first commit

.gitignore

@@ -0,0 +1,2 @@
+*.o
+/convotest

Makefile

@@ -0,0 +1,16 @@
+CFLAGS=    -Wfatal-errors -Wall -Wextra $(shell pkgconf --cflags sdl2 SDL2_ttf)
+LDFLAGS=   -s -lm $(shell pkgconf --libs sdl2 SDL2_ttf)
+OBJS=      main.o sy.o button.o tools.o
+
+all: convotest
+convotest: $(OBJS)
+	$(CC) $^ -o $@ $(CFLAGS) $(LDFLAGS)
+%.o: %.c %.h
+	$(CC) -c $< -o $@ $(CFLAGS) $(LDFLAGS)
+%.o: %.c
+	$(CC) -c $^ -o $@ $(CFLAGS) $(LDFLAGS)
+%.o: %.asm
+	nasm $(NASMFLAGS) $^ -o $@
+
+clean:
+	$(RM) *.o $(OBJS) convotest

button.c

@@ -0,0 +1,13 @@
+#include<SDL2/SDL.h>
+#include"button.h"
+#include"tools.h"
+
+void button_draw(SDL_Renderer*ren,TTF_Font*font,Button*button)
+{
+	if(!ren)return;
+	if(!button)return;
+	SDL_Rect r={.x=button->x,.y=button->y,.w=button->w,.h=button->h};
+	SDL_SetRenderDrawColor(ren,0,0,128,255);
+	SDL_RenderFillRect(ren,&r);
+	print_text(ren,font,0xffffff,button->x,button->y,button->label);
+}

button.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include<SDL2/SDL.h>
+#include<SDL2/SDL_ttf.h>
+
+typedef struct Button
+{
+	const char*label;
+	size_t x;
+	size_t y;
+	size_t w;
+	size_t h;
+} Button;
+
+void button_draw(SDL_Renderer*ren,TTF_Font*font,Button*button);

