/* ========================================
 *  VoiceOfTheStarship - VoiceOfTheStarship.h
 *  Copyright (c) 2016 airwindows, Airwindows uses the MIT license
 * ======================================== */

#include "VoiceOfTheStarship.h"

#ifdef SHR3D_SFX_CORE_AIRWINDOWS

namespace airwinconsolidated::VoiceOfTheStarship {

void VoiceOfTheStarship::processBlock(float **inputs, float **outputs, int sampleFrames) 
{
    float* in1  =  inputs[0];
    float* in2  =  inputs[1];
    float* out1 = outputs[0];
    float* out2 = outputs[1];
	double cutoff = pow((A*0.89)+0.1,3);
	if (cutoff > 1.0) cutoff = 1.0;
	double invcutoff = 1.0 - cutoff;
	//this is the lowpass
	
	double overallscale = ((1.0-A)*9.0)+1.0;
	double gain = overallscale;
	if (gain > 1.0) {f[0] = 1.0; gain -= 1.0;} else {f[0] = gain; gain = 0.0;}
	if (gain > 1.0) {f[1] = 1.0; gain -= 1.0;} else {f[1] = gain; gain = 0.0;}
	if (gain > 1.0) {f[2] = 1.0; gain -= 1.0;} else {f[2] = gain; gain = 0.0;}
	if (gain > 1.0) {f[3] = 1.0; gain -= 1.0;} else {f[3] = gain; gain = 0.0;}
	if (gain > 1.0) {f[4] = 1.0; gain -= 1.0;} else {f[4] = gain; gain = 0.0;}
	if (gain > 1.0) {f[5] = 1.0; gain -= 1.0;} else {f[5] = gain; gain = 0.0;}
	if (gain > 1.0) {f[6] = 1.0; gain -= 1.0;} else {f[6] = gain; gain = 0.0;}
	if (gain > 1.0) {f[7] = 1.0; gain -= 1.0;} else {f[7] = gain; gain = 0.0;}
	if (gain > 1.0) {f[8] = 1.0; gain -= 1.0;} else {f[8] = gain; gain = 0.0;}
	if (gain > 1.0) {f[9] = 1.0; gain -= 1.0;} else {f[9] = gain; gain = 0.0;}
	//this is the moving average with remainders
	if (overallscale < 1.0) overallscale = 1.0;
	f[0] /= overallscale;
	f[1] /= overallscale;
	f[2] /= overallscale;
	f[3] /= overallscale;
	f[4] /= overallscale;
	f[5] /= overallscale;
	f[6] /= overallscale;
	f[7] /= overallscale;
	f[8] /= overallscale;
	f[9] /= overallscale;
	//and now it's neatly scaled, too
	
	int lowcut = floor(B*16.9);
	if (lastAlgorithm != lowcut) {
		noiseAL = 0.0; noiseBL = 0.0; noiseCL = 0.0;
		noiseAR = 0.0; noiseBR = 0.0; noiseCR = 0.0;
		for(int count = 0; count < 11; count++) {bL[count] = 0.0; bR[count] = 0.0;}
		lastAlgorithm = lowcut;
	}
	//cuts the noise back to 0 if we are changing algorithms,
	//because that also changes gains and can make loud pops.
	//We still get pops, but they'd be even worse
	int dcut;
	if (lowcut > 15) {lowcut = 1151; dcut= 11517;}
	if (lowcut == 15) {lowcut = 113; dcut= 1151;}
	if (lowcut == 14) {lowcut = 71; dcut= 719;}
	if (lowcut == 13) {lowcut = 53; dcut= 541;}
	if (lowcut == 12) {lowcut = 31; dcut= 311;}
	if (lowcut == 11) {lowcut = 23; dcut= 233;}
	if (lowcut == 10) {lowcut = 19; dcut= 191;}
	if (lowcut == 9) {lowcut = 17; dcut= 173;}
	if (lowcut == 8) {lowcut = 13; dcut= 131;}
	if (lowcut == 7) {lowcut = 11; dcut= 113;}
	if (lowcut == 6) {lowcut = 7; dcut= 79;}
	if (lowcut == 5) {lowcut = 6; dcut= 67;}
	if (lowcut == 4) {lowcut = 5; dcut= 59;}
	if (lowcut == 3) {lowcut = 4; dcut= 43;}
	if (lowcut == 2) {lowcut = 3; dcut= 37;}
	if (lowcut == 1) {lowcut = 2; dcut= 23;}
	if (lowcut < 1) {lowcut = 1; dcut= 11;}
	//this is the mechanism for cutting back subs without filtering
	
	double rumbletrim = sqrt(lowcut);
	//this among other things is just to give volume compensation
	double inputSampleL;
	double inputSampleR;
	
	
    while (--sampleFrames >= 0)
    {
		inputSampleL = *in1;
		inputSampleR = *in2;
		//we then ignore this!

