From 78da8bb8161c47348371a7dfd6990c9204eaea02 Mon Sep 17 00:00:00 2001
From: James R <justsomejames2@gmail.com>
Date: Thu, 4 Apr 2024 05:10:27 -0700
Subject: [PATCH] ACS: add Music_Dim function, API to g_musicfade

---
 src/acs/call-funcs.cpp  | 31 +++++++++++++++++++++++++++++++
 src/acs/call-funcs.hpp  |  1 +
 src/acs/environment.cpp |  1 +
 3 files changed, 33 insertions(+)

diff --git a/src/acs/call-funcs.cpp b/src/acs/call-funcs.cpp
index 17e6474f7..020771a14 100644
--- a/src/acs/call-funcs.cpp
+++ b/src/acs/call-funcs.cpp
@@ -2399,6 +2399,37 @@ bool CallFunc_MusicRemap(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::
 	return false;
 }
 
+/*--------------------------------------------------
+	bool CallFunc_MusicDim(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC)
+
+		Fade level music into or out of silence.
+--------------------------------------------------*/
+bool CallFunc_MusicDim(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC)
+{
+	// 0: int fade time (tics) - time to fade between full volume and silence
+	// 1: [int duration (tics)] - silent duration (not including fade in and fade out), -1 = infinite (default if omitted)
+
+	// If a dim is ongoing, do not interrupt it
+	if (g_musicfade.start < leveltime && g_musicfade.end < leveltime)
+	{
+		g_musicfade.start = leveltime;
+	}
+
+	tic_t fade = argV[0];
+	tic_t duration = INFTICS;
+
+	if (argC > 1 && argV[1] >= 0)
+	{
+		duration = argV[1];
+	}
+
+	g_musicfade.end = duration != INFTICS ? leveltime + duration + 2*fade : INFTICS;
+	g_musicfade.fade = fade;
+	g_musicfade.ticked = false;
+
+	return false;
+}
+
 /*--------------------------------------------------
 	bool CallFunc_Freeze(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC)
 
diff --git a/src/acs/call-funcs.hpp b/src/acs/call-funcs.hpp
index 8ad5df737..8d304f558 100644
--- a/src/acs/call-funcs.hpp
+++ b/src/acs/call-funcs.hpp
@@ -103,6 +103,7 @@ bool CallFunc_ExitLevel(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::W
 bool CallFunc_MusicPlay(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC);
 bool CallFunc_MusicStopAll(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC);
 bool CallFunc_MusicRemap(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC);
+bool CallFunc_MusicDim(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC);
 
 bool CallFunc_DialogueSetSpeaker(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC);
 bool CallFunc_DialogueSetCustomSpeaker(ACSVM::Thread *thread, const ACSVM::Word *argV, ACSVM::Word argC);
diff --git a/src/acs/environment.cpp b/src/acs/environment.cpp
index 5c6a4ffd8..43fb3be97 100644
--- a/src/acs/environment.cpp
+++ b/src/acs/environment.cpp
@@ -187,6 +187,7 @@ Environment::Environment()
 	addFuncDataACS0( 509, addCallFunc(CallFunc_MusicStopAll));
 	addFuncDataACS0( 510, addCallFunc(CallFunc_MusicRemap));
 	addFuncDataACS0( 511, addCallFunc(CallFunc_Freeze));
+	addFuncDataACS0( 512, addCallFunc(CallFunc_MusicDim));
 
 	addFuncDataACS0( 600, addCallFunc(CallFunc_DialogueSetSpeaker));
 	addFuncDataACS0( 601, addCallFunc(CallFunc_DialogueSetCustomSpeaker));