Re-commit dbemuopl.cpp

adplug/dbemuopl.cpp

@@ -0,0 +1,97 @@
+//
+//  dbemuopl.cpp
+//  SDLPal
+//
+//  Created by louyihua on 15-08-03.
+//  Copyright (c) 2014 Wei Mingzhi. All rights reserved.
+//
+
+#include "dbemuopl.h"
+#include <stdlib.h>
+
+bool CDBemuopl::_inited = DBOPL::InitTables();
+
+static inline int16_t conver_to_int16(int32_t sample)
+{
+	if (sample > 32767)
+		return 32767;
+	else if (sample < -32768)
+		return -32768;
+	else
+		return (int16_t)sample;
+}
+
+static inline uint8_t conver_to_uint8(int32_t sample)
+{
+	if (sample > 32767)
+		return 0xff;
+	else if (sample < -32768)
+		return 0;
+	else
+		return (uint8_t)(sample >> 8) ^ 0x80;
+}
+
+CDBemuopl::CDBemuopl(int rate, bool bit16, bool usestereo)
+	: use16bit(bit16), stereo(usestereo), rate(rate)
+	, maxlen(0), buffer(NULL)
+{
+	currType = TYPE_OPL2;
+	chip.Setup(rate);
+}
+
+CDBemuopl::~CDBemuopl()
+{
+	if (buffer) delete[] buffer;
+}
+
+void CDBemuopl::init()
+{
+	chip.Setup(rate);
+}
+
+void CDBemuopl::update(short *buf, int samples)
+{
+	if (maxlen < samples)
+	{
+		if (buffer) delete[] buffer;
+		buffer = new int32_t[(maxlen = samples) * (stereo ? 2 : 1)];
+	}
+	if (chip.opl3Active)
+		chip.GenerateBlock3(samples, buffer);
+	else
+		chip.GenerateBlock2(samples, buffer);
+
+	if (use16bit)
+	{
+		if (stereo)
+		{
+			for (int i = 0; i < samples; i++)
+				buf[i * 2 + 1] = buf[i * 2] = conver_to_int16(buffer[i]);
+		}
+		else
+		{
+			for (int i = 0; i < samples; i++)
+				buf[i] = conver_to_int16(buffer[i]);
+		}
+	}
+	else
+	{
+		uint8_t* outbuf = (uint8_t*)buf;
+		if (stereo)
+		{
+			for (int i = 0; i < samples; i++)
+				outbuf[i * 2 + 1] = outbuf[i * 2] = conver_to_uint8(buffer[i]);
+		}
+		else
+		{
+			for (int i = 0; i < samples; i++)
+				outbuf[i] = conver_to_uint8(buffer[i]);
+		}
+	}
+}
+
+// template methods
+void CDBemuopl::write(int reg, int val)
+{
+	chip.WriteReg(reg, (Bit8u)val);
+}