X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fworld%2Fworld.cpp;h=920313653ac1104ee91073a2d55df97462e2a4ed;hb=ba93deae894a7e35d95aee32c548ac4e7400c771;hp=e4fb968ddfbb8014004a2b7a6a7647be53b2c2a5;hpb=04531ab5fc3d82ba5b5d456bcc277fe6499e1150;p=blank.git

diff --git a/src/world/world.cpp b/src/world/world.cpp
index e4fb968..9203136 100644
--- a/src/world/world.cpp
+++ b/src/world/world.cpp
@@ -1,4 +1,7 @@
 #include "Entity.hpp"
+#include "EntityCollision.hpp"
+#include "EntityController.hpp"
+#include "EntityDerivative.hpp"
 #include "EntityState.hpp"
 #include "Player.hpp"
 #include "World.hpp"
@@ -7,120 +10,357 @@
 #include "EntityCollision.hpp"
 #include "WorldCollision.hpp"
 #include "../app/Assets.hpp"
+#include "../geometry/const.hpp"
+#include "../geometry/distance.hpp"
+#include "../geometry/rotation.hpp"
 #include "../graphics/Format.hpp"
 #include "../graphics/Viewport.hpp"
 
 #include <algorithm>
 #include <cmath>
+#include <iostream>
 #include <limits>
+#include <glm/gtx/euler_angles.hpp>
 #include <glm/gtx/io.hpp>
+#include <glm/gtx/projection.hpp>
 #include <glm/gtx/quaternion.hpp>
+#include <glm/gtx/rotate_vector.hpp>
 #include <glm/gtx/transform.hpp>
 
 
 namespace blank {
 
+namespace {
+
+/// used as a buffer for merging collisions
+std::vector<WorldCollision> col;
+
+}
+
 Entity::Entity() noexcept
-: model()
+: steering(*this)
+, ctrl(nullptr)
+, model()
 , id(-1)
 , name("anonymous")
 , bounds()
+, radius(0.0f)
 , state()
+, heading(0.0f, 0.0f, -1.0f)
+, max_vel(5.0f)
+, max_force(25.0f)
 , ref_count(0)
 , world_collision(false)
-, dead(false) {
+, dead(false)
+, owns_controller(false) {
+
+}
+
+Entity::~Entity() noexcept {
+	UnsetController();
+}
+
+Entity::Entity(const Entity &other) noexcept
+: steering(*this)
+, ctrl(other.ctrl)
+, model(other.model)
+, id(-1)
+, name(other.name)
+, bounds(other.bounds)
+, state(other.state)
+, model_transform(1.0f)
+, view_transform(1.0f)
+, speed(0.0f)
+, heading(0.0f, 0.0f, -1.0f)
+, max_vel(other.max_vel)
+, max_force(other.max_force)
+, ref_count(0)
+, world_collision(other.world_collision)
+, dead(other.dead)
+, owns_controller(false) {
 
 }
 
+void Entity::SetController(EntityController *c) noexcept {
+	UnsetController();
+	ctrl = c;
+	owns_controller = true;
+}
+
+void Entity::SetController(EntityController &c) noexcept {
+	UnsetController();
+	ctrl = &c;
+	owns_controller = false;
+}
+
+void Entity::UnsetController() noexcept {
+	if (ctrl && owns_controller) {
+		delete ctrl;
+	}
+	ctrl = nullptr;
+}
+
+glm::vec3 Entity::ControlForce(const EntityState &s) const noexcept {
+	return steering.Force(s);
+}
 
 void Entity::Position(const glm::ivec3 &c, const glm::vec3 &b) noexcept {
-	state.chunk_pos = c;
-	state.block_pos = b;
+	state.pos.chunk = c;
+	state.pos.block = b;
 }
 
 void Entity::Position(const glm::vec3 &pos) noexcept {
-	state.block_pos = pos;
+	state.pos.block = pos;
 	state.AdjustPosition();
 }
 
