#include <u.h>
#include <libc.h>
#include <thread.h>
#include <draw.h>
#include <memdraw.h>
#include <mouse.h>
#include <keyboard.h>
#include <geometry.h>
#include "libobj/obj.h"
#include "libgraphics/graphics.h"
#include "fns.h"

enum {
	K↑,
	K↓,
	K←,
	K→,
	Krise,
	Kfall,
	KR↑,
	KR↓,
	KR←,
	KR→,
	KR↺,
	KR↻,
	Kzoomin,
	Kzoomout,
	Khud,
	Kfrustum,
	Ke
};

enum {
	Sfov,
	Scampos,
	Scambx, Scamby, Scambz,
	Sfps,
	Sframes,
	Se
};

typedef struct Camcfg Camcfg;
struct Camcfg
{
	Point3 p, lookat, up;
	double fov, clipn, clipf;
	int ptype;
};

Rune keys[Ke] = {
 [K↑]		= Kup,
 [K↓]		= Kdown,
 [K←]		= Kleft,
 [K→]		= Kright,
 [Krise]	= Kpgup,
 [Kfall]	= Kpgdown,
 [KR↑]		= 'w',
 [KR↓]		= 's',
 [KR←]		= 'a',
 [KR→]		= 'd',
 [KR↺]		= 'q',
 [KR↻]		= 'e',
 [Kzoomin]	= 'z',
 [Kzoomout]	= 'x',
 [Khud]		= 'h',
 [Kfrustum]	= ' ',
};
char stats[Se][256];
Image *screenb;
Mousectl *mctl;
Keyboardctl *kctl;
Channel *drawc;
int kdown;
Scene *scene;
Entity *subject;
Model *model;
Shadertab *shader;
QLock scenelk;
Mouse om;
Quaternion orient = {1,0,0,0};

Camera cam;
Camcfg camcfg = {
	0,2,4,1,
	0,0,0,1,
	0,1,0,0,
	40*DEG, 0.01, 10, PERSPECTIVE
};
Point3 center = {0,0,0,1};
LightSource light;		/* global point light */

static int doprof;
static int showhud;
Color (*tsampler)(Memimage*,Point2);

static int
min(int a, int b)
{
	return a < b? a: b;
}

static int
max(int a, int b)
{
	return a > b? a: b;
}

static Point3
Vecquat(Quaternion q)
{
	return Vec3(q.i, q.j, q.k);
}

static Point3
Ptquat(Quaternion q, double w)
{
	return Pt3(q.i, q.j, q.k, w);
}

void
materializefrustum(void)
{
	Primitive l;
	Framebuf *fb;
	Point3 p[4];
	int i;

	fb = cam.vp->getfb(cam.vp);
	p[0] = Pt3(0,0,1,1);
	p[1] = Pt3(Dx(fb->r),0,1,1);
	p[2] = Pt3(Dx(fb->r),Dy(fb->r),1,1);
	p[3] = Pt3(0,Dy(fb->r),1,1);
	memset(&l, 0, sizeof l);

	for(i = 0; i < nelem(p); i++){
		/* front frame */
		l.type = PLine;
		l.v[0].p = viewport2world(&cam, p[i]);
		l.v[1].p = viewport2world(&cam, p[(i+1)%nelem(p)]);
		qlock(&scenelk);
		model->prims = erealloc(model->prims, ++model->nprims*sizeof(*model->prims));
		model->prims[model->nprims-1] = l;
		qunlock(&scenelk);

		/* middle frame */
		l.v[0].p = viewport2world(&cam, subpt3(p[i], Vec3(0,0,0.5)));
		l.v[1].p = viewport2world(&cam, subpt3(p[(i+1)%nelem(p)], Vec3(0,0,0.5)));
		qlock(&scenelk);
		model->prims = erealloc(model->prims, ++model->nprims*sizeof(*model->prims));
		model->prims[model->nprims-1] = l;
		qunlock(&scenelk);

		/* back frame */
		l.v[0].p = viewport2world(&cam, subpt3(p[i], Vec3(0,0,1)));
		l.v[1].p = viewport2world(&cam, subpt3(p[(i+1)%nelem(p)], Vec3(0,0,1)));
		qlock(&scenelk);
		model->prims = erealloc(model->prims, ++model->nprims*sizeof(*model->prims));
		model->prims[model->nprims-1] = l;
		qunlock(&scenelk);

