shithub: tinyrend

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parallelize shader execution.

--- a/main.c

+++ b/main.c

@@ -9,12 +9,31 @@

 #include <geometry.h>

 typedef Point Triangle[3];

+typedef struct Sparams Sparams;

+typedef struct SUparams SUparams;

+/* shader params */

+struct Sparams

+{

+	Memimage *frag;

+	Point p;

+};

+/* shader unit params */

+struct SUparams

+{

+	Memimage *dst;

+	Rectangle r;

+	int id;

+	Channel *donec;

+	Memimage *(*shader)(Sparams*);

+};

+

+

 Memimage *fb;

 Memimage *red, *green, *blue;

-Memimage *frag;

 Channel *drawc;

+int nprocs;

 void resized(void);

 uvlong nanosec(void);

@@ -204,19 +223,60 @@

 }

 void

-shade(Memimage *dst, Rectangle r, Memimage *(*shader)(Point))

+shaderunit(void *arg)

 {

+	SUparams *params;

+	Sparams sp;

 	Point p;

 	Memimage *c;

-	for(p.y = r.min.y; p.y < r.max.y; p.y++)

-		for(p.x = r.min.x; p.x < r.max.x; p.x++)

-			if((c = shader(p)) != nil)

-				pixel(dst, p, c);

+	params = arg;

+	sp.frag = rgb(DBlack);

+

+	for(p.y = params->r.min.y; p.y < params->r.max.y; p.y++)

+		for(p.x = params->r.min.x; p.x < params->r.max.x; p.x++){

+			sp.p = p;

+			if((c = params->shader(&sp)) != nil)

+				pixel(params->dst, p, c);

+		}

+

+	freememimage(sp.frag);

+	sendp(params->donec, nil);

+	free(params);

+	threadexits(nil);

 }

+void

+shade(Memimage *dst, Memimage *(*shader)(Sparams*))

+{

+	int i;

+	Point dim;

+	SUparams *params;

+	Channel *donec;

+

+	/* shitty approach until i find a better algo */

+	dim.x = Dx(dst->r)/nprocs;

+

+	donec = chancreate(sizeof(void*), 0);

+

+	for(i = 0; i < nprocs; i++){

+		params = emalloc(sizeof *params);

+		params->dst = dst;

+		params->r = Rect(i*dim.x,0,min((i+1)*dim.x, dst->r.max.x),dst->r.max.y);

+		params->id = i;

+		params->donec = donec;

+		params->shader = shader;

+		proccreate(shaderunit, params, mainstacksize);

+		fprint(2, "spawned su %d for %R\n", params->id, params->r);

+	}

+

+	while(i--)

+		recvp(donec);

+	chanfree(donec);

+}

+

 Memimage *

-triangleshader(Point p)

+triangleshader(Sparams *sp)

 {

 	Triangle2 t;

 	Rectangle bbox;

@@ -231,10 +291,10 @@

 		min(min(t.p0.x, t.p1.x), t.p2.x), min(min(t.p0.y, t.p1.y), t.p2.y),

 		max(max(t.p0.x, t.p1.x), t.p2.x), max(max(t.p0.y, t.p1.y), t.p2.y)

 	);

-	if(!ptinrect(p, bbox))

+	if(!ptinrect(sp->p, bbox))

 		return nil;

-	bc = barycoords(t, Pt2(p.x,p.y,1));

+	bc = barycoords(t, Pt2(sp->p.x,sp->p.y,1));

 	if(bc.x < 0 || bc.y < 0 || bc.z < 0)

 		return nil;

@@ -242,18 +302,18 @@

 	cbuf[1] = 0xFF*bc.z;

 	cbuf[2] = 0xFF*bc.y;

 	cbuf[3] = 0xFF*bc.x;

-	memfillcolor(frag, *(ulong*)cbuf);

-	return frag;

+	memfillcolor(sp->frag, *(ulong*)cbuf);

+	return sp->frag;

 }

 Memimage *

-circleshader(Point p)

+circleshader(Sparams *sp)

 {

 	Point2 uv;

 	double r;

 	uchar cbuf[4];

-	uv = Pt2(p.x,p.y,1);

+	uv = Pt2(sp->p.x,sp->p.y,1);

 	uv.x /= Dx(fb->r);

 	uv.y /= Dy(fb->r);

 	r = 0.3;

@@ -266,8 +326,8 @@

 	cbuf[2] = 0xFF*uv.y;

 	cbuf[3] = 0xFF*uv.x;

-	memfillcolor(frag, *(ulong*)cbuf);

-	return frag;

+	memfillcolor(sp->frag, *(ulong*)cbuf);

+	return sp->frag;

 }

 void

@@ -312,7 +372,7 @@

 void

 usage(void)

 {

-	fprint(2, "usage: %s\n", argv0);

+	fprint(2, "usage: %s [-n nprocs]\n", argv0);

 	exits("usage");

 }

@@ -326,11 +386,17 @@

 	GEOMfmtinstall();

 	ARGBEGIN{

+	case 'n':

+		nprocs = strtoul(EARGF(usage()), nil, 10);

+		break;

 	default: usage();

 	}ARGEND;

-	if(argc > 0)

+	if(argc != 0)

 		usage();

+	if(nprocs < 1)

+		nprocs = strtoul(getenv("NPROC"), nil, 10);

+

 	if(newwindow(nil) < 0)

 		sysfatal("newwindow: %r");

 	if(initdraw(nil, nil, nil) < 0)

@@ -349,7 +415,7 @@

 	frag = rgb(DBlack);

 	t0 = nanosec();

-	shade(fb, fb->r, circleshader);

+	shade(fb, circleshader);

 	t1 = nanosec();

 	fprint(2, "shader took %lludns\n", t1-t0);

@@ -365,7 +431,7 @@

 	triangle(fb, Pt(400,230), Pt(450,180), Pt(150, 320), red);

 	t0 = nanosec();

-	shade(fb, fb->r, triangleshader);

+	shade(fb, triangleshader);

 	t1 = nanosec();

 	fprint(2, "shader took %lludns\n", t1-t0);