shithub: libgraphics

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clip: make Polygons hold a static amount of vertices

this speeds up clipping considerably.

arrived at 8 empirically, but the geometry tells
us that the maximum number of vertices you can end
up with in 2-d space is 7 (when a vertex of the
triangle clips a corner of the frustum, and the
other two clip independent planes); if you then
clip the result with another plane in 3-space
(near or far) you can get at most 8 vertices.

maybe i should make it 9, for cases where the near
plane is very close to the far one, or for scenes
with big triangles that could clip both planes.

i had to increase the tiler proc stack size
because the polygons blew up big time.

--- a/clip.c

+++ b/clip.c

@@ -31,9 +31,7 @@

 static int

 addvert(Polygon *p, BVertex v)

 {

-	if(++p->n > p->cap)

-		p->v = _erealloc(p->v, (p->cap = p->n)*sizeof(*p->v));

-	p->v[p->n-1] = v;

+	p->v[p->n++] = v;

 	return p->n;

 }

@@ -43,7 +41,7 @@

 	int i;

 	for(i = 0; i < p->n; i++)

-		fprint(fd, "%d/%lud p %V\n", i, p->n, p->v[i].p);

+		fprint(fd, "%d n %lud p %V\n", i, p->n, p->v[i].p);

 }

 /*

@@ -129,8 +127,6 @@

 			break;

 		}

 	}

-	free(Vout->v);

-	free(Vin->v);

 	return np;

 }

--- a/internal.h

+++ b/internal.h

@@ -26,9 +26,8 @@

 struct Polygon

 {

-	BVertex *v;

+	BVertex v[8];

 	ulong n;

-	ulong cap;

 };

 /* common task params */

--- a/render.c

+++ b/render.c

@@ -7,6 +7,9 @@

 #include "graphics.h"

 #include "internal.h"

+#define TILESTKSZ	(32*1024)

+#define PROCSTKSZ	(8*1024)

+

 static Vertexattr *

 sparams_getuniform(Shaderparams *sp, char *id)

 {

@@ -763,13 +766,13 @@

 		tp->taskc = ttaskchans[i];

 		tp->taskchans = rtaskchans;

 		tp->nproc = nproc;

-		proccreate(tiler, tp, mainstacksize);

+		proccreate(tiler, tp, TILESTKSZ);

 	}

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

 		rp = _emalloc(sizeof *rp);

 		rp->id = i;

 		rp->taskc = rtaskchans[i] = chancreate(sizeof(Rastertask), 2048);

-		proccreate(rasterizer, rp, mainstacksize);

+		proccreate(rasterizer, rp, PROCSTKSZ);

 	}

 	while(recv(ep->taskc, &task) > 0){

@@ -843,7 +846,7 @@

 	ep = _emalloc(sizeof *ep);

 	ep->rctl = rctl;

 	ep->taskc = chancreate(sizeof(Entitytask), 256);

-	proccreate(entityproc, ep, mainstacksize);

+	proccreate(entityproc, ep, PROCSTKSZ);

 	while((job = recvp(rctl->jobq)) != nil){

 		if(job->rctl->doprof)

@@ -891,6 +894,6 @@

 	memset(r, 0, sizeof *r);

 	r->jobq = chancreate(sizeof(Renderjob*), 8);

 	r->nprocs = nproc;

-	proccreate(renderer, r, mainstacksize);

+	proccreate(renderer, r, PROCSTKSZ);

 	return r;

 }

-- 

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