		/* struts */
		l.v[1].p = viewport2world(&cam, p[i]);
		qlock(&scenelk);
		model->prims = erealloc(model->prims, ++model->nprims*sizeof(*model->prims));
		model->prims[model->nprims-1] = l;
		qunlock(&scenelk);
	}
}

void
addcube(void)
{
	static Point3 axis[3] = {{0,1,0,0}, {1,0,0,0}, {0,0,1,0}};
	Primitive t[2];
	Point3 p, v1, v2;
	int i, j, k;

	memset(t, 0, sizeof t);
	t[0].type = t[1].type = PTriangle;

	p = Vec3(-0.5,-0.5,0.5);
	v1 = Vec3(1,0,0);
	v2 = Vec3(0,1,0);
	t[0].v[0].p = addpt3(center, p);
	t[0].v[1].p = addpt3(center, addpt3(p, v1));
	t[0].v[2].p = addpt3(center, addpt3(p, addpt3(v1, v2)));
	t[1].v[0].p = t[0].v[0].p;
	t[1].v[1].p = t[0].v[2].p;
	t[1].v[2].p = addpt3(center, addpt3(p, v2));

	for(i = 0; i < 6; i++){
		for(j = 0; j < 2; j++)
			for(k = 0; k < 3; k++){
				if(i > 0)
					t[j].v[k].p = qrotate(t[j].v[k].p, axis[i%3], PI/2);
				t[j].v[k].n = normvec3(subpt3(t[j].v[k].p, center));
			}

		qlock(&scenelk);
		model->prims = erealloc(model->prims, (model->nprims += 2)*sizeof(*model->prims));
		model->prims[model->nprims-2] = t[0];
		model->prims[model->nprims-1] = t[1];
		qunlock(&scenelk);
	}
}

Point3
gouraudvshader(VSparams *sp)
{
	static double Ka = 0.1;	/* ambient factor */
	static double Ks = 0.5;	/* specular factor */
	double Kd;		/* diffuse factor */
	double spec;
	Point3 pos, lightdir, lookdir;
	Material m;
	Color ambient, diffuse, specular;

	sp->v->n = Vecquat(mulq(mulq(orient, Quatvec(0, sp->v->n)), invq(orient)));
	sp->v->p = Ptquat(mulq(mulq(orient, Quatvec(0, sp->v->p)), invq(orient)), sp->v->p.w);
	pos = model2world(sp->su->entity, sp->v->p);
	if(sp->v->mtl != nil){
		m = *sp->v->mtl;

		ambient = mulpt3(light.c, Ka);
		ambient.r *= m.ambient.r;
		ambient.g *= m.ambient.g;
		ambient.b *= m.ambient.b;
		ambient.a *= m.ambient.a;

		lightdir = normvec3(subpt3(light.p, pos));
		Kd = fmax(0, dotvec3(sp->v->n, lightdir));
		diffuse = mulpt3(light.c, Kd);
		diffuse.r *= m.diffuse.r;
		diffuse.g *= m.diffuse.g;
		diffuse.b *= m.diffuse.b;
		diffuse.a *= m.diffuse.a;

		lookdir = normvec3(subpt3(cam.p, pos));
		lightdir = qrotate(lightdir, sp->v->n, PI);
		spec = pow(fmax(0, dotvec3(lookdir, lightdir)), m.shininess);
		specular = mulpt3(light.c, spec*Ks);
		specular.r *= m.specular.r;
		specular.g *= m.specular.g;
		specular.b *= m.specular.b;
		specular.a *= m.specular.a;

		sp->v->c = addpt3(ambient, addpt3(diffuse, specular));
	}
	return world2clip(&cam, pos);
}
 
Color
gouraudshader(FSparams *sp)
{
	Color tc, c;

	if(sp->v.mtl != nil && sp->v.mtl->diffusemap != nil && sp->v.uv.w != 0){
		tc = texture(sp->v.mtl->diffusemap, sp->v.uv, tsampler);
	}else if(sp->su->entity->mdl->tex != nil && sp->v.uv.w != 0)
		tc = texture(sp->su->entity->mdl->tex, sp->v.uv, tsampler);
	else
		tc = Pt3(1,1,1,1);

	c.a = 1;
	c.b = fclamp(sp->v.c.b*tc.b, 0, 1);
	c.g = fclamp(sp->v.c.g*tc.g, 0, 1);
	c.r = fclamp(sp->v.c.r*tc.r, 0, 1);

