From: Daniel Karbach <daniel.karbach@localhorst.tv>
Date: Sat, 2 Dec 2017 18:10:06 +0000 (+0100)
Subject: slightly better physics
X-Git-Url: https://git.localhorst.tv/?a=commitdiff_plain;h=b4deadd9f4e399207e2530ea39a447c0d9d260a3;p=blobs.git

slightly better physics
---

diff --git a/src/creature/Situation.hpp b/src/creature/Situation.hpp
index 4205cff..3c4a28a 100644
--- a/src/creature/Situation.hpp
+++ b/src/creature/Situation.hpp
@@ -66,6 +66,8 @@ public:
 	const glm::dvec3 &Velocity() const noexcept { return state.vel; }
 	bool Moving() const noexcept { return glm::length2(state.vel) > 0.0000001; }
 	void Move(const glm::dvec3 &dp) noexcept;
+	void Accelerate(const glm::dvec3 &dv) noexcept;
+	void EnforceConstraints(State &) noexcept;
 
 	void Heading(const glm::dvec3 &h) noexcept { state.dir = h; }
 	const glm::dvec3 &Heading() const noexcept { return state.dir; }
diff --git a/src/creature/creature.cpp b/src/creature/creature.cpp
index dc857ce..b95b531 100644
--- a/src/creature/creature.cpp
+++ b/src/creature/creature.cpp
@@ -278,10 +278,11 @@ void Creature::TickState(double dt) {
 	);
 	state.pos += f.vel * dt;
 	state.vel += f.acc * dt;
+	situation.EnforceConstraints(state);
 	if (length2(state.vel) > 0.000001) {
 		glm::dvec3 nvel(normalize(state.vel));
 		double ang = angle(nvel, state.dir);
-		double turn_rate = PI * 0.5 * dt;
+		double turn_rate = PI * 0.75 * dt;
 		if (ang < turn_rate) {
 			state.dir = normalize(state.vel);
 		} else if (std::abs(ang - PI) < 0.001) {
@@ -291,16 +292,33 @@ void Creature::TickState(double dt) {
 		}
 	}
 	situation.SetState(state);
-	stats.Exhaustion().Add(length(f.acc) * Mass() / Stamina() * dt);
+	stats.Exhaustion().Add(length(f.acc) * Mass() / Stamina() * 0.5 * dt);
 }
 
 Situation::Derivative Creature::Step(const Situation::Derivative &ds, double dt) const noexcept {
 	Situation::State s = situation.GetState();
 	s.pos += ds.vel * dt;
 	s.vel += ds.acc * dt;
+	glm::dvec3 force(steering.Force(s));
+	// gravity = antinormal * mass * Gm / r²
+	double elevation = s.pos[(situation.Surface() + 2) % 3];
+	glm::dvec3 normal(world::Planet::SurfaceNormal(situation.Surface()));
+	force += glm::dvec3(
+		-normal
+		* Mass() * situation.GetPlanet().GravitationalParameter()
+		/ (elevation * elevation));
+	// if net force is applied and in contact with surface
+	if (!allzero(force) && std::abs(std::abs(elevation) - situation.GetPlanet().Radius()) < 0.001) {
+		// apply friction = -|normal force| * tangential force * coefficient
+		glm::dvec3 fn(normal * dot(force, normal));
+		glm::dvec3 ft(force - fn);
+		double u = 0.4;
+		glm::dvec3 friction(-length(fn) * ft * u);
+		force += friction;
+	}
 	return {
 		s.vel,
-		steering.Force(s) / Mass()
+		force / Mass()
 	};
 }
 
@@ -576,7 +594,7 @@ void Split(Creature &c) {
 	// TODO: duplicate situation somehow
 	a->GetSituation().SetPlanetSurface(
 		s.GetPlanet(), s.Surface(),
-		s.Position() + glm::dvec3(0.0, a->Size() + 0.1, 0.0));
+		s.Position() + glm::dvec3(0.0, 0.55 * a->Size(), 0.0));
 	a->BuildVAO();
 	std::cout << "[" << int(c.GetSimulation().Time()) << "s] "
 		<< a->Name() << " was born" << std::endl;
@@ -590,7 +608,7 @@ void Split(Creature &c) {
 	s.GetPlanet().AddCreature(b);
 	b->GetSituation().SetPlanetSurface(
 		s.GetPlanet(), s.Surface(),
-		s.Position() + glm::dvec3(0.0, b->Size() - 0.1, 0.0));
+		s.Position() - glm::dvec3(0.0, 0.55 * b->Size(), 0.0));
 	b->BuildVAO();
 	std::cout << "[" << int(c.GetSimulation().Time()) << "s] "
 		<< b->Name() << " was born" << std::endl;
@@ -700,12 +718,26 @@ const world::TileType &Situation::GetTileType() const noexcept {
 
