This should fix the negative frequency bug that caused some sound effects

to not be played, and probably fixes wrong frequency on some that were
played. It's all guesswork, though. I don't know if this is what the
original did.

svn-id: r17882

4 files changed, 45 insertions, 72 deletions

diff --git a/gob/goblin.cpp b/gob/goblin.cpp
index 45779846c5..cb704fdf3e 100644
--- a/gob/goblin.cpp
+++ b/gob/goblin.cpp
@@ -213,10 +213,6 @@ void gob_playSound(Snd_SoundDesc *snd, int16 repCount, int16 freq) {
 }
 
 void gob_drawObjects(void) {
-	int16 tmp;
-	int16 sndItem;
-	int16 freq;
-	int16 repCount;
 	Util_ListNode *ptr;
 	Util_ListNode *ptr2;
 
@@ -368,61 +364,50 @@ void gob_drawObjects(void) {
 		if (objDesc->toRedraw == 0 || objDesc->type == 1)
 			continue;
 
-		tmp =
-		    objDesc->stateMach[objDesc->state][objDesc->stateColumn]->
-		    unk2;
-
-		if ((tmp >> 8) != 0) {
-			if (objDesc->curFrame == (tmp >> 8)) {
-				sndItem =
-				    objDesc->stateMach[objDesc->
-				    state][objDesc->stateColumn]->sndItem >> 8;
-				if (sndItem != -1) {
-					freq =
-					    (objDesc->stateMach[objDesc->
-						state][objDesc->stateColumn]->
-					    freq >> 8) * 100;
-					repCount =
-					    (objDesc->stateMach[objDesc->
-						state][objDesc->stateColumn]->
-					    repCount >> 8);
+		Gob_State *state = objDesc->stateMach[objDesc->state][objDesc->stateColumn];
+		int16 sndFrame;
+		int16 sndItem;
+		int16 freq;
+		int16 repCount;
+
+		if (state->sndFrame & 0xff00) {
+			// There are two frames which trigger a sound effect,
+			// so everything has to be encoded in one byte each.
+			// Note that the frequency is multiplied by 100, not -
+			// as I would have thought, 0x100.
+
+			sndFrame = (state->sndFrame >> 8) & 0xff;
+			sndItem = (state->sndItem >> 8) & 0xff;
+			freq = 100 * ((state->freq >> 8) & 0xff);
+			repCount = (state->repCount >> 8) & 0xff;
+
+			if (objDesc->curFrame == sndFrame) {
+				if (sndItem != 0xff) {
 					gob_playSound(gob_soundData[sndItem],
 					    repCount, freq);
 				}
 			}
 
-			if (objDesc->curFrame == (tmp & 0xff)) {
-				sndItem =
-				    objDesc->stateMach[objDesc->
-				    state][objDesc->stateColumn]->
-				    sndItem & 0xff;
-				if (sndItem != -1) {
-					freq =
-					    (objDesc->stateMach[objDesc->
-						state][objDesc->stateColumn]->
-					    freq & 0xff) * 100;
-					repCount =
-					    (objDesc->stateMach[objDesc->
-						state][objDesc->stateColumn]->
-					    repCount & 0xff);
+			sndFrame = state->sndFrame & 0xff;
+			sndItem = state->sndItem & 0xff;
+			freq = 100 * (state->freq & 0xff);
+			repCount = state->repCount & 0xff;
+
+			if (objDesc->curFrame == sndFrame) {
+				if (sndItem != 0xff) {
 					gob_playSound(gob_soundData[sndItem],
 					    repCount, freq);
 				}
 			}
 		} else {
-			if (objDesc->curFrame == tmp) {
-				sndItem =
-				    objDesc->stateMach[objDesc->
-				    state][objDesc->stateColumn]->sndItem;
+			// There is only one, so frequency etc. are used as is.
+			sndFrame = state->sndFrame;
+			sndItem = state->sndItem;
+			freq = state->freq;
+			repCount = state->repCount;
+
+			if (objDesc->curFrame == sndFrame) {
 				if (sndItem != -1) {
-					freq =
-					    objDesc->stateMach[objDesc->
-					    state][objDesc->stateColumn]->
-					    freq * 100;
-					repCount =
-					    objDesc->stateMach[objDesc->
-					    state][objDesc->stateColumn]->
-					    repCount;
 					gob_playSound(gob_soundData[sndItem],
 					    repCount, freq);
 				}
diff --git a/gob/goblin.h b/gob/goblin.h
index 31bbca0bc9..13862c1701 100644
--- a/gob/goblin.h
+++ b/gob/goblin.h
@@ -40,7 +40,7 @@ typedef struct Gob_State {
 	int16 sndItem;	// +8h, high/low byte - sound sample index
 	int16 freq;		// +Ah, high/low byte * 100 - frequency
 	int16 repCount;	// +Ch high/low byte - repeat count
-	int16 unk2;		// +Eh
+	int16 sndFrame;		// +Eh
 } GCC_PACK Gob_State;
 
