add pitch shift capability to snd.cpp and JS binding

This was SVN commit r1977.

source/lib/res/snd.cpp

@@ -1148,7 +1148,8 @@ struct VSrc
 
 	// AL source properties (set via snd_set*)
 	ALfloat pos[3];
-	ALfloat gain;
+	ALfloat gain;	// [0,1]
+	ALfloat pitch;	// (0,1]
 	ALboolean loop;
 	ALboolean relative;
 
@@ -1272,6 +1273,7 @@ static void vsrc_latch(VSrc* vs)
 	alSourcefv(vs->al_src, AL_POSITION,        vs->pos);
 	alSourcei (vs->al_src, AL_SOURCE_RELATIVE, vs->relative);
 	alSourcef (vs->al_src, AL_GAIN,            vs->gain);
+	alSourcef (vs->al_src, AL_PITCH,           vs->pitch);
 	alSourcei (vs->al_src, AL_LOOPING,         vs->loop);
 	al_check("vsrc_latch");
 }
@@ -1468,6 +1470,8 @@ static int VSrc_reload(VSrc* vs, const char* fn, Handle hvs)
 
 	// note: vs->gain can legitimately be > 1.0 - don't clamp.
 
+	vs->pitch = 1.0f;
+
 	vs->hvs = hvs;
 		// needed so we can snd_free ourselves when done playing.
 
@@ -1562,6 +1566,9 @@ int snd_set_gain(Handle hvs, float gain)
 {
 	H_DEREF(hvs, VSrc, vs);
 
+	if(!(0.0f <= gain && gain <= 1.0f))
+		return -1;
+
 	vs->gain = gain;
 
 	vsrc_latch(vs);
@@ -1569,6 +1576,25 @@ int snd_set_gain(Handle hvs, float gain)
 }
 
 
+// change pitch shift of the sound source.
+// 1.0 means no change; each reduction by 50% equals a pitch shift of
+// -12 semitones (one octave). zero is invalid.
+// may be called at any time; fails with invalid handle return if
+// the sound has already been closed (e.g. it never played).
+int snd_set_pitch(Handle hvs, float pitch)
+{
+	H_DEREF(hvs, VSrc, vs);
+
+	if(!(0.0f < pitch && pitch <= 1.0f))
+		return -1;
+
+	vs->pitch = pitch;
+
+	vsrc_latch(vs);
+	return 0;
+}
+
+
 // enable/disable looping on the sound source.
 // used to implement variable-length sounds (e.g. while building).
 // may be called at any time; fails with invalid handle return if

source/lib/res/snd.h

@@ -159,6 +159,13 @@ extern int snd_set_pos(Handle hs, float x, float y, float z, bool relative = fal
 // the sound has already been closed (e.g. it never played).
 extern int snd_set_gain(Handle hs, float gain);
 
+// change pitch shift of the sound source.
+// 1.0 means no change; each reduction by 50% equals a pitch shift of
+// -12 semitones (one octave). zero is invalid.
+// may be called at any time; fails with invalid handle return if
+// the sound has already been closed (e.g. it never played).
+extern int snd_set_pitch(Handle hs, float pitch);
+
 // enable/disable looping on the sound source.
 // used to implement variable-length sounds (e.g. while building).
 // may be called at any time; fails with invalid handle return if

source/sound/JSI_Sound.cpp

@@ -31,6 +31,17 @@ bool JSI_Sound::SetGain( JSContext* cx, uintN argc, jsval* argv )
 	return true;
 }
 
+bool JSI_Sound::SetPitch( JSContext* cx, uintN argc, jsval* argv )
+{
+	assert( argc >= 1 );
+	float pitch;
+	if( !ToPrimitive<float>( cx, argv[0], pitch) )
+		return false;
+
+	snd_set_pitch(m_Handle, pitch);
+	return true;
+}
+
 bool JSI_Sound::SetPosition( JSContext* cx, uintN argc, jsval* argv )
 {
 	assert( argc >= 1 );
@@ -82,6 +93,7 @@ void JSI_Sound::ScriptingInit()
 	AddMethod<bool, &JSI_Sound::Loop>( "loop", 0 );
 	AddMethod<bool, &JSI_Sound::Free>( "free", 0 );
 	AddMethod<bool, &JSI_Sound::SetGain>( "setGain", 0 );
+	AddMethod<bool, &JSI_Sound::SetPitch>( "setPitch", 0 );
 	AddMethod<bool, &JSI_Sound::SetPosition>( "setPosition", 0 );
 
 	CJSObject<JSI_Sound>::ScriptingInit( "Sound", &JSI_Sound::Construct, 1 );

source/sound/JSI_Sound.h

@@ -53,6 +53,8 @@ public:
 
 	bool SetGain( JSContext* cx, uintN argc, jsval* argv );
 
+	bool SetPitch( JSContext* cx, uintN argc, jsval* argv );
+
 	bool SetPosition( JSContext* cx, uintN argc, jsval* argv );
 
 	static JSBool Construct( JSContext* cx, JSObject* obj, unsigned int argc, jsval* argv, jsval* rval );