implement multiple maneuver nodes as linked list

src/game.cpp

@@ -125,39 +125,59 @@ selectOrbit(GameState* gs, GameOrbit* orbit)
 	gs->last_selected_orbit = orbit;
 }
 
+ManeuverNode*
+getFreeManeuver(GameState* gs)
+{
+	for (u32 i = 0; i < gs->max_maneuvers; i++) {
+		if (gs->maneuver_nodes[i].active == false) {
+			gs->maneuver_nodes[i].active = true;
+			return &gs->maneuver_nodes[i];
+		}
+	}
+
+	LOGF(Error, "No free maneuver nodes\n");
+	return nullptr;
+}
+
+// TODO: appendManeuver(orbit, node) would be better
 bool
-addManeuver(GameOrbit* orbit,
+addManeuver(GameState* gs,
+			GameOrbit* orbit,
 			ImpulseType impulse_type,
 			double true_anomaly,
 			double impulse_delta_v)
 {
-	ManeuverNode& node = orbit->maneuver;
-
 	if (true_anomaly < -M_PI || true_anomaly > M_PI) {
 		LOGF(Error, "invalid true true_anomaly: %f\n", true_anomaly);
 		return false;
 	}
 
-	if (node.active) {
-		LOGF(Warning, "cannot add multiple maneuvers (yet)\n");
-		return false;
-	}
-
 	if (impulse_delta_v == 0.f) {
 		LOGF(Warning, "refusing to add maneuver with 0 dv\n");
 		return false;
 	}
 
-	node.impulse_type = impulse_type;
+	ManeuverNode* node = getFreeManeuver(gs);
+	assert(node);
+
+	if (orbit->last_maneuver) {
+		node->previous_maneuver = orbit->last_maneuver;
+		orbit->last_maneuver->next_maneuver = node;
+		orbit->last_maneuver = node;
+	} else {
+		orbit->first_maneuver = node;
+		orbit->last_maneuver = node;
+	}
+
+	node->impulse_type = impulse_type;
 	// TODO: thrust calculations
 	//double flight_path_angle = orbit->system.sat.gamma;
 	//node.impulse_vector.x = ...
 
-
-	if (node.impulse_type == ImpulseType::PROGRADE) {
-		node.true_anomaly = true_anomaly;
-		node.impulse_delta_v = impulse_delta_v;
-		node.active = true;
+	if (node->impulse_type == ImpulseType::PROGRADE) {
+		node->true_anomaly = true_anomaly;
+		node->impulse_delta_v = impulse_delta_v;
+		node->active = true;
 
 		return true;
 	}
@@ -167,29 +187,17 @@ addManeuver(GameOrbit* orbit,
 	return false;
 }
 
-void
-removeManeuver(GameOrbit* orbit)
-{
-	// TODO: multiple maneuver nodes
-	ManeuverNode& node = orbit->maneuver;
-	node.impulse_type = ImpulseType::NONE;
-	node.true_anomaly = 0.f;
-	node.impulse_delta_v = 0.f;
-	node.active = false;
-}
-
 // NOTE: test if the maneuver node would have occured between 2 orbit positions
 // 	eg) between 2 time steps
 bool
-testManeuverStep(const ManeuverNode& maneuver,
+testManeuverStep(ManeuverNode* maneuver,
 		double previous_theta,
 		double next_theta)
 {
-	if (!maneuver.active)
-		return false;
+	assert(maneuver);
 
 	// NOTE: clamp angles between 0 and 2 pi to simplify inequalities
-	double r = orbitClampAngle(maneuver.true_anomaly);
+	double r = orbitClampAngle(maneuver->true_anomaly);
 	double clamped_previous_theta = orbitClampAngle(previous_theta);
 	double clamped_next_theta = orbitClampAngle(next_theta);
 
@@ -209,16 +217,16 @@ testManeuverStep(const ManeuverNode& maneuver,
 }
 
 void
-applyManeuver(GameOrbit* orbit, double previous_true_anomaly)
+applyManeuver(GameOrbit* orbit, ManeuverNode* maneuver)
 {
-	const ManeuverNode& node = orbit->maneuver;
 	TwoBodySystem& sys = orbit->system;
 
