page-visibility.  A shot-up cockpit drops to
    "target held, no lock"; a dead zone cannot be re-locked.
  * ed0 is the shared ZERO -- the right-hand side of the range-slide Abs()
    idiom (`dt * 500.0 <= 0.0` picks the sign) and of an `== 0.0f` test at
    @0x28C.  The 500 m/s slide rate is an IMMEDIATE (0x43fa0000).  The old
    "MaxTorsoSlew = 500.0f" read that backwards.
  * f90 (FlickerFloor 0.0f) was the only correct entry.  Its decay RATE is the
    object's own @0x298, not a constant -- the step-6 banner said "up to
    MaxTorsoSlew (500/sec)" and is corrected too (hud.cpp:229 already had it
    right, so the file disagreed with itself).

All four wrong constants were DEAD (zero code uses; MaxTorsoSlew appeared only
in a comment), so this changes no behaviour -- it stops the next reader
trusting them.  Renamed to what they are: LockOwnZoneDamageLimit,
LockTargetZoneDamageLimit, RangeBias, HudZero.  Builds clean.

GAP FOUND, filed not fixed: HudSimulation subtracts _DAT_004b7ecc (100.0f)
from RangeToTarget@0x1EC every frame while the timed flag @0x22C is set
(timer @0x21C accumulates to @0x1D8, then both clear).  Our targeting step
does the 500 m/s slide but never this bias, so the authentic timed -100 m
range offset is missing.  What sets @0x22C is unidentified.  -> open-questions.

KB swept: no context/ or docs/ file repeated the wrong constants (gauges-hud's
0-1200 ladder / 500 m/s / pegs-at-1200 claims are all correct); the error was
confined to hud.cpp.  gauges-hud.md gains the byte-grounded table + the gap.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018SgmXGNMXavXiafKXf9MDC
This commit is contained in:
Joe DiPrima
2026-08-08 06:11:59 -05:00
co-authored by Claude Opus 5
parent 7b003243ae
commit 832bec0966
3 changed files with 69 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files
game/reconstructed/hud.cpp
+40 -10
View File
@@ -52,15 +52,41 @@ struct HUDLayoutCheck
};
//
// Tuning constants observed as read-only float globals adjacent to the
// HudSimulation body (.rdata, recovered from section_dump.txt).
// Tuning constants read as read-only float globals adjacent to the
// HudSimulation body. The VALUES BELOW ARE THE BINARY'S, read straight off
// the .rdata rows in reference/decomp/section_dump.txt [T1]:
// 4b7ec0 8be55dc3 0000403f 0000803f 0000c842
// 4b7ed0 00000000
// -> ec4 = 0.75f ec8 = 1.0f ecc = 100.0f ed0 = 0.0f
//
// CORRECTED 2026-08-08. Every entry here used to be a 0.0f/500.0f STAND-IN
// under a guessed name, and the names described the wrong mechanism: there is
// no "heat threshold for HUD page visibility" at 0x4b7ec4 -- ec4/ec8 are the
// fire-control LOCK damage limits, and "MaxTorsoSlew = 500.0f" at ed0 read the
// range-slide Abs() idiom backwards (ed0 is the ZERO; 500.0 is an immediate).
// The LIVE implementation of the lock rule and the range slide is mech4.cpp's
// targeting step, which had both thresholds right all along. These stay so
// the addresses resolve to the truth for the next reader.
//
static const Point3D HudZeroVector(0.0f, 0.0f, 0.0f); // DAT_004e0f74/78/7c
static const Scalar SegmentTempLimit = 0.0f; // _DAT_004b7ec4 (heat threshold for HUD page visibility)
static const Scalar TargetTempLimit = 0.0f; // _DAT_004b7ec8
static const Scalar RangeBias = 0.0f; // _DAT_004b7ecc
static const Scalar MaxTorsoSlew = 500.0f; // _DAT_004b7ed0
static const Scalar FlickerFloor = 0.0f; // _DAT_004b7f90
// LOCK gate (a): your OWN HUD's host zone must be BELOW 75% damage, else
// fire-control lock is lost -- the `_DAT_004b7ec4 <= ownZone->damageLevel`
// arm of HudSimulation. A shot-up cockpit drops to "target held, no lock".
static const Scalar LockOwnZoneDamageLimit = 0.75f; // _DAT_004b7ec4
// LOCK gate (b): the TARGETED zone must be below 1.0 damage (a whole-mech
// target checks zone 0), so a dead zone cannot be re-locked.
static const Scalar LockTargetZoneDamageLimit = 1.0f; // _DAT_004b7ec8
// Subtracted from RangeToTarget (@0x1EC) every frame while the timed flag
// @0x22C is set (timer @0x21C accumulates to @0x1D8, then both clear).
// NOT reconstructed in the port's targeting step -- tracked, not implemented.
static const Scalar RangeBias = 100.0f; // _DAT_004b7ecc
// The shared ZERO: the right-hand side of the Abs() idiom on the range slide
// (`dt * 500.0 <= 0.0` picks the sign) and of an `== 0.0f` test at @0x28C.
// The 500 m/s slide RATE is an immediate literal (0x43fa0000), never this.
static const Scalar HudZero = 0.0f; // _DAT_004b7ed0
// The decay FLOOR for horizontalTorsoOffset (@0x294) in FUN_004b7ed4. The
// decay RATE is the object's own @0x298, not a constant. (Value verified.)
static const Scalar FlickerFloor = 0.0f; // _DAT_004b7f90
//
// Cross-family helper (definition lives in the mech game layer; declared here
@@ -322,9 +348,13 @@ Logical
// (+0x100), sliding at 500 m/s (:5652-5670), default 1200.0 with no
// target; the compass Scalar @0x214 = yaw euler[0] + torso twist (:5676).
// 6. Torso-horizon slew: horizontalTorsoOffset (@0x294) is moved toward the
// commanded torso heading at up to MaxTorsoSlew (500/sec), clamped to
// +/- horizontalLimit (@0x29C), then written to the graphic at
// mech +0x36C. The flicker helper (@004b7ed4) damps the settle.
// commanded torso heading, clamped to +/- horizontalLimit (@0x29C), then
// written to the graphic at mech +0x36C. The flicker helper (@004b7ed4)
// damps the settle: it decays @0x294 toward ZERO at the object's own
// @0x298 (horizontalMovementPerSecond) x time_slice. (CORRECTED
// 2026-08-08: this used to read "at up to MaxTorsoSlew (500/sec)" -- the
// rate is that per-object field, and there is no 500 constant here. The
// 500 m/s belongs to the RANGE slide in step 5, as an immediate.)
//
void
HUD::HudSimulation(Scalar time_slice)