From fcaea1862a1bbdbd3b40f6aa52be8a7e9f17cda5 Mon Sep 17 00:00:00 2001
From: arcattack <arcattackmusic@gmail.com>
Date: Tue, 14 Jul 2026 07:26:12 -0500
Subject: [PATCH] Diag: BT_AF_PERIOD=<sec> autofire cadence throttle +
 afc_dump.py (raw RES verify)

Closes the coolant/jam investigation. BT_AF_PERIOD pulses the trigger every <sec>s so
a slower-than-max fire rate can be tested; afc_dump.py reads the AFC100 record raw from
BTL4.RES. Both confirm the QA report is FAITHFULLY reproduced (see KB).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 game/reconstructed/mech4.cpp | 13 ++++++++++++-
 scratchpad/afc_dump.py       | 37 ++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 scratchpad/afc_dump.py

diff --git a/game/reconstructed/mech4.cpp b/game/reconstructed/mech4.cpp
index 43e2364..5f84b27 100644
--- a/game/reconstructed/mech4.cpp
+++ b/game/reconstructed/mech4.cpp
@@ -3825,7 +3825,18 @@ void
 			static int s_prevBtn[4] = {0, 0, 0, 0};
 			static int s_afPhase = 0;
 			s_afPhase ^= 1;
-			const int autofire = (gBTDrive.fireForced && targetInArc) ? s_afPhase : 0;
+			// DIAG (BT_AF_PERIOD=<sec>): throttle autofire cadence -- pulse the trigger
+			// only briefly every <sec> seconds, to test a slower-than-max fire rate (the
+			// coolant/jam mechanic is fire-rate dependent: at max spam the weapon overheats
+			// regardless; at a realistic cadence coolant priority decides the jam).
+			static float s_afClock = 0.0f;
+			s_afClock += dt;
+			static const float s_afPeriod =
+				getenv("BT_AF_PERIOD") ? (float)atof(getenv("BT_AF_PERIOD")) : 0.0f;
+			int afGate = 1;
+			if (s_afPeriod > 0.0f)
+				afGate = (fmodf(s_afClock, s_afPeriod) < 0.6f) ? 1 : 0;
+			const int autofire = (gBTDrive.fireForced && targetInArc && afGate) ? s_afPhase : 0;
 			const int buttons[4] = {
 				LBE4ControlsManager::ButtonJoystickTrigger,		// 0x40
 				LBE4ControlsManager::ButtonJoystickPinky,		// 0x45
diff --git a/scratchpad/afc_dump.py b/scratchpad/afc_dump.py
new file mode 100644
index 0000000..f885be1
--- /dev/null
+++ b/scratchpad/afc_dump.py
@@ -0,0 +1,37 @@
+import struct
+data = open(r'C:/git/bt411/content/BTL4.RES','rb').read()
+n = len(data)
+def f32(o): return struct.unpack_from('<f', data, o)[0]
+def i32(o): return struct.unpack_from('<i', data, o)[0]
+def cstr(o, m=32):
+    s = data[o:o+m].split(b'\0')[0]
+    try: return s.decode('ascii')
+    except: return None
+
+# find AFC100 subsystem records (name @+0, classID @+0x20)
+hits=[]
+i=0
+while i < n-0x28:
+    if data[i:i+7]==b'AFC100\0':
+        cid=struct.unpack_from('<I',data,i+0x20)[0]
+        sz=struct.unpack_from('<I',data,i+0x24)[0]
+        if 0xBB0<=cid<=0xBE5 and 0xE0<=sz<=0x300:
+            hits.append((i,cid,sz))
+    i+=1
+print("AFC100 records:", [(hex(p),hex(c),hex(s)) for p,c,s in hits])
+if hits:
+    p,cid,sz=hits[0]
+    print(f"\n=== AFC100 @ {hex(p)} classID={hex(cid)} size={hex(sz)} ===")
+    # dump the offsets the loader reads (per heat.cpp / mechweap.hpp comments)
+    fields = {
+        0xE4:"startingTemp", 0xE8:"degradationTemp", 0xEC:"failureTemp",
+        0xF0:"thermalConductance", 0xF4:"thermalMass",
+        0x1A4:"heatCostToFire", 0x1CC:"minJamChance",
+    }
+    for off,name in sorted(fields.items()):
+        print(f"  +{hex(off):>6} {name:20} f32={f32(p+off):<16g} i32={i32(p+off)}")
+    print("\n  --- full float scan (offset: value) for plausible fields 0xE0..0x1E0 ---")
+    for off in range(0xE0, 0x1E0, 4):
+        v=f32(p+off)
+        if abs(v)>1e-3 and abs(v)<1e12:
+            print(f"    +{hex(off):>6}: {v:g}")