	return c;
}

Point3
phongvshader(VSparams *sp)
{
	Point3 pos;
	Color a, d, s;
	double ss;

	sp->v->n = Vecquat(mulq(mulq(orient, Quatvec(0, sp->v->n)), invq(orient)));
	sp->v->p = Ptquat(mulq(mulq(orient, Quatvec(0, sp->v->p)), invq(orient)), sp->v->p.w);
	pos = model2world(sp->su->entity, sp->v->p);
	addvattr(sp->v, "pos", VAPoint, &pos);
	if(sp->v->mtl != nil){
		a = sp->v->mtl->ambient;
		d = sp->v->mtl->diffuse;
		s = sp->v->mtl->specular;
		ss = sp->v->mtl->shininess;
		addvattr(sp->v, "ambient", VAPoint, &a);
		addvattr(sp->v, "diffuse", VAPoint, &d);
		addvattr(sp->v, "specular", VAPoint, &s);
		addvattr(sp->v, "shininess", VANumber, &ss);
	}
	return world2clip(&cam, pos);
}

Color
phongshader(FSparams *sp)
{
	static double Ka = 0.1;	/* ambient factor */
	static double Ks = 0.5;	/* specular factor */
	double Kd;		/* diffuse factor */
	double spec;
	Color ambient, diffuse, specular, tc, c;
	Point3 pos, lookdir, lightdir;
	Material m;
	Vertexattr *va;

	va = getvattr(&sp->v, "pos");
	pos = va->p;
	
	va = getvattr(&sp->v, "ambient");
	m.ambient = va != nil? va->p: Pt3(1,1,1,1);
	va = getvattr(&sp->v, "diffuse");
	m.diffuse = va != nil? va->p: Pt3(1,1,1,1);
	va = getvattr(&sp->v, "specular");
	m.specular = va != nil? va->p: Pt3(1,1,1,1);
	va = getvattr(&sp->v, "shininess");
	m.shininess = va != nil? va->n: 1;

	ambient = mulpt3(light.c, Ka);
	ambient.r *= m.ambient.r;
	ambient.g *= m.ambient.g;
	ambient.b *= m.ambient.b;
	ambient.a *= m.ambient.a;

	lightdir = normvec3(subpt3(light.p, pos));
	Kd = fmax(0, dotvec3(sp->v.n, lightdir));
	diffuse = mulpt3(light.c, Kd);
	diffuse.r *= m.diffuse.r;
	diffuse.g *= m.diffuse.g;
	diffuse.b *= m.diffuse.b;
	diffuse.a *= m.diffuse.a;

	lookdir = normvec3(subpt3(cam.p, pos));
	lightdir = qrotate(lightdir, sp->v.n, PI);
	spec = pow(fmax(0, dotvec3(lookdir, lightdir)), m.shininess);
	specular = mulpt3(light.c, spec*Ks);
	specular.r *= m.specular.r;
	specular.g *= m.specular.g;
	specular.b *= m.specular.b;
	specular.a *= m.specular.a;

	if(sp->v.mtl != nil && sp->v.mtl->diffusemap != nil && sp->v.uv.w != 0)
		tc = texture(sp->v.mtl->diffusemap, sp->v.uv, tsampler);
	else if(sp->su->entity->mdl->tex != nil && sp->v.uv.w != 0)
		tc = texture(sp->su->entity->mdl->tex, sp->v.uv, tsampler);
	else
		tc = Pt3(1,1,1,1);

	c = addpt3(ambient, addpt3(diffuse, specular));
	c.a = 1;
	c.b = fclamp(c.b*tc.b, 0, 1);
	c.g = fclamp(c.g*tc.g, 0, 1);
	c.r = fclamp(c.r*tc.r, 0, 1);

	return c;
}

Point3
identvshader(VSparams *sp)
{
	Point3 pos, lightdir;
	double intens;

	sp->v->n = Vecquat(mulq(mulq(orient, Quatvec(0, sp->v->n)), invq(orient)));
	sp->v->p = Ptquat(mulq(mulq(orient, Quatvec(0, sp->v->p)), invq(orient)), sp->v->p.w);
	pos = model2world(sp->su->entity, sp->v->p);
	lightdir = normvec3(subpt3(light.p, pos));
	intens = fmax(0, dotvec3(sp->v->n, lightdir));
	addvattr(sp->v, "intensity", VANumber, &intens);
	if(sp->v->mtl != nil)
		sp->v->c = sp->v->mtl->diffuse;
	return world2clip(&cam, pos);
}

