Rack/plugins/community/repos/Bidoo/src/LIMBO.cpp

// Based on Will Pirkle's courses & Vadim Zavalishin's book

#include "Bidoo.hpp"
#include "BidooComponents.hpp"
#include "dsp/decimator.hpp"

using namespace std;

namespace rack_plugin_Bidoo {

#define pi 3.14159265359

struct FilterStage
{
	float mem = 0.0;

	float Filter(float sample, float freq, float smpRate, float gain, int mode)
	{
		float g = tan(pi*freq/smpRate);
		float G = g/(1.0 + g);
		float out;
		if (mode == 0) {
			out = (sample - mem) * G + mem;
		} else {
			out = (tanh(sample*gain)/tanh(gain) - mem) * G + mem;
		}
		mem = out + (sample - mem) * G	;
		return out;
	}
};

struct LadderFilter
{
	FilterStage stage1;
	FilterStage stage2;
	FilterStage stage3;
	FilterStage stage4;
	float q;
	float freq;
	float smpRate;
	int mode = 0;
	float gain = 1.0f;

	void setParams(float freq, float q, float smpRate, float gain, int mode) {
		this->freq = freq;
		this->q=q;
		this->smpRate=smpRate;
		this->mode = mode;
		this->gain = gain;
	}

	float calcOutput(float sample)
	{
		float g = tan(pi*freq/smpRate);
		float G = g/(1.0f + g);
		G = G*G*G*G;
		float S1 = stage1.mem/(1.0f + g);
		float S2 = stage2.mem/(1.0f + g);
		float S3 = stage3.mem/(1.0f + g);
		float S4 = stage4.mem/(1.0f + g);
		float S = G*G*G*S1 + G*G*S2 + G*S3 + S4;
		return stage4.Filter(stage3.Filter(stage2.Filter(stage1.Filter((sample - q*S)/(1.0f + q*G),
		freq,smpRate,gain,mode),freq,smpRate,gain,mode),freq,smpRate,gain,mode),freq,smpRate,gain,mode);
	}

};

struct LIMBO : Module {
	enum ParamIds {
		CUTOFF_PARAM,
		Q_PARAM,
		CMOD_PARAM,
		MUG_PARAM,
		MODE_PARAM,
		NUM_PARAMS
	};
	enum InputIds {
		IN_L,
		IN_R,
		CUTOFF_INPUT,
		Q_INPUT,
		MUG_INPUT,
		NUM_INPUTS
	};
	enum OutputIds {
		OUT_L,
		OUT_R,
		NUM_OUTPUTS
	};
	enum LightIds {
		LEARN_LIGHT,
		NUM_LIGHTS
	};
	LadderFilter lFilter,rFilter;

	LIMBO() : Module(NUM_PARAMS, NUM_INPUTS, NUM_OUTPUTS, NUM_LIGHTS) {
	}

	void step() override;

};

void LIMBO::step() {
	float cfreq = pow(2.0f,rescale(clamp(params[CUTOFF_PARAM].value + params[CMOD_PARAM].value * inputs[CUTOFF_INPUT].value / 5.0f,0.0f,1.0f),0.0f,1.0f,4.5f,13.0f));
	float q = 3.5f * clamp(params[Q_PARAM].value + inputs[Q_INPUT].value / 5.0f, 0.0f, 1.0f);
	float g = pow(2.0f,rescale(clamp(params[MUG_PARAM].value + inputs[MUG_INPUT].value / 5.0f,0.0f,1.0f),0.0f,1.0f,0.0f,3.0f));
	int mode = (int)params[MODE_PARAM].value;
	lFilter.setParams(cfreq,q,engineGetSampleRate(),g/3,mode);
	rFilter.setParams(cfreq,q,engineGetSampleRate(),g/3,mode);
	float inL = inputs[IN_L].value/5.0f; //normalise to -1/+1 we consider VCV Rack standard is #+5/-5V on VCO1
	float inR = inputs[IN_R].value/5.0f;
	inL = lFilter.calcOutput(inL)*5.0f*(mode == 0 ? g : 1);
	inR = rFilter.calcOutput(inR)*5.0f*(mode == 0 ? g : 1);
	outputs[OUT_L].value = inL;
	outputs[OUT_R].value = inR;
}


struct LIMBOWidget : ModuleWidget {
	LIMBOWidget(LIMBO *module) : ModuleWidget(module) {
		setPanel(SVG::load(assetPlugin(plugin, "res/LIMBO.svg")));

		addChild(Widget::create<ScrewSilver>(Vec(RACK_GRID_WIDTH, 0)));
		addChild(Widget::create<ScrewSilver>(Vec(box.size.x - 2 * RACK_GRID_WIDTH, 0)));
		addChild(Widget::create<ScrewSilver>(Vec(RACK_GRID_WIDTH, RACK_GRID_HEIGHT - RACK_GRID_WIDTH)));
		addChild(Widget::create<ScrewSilver>(Vec(box.size.x - 2 * RACK_GRID_WIDTH, RACK_GRID_HEIGHT - RACK_GRID_WIDTH)));

		addParam(ParamWidget::create<BidooHugeBlueKnob>(Vec(31, 61), module, LIMBO::CUTOFF_PARAM, 0.0f, 1.0f, 1.0f));
		addParam(ParamWidget::create<BidooLargeBlueKnob>(Vec(12, 143), module, LIMBO::Q_PARAM, 0.0f, 1.0f, 0.0f));
		addParam(ParamWidget::create<BidooLargeBlueKnob>(Vec(71, 143), module, LIMBO::MUG_PARAM, 0.0f, 1.0f, 0.0f));
		addParam(ParamWidget::create<BidooLargeBlueKnob>(Vec(12, 208), module, LIMBO::CMOD_PARAM, -1.0f, 1.0f, 0.0f));
		addParam(ParamWidget::create<CKSS>(Vec(83, 217), module, LIMBO::MODE_PARAM, 0.0f, 1.0f, 0.0f));

		addInput(Port::create<PJ301MPort>(Vec(12, 280), Port::INPUT, module, LIMBO::CUTOFF_INPUT));
		addInput(Port::create<PJ301MPort>(Vec(47, 280), Port::INPUT, module, LIMBO::Q_INPUT));
		addInput(Port::create<PJ301MPort>(Vec(82, 280), Port::INPUT, module, LIMBO::MUG_INPUT));

		addInput(Port::create<TinyPJ301MPort>(Vec(24, 319), Port::INPUT, module, LIMBO::IN_L));
		addInput(Port::create<TinyPJ301MPort>(Vec(24, 339), Port::INPUT, module, LIMBO::IN_R));
		addOutput(Port::create<TinyPJ301MPort>(Vec(95, 319), Port::OUTPUT, module, LIMBO::OUT_L));
		addOutput(Port::create<TinyPJ301MPort>(Vec(95, 339), Port::OUTPUT, module, LIMBO::OUT_R));
	}
};

} // namespace rack_plugin_Bidoo

using namespace rack_plugin_Bidoo;

RACK_PLUGIN_MODEL_INIT(Bidoo, LIMBO) {
   Model *modelLIMBO = Model::create<LIMBO, LIMBOWidget>("Bidoo", "lIMbO", "lIMbO filter", FILTER_TAG);
   return modelLIMBO;
}