-Ray Entity::Aim(const Chunk::Pos &chunk_offset) const noexcept {
-	glm::mat4 transform = Transform(chunk_offset);
-	glm::vec4 from = transform * glm::vec4(0.0f, 0.0f, 0.0f, 1.0f);
-	from /= from.w;
-	glm::vec4 to = transform * glm::vec4(0.0f, 0.0f, -1.0f, 1.0f);
-	to /= to.w;
-	return Ray{ glm::vec3(from), glm::normalize(glm::vec3(to - from)) };
+void Entity::TurnHead(float dp, float dy) noexcept {
+	SetHead(state.pitch + dp, state.yaw + dy);
 }
 
-namespace {
+void Entity::SetHead(float p, float y) noexcept {
+	state.pitch = p;
+	state.yaw = y;
+}
 
-glm::quat delta_rot(const glm::vec3 &av, float dt) {
-	glm::vec3 half(av * dt * 0.5f);
-	float mag = length(half);
-	if (mag > 0.0f) {
-		float smag = std::sin(mag) / mag;
-		return glm::quat(std::cos(mag), half * smag);
-	} else {
-		return glm::quat(1.0f, 0.0f, 0.0f, 0.0f);
+glm::mat4 Entity::Transform(const glm::ivec3 &reference) const noexcept {
+	return glm::translate(glm::vec3((state.pos.chunk - reference) * ExactLocation::Extent())) * model_transform;
+}
+
+glm::mat4 Entity::ViewTransform(const glm::ivec3 &reference) const noexcept {
+	return Transform(reference) * view_transform;
+}
+
+Ray Entity::Aim(const ExactLocation::Coarse &chunk_offset) const noexcept {
+	glm::mat4 transform = ViewTransform(chunk_offset);
+	return Ray{ glm::vec3(transform[3]), -glm::vec3(transform[2]) };
+}
+
+void Entity::Update(World &world, float dt) {
+	if (HasController()) {
+		GetController().Update(*this, dt);
 	}
+	steering.Update(world, dt);
+	UpdatePhysics(world, dt);
+	UpdateTransforms();
+	UpdateHeading();
+	UpdateModel(dt);
 }
 
+void Entity::UpdatePhysics(World &world, float dt) {
+	EntityState s(state);
+
+	EntityDerivative a(CalculateStep(world, s, 0.0f, EntityDerivative()));
+	EntityDerivative b(CalculateStep(world, s, dt * 0.5f, a));
+	EntityDerivative c(CalculateStep(world, s, dt * 0.5f, b));
+	EntityDerivative d(CalculateStep(world, s, dt, c));
+
+	EntityDerivative f;
+	constexpr float sixth = 1.0f / 6.0f;
+	f.position = sixth * (a.position + 2.0f * (b.position + c.position) + d.position);
+	f.velocity = sixth * (a.velocity + 2.0f * (b.velocity + c.velocity) + d.velocity);
+
+	s.pos.block += f.position * dt;
+	s.velocity += f.velocity * dt;
+	limit(s.velocity, max_vel);
+	world.ResolveWorldCollision(*this, s);
+	s.AdjustPosition();
+
+	SetState(s);
 }
 
-void Entity::Update(int dt) noexcept {
-	state.Update(dt);
+EntityDerivative Entity::CalculateStep(
+	World &world,
+	const EntityState &cur,
+	float dt,
+	const EntityDerivative &delta
+) const {
+	EntityState next(cur);
+	next.pos.block += delta.position * dt;
+	next.velocity += delta.velocity * dt;
+	limit(next.velocity, max_vel);
+	next.AdjustPosition();
+
+	EntityDerivative out;
+	out.position = next.velocity;
+	out.velocity = ControlForce(next) + world.GravityAt(next.pos); // by mass = 1kg
+	return out;
 }
 