 void Situation::Move(const glm::dvec3 &dp) noexcept {
 	state.pos += dp;
+	EnforceConstraints(state);
+}
+
+void Situation::Accelerate(const glm::dvec3 &dv) noexcept {
+	state.vel += dv;
+	EnforceConstraints(state);
+}
+
+void Situation::EnforceConstraints(State &s) noexcept {
 	if (OnSurface()) {
-		// enforce ground constraint
 		if (Surface() < 3) {
-			state.pos[(Surface() + 2) % 3] = std::max(0.0, state.pos[(Surface() + 2) % 3]);
+			if (s.pos[(Surface() + 2) % 3] < GetPlanet().Radius()) {
+				s.pos[(Surface() + 2) % 3] = GetPlanet().Radius();
+				s.vel[(Surface() + 2) % 3] = std::max(0.0, s.vel[(Surface() + 2) % 3]);
+			}
 		} else {
-			state.pos[(Surface() + 2) % 3] = std::min(0.0, state.pos[(Surface() + 2) % 3]);
+			if (s.pos[(Surface() + 2) % 3] > -GetPlanet().Radius()) {
+				s.pos[(Surface() + 2) % 3] = -GetPlanet().Radius();
+				s.vel[(Surface() + 2) % 3] = std::min(0.0, s.vel[(Surface() + 2) % 3]);
+			}
 		}
 	}
 }
@@ -715,6 +747,7 @@ void Situation::SetPlanetSurface(world::Planet &p, int srf, const glm::dvec3 &po
 	planet = &p;
 	surface = srf;
 	state.pos = pos;
+	EnforceConstraints(state);
 }
 
 
@@ -746,7 +779,7 @@ void Steering::DontSeparate() noexcept {
 }
 
 void Steering::ResumeSeparate() noexcept {
-	separating = false;
+	separating = true;
 }
 
 void Steering::Halt() noexcept {
diff --git a/src/ui/CreaturePanel.hpp b/src/ui/CreaturePanel.hpp
index 864fede..967e039 100644
--- a/src/ui/CreaturePanel.hpp
+++ b/src/ui/CreaturePanel.hpp
@@ -52,6 +52,8 @@ private:
 	Label *age;
 	Label *mass;
 	Label *pos;
+	Label *vel;
+	Label *dir;
 	Label *tile;
 	Label *goal;
 	Meter *stats[7];
diff --git a/src/ui/ui.cpp b/src/ui/ui.cpp
index 91ae106..becfb98 100644
--- a/src/ui/ui.cpp
+++ b/src/ui/ui.cpp
@@ -24,6 +24,8 @@ CreaturePanel::CreaturePanel(const app::Assets &assets)
 , age(new Label(assets.fonts.medium))
 , mass(new Label(assets.fonts.medium))
 , pos(new Label(assets.fonts.medium))
+, vel(new Label(assets.fonts.medium))
+, dir(new Label(assets.fonts.medium))
 , tile(new Label(assets.fonts.medium))
 , goal(new Label(assets.fonts.medium))
 , stats{nullptr}
@@ -69,6 +71,26 @@ CreaturePanel::CreaturePanel(const app::Assets &assets)
 		->Spacing(10.0f)
 		->Direction(Panel::HORIZONTAL);
 
