Adds waveform generation logic to the new factoring.

Components/OPL2/Implementation/KeyLevelScaler.hpp

@@ -27,7 +27,7 @@ template <int frequency_precision> class KeyLevelScaler {
 			// on the sign bit to clamp to zero.
 			level_ = key_level_scales[period >> (frequency_precision - 4)];
 			level_ -= 16 * (octave ^ 7);
-			level_ &= masks[(key_scale_rate_ >> ((sizeof(int) * 8) - 1)) & 1];
+			level_ &= masks[(level_ >> ((sizeof(int) * 8) - 1)) & 1];
 		}
 
 		/*!

Components/OPL2/Implementation/PhaseGenerator.hpp

@@ -51,6 +51,13 @@ template <int precision> class PhaseGenerator {
 			return phase_ >> precision_shift;
 		}
 
+		/*!
+			@returns Current phase, scaled up by (1 << precision).
+		*/
+		int scaled_phase() const {
+			return phase_ >> 1;
+		}
+
 		/*!
 			Sets the multiple for this phase generator, in the same terms as an OPL programmer,
 			i.e. a 4-bit number that is used as a lookup into the internal multiples table.

Components/OPL2/Implementation/WaveformGenerator.hpp

@@ -0,0 +1,92 @@
+//
+//  WaveformGenerator.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 03/05/2020.
+//  Copyright © 2020 Thomas Harte. All rights reserved.
+//
+
+#ifndef WaveformGenerator_h
+#define WaveformGenerator_h
+
+#include "Tables.hpp"
+#include "LowFrequencyOscillator.hpp"
+
+namespace Yamaha {
+namespace OPL {
+
+template <int phase_precision> class WaveformGenerator {
+	public:
+		enum class Waveform {
+			Sine, HalfSine, AbsSine, PulseSine
+		};
+
+		/*!
+			@returns The output of waveform @c form at [integral] phase @c phase.
+		*/
+		static constexpr LogSign wave(Waveform form, int phase) {
+			constexpr int waveforms[4][4] = {
+				{1023, 1023, 1023, 1023},	// Sine: don't mask in any quadrant.
+				{511, 511, 0, 0},			// Half sine: keep the first half intact, lock to 0 in the second half.
+				{511, 511, 511, 511},		// AbsSine: endlessly repeat the first half of the sine wave.
+				{255, 0, 255, 0},			// PulseSine: act as if the first quadrant is in the first and third; lock the other two to 0.
+			};
+			return negative_log_sin(phase & waveforms[int(form)][(phase >> 8) & 3]);
+		}
+
+		/*!
+			@returns The output of waveform @c form at [scaled] phase @c scaled_phase given the modulation input @c modulation.
+		*/
+		static constexpr LogSign wave(Waveform form, int scaled_phase, LogSign modulation) {
+			const int scaled_phase_offset = modulation.level(phase_precision);
+			const int phase = (scaled_phase + scaled_phase_offset) >> phase_precision;
+			return wave(form, phase);
+		}
+
+		/*!
+			@returns Snare output, calculated from the current LFSR state as captured in @c oscillator and an operator's phase.
+		*/
+		static constexpr LogSign snare(const LowFrequencyOscillator &oscillator, int phase) {
+			// If noise is 0, output is positive.
+			// If noise is 1, output is negative.
+			// If (noise ^ sign) is 0, output is 0. Otherwise it is max.
+			const int sign = phase & 0x200;
+			const int level = ((phase >> 9) & 1) ^ oscillator.lfsr;
+			return negative_log_sin(sign + (level << 8));
+		}
+
+		/*!
+			@returns Cymbal output, calculated from an operator's phase and a modulator's phase.
+		*/
+		static constexpr LogSign cymbal(int carrier_phase, int modulator_phase) {
+			return negative_log_sin(256 + (phase_combination(carrier_phase, modulator_phase) << 9));
+		}
+
+		/*!
+			@returns High-hat output, calculated from the current LFSR state as captured in @c oscillator, an operator's phase and a modulator's phase.
+		*/
+		static constexpr LogSign high_hat(const LowFrequencyOscillator &oscillator, int carrier_phase, int modulator_phase) {
+			constexpr int angles[] = {0x234, 0xd0, 0x2d0, 0x34};
+			return negative_log_sin(angles[
+				phase_combination(carrier_phase, modulator_phase) |
+				(oscillator.lfsr << 1)
+			]);
+		}
+
+	private:
+		/*!
+			@returns The phase bit used for cymbal and high-hat generation, which is a function of two operators' phases.
+		*/
+		static constexpr int phase_combination(int carrier_phase, int modulator_phase) {
+			return (
+				((carrier_phase >> 5) ^ (carrier_phase >> 3)) &
+				((modulator_phase >> 7) ^ (modulator_phase >> 2)) &
+				((carrier_phase >> 5) ^ (modulator_phase >> 3))
+			) & 1;
+		}
+};
+
+}
+}
+
+#endif /* WaveformGenerator_h */

Components/OPL2/OPL2.cpp

@@ -13,6 +13,8 @@
 
 #include "Implementation/PhaseGenerator.hpp"
 #include "Implementation/EnvelopeGenerator.hpp"
+#include "Implementation/KeyLevelScaler.hpp"
+#include "Implementation/WaveformGenerator.hpp"
 
 using namespace Yamaha::OPL;
 

OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj

@@ -1154,6 +1154,7 @@
 		4B619092245BC1000013F202 /* PhaseGenerator.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = PhaseGenerator.hpp; sourceTree = "<group>"; };
 		4B619093245CD63E0013F202 /* EnvelopeGenerator.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = EnvelopeGenerator.hpp; sourceTree = "<group>"; };
 		4B619094245E73B90013F202 /* KeyLevelScaler.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = KeyLevelScaler.hpp; sourceTree = "<group>"; };
+		4B619095245FA04B0013F202 /* WaveformGenerator.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = WaveformGenerator.hpp; sourceTree = "<group>"; };
 		4B622AE3222E0AD5008B59F2 /* DisplayMetrics.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; name = DisplayMetrics.cpp; path = ../../Outputs/DisplayMetrics.cpp; sourceTree = "<group>"; };
 		4B622AE4222E0AD5008B59F2 /* DisplayMetrics.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; name = DisplayMetrics.hpp; path = ../../Outputs/DisplayMetrics.hpp; sourceTree = "<group>"; };
 		4B643F381D77AD1900D431D6 /* CSStaticAnalyser.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CSStaticAnalyser.h; path = StaticAnalyser/CSStaticAnalyser.h; sourceTree = "<group>"; };
@@ -3538,6 +3539,7 @@
 				4B619092245BC1000013F202 /* PhaseGenerator.hpp */,
 				4B619093245CD63E0013F202 /* EnvelopeGenerator.hpp */,
 				4B619094245E73B90013F202 /* KeyLevelScaler.hpp */,
+				4B619095245FA04B0013F202 /* WaveformGenerator.hpp */,
 			);
 			path = Implementation;
 			sourceTree = "<group>";