Color
identshader(FSparams *sp)
{
	Color tc, c;

	if(sp->v.mtl != nil && sp->v.mtl->diffusemap != nil && sp->v.uv.w != 0)
		tc = texture(sp->v.mtl->diffusemap, sp->v.uv, tsampler);
	else if(sp->su->entity->mdl->tex != nil && sp->v.uv.w != 0)
		tc = texture(sp->su->entity->mdl->tex, sp->v.uv, tsampler);
	else
		tc = Pt3(1,1,1,1);

	c.a = 1;
	c.b = fclamp(sp->v.c.b*tc.b, 0, 1);
	c.g = fclamp(sp->v.c.g*tc.g, 0, 1);
	c.r = fclamp(sp->v.c.r*tc.r, 0, 1);

	return c;
}

Shadertab shadertab[] = {
	{ "ident", identvshader, identshader },
	{ "gouraud", gouraudvshader, gouraudshader },
	{ "phong", phongvshader, phongshader },
};
Shadertab *
getshader(char *name)
{
	int i;

	for(i = 0; i < nelem(shadertab); i++)
		if(strcmp(shadertab[i].name, name) == 0)
			return &shadertab[i];
	return nil;
}

void
zoomin(void)
{
	cam.fov = fclamp(cam.fov - 1*DEG, 1*DEG, 180*DEG);
	reloadcamera(&cam);
}

void
zoomout(void)
{
	cam.fov = fclamp(cam.fov + 1*DEG, 1*DEG, 180*DEG);
	reloadcamera(&cam);
}

void
drawstats(void)
{
	int i;

	snprint(stats[Sfov], sizeof(stats[Sfov]), "FOV %g°", cam.fov/DEG);
	snprint(stats[Scampos], sizeof(stats[Scampos]), "%V", cam.p);
	snprint(stats[Scambx], sizeof(stats[Scambx]), "bx %V", cam.bx);
	snprint(stats[Scamby], sizeof(stats[Scamby]), "by %V", cam.by);
	snprint(stats[Scambz], sizeof(stats[Scambz]), "bz %V", cam.bz);
	snprint(stats[Sfps], sizeof(stats[Sfps]), "FPS %.0f/%.0f/%.0f/%.0f", !cam.stats.max? 0: 1e9/cam.stats.max, !cam.stats.avg? 0: 1e9/cam.stats.avg, !cam.stats.min? 0: 1e9/cam.stats.min, !cam.stats.v? 0: 1e9/cam.stats.v);
	snprint(stats[Sframes], sizeof(stats[Sframes]), "frame %llud", cam.stats.nframes);
	for(i = 0; i < Se; i++)
		stringbg(screen, addpt(screen->r.min, Pt(10,10 + i*font->height)), display->black, ZP, font, stats[i], display->white, ZP);
}

void
redraw(void)
{
	static Image *bg;

	if(bg == nil)
		bg = eallocimage(display, UR, RGB24, 1, 0x888888FF);

	lockdisplay(display);
	cam.vp->draw(cam.vp, screenb);
	draw(screen, screen->r, bg, nil, ZP);
	draw(screen, screen->r, screenb, nil, ZP);
	if(showhud)
		drawstats();
	flushimage(display, 1);
	unlockdisplay(display);
}

void
drawproc(void *)
{
	uvlong t0, Δt;

	threadsetname("drawproc");

	t0 = nsec();
	for(;;){
		qlock(&scenelk);
		shootcamera(&cam, shader);
		qunlock(&scenelk);
		if(doprof)
		fprint(2, "R %llud %llud\nE %llud %llud\nT %llud %llud\nr %llud %llud\n\n",
			cam.times.R[cam.times.cur-1].t0, cam.times.R[cam.times.cur-1].t1,
			cam.times.E[cam.times.cur-1].t0, cam.times.E[cam.times.cur-1].t1,
			cam.times.Tn[cam.times.cur-1].t0, cam.times.Tn[cam.times.cur-1].t1,
			cam.times.Rn[cam.times.cur-1].t0, cam.times.Rn[cam.times.cur-1].t1);
		Δt = nsec() - t0;
		if(Δt > HZ2MS(60)*1000000ULL){
			nbsend(drawc, nil);
			t0 += Δt;
		}
	}
}

