vehicleSubSystems follow-up: reconstruct SegmentArc270 recharge dial

Reconstruct SegmentArc270 (@004c6244): engine SegmentArc base + a Scalar connection
driving currentValue + the |n|/(|n|-1)*0.75 segment-span factor.  Wire it into
WeaponCluster as the recharge dial (was a deferred NULL), reading the weapon's real
PercentDone attribute.  Render-verified (BT_DEV_GAUGES_DOCK): the green segmented
recharge circles draw in the weapon panels; 7 panels build, 0 crashes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

game/reconstructed/btl4gau2.cpp

@@ -1124,10 +1124,12 @@ WeaponCluster::WeaponCluster(
 		warningCenterY = 0x6d - (img->Data.Size.y >> 1);
 	}
 
-	// rechargeArc (SegmentArc270 @004c6244, 0..360 recharge dial reading PercentDone).
+	// rechargeArc (SegmentArc270 @004c6244): the 0..360 recharge dial reading the
-	// BRING-UP: the SegmentArc270 ctor is a placeholder in btl4gaug.hpp (its real
+	// weapon's PercentDone attribute (a real 0..1 fraction).
-	// @004c6244 body is not yet reconstructed); tracked NULL until it lands.
+	rechargeArc = (GraphicGauge *)new SegmentArc270((GaugeRate)0xffff, mfd_mode,	// @004c6244
-	rechargeArc = NULL;									// @0x34
+		renderer_in, owner_ID, mfd_port, x + 0x41, y + 0x6d, 40.0f, 60.0f, 40.0f,
+		60.0f, 0.0f, 360.0f, 0x14, 0, 0xff, (Scalar *)percentDoneAttr, True,
+		"SegmentArc270");
 
 	configMap = new ConfigMapGauge(ChildRate(), mfd_mode, renderer_in,			// @004c6d80
 		mfd_port, x + 0xee, y + 0x38, (Entity *)subsystem_in, "ConfigMap");

game/reconstructed/btl4gaug.cpp

@@ -2143,4 +2143,31 @@ void
 	SegmentArc::Execute();								// 0x474300 -- the base draw
 }
 
+//
+// @004c6244 -- SegmentArc270 ctor (vtable 0x5189d0).  Engine SegmentArc base + one
+// Scalar connection driving currentValue (a 0..1 fraction, e.g. a weapon's
+// PercentDone recharge) + the segment-span factor (|n|/(|n|-1) * 0.75, integer
+// division == 0.75 for n>=2).  Inherits SegmentArc::Execute (draws the lit segments
+// up to currentValue).  Used as the WeaponCluster recharge dial.
+//
+SegmentArc270::SegmentArc270(
+	GaugeRate rate, ModeMask mode_mask, L4GaugeRenderer *renderer_in, int owner_ID,
+	int graphics_port_number, int center_x, int center_y,
+	Scalar inner0, Scalar outer0, Scalar inner1, Scalar outer1,
+	Scalar deg0, Scalar deg1, int number_of_segs,
+	int background_color, int foreground_color,
+	Scalar *value_pointer, Logical use_thick_lines, const char *identification_string
+):
+	SegmentArc(rate, mode_mask, renderer_in, owner_ID, graphics_port_number,
+		center_x, center_y, inner0, outer0, inner1, outer1, deg0, deg1,
+		number_of_segs, background_color, foreground_color, use_thick_lines,
+		identification_string)
+{
+	AddConnection(new GaugeConnectionDirectOf<Scalar>(0, &currentValue, value_pointer));
+	int n = (number_of_segs < 0) ? -number_of_segs : number_of_segs;
+	segmentSpan = (Scalar)(n / (n - 1)) * 0.75f;			// _DAT_004c62d4 = 0.75
+}
+
+SegmentArc270::~SegmentArc270() {}							// @004c66b3 (base chain)
+
 // === btl4gau2.cpp begins at @004c6798 (SeekVoltage gauge) -- not part of this TU.

game/reconstructed/btl4gaug.hpp

@@ -517,13 +517,20 @@
 	//   SegmentArcRatio @004c6394  Make @004c62fc  (adds two connections)
 	//#######################################################################
 	class SegmentArc270 :
-		public SegmentArc							// MUNGA L4 base (FUN_004745e0; engine class SegmentArc)
+		public SegmentArc							// MUNGA L4 base (engine class SegmentArc)
 	{
 	public:
-		SegmentArc270(/* ...arc geometry... */);	// @004c6244
+		SegmentArc270(								// @004c6244
+			GaugeRate, ModeMask, L4GaugeRenderer *, int owner_ID,
+			int graphics_port_number, int center_x, int center_y,
+			Scalar inner0, Scalar outer0, Scalar inner1, Scalar outer1,
+			Scalar deg0, Scalar deg1, int number_of_segs,
+			int background_color, int foreground_color,
+			Scalar *value_pointer, Logical use_thick_lines,
+			const char *identification_string);
 		~SegmentArc270();							// dtor thunk @004c66b3
 	protected:
-		int		segmentSpan;						// @0xC0  this[0x30]
+		Scalar	segmentSpan;						// @0xC0  this[0x30]
 	};
 
 	class SegmentArcRatio :