 
-EntityState::EntityState()
-: chunk_pos(0)
-, block_pos(0.0f)
-, velocity(0.0f)
-, orient(1.0f, 0.0f, 0.0f, 0.0f)
-, ang_vel(0.0f) {
+void Entity::UpdateTransforms() noexcept {
+	// model transform is the one given by current state
+	model_transform = state.Transform(state.pos.chunk);
+	// view transform is either the model's eyes transform or,
+	// should the entity have no model, the pitch (yaw already is
+	// in model transform)
+	if (model) {
+		view_transform = model.EyesTransform();
+	} else {
+		view_transform = toMat4(glm::quat(glm::vec3(state.pitch, state.yaw, 0.0f)));
+	}
+}
+
+void Entity::UpdateHeading() noexcept {
+	speed = length(Velocity());
+	if (speed > std::numeric_limits<float>::epsilon()) {
+		heading = Velocity() / speed;
+	} else {
+		speed = 0.0f;
+		// use -Z (forward axis) of model transform (our "chest")
+		heading = -glm::vec3(model_transform[2]);
+	}
+}
 
+void Entity::UpdateModel(float dt) noexcept {
+	// first, sanitize the pitch and yaw fields of state (our input)
+	// those indicate the head orientation in the entity's local cosystem
+	state.AdjustHeading();
+	// TODO: this flickers horrible and also shouldn't be based on velocity, but on control force
+	//OrientBody(dt);
+	OrientHead(dt);
+}
+
+void Entity::OrientBody(float dt) noexcept {
+	// maximum body rotation per second (due to velocity orientation) (90°)
+	constexpr float max_body_turn_per_second = PI_0p5;
+	const float max_body_turn = max_body_turn_per_second * dt;
+	// minimum speed to apply body correction
+	constexpr float min_speed = 0.0625f;
+	// use local Y as up
+	const glm::vec3 up(model_transform[1]);
+	if (speed > min_speed) {
+		// check if our orientation and velocity are aligned
+		const glm::vec3 forward(-model_transform[2]);
+		// facing is local -Z rotated about local Y by yaw and transformed into world space
+		const glm::vec3 facing(normalize(glm::vec3(glm::vec4(rotateY(glm::vec3(0.0f, 0.0f, -1.0f), state.yaw), 0.0f) * transpose(model_transform))));
+		// only adjust if velocity isn't almost parallel to up
+		float vel_dot_up = dot(Velocity(), up);
+		if (std::abs(1.0f - std::abs(vel_dot_up)) > std::numeric_limits<float>::epsilon()) {
+			// get direction of velocity projected onto model plane
+			glm::vec3 direction(normalize(Velocity() - (Velocity() * vel_dot_up)));
+			// if velocity points away from our facing (with a little bias), flip it around
+			// (the entity is "walking backwards")
+			if (dot(facing, direction) < -0.1f) {
+				direction = -direction;
+			}
+			// calculate the difference between forward and direction
+			const float absolute_difference = std::acos(dot(forward, direction));
+			// if direction is clockwise with respect to up vector, invert the angle
+			const float relative_difference = dot(cross(forward, direction), up) < 0.0f
+				? -absolute_difference
+				: absolute_difference;
+			// only correct by half the difference max
+			const float correction = glm::clamp(relative_difference * 0.5f, -max_body_turn, max_body_turn);
+			if (ID() == 1) {
+				std::cout << "orientation before: " << state.orient << std::endl;
+				std::cout << "up:        " << up << std::endl;
+				std::cout << "forward:   " << forward << std::endl;
+				std::cout << "facing:    " << facing << std::endl;
+				std::cout << "direction: " << direction << std::endl;
+				std::cout << "difference: " << glm::degrees(relative_difference) << "°" << std::endl;
+				std::cout << "correction: " << glm::degrees(correction) << "°" << std::endl;
+				std::cout << std::endl;
+			}
+			// now rotate body by correction and head by -correction
+			state.orient = rotate(state.orient, correction, up);
+			state.yaw -= correction;
+		}
+	}
 }
 
