ref: 2f0e76f7629731c0b01c1c56c1117f3b5f65fb93
dir: /vis.c/
#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 "dat.h" #include "fns.h" 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', [Kcam0] = KF|1, [Kcam1] = KF|2, [Kcam2] = KF|3, [Kcam3] = KF|4, [Khud] = 'h', }; char stats[Se][256]; Image *screenb; Mousectl *mctl; Keyboardctl *kctl; Channel *drawc; int kdown; Shadertab *shader; Model *model; Entity *subject; Scene *scene; double θ, ω = 0; Camera cams[4], *maincam; Camcfg camcfgs[4] = { 2,0,-4,1, 0,0,0,1, 0,1,0,0, 0, 0.01, 100, ORTHOGRAPHIC, -2,0,-4,1, 0,0,0,1, 0,1,0,0, 120*DEG, 0.01, 100, PERSPECTIVE, -2,0,4,1, 0,0,0,1, 0,1,0,0, 0, 0.01, 100, ORTHOGRAPHIC, 2,0,4,1, 0,0,0,1, 0,1,0,0, 80*DEG, 0.01, 100, PERSPECTIVE }; Point3 center = {0,0,0,1}; LightSource light; /* global point light */ static int doprof; static int inception; 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; } //void //drawaxis(void) //{ // Point3 op = Pt3(0,0,0,1), // px = Pt3(1,0,0,1), // py = Pt3(0,1,0,1), // pz = Pt3(0,0,1,1); // // line3(maincam, op, px, 0, Endarrow, display->black); // string3(maincam, px, display->black, font, "x"); // line3(maincam, op, py, 0, Endarrow, display->black); // string3(maincam, py, display->black, font, "y"); // line3(maincam, op, pz, 0, Endarrow, display->black); // string3(maincam, pz, display->black, font, "z"); //} 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 = qrotate(sp->v->n, Vec3(0,1,0), θ+fmod(ω*sp->su->uni_time/1e9, 2*PI)); sp->v->p = qrotate(sp->v->p, Vec3(0,1,0), θ+fmod(ω*sp->su->uni_time/1e9, 2*PI)); 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(maincam->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(maincam, 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 = qrotate(sp->v->n, Vec3(0,1,0), θ+fmod(ω*sp->su->uni_time/1e9, 2*PI)); sp->v->p = qrotate(sp->v->p, Vec3(0,1,0), θ+fmod(ω*sp->su->uni_time/1e9, 2*PI)); 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(maincam, 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(maincam->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; 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(maincam, pos); } Color toonshader(FSparams *sp) { Vertexattr *va; double intens; va = getvattr(&sp->v, "intensity"); intens = va->n; intens = intens > 0.85? 1: intens > 0.60? 0.80: intens > 0.45? 0.60: intens > 0.30? 0.45: intens > 0.15? 0.30: 0; return Pt3(intens, 0.6*intens, 0, 1); } 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; } Point3 ivshader(VSparams *sp) { return world2clip(maincam, model2world(sp->su->entity, sp->v->p)); } Color triangleshader(FSparams *sp) { Triangle2 t; Rectangle bbox; Point3 bc; t.p0 = Pt2(240,200,1); t.p1 = Pt2(400,40,1); t.p2 = Pt2(240,40,1); bbox = Rect( 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(sp->p, bbox)) return Vec3(0,0,0); bc = barycoords(t, Pt2(sp->p.x,sp->p.y,1)); if(bc.x < 0 || bc.y < 0 || bc.z < 0) return Vec3(0,0,0); return Pt3(bc.x, bc.y, bc.z, 1); } Color circleshader(FSparams *sp) { Point2 uv; double r, d; uv = Pt2(sp->p.x,sp->p.y,1); uv.x /= Dx(sp->su->fb->r); uv.y /= Dy(sp->su->fb->r); // r = 0.3; r = 0.3*fabs(sin(sp->su->uni_time/1e9)); d = vec2len(subpt2(uv, Vec2(0.5,0.5))); if(d > r + r*0.05 || d < r - r*0.05) return Vec3(0,0,0); return Pt3(uv.x, uv.y, 0, 1); } /* some shaping functions from The Book of Shaders, Chapter 5 */ Color sfshader(FSparams *sp) { Point2 uv; double y, pct; uv = Pt2(sp->p.x,sp->p.y,1); uv.x /= Dx(sp->su->fb->r); uv.y /= Dy(sp->su->fb->r); uv.y = 1 - uv.y; /* make [0 0] the bottom-left corner */ // y = step(0.5, uv.x); // y = pow(uv.x, 5); // y = sin(uv.x); y = sin(uv.x*sp->su->uni_time/1e8)/2.0 + 0.5; // y = smoothstep(0.1, 0.9, uv.x); pct = smoothstep(y-0.02, y, uv.y) - smoothstep(y, y+0.02, uv.y); return