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#include <klang.h>
using namespace klang::optimised;

// Physical model of a guitar
// (based on Karplus-Strong)

struct Guitar : Synth {

	struct String : Note {

		struct Excitation : Generator {
			Envelope env;
			LPF filter;
			Noise noise;

			void process() {
				(env * noise) >> filter >> out;
			}
		} pluck;

		struct Resonator : Modifier {
			Delay<44100> delay;
			LPF filter;
			param gain;

			void process() {
				signal feedback = (delay * gain) >> filter;
				(in + feedback) >> out;
				delay << out; // feed back to delay
			}
		} string;

		void process() {
			pluck >> string >> out;
		}

		event on(Pitch pitch, Amplitude velocity) {
			const param resonance = controls[0], 
						      brightness = controls[1], 
						      finger = controls[2];

			const param f = (pitch -> Frequency);
			const param delay = 1 / f * klang::fs;

			pluck.filter.set(controls[2]);
			pluck.env = {	{ 0.000, 0         }, 
							      { 0.001, velocity  }, 
							      { 0.003, -velocity }, 
							      { 0.004, 0         } };

			string.delay.clear();
			string.delay.set(delay);
			string.filter.set(brightness);
			string.gain = resonance;
		}
	};

  Guitar() {
		controls = {
			Dial("Resonance",   0.97, 0.999, 0.994),
			Dial("Brightness", -0.1,  0.1,   0.025),
			Dial("Pluck",       0.5,  1.0,   0.6),
		};

		presets = {
			{ "Classical", { 0.994, 0.025, 0.6 } },
			{ "Banjo",     { 0.990, 0.144, 0.6 } },
		};

		notes.add<String>(6);
	}
};