void
lmb(void)
{
	if((om.buttons^mctl->buttons) == 0)
		qball(screen->r, om.xy, mctl->xy, &orient, nil);
}

void
mmb(void)
{
	enum {
		TSNEAREST,
		TSBILINEAR,
		SP,
		QUIT,
	};
	static char *items[] = {
	 [TSNEAREST]	"use nearest sampler",
	 [TSBILINEAR]	"use bilinear sampler",
	 [SP]	"",
	 [QUIT]	"quit",
		nil,
	};
	static Menu menu = { .item = items };

	switch(menuhit(2, mctl, &menu, _screen)){
	case TSNEAREST:
		tsampler = neartexsampler;
		break;
	case TSBILINEAR:
		tsampler = bilitexsampler;
		break;
	case QUIT:
		threadexitsall(nil);
	}
	nbsend(drawc, nil);
}

static char *
genrmbmenuitem(int idx)
{
	if(idx < nelem(shadertab))
		return shadertab[idx].name;
	else if(idx == nelem(shadertab))
		return "";
	else if(idx == nelem(shadertab)+1)
		return "add cube";
	return nil;
}

void
rmb(void)
{
	static Menu menu = { .gen = genrmbmenuitem };
	int idx;

	idx = menuhit(3, mctl, &menu, _screen);
	if(idx < 0)
		return;
	if(idx < nelem(shadertab)){
		shader = &shadertab[idx];
		memset(&cam.stats, 0, sizeof(cam.stats));
	}else if(idx == nelem(shadertab)+1)
		addcube();
	nbsend(drawc, nil);
}

void
mouse(void)
{
	if((mctl->buttons & 1) != 0)
		lmb();
	if((mctl->buttons & 2) != 0)
		mmb();
	if((mctl->buttons & 4) != 0)
		rmb();
	if((mctl->buttons & 8) != 0)
		zoomin();
	if((mctl->buttons & 16) != 0)
		zoomout();
	om = mctl->Mouse;
}

void
kbdproc(void *)
{
	Rune r, *a;
	char buf[128], *s;
	int fd, n;

	threadsetname("kbdproc");

	if((fd = open("/dev/kbd", OREAD)) < 0)
		sysfatal("kbdproc: %r");
	memset(buf, 0, sizeof buf);

	for(;;){
		if(buf[0] != 0){
			n = strlen(buf)+1;
			memmove(buf, buf+n, sizeof(buf)-n);
		}
		if(buf[0] == 0){
			if((n = read(fd, buf, sizeof(buf)-1)) <= 0)
				break;
			buf[n-1] = 0;
			buf[n] = 0;
		}
		if(buf[0] == 'c'){
			chartorune(&r, buf+1);
			if(r == Kdel){
				close(fd);
				threadexitsall(nil);
			}else
				nbsend(kctl->c, &r);
		}
		if(buf[0] != 'k' && buf[0] != 'K')
			continue;
		s = buf+1;
		kdown = 0;
		while(*s){
			s += chartorune(&r, s);
			for(a = keys; a < keys+Ke; a++)
				if(r == *a){
					kdown |= 1 << a-keys;
					break;
				}
		}
	}
}

void
keyproc(void *c)
{
	threadsetname("keyproc");

	for(;;){
		nbsend(c, nil);
		sleep(HZ2MS(100));	/* key poll rate */
	}
}

void
handlekeys(void)
{
	static int okdown;

	if(kdown & 1<<K↑)
		placecamera(&cam, subpt3(cam.p, mulpt3(cam.bz, 0.1)), cam.bz, cam.by);
	if(kdown & 1<<K↓)
		placecamera(&cam, addpt3(cam.p, mulpt3(cam.bz, 0.1)), cam.bz, cam.by);
	if(kdown & 1<<K←)
		placecamera(&cam, subpt3(cam.p, mulpt3(cam.bx, 0.1)), cam.bz, cam.by);
	if(kdown & 1<<K→)
		placecamera(&cam, addpt3(cam.p, mulpt3(cam.bx, 0.1)), cam.bz, cam.by);
	if(kdown & 1<<Krise)
		placecamera(&cam, addpt3(cam.p, mulpt3(cam.by, 0.1)), cam.bz, cam.by);
	if(kdown & 1<<Kfall)
		placecamera(&cam, subpt3(cam.p, mulpt3(cam.by, 0.1)), cam.bz, cam.by);
	if(kdown & 1<<KR↑)
		aimcamera(&cam, qrotate(cam.bz, cam.bx, 1*DEG));
	if(kdown & 1<<KR↓)
		aimcamera(&cam, qrotate(cam.bz, cam.bx, -1*DEG));
	if(kdown & 1<<KR←)
		aimcamera(&cam, qrotate(cam.bz, cam.by, 1*DEG));
	if(kdown & 1<<KR→)
		aimcamera(&cam, qrotate(cam.bz, cam.by, -1*DEG));
	if(kdown & 1<<KR↺)
		placecamera(&cam, cam.p, cam.bz, qrotate(cam.by, cam.bz, 1*DEG));
	if(kdown & 1<<KR↻)
		placecamera(&cam, cam.p, cam.bz, qrotate(cam.by, cam.bz, -1*DEG));
	if(kdown & 1<<Kzoomin)
		zoomin();
	if(kdown & 1<<Kzoomout)
		zoomout();