Pt3(flerp(y, 0, pct), flerp(y, 1, pct), flerp(y, 0, pct), 1); } Color boxshader(FSparams *sp) { Point2 uv, p; Point2 r; uv = Pt2(sp->p.x,sp->p.y,1); uv.x /= Dx(sp->su->fb->r); uv.y /= Dy(sp->su->fb->r); r = Vec2(0.2,0.4); p = Pt2(fabs(uv.x - 0.5), fabs(uv.y - 0.5), 1); p = subpt2(p, r); p.x = fmax(p.x, 0); p.y = fmax(p.y, 0); if(vec2len(p) > 0) return Vec3(0,0,0); return Pt3(uv.x, uv.y, smoothstep(0,1,uv.x+uv.y), 1); } Shadertab shadertab[] = { { "triangle", ivshader, triangleshader }, { "circle", ivshader, circleshader }, { "box", ivshader, boxshader }, { "sf", ivshader, sfshader }, { "toon", identvshader, toonshader }, { "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) { maincam->fov = fclamp(maincam->fov - 1*DEG, 1*DEG, 359*DEG); reloadcamera(maincam); } void zoomout(void) { maincam->fov = fclamp(maincam->fov + 1*DEG, 1*DEG, 359*DEG); reloadcamera(maincam); } void drawstats(void) { int i; snprint(stats[Scamno], sizeof(stats[Scamno]), "CAM %lld", maincam-cams+1); snprint(stats[Sfov], sizeof(stats[Sfov]), "FOV %g°", maincam->fov/DEG); snprint(stats[Scampos], sizeof(stats[Scampos]), "%V", maincam->p); snprint(stats[Scambx], sizeof(stats[Scambx]), "bx %V", maincam->bx); snprint(stats[Scamby], sizeof(stats[Scamby]), "by %V", maincam->by); snprint(stats[Scambz], sizeof(stats[Scambz]), "bz %V", maincam->bz); snprint(stats[Sfps], sizeof(stats[Sfps]), "FPS %.0f/%.0f/%.0f/%.0f", !maincam->stats.max? 0: 1e9/maincam->stats.max, !maincam->stats.avg? 0: 1e9/maincam->stats.avg, !maincam->stats.min? 0: 1e9/maincam->stats.min, !maincam->stats.v? 0: 1e9/maincam->stats.v); snprint(stats[Sframes], sizeof(stats[Sframes]), "frame %llud", maincam->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); maincam->vp->draw(maincam->vp, screenb); draw(screen, screen->r, bg, nil, ZP); draw(screen, screen->r, screenb, nil, ZP); // drawaxis(); if(showhud) drawstats(); flushimage(display, 1); unlockdisplay(display); } void drawproc(void *) { uvlong t0, Δt; int fd; threadsetname("drawproc"); fd = -1; if(inception){ fd = open("/dev/screen", OREAD); if(fd < 0) sysfatal("open: %r"); freememimage(model->tex); if((model->tex = readmemimage(fd)) == nil) sysfatal("readmemimage: %r"); } t0 = nsec(); for(;;){ shootcamera(maincam, shader); Δt = nsec() - t0; if(Δt > HZ2MS(60)*1000000ULL){ nbsend(drawc, nil); t0 += Δt; if(inception){ freememimage(model->tex); seek(fd, 0, 0); if((model->tex = readmemimage(fd)) == nil) sysfatal("readmemimage: %r"); } light.p = qrotate(light.p, Vec3(0,1,0), θ+fmod(ω*Δt/1e9, 2*PI)); } } } void mmb(void) { enum { MOVELIGHT, TSNEAREST, TSBILINEAR, }; static char *items[] = { [MOVELIGHT] "move light", [TSNEAREST] "use nearest sampler", [TSBILINEAR] "use bilinear sampler", nil, }; static Menu menu = { .item = items }; char buf[256], *f[3]; int nf; switch(menuhit(2, mctl, &menu, _screen)){ case MOVELIGHT: snprint(buf, sizeof buf, "%g %g %g", light.p.x, light.p.y, light.p.z); if(enter("light pos", buf, sizeof buf, mctl, kctl, nil) <= 0) return; nf = tokenize(buf, f, 3); if(nf != 3) return; light.p.x = strtod(f[0], nil); light.p.y = strtod(f[1], nil); light.p.z = strtod(f[2], nil); break; case TSNEAREST: tsampler = neartexsampler; break; case TSBILINEAR: tsampler = bilitexsampler; break; } nbsend(drawc, nil); } static char * genrmbmenuitem(int idx) { if(idx < nelem(shadertab)) return shadertab[idx].name; return nil; } void rmb(void) { static Menu menu = { .gen = genrmbmenuitem }; int idx; idx = menuhit(3, mctl, &menu, _screen); if(idx < 0) return; shader = &shadertab[idx]; for(idx = 0; idx < nelem(cams); idx++) memset(&cams[idx].stats, 0, sizeof(cams[idx].stats)); nbsend(drawc, nil); } void mouse(void) { if((mctl->buttons & 2) != 0) mmb(); if((mctl->buttons & 4) != 0) rmb(); if((mctl->buttons & 8) != 0) zoomin(); if((mctl->buttons & 16) != 0) zoomout(); } 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(maincam, subpt3(maincam->p, mulpt3(maincam->bz, 0.1)), maincam->bz, maincam->by); if(kdown & 1<<K↓) placecamera(maincam, addpt3(maincam->p, mulpt3(maincam->bz, 0.1)), maincam->bz, maincam->by); if(kdown & 1<<K←) placecamera(maincam, subpt3(maincam->p, mulpt3(maincam->bx, 0.1)), maincam->bz, maincam->by); if(kdown & 1<<K→) placecamera(maincam, addpt3(maincam->p, mulpt3(maincam->bx, 0.1)), maincam->bz, maincam->by); if(kdown & 1<<Krise) placecamera(maincam, addpt3(maincam->p, mulpt3(maincam->by, 0.1)), maincam->bz, maincam->by); if(kdown & 1<<Kfall) placecamera(maincam, subpt3(maincam->p, mulpt3(maincam->by, 0.1)), maincam->bz, maincam->by); if(kdown & 1<<KR↑) aimcamera(maincam, qrotate(maincam->bz, maincam->bx, 1*DEG)); if(kdown & 1<<KR↓) aimcamera(maincam, qrotate(maincam->bz, maincam->bx, -1*DEG)); if(kdown & 1<<KR←) aimcamera(maincam, qrotate(maincam->bz, maincam->by, 1*DEG)); if(kdown & 1<<KR→) aimcamera(maincam, qrotate(maincam->bz, maincam->by, -1*DEG)); if(kdown & 1<<KR↺) placecamera(maincam, maincam->p, maincam->bz, qrotate(maincam->by, maincam->bz, 1*DEG)); if(kdown & 1<<KR↻) placecamera(maincam, maincam->p, maincam->bz, qrotate(maincam->by, maincam->bz, -1*DEG)); if(kdown & 1<<Kzoomin) zoomin(); if(kdown & 1<<Kzoomout) zoomout(); if(kdown & 1<<Kcam0) maincam = &cams[0]; if(kdown & 1<<Kcam1) maincam = &cams[1]; if(kdown & 1<<Kcam2) maincam = &cams[2]; if(kdown & 1<<Kcam3) maincam = &cams[3]; if((okdown & 1<<Khud) == 0 && (kdown & 1<<Khud) != 0) showhud ^= 1; 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"); // fprint(fd, "pri 15\n"); // fprint(fd, "wired 0\n"); // setfcr(getfcr() & ~FPINVAL); close(fd); } void usage(void) { fprint(2, "usage: %s [-t texture] [-n normals] [-s shader] [-ω yrot] model...\n", argv0); exits("usage"); } void threadmain(int argc, char *argv[]) { Viewport *v; Renderer *rctl; Channel *keyc; OBJ *obj; char *texpath, *norpath, *sname, *mdlpath; int i, fd; GEOMfmtinstall(); texpath = nil; norpath = nil; sname = "gouraud"; ARGBEGIN{ case 't': texpath = EARGF(usage()); break; case 'n': norpath = EARGF(usage()); break; case 's': sname = EARGF(usage()); break; case L'ω': ω = strtod(EARGF(usage()), nil)*DEG; break; case L'ι': inception++; break; case 'p': doprof++; break; default: usage(); }ARGEND; if(argc < 1) usage(); confproc(); if((shader = getshader(sname)) == nil) sysfatal("couldn't find %s shader", sname); scene = newscene(nil); while(argc--){ mdlpath = argv[argc]; model = newmodel(); subject = newentity(model); subject->p.x = argc*4; scene->addent(scene, subject); if((obj = objparse(mdlpath)) == nil) sysfatal("objparse: %r"); loadobjmodel(model, obj); objfree(obj); if(argc == 0 && texpath != nil){ fd = open(texpath, OREAD); if(fd < 0) sysfatal("open: %r"); if((model->tex = readmemimage(fd)) == nil) sysfatal("readmemimage: %r"); close(fd); } if(argc == 0 && norpath != nil){ fd = open(norpath, OREAD); if(fd < 0) sysfatal("open: %r"); if((model->nor = readmemimage(fd)) == nil) sysfatal("readmemimage: %r"); close(fd); } } if(memimageinit() != 0) sysfatal("memimageinit: %r"); if((rctl = initgraphics()) == nil) sysfatal("initgraphics: %r"); if(initdraw(nil, nil, "3d") < 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); for(i = 0; i < nelem(cams); i++){ v = mkviewport(screenb->r); placecamera(&cams[i], camcfgs[i].p, camcfgs[i].lookat, camcfgs[i].up); configcamera(&cams[i], v, camcfgs[i].fov, camcfgs[i].clipn, camcfgs[i].clipf, camcfgs[i].ptype); cams[i].s = scene; cams[i].rctl = rctl; } maincam = &cams[3]; 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; } } }