shithub: prismriver

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Frequency as a generation time argument, PCM-backed generator

The PCM-backed generator is currently untested

--- a/p-pcm.c

+++ b/p-pcm.c

@@ -12,7 +12,7 @@

 	 */

 	Buffer *b = emallocz(sizeof(Buffer));

 	b->size = s;

-	b->data = emallocz(s * sizeof(STuple));

+	b->data = emallocz(s * sizeof(Stuple));

 	return b;

 }

@@ -19,7 +19,7 @@

 Buffer*

 resizebuffer(Buffer *b, ulong ns)

 {

-	b->data = erealloc(b->data, ns * sizeof(STuple));

+	b->data = erealloc(b->data, ns * sizeof(Stuple));

 	b->size = ns;

 	return b;

 }

@@ -34,5 +34,5 @@

 void

 play(Buffer *b, int fd)

 {

-	write(fd, b->data, b->size * sizeof(STuple));

+	write(fd, b->data, b->size * sizeof(Stuple));

 }

--- a/p-wavegen.c

+++ b/p-wavegen.c

@@ -11,17 +11,20 @@

 }

 Buffer*

-buffermap(Buffer *buf, Wavegen *gen, int d, ulong s, ulong sz)

+buffermap(Buffer *buf, Wavegen *gen, double freq, ulong *pc, int d, ulong s, ulong sz)

 {

 	if(buf == nil)

 		buf = createbuffer(s + sz);

 	for(ulong c = s; c < sz; c++)

-		buf->data[c] = gen->fn(gen, c);

+		buf->data[c] = gen->fn(gen, freq, c + (pc == nil ? 0 : *pc));

 	if(d)

 		destroywavegen(gen);

+	if(pc != nil)

+		*pc += sz;

+

 	return buf;

 }

@@ -31,16 +34,16 @@

 {

 	Wavegen;

 	double (*wavefn)(double);

-	double amp, freq, phase;

+	double amp, phase;

 } Waveprops;

-STuple

-waveformfn(Wavegen *w, ulong t)

+Stuple

+waveformfn(Wavegen *w, double freq, ulong t)

 {

 	Waveprops *p = (Waveprops*)w;

-	double v	= p->amp * p->wavefn(s2d(t) * p->freq + p->phase);

+	double v	= p->amp * p->wavefn(s2d(t) * freq + p->phase);

 	sample val	= truncate(v);

-	return (STuple)

+	return (Stuple)

 	{

 		val, val

 	};

@@ -47,7 +50,7 @@

 }

 Wavegen*

-waveform(double (*fn)(double), double amp, double freq, double φ)

+waveform(double (*fn)(double), double amp, double φ)

 {

 	Waveprops *p = emallocz(sizeof(Waveprops));

 	p->fn		= waveformfn;

@@ -54,7 +57,6 @@

 	p->destroy 	= (void(*)(Wavegen*))free;

 	p->wavefn	= fn;

 	p->amp		= amp;

-	p->freq		= freq;

 	p->phase	= φ;

 	return p;

 }

@@ -87,4 +89,40 @@

 triangle(double num)

 {

 	return 2 * fabs(saw(num)) - 1;

+}

+

+/** PCM-backed wave "generators" **/

+

+typedef struct

+{

+	Wavegen;

+	Buffer *buf;

+} Pcmprops;

+

+Stuple

+pcmfn(Wavegen *w, double freq, ulong t)

+{

+	(void)freq;

+	Pcmprops *p = (Pcmprops*)w;

+	if(t < p->buf->size)

+		return p->buf->data[t];

+	return (Stuple) { 0, 0 };

+}

+

+void

+pcmdestroy(Wavegen *w)

+{

+	Pcmprops *p = (Pcmprops*)w;

+	destroybuffer(p->buf);

+	free(p);

+}

+

+Wavegen*

+pcm(Buffer *buf)

+{

+	Pcmprops *p = emallocz(sizeof(*p));

+	p->fn		= pcmfn;

+	p->destroy	= pcmdestroy;

+	p->buf		= buf;

+	return p;

 }

--- a/prismriver.h

+++ b/prismriver.h

@@ -9,7 +9,7 @@

 typedef struct

 {

 	sample l, r;

-} STuple;

+} Stuple;

 /** PCM API **/

@@ -16,7 +16,7 @@

 typedef struct

 {

 	ulong size;

-	STuple *data;

+	Stuple *data;

 } Buffer;

 Buffer*	createbuffer(ulong size);

@@ -29,15 +29,16 @@

 typedef struct Wavegen

 {

-	STuple	(*fn)(struct Wavegen*, ulong);

+	Stuple	(*fn)(struct Wavegen*, double, ulong);

 	void	(*destroy)(struct Wavegen*);

 } Wavegen;

 void destroywavegen(Wavegen *gen);

-Buffer*	buffermap(Buffer *buf, Wavegen *gen, int d, ulong s, ulong sz);

+Buffer*	buffermap(Buffer *buf, Wavegen *gen, double freq, ulong *clock, int d, ulong s, ulong sz);

-Wavegen* waveform(double (*fn)(double), double amp, double freq, double φ);

+Wavegen* waveform(double (*fn)(double), double amp, double φ);

+Wavegen* pcm(Buffer *buf);

 double sine(double);

 double saw(double);