Audio: FOOTSTEPS WORK -- reconstruct the lost game-side step-intensity broadcast (task #50)

The final link: the footstep source's volume + brightness mix from two
AudioControlMixer inputs (ctl 100 walk / 101 run) behind an entity-registered
AudioControlSplitter.  The object stream only ZERO-initializes those inputs
(AudioControlSend one-shot initializers; mixer ctor inits 0.0) -- the runtime
feed was BT game code (lost with the source), using the engine's game-facing
Entity::AudioSocketIterator broadcast (the only path to those anonymous
components; the splitter registers via entity->AddAudioComponent).

Reconstruction [T3]: on each foot plant (the SetBodyAnimation locomotion-clip
pulse), broadcast the step intensity (live ground speed on the authored
0..40 -> 0..1 velocity-curve family, floored at 0.35 to clear the 0.3
transient-drop gate) on the gait-appropriate input (run-family clips
0x0a..0x0f -> 101, walk family -> 100; the other input zeroed so gait
changes don't stack).  Patch-source components (VDATA 1001/1002/1005) are
skipped -- AudioSource::ReceiveControl Fail()s on input-range ids.

VERIFIED: FootFallInt01.wav (bank2 patch39) delivers + plays per stride;
mixer sums nonzero (vol=1 at run speed); 30s drive+fire regression clean --
weapon charge/fire/sustain cycles, ready dings, buttons, engine loops, state
audio (0 skips), gait advancing normally, no crashes, no stuck loops.

Also this session: [seqcfg] sequence config dump (decoded the authored event
streams: ctl 8=note/6=attack-vol/1=start/2=stop patterns), BT_AUDIO_NODROP
diagnostic (force low-volume transient delivery at a 0.7 floor).

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

engine/MUNGA/AUDREND.cpp

@@ -208,6 +208,18 @@ void
 	// Then return
 	//--------------------------------------------------------------------------
 	//
+	// DIAG (BT_AUDIO_NODROP): deliver low-volume transient starts anyway (at a
+	// floor volume) to isolate volume-feed problems from the rest of the chain.
+	if (getenv("BT_AUDIO_NODROP") &&
+		message->controlID == StartAudioControlID &&
+		audio_source->GetAudioRenderType() == TransientAudioRenderType &&
+		audio_source_volume_scale < LowAudioVolumeThreshold)
+	{
+		DEBUG_STREAM << "[spatial] NODROP forcing start src=" << (void*)audio_source
+			<< " vol=" << audio_source_volume_scale << "\n" << std::flush;
+		audio_source->ReceiveControl(VolumeAudioControlID, 0.7f);
+		audio_source_volume_scale = 0.7f;
+	}
 	if (
 		message->controlID == StartAudioControlID &&
 		audio_source->GetAudioRenderType() == TransientAudioRenderType &&

engine/MUNGA/AUDSEQ.cpp

@@ -193,6 +193,16 @@ AudioControlSequence::AudioControlSequence(
 		audioControlEventSocket.Add(audio_control_event);
 	}
 
+	if (getenv("BT_ATTRBIND_LOG")) { static int s_sq=0; if (s_sq++<60) {
+		DEBUG_STREAM << "[seqcfg] seq=" << (void*)this << " tgt=" << (void*)audio_component
+			<< " looped=" << (int)is_looped << " div=" << (int)divisions_per_beat
+			<< " tempo=" << (int)tempo << " events=" << (int)number_of_control_events << " ";
+		{ SChainIteratorOf<AudioControlEvent*> it(&audioControlEventSocket);
+		  AudioControlEvent *e; int n=0;
+		  while ((e = it.ReadAndNext()) != NULL && n++ < 24)
+			DEBUG_STREAM << *e; }
+		DEBUG_STREAM << "\n" << std::flush; } }
+
 	AudioControlSequenceX(
 		audio_component,
 		entity,

game/reconstructed/mech2.cpp

@@ -90,6 +90,7 @@
 //
 
 #include <bt.hpp>
+#include <AUDCMP.hpp>		// AudioComponent -- the foot-plant step-intensity broadcast
 #pragma hdrstop
 
 #if !defined(MECH_HPP)
@@ -263,7 +264,45 @@ void
 		footStep      = 1;
 		footStepDecay = 150;			// ms: ~1.5 poll periods ON, OFF well before the next stride
 		if (getenv("BT_AUDIO_LOG")) { static int s_fs=0; if (s_fs++<40)
-			DEBUG_STREAM << "[audio] footstep pulse (clip " << state << ") leftover=" << footStepDecay << "\n" << std::flush; }
+			DEBUG_STREAM << "[audio] footstep pulse (clip " << state << ")\n" << std::flush; }
+
+		// STEP-INTENSITY SEND [T3]: the authored footstep audio graph mixes its
+		// volume + brightness from two mixer inputs (ctl 100 walk / 101 run,
+		// reached through an entity-registered AudioControlSplitter) that the
+		// object stream only ZERO-initializes -- the runtime feed was BT game
+		// code (lost), using the engine's Entity::AudioSocketIterator broadcast
+		// (the only game-facing path to those anonymous components).  Reconstruct
+		// it: on each plant, broadcast the step intensity from the live ground
+		// speed (the same 0..40 -> 0..1 curve family the authored velocity scales
+		// use), on the walking input for walk-family clips and the running input
+		// for run-family clips.  Mixer slots are stateful; the other input is
+		// zeroed so gait changes don't stack.  Components with matching input
+		// ids elsewhere (velocity-fed multiplier slots) are re-driven every frame
+		// by their own scales, so the broadcast cannot durably disturb them.
+		{
+			Scalar speed = localVelocity.linearMotion.Length();
+			Scalar intensity = speed * (1.0f / 40.0f);
+			if (intensity > 1.0f) intensity = 1.0f;
+			if (intensity < 0.35f) intensity = 0.35f;	// audible floor (> the 0.3 transient drop gate)
+			int runFamily = (state >= 0x0a && state <= 0x0f);	// wrr/wrl/rrr/rrl/rwr/rwl
+			Entity::AudioSocketIterator it(this);
+			Component *c;
+			while ((c = it.ReadAndNext()) != NULL)
+			{
+				// Only the control-graph components (mixers/multipliers/splitters)
+				// accept the 100+ input-range ids; an AudioSource's ReceiveControl
+				// Fail()s on unknown ids, so skip the patch-source classes
+				// (Direct/Dynamic3D/Static3D -- VDATA L4 ids 1001/1002/1005).
+				{
+					int cid = (int)c->GetClassID();
+					if (cid == 1001 || cid == 1002 || cid == 1005)
+						continue;
+				}
+				AudioComponent *ac = (AudioComponent *)c;
+				ac->ReceiveControl((AudioControlID)(runFamily ? 101 : 100), intensity);
+				ac->ReceiveControl((AudioControlID)(runFamily ? 100 : 101), 0.0f);
+			}
+		}
 	}
 }