Add amplitude() to AudioSynthWaveformSine

keywords.txt

 AudioPlaySdWav	KEYWORD2
 AudioSynthToneSweep	KEYWORD2
 AudioSynthWaveform	KEYWORD2
+AudioSynthWaveformSine	KEYWORD2
+AudioSynthWaveformSineModulated	KEYWORD2
 isPlaying	KEYWORD2
 positionMillis	KEYWORD2
 lengthMillis	KEYWORD2

synth_sine.cpp

 			scale = (ph >> 8) & 0xFFFF;
 			val2 *= scale;
 			val1 *= 0xFFFF - scale;
-			block->data[i] = (val1 + val2) >> 16;
+			//block->data[i] = (((val1 + val2) >> 16) * magnitude) >> 16;
+			block->data[i] = multiply_32x32_rshift32(val1 + val2, magnitude);
 			ph += inc;
 		}
 		phase = ph;
 			scale = (ph >> 8) & 0xFFFF;
 			val2 *= scale;
 			val1 *= 0xFFFF - scale;
-			block->data[i] = (val1 + val2) >> 16;
+			//block->data[i] = (((val1 + val2) >> 16) * magnitude) >> 16;
+			block->data[i] = multiply_32x32_rshift32(val1 + val2, magnitude);
 			// -32768 = no phase increment
 			// 32767 = double phase increment
 			mod = modinput->data[i];

synth_sine.h

 class AudioSynthWaveformSine : public AudioStream
 {
 public:
-	AudioSynthWaveformSine() : AudioStream(0, NULL) {}
+	AudioSynthWaveformSine() : AudioStream(0, NULL), magnitude(16384) {}
 	void frequency(float freq);
-	//void amplitude(q15 n);
+	void amplitude(float n) {
+		if (n < 0) n = 0;
+		else if (n > 1.0) n = 1.0;
+		magnitude = n * 65536.0;
+	}
 	virtual void update(void);
 private:
 	uint32_t phase;
 	uint32_t phase_increment;
+	int32_t magnitude;
 };
 
 class AudioSynthWaveformSineModulated : public AudioStream
 {
 public:
-	AudioSynthWaveformSineModulated() : AudioStream(1, inputQueueArray) {}
+	AudioSynthWaveformSineModulated() : AudioStream(1, inputQueueArray), magnitude(16384) {}
 	void frequency(float freq);
-	//void amplitude(q15 n);
+	void amplitude(float n) {
+		if (n < 0) n = 0;
+		else if (n > 1.0) n = 1.0;
+		magnitude = n * 65536.0;
+	}
 	virtual void update(void);
 private:
 	uint32_t phase;
 	uint32_t phase_increment;
 	audio_block_t *inputQueueArray[1];
+	int32_t magnitude;
 };