-void EntityState::Update(int dt) noexcept {
-	float fdt = float(dt);
-	block_pos += velocity * fdt;
-	orient = delta_rot(ang_vel, fdt) * orient;
-	AdjustPosition();
+void Entity::OrientHead(float dt) noexcept {
+	// maximum yaw of head (60°)
+	constexpr float max_head_yaw = PI / 3.0f;
+	// use local Y as up
+	const glm::vec3 up(model_transform[1]);
+	// if yaw is bigger than max, rotate the body to accomodate
+	if (std::abs(state.yaw) > max_head_yaw) {
+		float deviation = state.yaw < 0.0f ? state.yaw + max_head_yaw : state.yaw - max_head_yaw;
+		// rotate the entity by deviation about local Y
+		state.orient = rotate(state.orient, deviation, up);
+		// and remove from head yaw
+		state.yaw -= deviation;
+		// shouldn't be necessary if max_head_yaw is < PI, but just to be sure :p
+		state.AdjustHeading();
+	}
+	// update model if any
+	if (model) {
+		model.EyesState().orientation = glm::quat(glm::vec3(state.pitch, state.yaw, 0.0f));
+	}
 }
 
-void EntityState::AdjustPosition() noexcept {
-	while (block_pos.x >= Chunk::width) {
-		block_pos.x -= Chunk::width;
-		++chunk_pos.x;
+
+EntityCollision::EntityCollision(Entity *e, float d, const glm::vec3 &n)
+: depth(d)
+, normal(n)
+, entity(e) {
+	if (entity) {
+		entity->Ref();
+	}
+}
+
+EntityCollision::~EntityCollision() {
+	if (entity) {
+		entity->UnRef();
 	}
-	while (block_pos.x < 0) {
-		block_pos.x += Chunk::width;
-		--chunk_pos.x;
+}
+
+EntityCollision::EntityCollision(const EntityCollision &other)
+: depth(other.depth)
+, normal(other.normal)
+, entity(other.entity) {
+	if (entity) {
+		entity->Ref();
 	}
-	while (block_pos.y >= Chunk::height) {
-		block_pos.y -= Chunk::height;
-		++chunk_pos.y;
+}
+
+EntityCollision &EntityCollision::operator =(const EntityCollision &other) {
+	if (entity) {
+		entity->UnRef();
 	}
-	while (block_pos.y < 0) {
-		block_pos.y += Chunk::height;
-		--chunk_pos.y;
+	depth = other.depth;
+	normal = other.normal;
+	entity = other.entity;
+	if (entity) {
+		entity->Ref();
 	}
-	while (block_pos.z >= Chunk::depth) {
-		block_pos.z -= Chunk::depth;
-		++chunk_pos.z;
+	return *this;
+}
+
+
+EntityController::~EntityController() {
+
+}
+
+
+EntityState::EntityState()
+: pos()
+, velocity(0.0f)
+, orient(1.0f, 0.0f, 0.0f, 0.0f)
+, pitch(0.0f)
+, yaw(0.0f) {
+
+}
+
+void EntityState::AdjustPosition() noexcept {
+	pos.Correct();
+}
+
+void EntityState::AdjustHeading() noexcept {
+	pitch = glm::clamp(pitch, -PI_0p5, PI_0p5);
+	while (yaw > PI) {
+		yaw -= PI_2p0;
 	}
-	while (block_pos.z < 0) {
-		block_pos.z += Chunk::depth;
-		--chunk_pos.z;
+	while (yaw < -PI) {
+		yaw += PI_2p0;
 	}
 }
 
 glm::mat4 EntityState::Transform(const glm::ivec3 &reference) const noexcept {
 	const glm::vec3 translation = RelativePosition(reference);
 	glm::mat4 transform(toMat4(orient));
-	transform[3].x = translation.x;
-	transform[3].y = translation.y;
-	transform[3].z = translation.z;
+	transform[3] = glm::vec4(translation, 1.0f);
 	return transform;
 }
 