main.c

@@ -0,0 +1,222 @@
+#include<assert.h>
+#include<inttypes.h>
+#include<stdbool.h>
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#include<unistd.h>
+#include<time.h>
+#include<SDL2/SDL.h>
+#include<SDL2/SDL_ttf.h>
+#include<SDL2/SDL_image.h>
+
+#include"sy.h"
+#include"wav.h"
+#include"button.h"
+#include"tools.h"
+
+#define max(x,y) (((x)>(y))?(x):(y))
+#define min(x,y) (((x)<(y))?(x):(y))
+
+#define WIDTH 320
+#define HEIGHT 240
+
+enum{BLP,BNS,BTR,BSQ,BSN};
+
+int main(void)
+{
+	SDL_Event event;
+	SDL_Renderer*ren=NULL;
+	SDL_Window*win=NULL;
+	TTF_Font*font=NULL;
+	Button buttons[16];
+	bool running=true;
+	const size_t samplerate=44100;
+	const size_t waveform_size=1024;
+	float waveform[waveform_size];
+	size_t filt_cutoff=500;
+	size_t nbuttons=0;
+	size_t osc_freq=440;
+
+	// Init SDL2
+	if(SDL_Init(SDL_INIT_EVERYTHING)<0)
+	{
+		fprintf(stderr,"error: failed to initialize SDL2\n");
+		goto quit;
+	}
+
+	// Init TTF
+	TTF_Init();
+	font=TTF_OpenFont("DejaVuSerif.ttf",12);
+	if(!font)
+	{
+		fprintf(stderr,"error: failed initialize SDL2 TTF\n");
+		goto quit;
+	}
+
+	// Create window
+	win=SDL_CreateWindow("ok",SDL_WINDOWPOS_UNDEFINED,
+			SDL_WINDOWPOS_UNDEFINED,
+			WIDTH,HEIGHT,0);
+	if(!win)
+	{
+		fprintf(stderr,"error: failed to create window\n");
+		goto quit;
+	}
+
+	// Create renderer
+	ren=SDL_CreateRenderer(win,-1,0);
+	if(!ren)
+	{
+		fprintf(stderr,"error: failed to create renderer\n");
+		goto quit;
+	}
+
+	// Clear window
+	SDL_SetRenderDrawColor(ren,0,0,0,0);
+	SDL_RenderClear(ren);
+	SDL_RenderPresent(ren);
+
+	// Create buttons
+#define create_button(n,_label) do{buttons[n]=(Button){.label=(_label),.x=nbuttons*25+5,.y=HEIGHT-20,.w=20,.h=16};++nbuttons;}while(0)
+	create_button(BLP,"LP");
+	create_button(BNS,"Ns");
+	create_button(BTR,"Tr");
+	create_button(BSQ,"Sq");
+	create_button(BSN,"Sn");
+#undef create_button
+
+	// Initialize data
+	srand(time(NULL));
+	nois(waveform,waveform_size);
+
+	// Main loop
+	while(running)
+	{
+		if(SDL_PollEvent(&event))
+		{
+			switch(event.type)
+			{
+
+				case SDL_QUIT:
+					running=false;
+					break;
+
+					// Mouse input
+				case SDL_MOUSEBUTTONDOWN:
+					switch(event.button.button)
+					{
+
+						case SDL_BUTTON_LEFT:
+
+							// Check each button
+							for(size_t i=0;i<nbuttons;++i)
+								if(event.button.x>(int)buttons[i].x&&
+										event.button.x<(int)buttons[i].x+(int)buttons[i].w&&
+										event.button.y>(int)buttons[i].y&&
+										event.button.y<(int)buttons[i].y+(int)buttons[i].h)
+								{
+									switch(i)
+									{
+
+										case BLP:
+											float windowsize=(((float)samplerate)/filt_cutoff);
+											/* printf("%luHz: %g\n",filt_cutoff,windowsize); */
+											/* printf("%luHz(44.1kHz): %g\n",filt_cutoff,((float)44100)/filt_cutoff); */
+											avgwindow(waveform,waveform_size,windowsize);
+											break;
+										case BNS:nois(waveform,waveform_size);break;
+										case BTR:tri(waveform,waveform_size,osc_freq);break;
+										case BSQ:sq(waveform,waveform_size,osc_freq);break;
+										case BSN:sn(waveform,waveform_size,osc_freq);break;
+
+									}
+									/* printf("'%s' pressed\n",buttons[i].label); */
+									break; // Do not click more than one button
+								}
+							break;
+
+					}
+					break;
+
+					// Keyboard input
+				case SDL_KEYDOWN:
+					switch(event.key.keysym.sym)
+					{
+
+							// UI
+						case SDLK_ESCAPE:
+						case SDLK_q:
+							running=false;
+							break;
+
+							// Oscillators
+						case SDLK_n:nois(waveform,waveform_size);break;
+						case SDLK_t:tri(waveform,waveform_size,osc_freq);break;
+						case SDLK_e:sq(waveform,waveform_size,osc_freq);break;
+						case SDLK_i:sn(waveform,waveform_size,osc_freq);break;
+
+							// Filters, envelopes, etc.
+						case SDLK_s:sort(waveform,waveform_size);break;
+						case SDLK_r:shuf(waveform,waveform_size);break;
+						case SDLK_y:atk(waveform,waveform_size,5);break;
+						case SDLK_u:rel(waveform,waveform_size,10);break;
+						case SDLK_o:rotl(waveform,waveform_size);break;
+						case SDLK_a:
+							{
+								float windowsize=(((float)samplerate)/filt_cutoff);
+								/* printf("%luHz: %g\n",filt_cutoff,windowsize); */
+								/* printf("%luHz(44.1kHz): %g\n",filt_cutoff,((float)44100)/filt_cutoff); */
+								avgwindow(waveform,waveform_size,windowsize);
+							}
+							break;
+
+							// Parameters
+						case SDLK_UP:osc_freq+=(1/12.0)*osc_freq;break;
+						case SDLK_DOWN:osc_freq-=(1/12.0)*osc_freq;if(osc_freq<1)osc_freq=1;break;
+						case SDLK_EQUALS:filt_cutoff+=(1/12.0)*filt_cutoff;break;
+						case SDLK_MINUS:filt_cutoff-=(1/12.0)*filt_cutoff;if(filt_cutoff<1)filt_cutoff=1;break;
+
+					}
+					break;
+
+				default:
+					break;
+			}
+		}
+
+		// Render
+		SDL_SetRenderDrawColor(ren,0,0,0,255);
+		SDL_RenderClear(ren);
+		SDL_SetRenderDrawColor(ren,255,0,0,255);
+
+		for(size_t i=0;i<WIDTH;++i)
+			SDL_RenderDrawLine(ren,i,HEIGHT/2,i,max(HEIGHT/2-waveform[i*(waveform_size/WIDTH)]*100,0));
+
+		for(size_t i=0;i<nbuttons;++i)
+			button_draw(ren,font,&buttons[i]);
+
+		ttfprintf(ren,font,0xffffff,5,5,
+				"sr:%lu  ns:%lu  f:%lu  co:%lu",
+				samplerate,
+				waveform_size,
+				osc_freq,
+				filt_cutoff
+				);
+
+		SDL_RenderPresent(ren);
+		SDL_Delay(20);
+		//usleep(20000);
+	}
+
+	// Clean up, exit
+quit:
+	if(win)
+		SDL_DestroyWindow(win);
+	if(ren)
+		SDL_DestroyRenderer(ren);
+	if(font)
+		TTF_CloseFont(font);
+	SDL_Quit();
+	TTF_Quit();
+}

