From 861ae5156f0f83b7bbc83fce0c4225cf51bb9164 Mon Sep 17 00:00:00 2001
From: dinkc64 <12570148+dinkc64@users.noreply.github.com>
Date: Sat, 8 Aug 2015 00:37:03 +0000
Subject: [PATCH] pokey update: eliminate clipping & add volume attenuation.
 also make centipede & millipede the same volume

---
 src/burn/drv/pre90s/d_atetris.cpp   |  2 +-
 src/burn/drv/pre90s/d_millipede.cpp |  4 ++--
 src/burn/snd/pokey.cpp              | 16 +++++++++++-----
 src/burn/snd/pokey.h                |  2 +-
 4 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/burn/drv/pre90s/d_atetris.cpp b/src/burn/drv/pre90s/d_atetris.cpp
index cbdbc7082..4a9bb0a83 100644
--- a/src/burn/drv/pre90s/d_atetris.cpp
+++ b/src/burn/drv/pre90s/d_atetris.cpp
@@ -327,7 +327,7 @@ static INT32 CommonInit(INT32 boot)
 		SN76496SetRoute(1, 0.50, BURN_SND_ROUTE_BOTH);
 		SN76496SetRoute(2, 0.50, BURN_SND_ROUTE_BOTH);
 	} else {
-		PokeyInit(0, 2, 6, 0);
+		PokeyInit(0, 2, 1.00, 0);
 	}
 
 	GenericTilesInit();
diff --git a/src/burn/drv/pre90s/d_millipede.cpp b/src/burn/drv/pre90s/d_millipede.cpp
index d0e1100fd..490548044 100644
--- a/src/burn/drv/pre90s/d_millipede.cpp
+++ b/src/burn/drv/pre90s/d_millipede.cpp
@@ -726,7 +726,7 @@ static INT32 DrvInit()
 	M6502SetReadOpHandler(millipede_read);
 	M6502Close();
 
-	PokeyInit(12096000/8, 2, 6, 0);
+	PokeyInit(12096000/8, 2, 1.00, 0);
 
 	init_penmask();
 
@@ -777,7 +777,7 @@ static INT32 DrvInitcentiped()
 	M6502SetReadOpHandler(centipede_read);
 	M6502Close();
 
-	PokeyInit(12096000/8, 2, 6, 0);
+	PokeyInit(12096000/8, 2, 2.40, 0);
 
 	init_penmask();
 
diff --git a/src/burn/snd/pokey.cpp b/src/burn/snd/pokey.cpp
index 3a844ae07..e98239dc7 100644
--- a/src/burn/snd/pokey.cpp
+++ b/src/burn/snd/pokey.cpp
@@ -56,6 +56,8 @@
  * I use 15/11 = 1.3636, so this is a little lower.
  */
 #define POKEY_DEFAULT_GAIN (32767/11/4)
+static double pokey_mastervol = 1.0;
+static INT32 nLeftSample = 0, nRightSample = 0;
 
 #define VERBOSE 		0
 #define VERBOSE_SOUND	0
@@ -326,9 +328,12 @@ static UINT8 *rand17;
 		pokey[chip].samplepos_fract &= 0x000000ff;						\
 	}																	\
 	/* store sum of output signals into the buffer */					\
-	*buffer++ += (sum > 65535) ? 0x7fff : sum - 0x8000;					\
-	*buffer++ += (sum > 65535) ? 0x7fff : sum - 0x8000;					\
-	length--
+	nLeftSample  = buffer[0] + (sum * pokey_mastervol);                 \
+	nRightSample = buffer[1] + (sum * pokey_mastervol);                 \
+	buffer[0] = BURN_SND_CLIP(nLeftSample);                             \
+	buffer[1] = BURN_SND_CLIP(nRightSample);                            \
+	buffer++; buffer++;                                                 \
+	length--;
 
 #if HEAVY_MACRO_USAGE
 
@@ -570,14 +575,15 @@ static void rand_init(UINT8 *rng, int size, int left, int right, int add)
 	}
 }
 
-int PokeyInit(int clock, int num, int vol, int addtostream)
+int PokeyInit(int clock, int num, double vol, int addtostream)
 {
 	int chip, sample_rate;
 
 	memset(&intf, 0, sizeof(intf));
 	sample_rate = nBurnSoundRate;
 	intf.num = num;
-	intf.mixing_level[0] = vol;
+	//intf.mixing_level[0] = vol;
+	pokey_mastervol = vol;
 	intf.baseclock = (clock) ? clock : FREQ_17_EXACT;
 	intf.addtostream = addtostream;
 
diff --git a/src/burn/snd/pokey.h b/src/burn/snd/pokey.h
index 1edaa6783..e1ed4a998 100644
--- a/src/burn/snd/pokey.h
+++ b/src/burn/snd/pokey.h
@@ -98,7 +98,7 @@ struct POKEYinterface {
 };
 
 
-int PokeyInit (int clock, int num, int vol, int addtostream);
+int PokeyInit (int clock, int num, double vol, int addtostream);
 void PokeyExit (void);
 
 void pokey_update(int num, INT16 *buffer, int length);