 typedef struct Gob_State *Gob_PState;
diff --git a/gob/map.cpp b/gob/map.cpp
index a947996ff8..6671e33895 100644
--- a/gob/map.cpp
+++ b/gob/map.cpp
@@ -554,7 +554,7 @@ void map_loadMapObjects(char *avjFile) {
 				}
 				tmpState->freq = map_loadFromAvo_LE_UINT16();
 				tmpState->repCount = map_loadFromAvo_LE_UINT16();
-				tmpState->unk2 = map_loadFromAvo_LE_UINT16();
+				tmpState->sndFrame = map_loadFromAvo_LE_UINT16();
 			}
 		}
 	}
@@ -583,13 +583,13 @@ void map_loadMapObjects(char *avjFile) {
 	pState->unk1 = 0;
 	pState->sndItem = -1;
 
-	gob_goblins[2]->stateMach[10][0]->unk2 = 13;
-	gob_goblins[2]->stateMach[11][0]->unk2 = 13;
-	gob_goblins[2]->stateMach[28][0]->unk2 = 13;
-	gob_goblins[2]->stateMach[29][0]->unk2 = 13;
+	gob_goblins[2]->stateMach[10][0]->sndFrame = 13;
+	gob_goblins[2]->stateMach[11][0]->sndFrame = 13;
+	gob_goblins[2]->stateMach[28][0]->sndFrame = 13;
+	gob_goblins[2]->stateMach[29][0]->sndFrame = 13;
 
-	gob_goblins[1]->stateMach[10][0]->unk2 = 13;
-	gob_goblins[1]->stateMach[11][0]->unk2 = 13;
+	gob_goblins[1]->stateMach[10][0]->sndFrame = 13;
+	gob_goblins[1]->stateMach[11][0]->sndFrame = 13;
 
 	for (state = 40; state < 70; state++) {
 		pState = (Gob_State *)malloc(sizeof(Gob_State));
@@ -599,7 +599,7 @@ void map_loadMapObjects(char *avjFile) {
 		pState->animation = 9;
 		pState->layer = state - 40;
 		pState->sndItem = -1;
-		pState->unk2 = 0;
+		pState->sndFrame = 0;
 	}
 
 	gob_objCount = map_loadFromAvo_LE_UINT16();
@@ -651,10 +651,9 @@ void map_loadMapObjects(char *avjFile) {
 				}
 				tmpState->freq = map_loadFromAvo_LE_UINT16();
 				tmpState->repCount = map_loadFromAvo_LE_UINT16();
-				tmpState->unk2 = map_loadFromAvo_LE_UINT16();
+				tmpState->sndFrame = map_loadFromAvo_LE_UINT16();
 			}
 		}
-
 	}
 
 	gob_objects[10] = (Gob_Object *)malloc(sizeof(Gob_Object));
@@ -672,7 +671,7 @@ void map_loadMapObjects(char *avjFile) {
 	pState->unk0 = 0;
 	pState->unk1 = 0;
 	pState->sndItem = -1;
-	pState->unk2 = 0;
+	pState->sndFrame = 0;
 
 	gob_placeObject(gob_objects[10], 1);
 
diff --git a/gob/sound.cpp b/gob/sound.cpp
index 023384c2ba..17e0570aff 100644
--- a/gob/sound.cpp
+++ b/gob/sound.cpp
@@ -53,19 +53,8 @@ void snd_speakerOff(void) {return;}
 void snd_stopSound(int16 arg){return;}
 void snd_setResetTimerFlag(char flag){return;}
 
-// This is mostly to see if we are interpreting the sound effects correctly. If
-// we want to implement looping etc. we're probably going to need something a
-// bit more elaborate.
-//
-// Currently we ignore looping completely. We also ignore samples with negative
-// sample frequency. Something wacky is going on here, and I don't think it's
-// a simple signed/unsigned issue.
-
 void snd_playSample(Snd_SoundDesc *sndDesc, int16 repCount, int16 frequency) {
-	if (frequency < 0) {
-		warning("snd_playSample: frequency = %d - this is weird", frequency);
-		return;
-	}
+	assert(frequency > 0);
 
 	if (!_vm->_mixer->isSoundHandleActive(sndDesc->handle)) {
 		_vm->_mixer->playRaw(&sndDesc->handle, sndDesc->data, sndDesc->size, frequency, 0);