+	vel->Text("<00.0, 00.0, 00.0>");
+	Label *vel_label = new Label(assets.fonts.medium);
+	vel_label->Text("Vel");
+	Panel *vel_panel = new Panel;
+	vel_panel
+		->Add(vel_label)
+		->Add(vel)
+		->Spacing(10.0f)
+		->Direction(Panel::HORIZONTAL);
+
+	dir->Text("<0.00, 0.00, 0.00>");
+	Label *dir_label = new Label(assets.fonts.medium);
+	dir_label->Text("Dir");
+	Panel *dir_panel = new Panel;
+	dir_panel
+		->Add(dir_label)
+		->Add(dir)
+		->Spacing(10.0f)
+		->Direction(Panel::HORIZONTAL);
+
 	tile->Text("<00, 00> (mountains)");
 	Label *tile_label = new Label(assets.fonts.medium);
 	tile_label->Text("Tile");
@@ -165,6 +187,8 @@ CreaturePanel::CreaturePanel(const app::Assets &assets)
 		->Add(born_panel)
 		->Add(mass_panel)
 		->Add(pos_panel)
+		->Add(vel_panel)
+		->Add(dir_panel)
 		->Add(tile_panel)
 		->Add(goal_panel)
 		->Add(stat_panel)
@@ -201,6 +225,20 @@ void CreaturePanel::Draw(app::Assets &assets, graphics::Viewport &viewport) noex
 			<< "<" << p.x << ", " << p.y << ", " << p.z << ">";
 		pos->Text(ss.str());
 	}
+	{
+		const glm::dvec3 &v = c->GetSituation().Velocity();
+		std::stringstream ss;
+		ss << std::fixed << std::setprecision(1)
+			<< "<" << v.x << ", " << v.y << ", " << v.z << ">";
+		vel->Text(ss.str());
+	}
+	{
+		const glm::dvec3 &d = c->GetSituation().GetState().dir;
+		std::stringstream ss;
+		ss << std::fixed << std::setprecision(2)
+			<< "<" << d.x << ", " << d.y << ", " << d.z << ">";
+		dir->Text(ss.str());
+	}
 	{
 		glm::ivec2 t = c->GetSituation().SurfacePosition();
 		std::stringstream ss;
diff --git a/src/world/CreatureCreatureCollision.hpp b/src/world/CreatureCreatureCollision.hpp
index 1a903ec..a26b050 100644
--- a/src/world/CreatureCreatureCollision.hpp
+++ b/src/world/CreatureCreatureCollision.hpp
@@ -30,10 +30,12 @@ public:
 	creature::Creature &A() noexcept { return *a; }
 	const creature::Creature &A() const noexcept { return *a; }
 	const glm::dvec3 &APos() const noexcept;
+	const glm::dvec3 &AVel() const noexcept;
 
 	creature::Creature &B() noexcept { return *b; }
 	const creature::Creature &B() const noexcept { return *b; }
 	const glm::dvec3 &BPos() const noexcept;
+	const glm::dvec3 &BVel() const noexcept;
 
 	const glm::dvec3 &Normal() const noexcept { return normal; }
 	double Depth() const noexcept { return depth; }
diff --git a/src/world/world.cpp b/src/world/world.cpp
index 9cd1e02..d7e293a 100644
--- a/src/world/world.cpp
+++ b/src/world/world.cpp
@@ -208,7 +208,8 @@ void Body::CheckCollision() noexcept {
 	for (auto &c : collisions) {
 		c.A().GetSituation().Move(c.Normal() * (c.Depth() * -0.5));
 		c.B().GetSituation().Move(c.Normal() * (c.Depth() * 0.5));
-		// TODO: adjust velocities as well
+		c.A().GetSituation().Accelerate(c.Normal() * -dot(c.Normal(), c.AVel()));
+		c.B().GetSituation().Accelerate(c.Normal() * -dot(c.Normal(), c.BVel()));
 		// TODO: notify participants so they can be annoyed
 	}
 }
@@ -232,10 +233,18 @@ const glm::dvec3 &CreatureCreatureCollision::APos() const noexcept {
 	return a->GetSituation().Position();
 }
 
+const glm::dvec3 &CreatureCreatureCollision::AVel() const noexcept {
+	return a->GetSituation().Velocity();
+}
+
 const glm::dvec3 &CreatureCreatureCollision::BPos() const noexcept {
 	return b->GetSituation().Position();
 }
 
+const glm::dvec3 &CreatureCreatureCollision::BVel() const noexcept {
+	return b->GetSituation().Velocity();
+}
+
 
 Orbit::Orbit()
 : sma(1.0)