@@ -154,19 +394,270 @@ void Player::Update(int dt) {
 }
 
 
+Steering::Steering(const Entity &e)
+: entity(e)
+, target_entity(nullptr)
+, target_velocity(0.0f)
+, accel(1.0f)
+, speed(entity.MaxVelocity())
+, wander_radius(1.0f)
+, wander_dist(2.0f)
+, wander_disp(1.0f)
+, wander_pos(1.0f, 0.0f, 0.0f)
+, obstacle_dir(0.0f)
+, enabled(0) {
+
+}
+
+Steering::~Steering() {
+	ClearTargetEntity();
+}
+
+Steering &Steering::SetTargetEntity(Entity &e) noexcept {
+	ClearTargetEntity();
+	target_entity = &e;
+	e.Ref();
+	return *this;
+}
+
+Steering &Steering::ClearTargetEntity() noexcept {
+	if (target_entity) {
+		target_entity->UnRef();
+		target_entity = nullptr;
+	}
+	return *this;
+}
+
+void Steering::Update(World &world, float dt) {
+	if (AnyEnabled(WANDER)) {
+		UpdateWander(world, dt);
+	}
+	if (AnyEnabled(OBSTACLE_AVOIDANCE)) {
+		UpdateObstacle(world);
+	}
+}
+
+void Steering::UpdateWander(World &world, float dt) {
+	glm::vec3 displacement(
+		world.Random().SNorm() * wander_disp,
+		world.Random().SNorm() * wander_disp,
+		world.Random().SNorm() * wander_disp
+	);
+	if (!iszero(displacement)) {
+		wander_pos = normalize(wander_pos + displacement * dt) * wander_radius;
+	}
+}
+
+void Steering::UpdateObstacle(World &world) {
+	if (!entity.Moving()) {
+		obstacle_dir = glm::vec3(0.0f);
+		return;
+	}
+	AABB box(entity.Bounds());
+	box.min.z = -entity.Speed();
+	box.max.z = 0.0f;
+	glm::mat4 transform(find_rotation(glm::vec3(0.0f, 0.0f, -1.0f), entity.Heading()));
+	transform[3] = glm::vec4(entity.Position(), 1.0f);
+	// check if that box intersects with any blocks
+	col.clear();
+	if (!world.Intersection(box, transform, entity.ChunkCoords(), col)) {
+		obstacle_dir = glm::vec3(0.0f);
+		return;
+	}
+	// if so, pick the nearest collision
+	const WorldCollision *nearest = nullptr;
+	glm::vec3 difference(0.0f);
+	float distance = std::numeric_limits<float>::infinity();
+	for (const WorldCollision &c : col) {
+		// diff points from block to state
+		glm::vec3 diff = entity.GetState().RelativePosition(c.ChunkPos()) - c.BlockCoords();
+		float dist = length2(diff);
+		if (dist < distance) {
+			nearest = &c;
+			difference = diff;
+			distance = dist;
+		}
+	}
+	if (!nearest) {
+		// intersection test lied to us
+		obstacle_dir = glm::vec3(0.0f);
+		return;
+	}
+	// and try to avoid it
+	float to_go = dot(difference, entity.Heading());
+	glm::vec3 point(entity.Position() + entity.Heading() * to_go);
+	obstacle_dir = normalize(point - nearest->BlockCoords()) * (entity.Speed() / std::sqrt(distance));
+}
+
+glm::vec3 Steering::Force(const EntityState &state) const noexcept {
+	glm::vec3 force(0.0f);
+	if (!enabled) {
+		return force;
+	}
+	const float max = entity.MaxControlForce();
+	if (AnyEnabled(HALT)) {
+		if (SumForce(force, Halt(state), max)) {
+			return force;
+		}
+	}
+	if (AnyEnabled(TARGET_VELOCITY)) {
+		if (SumForce(force, TargetVelocity(state, target_velocity), max)) {
+			return force;
+		}
+	}
+	if (AnyEnabled(OBSTACLE_AVOIDANCE)) {
+		if (SumForce(force, ObstacleAvoidance(state), max)) {
+			return force;
+		}
+	}
+	if (AnyEnabled(EVADE_TARGET)) {
+		if (HasTargetEntity()) {
+			if (SumForce(force, Evade(state, GetTargetEntity()), max)) {
+				return force;
+			}
+		} else {
+			std::cout << "Steering: evade enabled, but target entity not set" << std::endl;
+		}
+	}
+	if (AnyEnabled(PURSUE_TARGET)) {
+		if (HasTargetEntity()) {
+			if (SumForce(force, Pursuit(state, GetTargetEntity()), max)) {