+	assert(maneuver);
 	// FIXME: assuming prograde impulse vector
-	assert(node.impulse_type == ImpulseType::PROGRADE);
+	assert(maneuver->impulse_type == ImpulseType::PROGRADE);
 
 	// re-calculate state vectors at the maneuver node
-	double theta = node.true_anomaly;
+	double theta = maneuver->true_anomaly;
 	double mu = sys.body.mu;
 	double r = orbitGetRadialDistance(sys.ep.e, sys.ep.p, theta);
 
@@ -229,7 +237,7 @@ applyManeuver(GameOrbit* orbit, double previous_true_anomaly)
 	vel = sys.rotation * vel;
 
 	// apply impulse along velocity vector
-	dvec3 impulse = glm::normalize(vel) * node.impulse_delta_v;
+	dvec3 impulse = glm::normalize(vel) * maneuver->impulse_delta_v;
 	vel = vel + impulse;
 	sys.elements = orbitGetElementsFromStateVectors(pos, vel, mu);
 	systemInit(orbit->system, sys.body, sys.elements);
@@ -245,6 +253,29 @@ applyManeuver(GameOrbit* orbit, double previous_true_anomaly)
 	updateGLBuffer(buf, orbit->e3d.vertices);
 }
 
+void
+removeManeuver(GameOrbit* orbit, ManeuverNode* maneuver)
+{
+	assert(maneuver);
+	// FIXME: we're only removing the first maneuver for now
+	assert(maneuver == orbit->first_maneuver);
+
+	if (orbit->last_maneuver == maneuver) {
+		orbit->first_maneuver = nullptr;
+		orbit->last_maneuver = nullptr;
+	} else {
+		orbit->first_maneuver = maneuver->next_maneuver;
+		maneuver->previous_maneuver = nullptr;
+	}
+
+	maneuver->impulse_type = ImpulseType::NONE;
+	maneuver->true_anomaly = 0.f;
+	maneuver->impulse_delta_v = 0.f;
+	maneuver->active = false;
+	maneuver->previous_maneuver = nullptr;
+	maneuver->next_maneuver = nullptr;
+}
+
 
 // internal
 

src/game.h

@@ -40,16 +40,16 @@ struct ManeuverNode
 	double impulse_delta_v;
 	bool active;
 
-	// TODO: thrust calculations
-	//vec3 impulse_vector;
+	ManeuverNode* previous_maneuver;
+	ManeuverNode* next_maneuver;
 };
 
 struct GameOrbit
 {
 	TwoBodySystem system;
 	Ellipse3D e3d;
-	// TODO: multiple maneuvers
-	ManeuverNode maneuver;
+	ManeuverNode* first_maneuver;
+	ManeuverNode* last_maneuver;
 
 	Entity* grav_body;
 	Entity* ellipse_entity;
@@ -71,6 +71,9 @@ struct GameState
 	u32 num_orbits;
 	u32 max_orbits;
 
+	ManeuverNode* maneuver_nodes;
+	u32 max_maneuvers;
+
 	GameOrbit* last_selected_orbit;
 	Entity* coord_overlay;
 };
@@ -89,15 +92,16 @@ void ellipse3DUpdate(dmat3 rotation, EllipseParameters ep, Ellipse3D& e3d);
 
 void selectOrbit(GameState* gs, GameOrbit* orbit);
 
-bool addManeuver(GameOrbit* orbit,
+bool addManeuver(GameState* gs,
+		GameOrbit* orbit,
 		ImpulseType impulse_type,
 		double true_anomaly,
 		double impulse_delta_v);
 
-void removeManeuver(GameOrbit* orbit);
-
-bool testManeuverStep(const ManeuverNode& maneuver,
+bool testManeuverStep(ManeuverNode* maneuver,
 		double previous_theta,
 		double next_theta);
 