readme

@@ -0,0 +1,19 @@
+Keyboard keys:
+
+GENERATOR/OSCILLATORS:
+E:    Generate square wave
+I:    Generate sine wave
+N:    Generate noise wave
+T:    Generate triangle wave
+
+WAVEFORM ACTIONS:
+A:    Average (convolution low-pass)
+R:    Shuffle (randomize)
+S:    Sort
+O:    Rotate left
+
+PARAMETER MODIFICATION:
++/=:  Increase filter cutoff frequency
+-/_:  Decrease filter cutoff frequency
+Up:   Increase generator frequency
+Down: Decrease generator frequency

sy.c

@@ -0,0 +1,176 @@
+#include"sy.h"
+
+void nois(float*a,size_t n)
+{
+	int amp=2;
+	for(size_t i=0;i<n;++i)
+		a[i]=frand()*amp-amp/2;
+}
+
+// triangle oscillator
+void tri(float*a,int n,int freq)
+{
+	int period=44100.0/freq;
+	int amp=2;
+	float ratio=amp/((float)period/2);
+	for(int j=0;j<n;++j)
+	{
+		int i=j+period/4; // adjust phase
+		if(i%period<period/2)
+			a[j]=i%period;
+		else
+			a[j]=period-(i%period);
+		// a[i] is half of a ratio
+		// and needs to be adjusted
+		// for amplitude
+		a[j]*=ratio;
+		a[j]-=amp/2;
+	}
+}
+
+// square oscillator
+void sq(float*a,int n,int freq)
+{
+	int period=44100.0/freq;
+	for(int i=0;i<n;++i)
+	{
+		if(i%period<period/2)
+			a[i]=1;
+		else
+			a[i]=-1;
+	}
+}
+
+// sine oscillator
+void sn(float*a,int n,int freq)
+{
+	int period=44100.0/freq;
+	for(int i=0;i<n;++i)
+		a[i]=sin(2*(M_PI)*((float)i/period));
+}
+
+void atk(float*a,size_t n,size_t t)
+{
+	if(!a)return;
+	for(size_t i=0;i<t&&i<n;++i)
+		a[i]*=i/((float)t);
+}
+
+void rel(float*a,size_t n,size_t t)
+{
+	if(!a)return;
+	for(size_t i=1;i<t&&i<n;++i)
+		a[n-i]*=i/((float)t);
+}
+
+// Convolving average lowpass filter
+// Smooth high frequencies
+// samplerate: 44100 Hz
+// cutoff:     440 Hz
+// window:     44100/440=100
+void avgwindow(float*a,int n,int windowsize)
+{
+	if(!a)return;
+	for(int k=0;k<n;++k)
+	{
+		int i=k-windowsize/2;
+		float sum=0;
+		while(i<0)i+=n;
+		for(int j=0;j<windowsize;++j)
+		{
+			sum+=a[i];
+			i=(i+1)%n;
+		}
+		a[k]=sum/windowsize;
+	}
+}
+
+/* void avg(float*a,size_t n,float w) */
+/* { */
+/* 	if(!w)return; */
+/* 	if(!a)return; */
+/* 	w=ceil(w)+1; */
+/* 	for(size_t i=0;i<n;++i) */
+/* 	{ */
+/* 		if(i<w) */
+/* 			for(size_t j=0;j<w;++j) */
+/* 			{ */
+/* 				if(j<i)a[i]+=a[j]; */
+/* 			} */
+/* 		else */
+/* 			for(size_t j=i-w+1;j<i&&j<n;++j) */
+/* 				a[i]+=a[j]; */
+/* 		a[i]/=w; */
+/* 	} */
+/* } */
+
+void printwindow(float*a,int n,int windowsize)
+{
+	if(!a)return;
+	int i=n-windowsize/2;
+	if(i<0)i+=n;
+	for(int j=0;j<windowsize;++j)
+	{
+		printf("%f",a[i]);
+		if(j<windowsize-1)
+			printf(", ");
+
+		i=(i+1)%n;
+	}
+	printf("\n");
+}
+
+void printwindowall(float*a,int n,int windowsize)
+{
+	if(!a)return;
+	for(int k=0;k<n;++k)
+	{
+		int i=k-windowsize/2;
+		while(i<0)i+=n;
+		printf("(");
+		for(int j=0;j<windowsize;++j)
+		{
+			printf("%f",a[i]);
+			if(j<windowsize-1)
+				printf(", ");
+
+			i=(i+1)%n;
+		}
+		printf(")\n");
+	}
+}
+
+// Insert integer into correct place
+// starting from 0 to n
+void sort(float*a,size_t n)
+{
+	float t;
+	if(!a)return;
+	for(size_t i=0;i<n-1;++i)
+		for(size_t j=i+1;j<n;++j)
+			if(a[i]>a[j])
+				t=a[i],
+				a[i]=a[j],
+				a[j]=t;
+}
+
+void shuf(float*a,size_t n)
+{
+	float t;
+	for(size_t i=0;i<n;++i)
+	{
+		size_t sw=rand()%n;
+		t=a[i],
+		a[i]=a[sw],
+		a[sw]=t;
+	}
+}
+
+void rotl(float*a,size_t n)
+{
+	if(!a)return;
+	float t=a[0];
+	for(size_t i=1;i<n;++i)
+		a[i-1]=a[i];
+	a[n-1]=t;
+}