+				return force;
+			}
+		} else {
+			std::cout << "Steering: pursuit enabled, but target entity not set" << std::endl;
+		}
+	}
+	if (AnyEnabled(WANDER)) {
+		if (SumForce(force, Wander(state), max)) {
+			return force;
+		}
+	}
+	return force;
+}
+
+bool Steering::SumForce(glm::vec3 &out, const glm::vec3 &in, float max) noexcept {
+	if (iszero(in) || any(isnan(in))) {
+		return false;
+	}
+	float current = iszero(out) ? 0.0f : length(out);
+	float remain = max - current;
+	if (remain <= 0.0f) {
+		return true;
+	}
+	float additional = length(in);
+	if (additional > remain) {
+		out += normalize(in) * remain;
+		return true;
+	} else {
+		out += in;
+		return false;
+	}
+}
+
+glm::vec3 Steering::Halt(const EntityState &state) const noexcept {
+	return state.velocity * -accel;
+}
+
+glm::vec3 Steering::TargetVelocity(const EntityState &state, const glm::vec3 &vel) const noexcept {
+	return (vel - state.velocity) * accel;
+}
+
+glm::vec3 Steering::Seek(const EntityState &state, const ExactLocation &loc) const noexcept {
+	const glm::vec3 diff(loc.Difference(state.pos).Absolute());
+	if (iszero(diff)) {
+		return glm::vec3(0.0f);
+	} else {
+		return TargetVelocity(state, normalize(diff) * speed);
+	}
+}
+
+glm::vec3 Steering::Flee(const EntityState &state, const ExactLocation &loc) const noexcept {
+	const glm::vec3 diff(state.pos.Difference(loc).Absolute());
+	if (iszero(diff)) {
+		return glm::vec3(0.0f);
+	} else {
+		return TargetVelocity(state, normalize(diff) * speed);
+	}
+}
+
+glm::vec3 Steering::Arrive(const EntityState &state, const ExactLocation &loc) const noexcept {
+	const glm::vec3 diff(loc.Difference(state.pos).Absolute());
+	const float dist = length(diff);
+	if (dist < std::numeric_limits<float>::epsilon()) {
+		return glm::vec3(0.0f);
+	} else {
+		const float att_speed = std::min(dist * accel, speed);
+		return TargetVelocity(state, diff * att_speed / dist);
+	}
+}
+
+glm::vec3 Steering::Pursuit(const EntityState &state, const Entity &other) const noexcept {
+	const glm::vec3 diff(state.Diff(other.GetState()));
+	if (iszero(diff)) {
+		return TargetVelocity(state, other.Velocity());
+	} else {
+		const float time_estimate = length(diff) / speed;
+		ExactLocation prediction(other.ChunkCoords(), other.Position() + (other.Velocity() * time_estimate));
+		return Seek(state, prediction);
+	}
+}
+
+glm::vec3 Steering::Evade(const EntityState &state, const Entity &other) const noexcept {
+	const glm::vec3 diff(state.Diff(other.GetState()));
+	if (iszero(diff)) {
+		return TargetVelocity(state, -other.Velocity());
+	} else {
+		const float time_estimate = length(diff) / speed;
+		ExactLocation prediction(other.ChunkCoords(), other.Position() + (other.Velocity() * time_estimate));
+		return Flee(state, prediction);
+	}
+}
+
+glm::vec3 Steering::Wander(const EntityState &state) const noexcept {
+	return TargetVelocity(state, normalize(entity.Heading() * wander_dist + wander_pos) * speed);
+}
+
+glm::vec3 Steering::ObstacleAvoidance(const EntityState &state) const noexcept {
+	return obstacle_dir;
+}
+
+
 World::World(const BlockTypeRegistry &types, const Config &config)
 : config(config)
 , block_type(types)
 , chunks(types)
 , players()
 , entities()
+, rng(
+#ifdef BLANK_PROFILING
+0
+#else
+std::time(nullptr)
+#endif
+)
 , light_direction(config.light_direction)
 , fog_density(config.fog_density) {
-
+	for (int i = 0; i < 4; ++i) {
+		rng.Next<int>();
+	}
 }
 
