shithub: musw

--- a/dat.h

+++ b/dat.h

@@ -30,7 +30,6 @@

 typedef struct Ship Ship;

 typedef struct Star Star;

 typedef struct Universe Universe;

-typedef struct GameState GameState;

 typedef struct Derivative Derivative;

 typedef struct Conn Conn;

 typedef struct Player Player;

@@ -106,12 +105,6 @@

 	void (*reset)(Universe*);

};

-struct GameState

-{

-	double t, timeacc;

-	Point2 p, v;

-};

 struct Derivative

 	Point2 dx; /* v */

@@ -155,9 +148,6 @@

 	Player players[2];	/* the needle and the wedge */

 	Universe *u;

 	Party *prev, *next;

-	/* testing */

-	GameState state;

};

--- a/fns.h

+++ b/fns.h

@@ -10,8 +10,7 @@

/*

  * physics

*/

-void integrate(GameState*, double, double);

-void integrateu(Universe*, double, double);

+void integrate(Universe*, double, double);

/*

  * nanosec

--- a/musw.c

+++ b/musw.c

@@ -30,14 +30,7 @@

};

 ulong kdown;

-typedef struct Ball Ball;

-struct Ball

-{

-	Point2 p, v;

-};

 RFrame screenrf;

-Ball bouncer;

 Universe *universe;

 VModel *needlemdl;

 Image *skymap;

@@ -123,11 +116,11 @@

 	Matrix T = {

 		1, 0, ship->p.x,

 		0, 1, ship->p.y,

-		0, 0, 1

+		0, 0, 1,

 	}, R = {

 		cos(ship->θ), -sin(ship->θ), 0,

 		sin(ship->θ),  cos(ship->θ), 0,

-		0, 0, 1

+		0, 0, 1,

};

 	mulm(T, R);

@@ -212,7 +205,7 @@

 	io = ioproc();

 	while((n = ioread(io, fd, buf, sizeof buf)) > 0){

-		unpack(buf, n, "PPdPdP", &bouncer.p,

+		unpack(buf, n, "PdPdP",

 			&universe->ships[0].p, &universe->ships[0].θ,

 			&universe->ships[1].p, &universe->ships[1].θ,

 			&universe->star.p);

@@ -279,7 +272,6 @@

 	lockdisplay(display);

 	draw(screen, screen->r, skymap, nil, ZP);

-	fillellipse(screen, toscreen(bouncer.p), 2, 2, display->white, ZP);

 	drawship(&universe->ships[0], screen);

 	drawship(&universe->ships[1], screen);

--- a/muswd.c

+++ b/muswd.c

@@ -91,8 +91,7 @@

 	Party *p;

 	for(p = theparty.next; p != &theparty; p = p->next){

-		n = pack(buf, sizeof buf, "PPdPdP",

-			p->state.p,

+		n = pack(buf, sizeof buf, "PdPdP",

 			p->u->ships[0].p, p->u->ships[0].θ,

 			p->u->ships[1].p, p->u->ships[1].θ,

 			p->u->star.p);

@@ -112,13 +111,6 @@

 void

-resetsim(Party *p)

-{

-	memset(&p->state, 0, sizeof p->state);

-	p->state.p = Pt2(0,100,1);

-}

-void

 threadsim(void *)

 	uvlong then, now;

@@ -136,7 +128,6 @@

 		if(lobby->getcouple(lobby, couple) != -1){

 			newparty(couple);

-			resetsim(theparty.prev);

 			theparty.prev->u->reset(theparty.prev->u);

@@ -146,7 +137,6 @@

 		for(p = theparty.next; p != &theparty; p = p->next){

 			p->u->timeacc += frametime/1e9;

-			p->state.timeacc += frametime/1e9;

 			while(p->u->timeacc >= Δt){

 				p->u->step(p->u, Δt);

@@ -153,12 +143,6 @@

 				p->u->timeacc -= Δt;

 				p->u->t += Δt;

-			while(p->state.timeacc >= Δt){

-				integrate(&p->state, p->state.t, Δt);

-				p->state.timeacc -= Δt;

-				p->state.t += Δt;

-			}

 		broadcaststate();

@@ -193,8 +177,6 @@

 	Ship *s;

 	for(p = theparty.next; p != &theparty; p = p->next, i++){

-		fprint(fd, "%lud p %v	v %v\n",

-			i, p->state.p, p->state.v);

 		for(s = &p->u->ships[0]; s-p->u->ships < nelem(p->u->ships); s++){

 			fprint(fd, "%lud s%lld k%d p %v v %v θ %g ω %g m %g f %d\n",

 				i, s-p->u->ships, s->kind, s->p, s->v, s->θ, s->ω, s->mass, s->fuel);

--- a/physics.c

+++ b/physics.c

@@ -7,108 +7,16 @@

 static double G = 6.674e-11;

/*

  *	Dynamics stepper

*/

 static Point2

-accel(GameState *s, double)

-{

-	static double k = 15, b = 0.1;

-	return Vec2(0, -k*s->p.y - b*s->v.y);

-}

-static Derivative

-eval(GameState *s0, double t, double Δt, Derivative *d)

-{

-	GameState s;

-	Derivative res;

-	s.p = addpt2(s0->p, mulpt2(d->dx, Δt));

-	s.v = addpt2(s0->v, mulpt2(d->dv, Δt));

-	res.dx = s.v;

-	res.dv = accel(&s, t+Δt);

-	return res;

-}

-/*

- *	Explicit Euler Integrator

- */

-static void

-euler0(GameState *s, double t, double Δt)

-{

-	static Derivative ZD = {0};

-	Derivative d;

-	d = eval(s, t, Δt, &ZD);

-	s->p = addpt2(s->p, mulpt2(d.dx, Δt));