sy.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include<assert.h>
+#include<inttypes.h>
+#include<stdbool.h>
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#include<unistd.h>
+#include<time.h>
+#include<math.h>
+
+#define frand() ((float)(rand()%10000)/10000)
+
+void atk(float*a,size_t n,size_t t);
+void avgwindow(float*a,int n,int windowsize);
+void nois(float*a,size_t n);
+void printwindow(float*a,int n,int windowsize);
+void printwindowall(float*a,int n,int windowsize);
+void rel(float*a,size_t n,size_t t);
+void rotl(float*a,size_t n);
+void shuf(float*a,size_t n);
+void sn(float*a,int n,int freq);
+void sort(float*a,size_t n);
+void sq(float*a,int n,int freq);
+void tri(float*a,int n,int freq);

tools.c

@@ -0,0 +1,32 @@
+#include<assert.h>
+#include<inttypes.h>
+#include<stdbool.h>
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#include<unistd.h>
+#include<time.h>
+#include<SDL2/SDL.h>
+#include<SDL2/SDL_ttf.h>
+#include<SDL2/SDL_image.h>
+
+#include"tools.h"
+
+void print_text(SDL_Renderer*ren,TTF_Font*font,int color,int x,int y,const char*str)
+{
+	SDL_Color c=(SDL_Color){
+		.r=(color>>16)&0xff,
+		.g=(color>>8)&0xff,
+		.b=(color>>0)&0xff,
+		.a=0xff,
+	};
+	SDL_Surface*surface=TTF_RenderText_Solid(font,str,c);
+	SDL_Texture*texture=SDL_CreateTextureFromSurface(ren,surface);
+	SDL_Rect rect={.x=x,.y=y,.w=surface->w,.h=surface->h};
+
+	SDL_RenderCopy(ren,texture,NULL,&rect);
+
+	SDL_FreeSurface(surface);
+	SDL_DestroyTexture(texture);
+}
+

tools.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include<assert.h>
+#include<inttypes.h>
+#include<stdbool.h>
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#include<unistd.h>
+#include<time.h>
+#include<SDL2/SDL.h>
+#include<SDL2/SDL_ttf.h>
+#include<SDL2/SDL_image.h>
+
+// SDL2_ttf printf-like macro
+#define ttfprintf(ren,font,col,x,y,fmt,...) do{\
+	char _b[128];sprintf(_b,fmt,__VA_ARGS__);\
+	print_text(ren,font,col,x,y,_b);}while(0)
+
+void print_text(SDL_Renderer*ren,TTF_Font*font,int color,int x,int y,const char*str);

wav.h

@@ -0,0 +1,25 @@
+#pragma once
+#include<stdint.h>
+#include<stdlib.h>
+#include<string.h>
+
+// Struct to contain .WAV file header data for exporting .WAV files
+typedef struct WAVE
+{
+	int8_t riff[4];				// "RIFF" mark
+	uint32_t filesize;			// File size
+	int8_t wave[4];				// "WAVE" mark
+	int8_t fmt[4];				// "fmt " mark
+	uint32_t formatdatalength;	// Length of format data
+	uint16_t formattype;		// Type (PCM for our purpose)
+	uint16_t channels;			// Mono/stereo
+	uint32_t samplerate;		// Samples per second
+	uint32_t bitspersecond;		// Samplerate * Bits per sample
+	uint16_t bittype;			// 1=>8bit mono, 2=>8bit stereo, 4=>16bit stereo...
+	uint16_t bitspersample;		// e.g., 16, 32
+	int8_t data[4];				// "data" mark
+	uint32_t datalength;		// Length of audio
+} WAVE;
+
+// Create a custom WAVE header data struct for .WAV files
+WAVE wav_create(uint32_t samplerate,uint16_t bitspersample,uint16_t channels,uint32_t length);