@@ -1,7 +1,7 @@

 /*

  * SSEQ Player - Channel structures

  * By Naram Qashat (CyberBotX) [cyberbotx@cyberbotx.com]

- * Last modification on 2013-04-12

+ * Last modification on 2013-04-18

  *

  * Adapted from source code of FeOS Sound System

  * By fincs

@@ -47,6 +47,7 @@ Channel::Channel() : chnId(-1), tempReg(), state(CS_NONE), trackId(-1), prio(0),

 	key(0), ampl(0), extTune(0), orgKey(0), modType(0), modSpeed(0), modDepth(0), modRange(0), modDelay(0), modDelayCnt(0), modCounter(0),

 	sweepLen(0), sweepCnt(0), sweepPitch(0), attackLvl(0), sustainLvl(0x7F), decayRate(0), releaseRate(0xFFFF), noteLength(-1), vol(0), ply(nullptr), reg()

 {

+	this->clearHistory();

 }

 void Channel::UpdateVol(const Track &trk)

@@ -122,6 +123,7 @@ void Channel::Kill()

 	this->reg.ClearControlRegister();

 	this->vol = 0;

 	this->noteLength = -1;

+	this->clearHistory();

 }

 static inline int getModFlag(int type)

@@ -585,38 +587,17 @@ int32_t Channel::Interpolate()

 	double ratio = this->reg.samplePosition;

 	ratio -= static_cast<int32_t>(ratio);

-	uint32_t loc = static_cast<uint32_t>(this->reg.samplePosition);

-	const auto &data = &this->reg.source->dataptr[loc];

-	int32_t a = data[0], b;

-	if (loc + 1 < this->reg.totalLength)

-		b = data[1];

-	else

-		b = a;

+	const auto &data = &this->sampleHistory[this->sampleHistoryPtr + 5];

+	int32_t a = data[0], b = data[1];

 	double c0, c1, c2, c3, c4, c5;

 	if (this->ply->interpolation > INTERPOLATION_COSINE)

 	{

-		int32_t c, z;

-		if (loc + 2 < this->reg.totalLength)

-			c = data[2];

-		else

-			c = b;

-		if (loc)

-			z = data[-1];

-		else

-			z = a;

+		int32_t c = data[2], z = data[-1];

 		if (this->ply->interpolation > INTERPOLATION_4POINTBSPLINE)

 		{

-			int32_t d, y;

-			if (loc + 3 < this->reg.totalLength)

-				d = data[3];

-			else

-				d = c;

-			if (loc > 1)

-				y = data[-2];

-			else

-				y = z;

+			int32_t d = data[3], y = data[-2];

 			if (this->ply->interpolation == INTERPOLATION_6POINTBSPLINE)

 			{

@@ -631,7 +612,7 @@ int32_t Channel::Interpolate()

 				c5 = 1 / 120.0 * (d - y) + 1 / 24.0 * (z - c) + 1 / 12.0 * (b - a);

 				return static_cast<int32_t>(((((c5 * ratio + c4) * ratio + c3) * ratio + c2) * ratio + c1) * ratio + c0);

 			}

-			else

+			else // INTERPOLATION_6POINTOSCULATING

 			{

 				ratio -= 0.5;

 				double even1 = y + d, odd1 = y - d;

@@ -646,7 +627,7 @@ int32_t Channel::Interpolate()

 				return static_cast<int32_t>(((((c5 * ratio + c4) * ratio + c3) * ratio + c2) * ratio + c1) * ratio + c0);

 			}

 		}

-		else

+		else // INTERPOLATION_4POINTBSPLINE

 		{

 			double ym1py1 = z + b;

 			c0 = 1 / 6.0 * ym1py1 + 2 / 3.0 * a;

@@ -661,7 +642,7 @@ int32_t Channel::Interpolate()

 		double ratio2 = (1.0 - std::cos(ratio * M_PI)) * 0.5;

 		return static_cast<int32_t>(a + ratio2 * (b - a));

 	}

-	else

+	else // INTERPOLATION_LINEAR

 		return static_cast<int32_t>(a + ratio * (b - a));

 }

@@ -712,7 +693,29 @@ int32_t Channel::GenerateSample()

 void Channel::IncrementSample()

 {

-	this->reg.samplePosition += this->reg.sampleIncrease;

+	double samplePosition = this->reg.samplePosition + this->reg.sampleIncrease;

+

+	if (this->reg.format != 3 && this->reg.samplePosition >= 0)

+	{

+		uint32_t loc = static_cast<uint32_t>(this->reg.samplePosition);

+		uint32_t newloc = static_cast<uint32_t>(samplePosition);

+

+		if (newloc >= this->reg.totalLength)

+			newloc -= this->reg.length;

+

+		while (loc != newloc)

+		{

+			this->sampleHistory[this->sampleHistoryPtr] = this->sampleHistory[this->sampleHistoryPtr + 8] = this->reg.source->dataptr[loc++];

+

+			this->sampleHistoryPtr = (this->sampleHistoryPtr + 1) & 7;

+

+			if (loc >= this->reg.totalLength)

+				loc -= this->reg.length;

+		}

+	}

+

+	this->reg.samplePosition = samplePosition;

+

 	if (this->reg.format != 3 && this->reg.samplePosition >= this->reg.totalLength)

 	{

 		if (this->reg.repeatMode == 1)

@@ -724,3 +727,9 @@ void Channel::IncrementSample()

 			this->Kill();

 	}

 }

+

+void Channel::clearHistory()

+{

+	this->sampleHistoryPtr = 0;

+	memset(this->sampleHistory, 0, sizeof(this->sampleHistory));

+}

@@ -1,7 +1,7 @@

 /*

  * SSEQ Player - Channel structures

  * By Naram Qashat (CyberBotX) [cyberbotx@cyberbotx.com]

- * Last modification on 2013-04-02

+ * Last modification on 2013-04-18

  *

  * Adapted from source code of FeOS Sound System

  * By fincs

@@ -127,6 +127,14 @@ struct Channel

 	const Player *ply;

 	NDSSoundRegister reg;

+	/*

+	 * Interpolation history buffer, which contains the maximum number of

+	 * samples required for any given interpolation mode. Doubled to

+	 * simplify the case of wrapping. Thanks to kode54 for providing this.

+	 */

+	uint32_t sampleHistoryPtr;

+	int16_t sampleHistory[16];

+

 	Channel();

 	void UpdateVol(const Track &trk);

@@ -141,6 +149,7 @@ struct Channel

 	int32_t Interpolate();

 	int32_t GenerateSample();

 	void IncrementSample();

+	void clearHistory();

 };

 #endif

@@ -1,7 +1,7 @@

 /*

  * SSEQ Player - Player structure

  * By Naram Qashat (CyberBotX) [cyberbotx@cyberbotx.com]

- * Last modification on 2013-04-01

+ * Last modification on 2013-04-18

  *

  * Adapted from source code of FeOS Sound System

  * By fincs

@@ -120,6 +120,7 @@ int Player::ChannelAlloc(int type, int priority)

 	this->channels[curChnNo].ply = this;

 	this->channels[curChnNo].noteLength = -1;

 	this->channels[curChnNo].vol = 0;

+	this->channels[curChnNo].clearHistory();

 	return curChnNo;

 }