	if((okdown & 1<<Khud) == 0 && (kdown & 1<<Khud) != 0)
		showhud ^= 1;

	if((okdown & 1<<Kfrustum) == 0 && (kdown & 1<<Kfrustum) != 0)
		materializefrustum();

	okdown = kdown;
}

void
resize(void)
{
	lockdisplay(display);
	if(getwindow(display, Refnone) < 0)
		fprint(2, "can't reattach to window\n");
	unlockdisplay(display);
	nbsend(drawc, nil);
}

static void
confproc(void)
{
	char buf[64];
	int fd;

	snprint(buf, sizeof buf, "/proc/%d/ctl", getpid());
	fd = open(buf, OWRITE);
	if(fd < 0)
		sysfatal("open: %r");

	if(doprof)
		fprint(fd, "profile\n");

	close(fd);
}

void
usage(void)
{
	fprint(2, "usage: %s\n", argv0);
	exits("usage");
}

void
threadmain(int argc, char *argv[])
{
	Viewport *v;
	Renderer *rctl;
	Channel *keyc;

	GEOMfmtinstall();
	ARGBEGIN{
	case 'p': doprof++; break;
	default: usage();
	}ARGEND;
	if(argc != 0)
		usage();

	confproc();

	if((shader = getshader("gouraud")) == nil)
		sysfatal("couldn't find main shader");

	scene = newscene(nil);
	model = newmodel();
	subject = newentity(model);
	scene->addent(scene, subject);

	if(memimageinit() != 0)
		sysfatal("memimageinit: %r");
	if((rctl = initgraphics()) == nil)
		sysfatal("initgraphics: %r");
	if(initdraw(nil, nil, "med") < 0)
		sysfatal("initdraw: %r");
	if((mctl = initmouse(nil, screen)) == nil)
		sysfatal("initmouse: %r");

	screenb = eallocimage(display, rectsubpt(screen->r, screen->r.min), RGBA32, 0, DNofill);
	v = mkviewport(screenb->r);
	placecamera(&cam, camcfg.p, camcfg.lookat, camcfg.up);
	configcamera(&cam, v, camcfg.fov, camcfg.clipn, camcfg.clipf, camcfg.ptype);
	cam.s = scene;
	cam.rctl = rctl;
	light.p = Pt3(0,100,100,1);
	light.c = Pt3(1,1,1,1);
	light.type = LIGHT_POINT;
	tsampler = neartexsampler;

	kctl = emalloc(sizeof *kctl);
	kctl->c = chancreate(sizeof(Rune), 16);
	keyc = chancreate(sizeof(void*), 1);
	drawc = chancreate(sizeof(void*), 1);
	display->locking = 1;
	unlockdisplay(display);

	proccreate(kbdproc, nil, mainstacksize);
	proccreate(keyproc, keyc, mainstacksize);
	proccreate(drawproc, nil, mainstacksize);

	for(;;){
		enum {MOUSE, RESIZE, KEY, DRAW};
		Alt a[] = {
			{mctl->c, &mctl->Mouse, CHANRCV},
			{mctl->resizec, nil, CHANRCV},
			{keyc, nil, CHANRCV},
			{drawc, nil, CHANRCV},
			{nil, nil, CHANEND}
		};
		switch(alt(a)){
		case MOUSE: mouse(); break;
		case RESIZE: resize(); break;
		case KEY: handlekeys(); break;
		case DRAW: redraw(); break;
		}
	}
}