-void applyManeuver(GameOrbit* orbit, double previous_true_anomaly);
+void applyManeuver(GameOrbit* orbit, ManeuverNode* node);
+
+void removeManeuver(GameOrbit* orbit, ManeuverNode* maneuver);

src/gooey.cpp

@@ -273,15 +273,15 @@ drawManeuverWindow(GameState* gs)
 	static float dv = 0.f;
 
 	if (orbit) {
-		if (orbit->maneuver.active) {
+		if (orbit->last_maneuver) {
 			Text("Orbital Maneuver");
 			Indent();
-			Text("true anomaly: %f", orbit->maneuver.true_anomaly);
-			Text("impulse dv: %f km/s", orbit->maneuver.impulse_delta_v);
+			Text("true anomaly: %f", orbit->first_maneuver->true_anomaly);
+			Text("impulse dv: %f km/s", orbit->first_maneuver->impulse_delta_v);
 			Unindent();
 
 			if (Button("remove")) {
-				removeManeuver(orbit);
+				removeManeuver(orbit, orbit->first_maneuver);
 				item_current_idx = 0;
 				anom = 0.f;
 				dv = 0.f;
@@ -307,7 +307,7 @@ drawManeuverWindow(GameState* gs)
 			InputFloat("impulse dv, km/s", &dv, 0.1, 4.0, "%.1f");
 
 			if (Button("apply")) {
-				if (!addManeuver(orbit, ImpulseType::PROGRADE, anom, dv)) {
+				if (!addManeuver(gs, orbit, ImpulseType::PROGRADE, anom, dv)) {
 					// flash a color or something?
 				}
 			}

src/main.cpp

@@ -258,7 +258,12 @@ loadScene(GameState* gs, RenderState* rs)
 	//GameOrbit* go_2 = loadOrbit(gs, rs, body, el2, rg, "sat_02");
 
 	double v_transfer = orbitGetTransferVelocity(go_1->system, el2);
-	addManeuver(go_1, ImpulseType::PROGRADE, DEG2RAD(180), v_transfer);
+	addManeuver(gs, go_1, ImpulseType::PROGRADE, DEG2RAD(180), v_transfer);
+	// FIXME: can't get circularization here unless we simulate the transfer
+	// 	orbit ahead of time, eg) applyManeuver to a dummy orbit
+	// 	could also add a ImpulseType::CIRCULARIZE and calculate in
+	// 	applyManeuver()
+	addManeuver(gs, go_1, ImpulseType::PROGRADE, DEG2RAD(180), 0.500);
 
 	return true;
 }
@@ -301,12 +306,13 @@ updateOrbit(GameOrbit* orbit, bool running, double time_step)
 		updateSatelliteModel(orbit->system, time_step);
 		setEntityPosition(orbit->satellite_entity, orbit->system.sat.position);
 
-		if (testManeuverStep(orbit->maneuver,
+		if (orbit->first_maneuver
+			&& testManeuverStep(orbit->first_maneuver,
 					previous_true_anom,
 					orbit->system.sat.theta))
 		{
-			applyManeuver(orbit, previous_true_anom);
-			removeManeuver(orbit);
+			applyManeuver(orbit, orbit->first_maneuver);
+			removeManeuver(orbit, orbit->first_maneuver);
 		}
 	}
 }
@@ -333,6 +339,7 @@ postFrameCallback(RenderState* rs, void* user_data = nullptr)
 #define DEFAULT_SIM_SPEED 500
 #define GAME_ARENA_SIZE 16 * 1024 * 1024	// 16MB
 #define DEFAULT_MAX_ORBITS 10000
+#define DEFAULT_MANUEVER_NODES 3 * DEFAULT_MAX_ORBITS
 int
 main()
 {
@@ -355,6 +362,9 @@ main()
 	gs.sim_speed = DEFAULT_SIM_SPEED;
 	gs.max_orbits = DEFAULT_MAX_ORBITS;
 	gs.orbits = ARENA_ALLOC(gs.arena, GameOrbit, DEFAULT_MAX_ORBITS);
+	gs.max_maneuvers = DEFAULT_MANUEVER_NODES;
+	gs.maneuver_nodes =
+		ARENA_ALLOC(gs.arena, ManeuverNode, DEFAULT_MANUEVER_NODES);
 
 	if (!loadScene(&gs, rs)) {
 		LOGF(Error, "Error loading scene\n");