A noisy square-wave drone synth

squarewavesynth.lua

--[[
name: square demo
description: > generate a squarewave with pulse width control
author: synaesmedia
See https://www.youtube.com/watch?v=8kXs8XIyq1U

--]]

require "include/protoplug"

function freq_to_delta(f)
		local sr = plugin.isSampleRateKnown() and plugin.getSampleRate() or 44100
	    return 2*math.pi*f/sr
end

function make_osc(init_freq, init_amp,init_pw) 
    o = {
        freq=init_freq,
        amp=init_amp,
        delta=0.06,
        phase=0,
        pulse_width=init_pw,
        next=function(self)
            local v = 1
            local s = math.sin(self.phase)
		    if s > self.pulse_width then 
		        v = 1
	        else 
	            v = -1
	        end
	        self.phase=self.phase+self.delta
	        return v*self.amp
        end,
        set_freq=function(self,f)
            self.freq = f
            self.delta = freq_to_delta(f)
        end,
        set_amp=function(self,a)
            self.amp=a
        end,
        set_pw=function(self,pw)
            self.pulse_width=pw
        end
    }
    o:set_freq(init_freq) -- so that delta is initialized properly
    return o
end

local osc1 = make_osc(440,0.5,0.5)
local osc2 = make_osc(441,0.5,0.5)

local lfo1 = make_osc(4,1,0.5)
local lfo_amp = 0

function plugin.processBlock(samples, smax)
	for i=0,smax do
	    vlfo = lfo1:next()
        v1 = osc1:next()
        v2 = osc2:next()
        v = (v1+v2)/2
        vf = ((v*lfo_amp*vlfo)+(v*(1-lfo_amp)))/2
        samples[0][i] = vf
		samples[1][i] = vf
	end
end


plugin.manageParams {
	{
		name = "OSC1 Amplitude";
		changed = function(val)
		    osc1:set_amp(val) 
		end;
	};
		
	{
		name = "OSC1 Freq";
		changed = function(val)
		    osc1:set_freq(val*3000)
		end;
	};
	{
	    name = "OSC1 Pulse Width";
	    max = 2;
	    changed = function(val)
	        osc1:set_pw(val-1)
	    end;
	};

		{
		name = "OSC2 Amplitude";
		changed = function(val)
		    osc2:set_amp(val) 
		end;
	};
		
	{
		name = "OSC2 Freq";
		changed = function(val)
		    osc2:set_freq(val*3000)
		end;
	};
	{
	    name = "OSC2 Pulse Width";
	    max = 2;
	    changed = function(val)
	        osc2:set_pw(val-1)
	    end;
	};

			
	{
		name = "LFO1 Amplitude";
		changed = function(val)
		    lfo_amp = val 
		end;
	};
		
	{
		name = "LFO1 Freq";
		changed = function(val)
		    lfo1:set_freq(val*val*1000)
		end;
	};
	{
	    name = "LFO1 Pulse Width";
	    max = 2;
	    changed = function(val)
	        lfo1:set_pw(val-1)
	    end;
	};

}