		quadratic -= 1;
		if (quadratic < 0)
		{
			position += 1;		
			quadratic = position * position;
			quadratic = quadratic % 170003; //% is C++ mod operator
			quadratic *= quadratic;
			quadratic = quadratic % 17011; //% is C++ mod operator
			quadratic *= quadratic;
			quadratic = quadratic % 1709; //% is C++ mod operator
			quadratic *= quadratic;
			quadratic = quadratic % dcut; //% is C++ mod operator
			quadratic *= quadratic;
			quadratic = quadratic % lowcut;
			//sets density of the centering force
			if (noiseAL < 0) {flipL = true;}
			else {flipL = false;}
			if (noiseAR < 0) {flipR = true;}
			else {flipR = false;}
			//every time we come here, we force the random walk to be
			//toward the center of the waveform. Without this,
			//it's a pure random walk that will generate DC.
		}
		
		if (flipL) noiseAL += (double(fpdL)/UINT32_MAX);
		else noiseAL -= (double(fpdL)/UINT32_MAX);
		if (flipR) noiseAR += (double(fpdR)/UINT32_MAX);
		else noiseAR -= (double(fpdR)/UINT32_MAX);
		//here's the guts of the random walk
		
		if (filterflip)
		{
			noiseBL *= invcutoff; noiseBL += (noiseAL*cutoff);
			inputSampleL = noiseBL;
			noiseBR *= invcutoff; noiseBR += (noiseAR*cutoff);
			inputSampleR = noiseBR;
		}
		else 
		{
			noiseCL *= invcutoff; noiseCL += (noiseAL*cutoff);
			inputSampleL = noiseCL;
			noiseCR *= invcutoff; noiseCR += (noiseAR*cutoff);
			inputSampleR = noiseCR;
		}
		//now we have the output of the filter as inputSample.
		//this filter is shallower than a straight IIR: it's interleaved
		
		
		
		
		bL[9] = bL[8]; bL[8] = bL[7]; bL[7] = bL[6]; bL[6] = bL[5];
		bL[5] = bL[4]; bL[4] = bL[3]; bL[3] = bL[2]; bL[2] = bL[1];
		bL[1] = bL[0]; bL[0] = inputSampleL;
		
		bR[9] = bR[8]; bR[8] = bR[7]; bR[7] = bR[6]; bR[6] = bR[5];
		bR[5] = bR[4]; bR[4] = bR[3]; bR[3] = bR[2]; bR[2] = bR[1];
		bR[1] = bR[0]; bR[0] = inputSampleR;
		
		inputSampleL *= f[0];
		inputSampleL += (bL[1] * f[1]);
		inputSampleL += (bL[2] * f[2]);
		inputSampleL += (bL[3] * f[3]);
		inputSampleL += (bL[4] * f[4]);
		inputSampleL += (bL[5] * f[5]);
		inputSampleL += (bL[6] * f[6]);
		inputSampleL += (bL[7] * f[7]);
		inputSampleL += (bL[8] * f[8]);
		inputSampleL += (bL[9] * f[9]);

		inputSampleR *= f[0];
		inputSampleR += (bR[1] * f[1]);
		inputSampleR += (bR[2] * f[2]);
		inputSampleR += (bR[3] * f[3]);
		inputSampleR += (bR[4] * f[4]);
		inputSampleR += (bR[5] * f[5]);
		inputSampleR += (bR[6] * f[6]);
		inputSampleR += (bR[7] * f[7]);
		inputSampleR += (bR[8] * f[8]);
		inputSampleR += (bR[9] * f[9]);

		inputSampleL *= 0.1;
		inputSampleR *= 0.1;
		inputSampleL *= invcutoff;
		inputSampleR *= invcutoff;
		inputSampleL /= rumbletrim;
		inputSampleR /= rumbletrim;
		
		flipL = !flipL;
		flipR = !flipR;
		filterflip = !filterflip;
		
		
		//begin 32 bit stereo floating point dither
		int expon; frexpf((float)inputSampleL, &expon);
		fpdL ^= fpdL << 13; fpdL ^= fpdL >> 17; fpdL ^= fpdL << 5;
		inputSampleL += double((double(fpdL)-uint32_t(0x7fffffff)) * 5.5e-36l * pow(2.0,expon+62.0));
		frexpf((float)inputSampleR, &expon);
		fpdR ^= fpdR << 13; fpdR ^= fpdR >> 17; fpdR ^= fpdR << 5;
		inputSampleR += double((double(fpdR)-uint32_t(0x7fffffff)) * 5.5e-36l * pow(2.0,expon+62.0));
		//end 32 bit stereo floating point dither

		*out1 = float(inputSampleL);
		*out2 = float(inputSampleR);

		in1++;
		in2++;
		out1++;
		out2++;
    }
}

} // end namespace

#endif // SHR3D_SFX_CORE_AIRWINDOWS