-	s->v = addpt2(s->v, mulpt2(d.dv, Δt));

-}

-/*

- *	Semi-implicit Euler Integrator

- */

-static void

-euler1(GameState *s, double t, double Δt)

-{

-	static Derivative ZD = {0};

-	Derivative d;

-	d = eval(s, t, Δt, &ZD);

-	s->v = addpt2(s->v, mulpt2(d.dv, Δt));

-	s->p = addpt2(s->p, mulpt2(s->v, Δt));

-}

-/*

- *	RK4 Integrator

- */

-static void

-rk4(GameState *s, double t, double Δt)

-{

-	static Derivative ZD = {0};

-	Derivative a, b, c, d;

-	Point2 dxdt, dvdt;

-	a = eval(s, t, 0, &ZD);

-	b = eval(s, t, Δt/2, &a);

-	c = eval(s, t, Δt/2, &b);

-	d = eval(s, t, Δt, &c);

-	dxdt = divpt2(addpt2(addpt2(a.dx, mulpt2(addpt2(b.dx, c.dx), 2)), d.dx), 6);

-	dvdt = divpt2(addpt2(addpt2(a.dv, mulpt2(addpt2(b.dv, c.dv), 2)), d.dv), 6);

-	s->p = addpt2(s->p, mulpt2(dxdt, Δt));

-	s->v = addpt2(s->v, mulpt2(dvdt, Δt));

-}

-/*

- *	The Integrator

- */

-void

-integrate(GameState *s, double t, double Δt)

-{

-	//euler0(s, t, Δt);

-	//euler1(s, t, Δt);

-	rk4(s, t, Δt);

-}

-/*

- *

- * UNIVERSE MIGRATION. KEEP CALM AND FASTEN YOUR SEAT BELTS.

- *

- */

-/*

- * XXX: remember to take thrust into account, based on user input.

- */

-static Point2

 accelship(Universe *u, Particle *p, double)

 	double g, d;

+	/* XXX: remember to take thrust into account, based on user input. */

 	d = vec2len(subpt2(u->star.p, p->p));

 	d *= 1e5; /* scale to the 100km/px range */

 	g = G*u->star.mass/(d*d);

@@ -122,7 +30,7 @@

 static Derivative

-evalu(Universe *u, Particle *p0, double t, double Δt, Derivative *d, Point2 (*a)(Universe*,Particle*,double))

+eval(Universe *u, Particle *p0, double t, double Δt, Derivative *d, Point2 (*accel)(Universe*,Particle*,double))

 	Particle p;

 	Derivative res;

@@ -131,33 +39,39 @@

 	p.v = addpt2(p0->v, mulpt2(d->dv, Δt));

 	res.dx = p.v;

-	res.dv = a(u, &p, t+Δt);

+	res.dv = accel(u, &p, t+Δt);

 	return res;

+/*

+ *	Semi-implicit Euler Integrator

+ */

 static void

-euler1u(Universe *u, Particle *p, double t, double Δt)

+euler1(Universe *u, Particle *p, double t, double Δt, Point2 (*accel)(Universe*,Particle*,double))

 	static Derivative ZD = {0};

 	Derivative d;

-	d = evalu(u, p, t, Δt, &ZD);

+	d = eval(u, p, t, Δt, &ZD, accel);

 	p->v = addpt2(p->v, mulpt2(d.dv, Δt));

 	p->p = addpt2(p->p, mulpt2(p->v, Δt));

+/*

+ *	RK4 Integrator

+ */

 static void

-rk4u(Universe *u, Particle *p, double t, double Δt, Point2 (*acc)(Universe*,Particle*,double))

+rk4(Universe *u, Particle *p, double t, double Δt, Point2 (*accel)(Universe*,Particle*,double))

 	static Derivative ZD = {0};

 	Derivative a, b, c, d;

 	Point2 dxdt, dvdt;

-	a = evalu(u, p, t, 0, &ZD, acc);

-	b = evalu(u, p, t, Δt/2, &a, acc);

-	c = evalu(u, p, t, Δt/2, &b, acc);

-	d = evalu(u, p, t, Δt, &c, acc);

+	a = eval(u, p, t, 0, &ZD, accel);

+	b = eval(u, p, t, Δt/2, &a, accel);

+	c = eval(u, p, t, Δt/2, &b, accel);

+	d = eval(u, p, t, Δt, &c, accel);

 	dxdt = divpt2(addpt2(addpt2(a.dx, mulpt2(addpt2(b.dx, c.dx), 2)), d.dx), 6);

 	dvdt = divpt2(addpt2(addpt2(a.dv, mulpt2(addpt2(b.dv, c.dv), 2)), d.dv), 6);

@@ -166,15 +80,18 @@

 	p->v = addpt2(p->v, mulpt2(dvdt, Δt));

+/*

+ *	The Integrator

+ */

 void

-integrateu(Universe *u, double t, double Δt)

+integrate(Universe *u, double t, double Δt)

 	int i, j;

 	for(i = 0; i < nelem(u->ships); i++){

-		rk4u(u, &u->ships[i], t, Δt, accelship);

+		rk4(u, &u->ships[i], t, Δt, accelship);

 		for(j = 0; j < nelem(u->ships[i].rounds); j++)

 			if(u->ships[i].rounds[j].fired)

-				euler1u(u, &u->ships[i].rounds[j], t, Δt, accelbullet);

+				euler1(u, &u->ships[i].rounds[j], t, Δt, accelbullet);

--- a/universe.c

+++ b/universe.c

@@ -8,7 +8,7 @@

 static void

 universe_step(Universe *u, double Δt)

-	integrateu(u, u->t, Δt);

+	integrate(u, u->t, Δt);

 static void