 World::~World() {
-
+	for (Entity &e : entities) {
+		e.Kill();
+	}
+	std::size_t removed = 0;
+	do {
+		removed = 0;
+		for (auto e = entities.begin(), end = entities.end(); e != end; ++e) {
+			if (e->CanRemove()) {
+				e = RemoveEntity(e);
+				end = entities.end();
+				++removed;
+			}
+		}
+	} while (removed > 0 && !entities.empty());
 }
 
 
@@ -178,7 +669,7 @@ Player *World::AddPlayer(const std::string &name) {
 	}
 	Entity &entity = AddEntity();
 	entity.Name(name);
-	entity.Bounds({ { -0.5f, -0.5f, -0.5f }, { 0.5f, 0.5f, 0.5f } });
+	entity.Bounds({ { -0.4f, -0.9f, -0.4f }, { 0.4f, 0.9f, 0.4f } });
 	entity.WorldCollidable(true);
 	ChunkIndex &index = chunks.MakeIndex(entity.ChunkCoords(), 6);
 	players.emplace_back(entity, index);
@@ -196,7 +687,7 @@ Player *World::AddPlayer(const std::string &name, std::uint32_t id) {
 		return nullptr;
 	}
 	entity->Name(name);
-	entity->Bounds({ { -0.5f, -0.5f, -0.5f }, { 0.5f, 0.5f, 0.5f } });
+	entity->Bounds({ { -0.4f, -0.9f, -0.4f }, { 0.4f, 0.9f, 0.4f } });
 	entity->WorldCollidable(true);
 	ChunkIndex &index = chunks.MakeIndex(entity->ChunkCoords(), 6);
 	players.emplace_back(*entity, index);
@@ -285,15 +776,14 @@ std::vector<Candidate> candidates;
 
 bool World::Intersection(
 	const Ray &ray,
-	const glm::mat4 &M,
-	const Chunk::Pos &reference,
+	const ExactLocation::Coarse &reference,
 	WorldCollision &coll
 ) {
 	candidates.clear();
 
 	for (Chunk &cur_chunk : chunks) {
 		float cur_dist;
-		if (cur_chunk.Intersection(ray, M * cur_chunk.Transform(reference), cur_dist)) {
+		if (cur_chunk.Intersection(ray, reference, cur_dist)) {
 			candidates.push_back({ &cur_chunk, cur_dist });
 		}
 	}
@@ -309,7 +799,7 @@ bool World::Intersection(
 	for (Candidate &cand : candidates) {
 		if (cand.dist > coll.depth) continue;
 		WorldCollision cur_coll;
-		if (cand.chunk->Intersection(ray, M * cand.chunk->Transform(reference), cur_coll)) {
+		if (cand.chunk->Intersection(ray, reference, cur_coll)) {
 			if (cur_coll.depth < coll.depth) {
 				coll = cur_coll;
 			}
@@ -321,40 +811,60 @@ bool World::Intersection(
 
 bool World::Intersection(
 	const Ray &ray,
-	const glm::mat4 &M,
 	const Entity &reference,
 	EntityCollision &coll
 ) {
-	coll.entity = nullptr;
-	coll.depth = std::numeric_limits<float>::infinity();
+	coll = EntityCollision(nullptr, std::numeric_limits<float>::infinity(), glm::vec3(0.0f));
 	for (Entity &cur_entity : entities) {
 		if (&cur_entity == &reference) {
 			continue;
 		}
 		float cur_dist;
 		glm::vec3 cur_normal;
-		if (blank::Intersection(ray, cur_entity.Bounds(), M * cur_entity.Transform(reference.ChunkCoords()), &cur_dist, &cur_normal)) {
+		if (blank::Intersection(ray, cur_entity.Bounds(), cur_entity.Transform(reference.ChunkCoords()), &cur_dist, &cur_normal)) {
 			// TODO: fine grained check goes here? maybe?
 			if (cur_dist < coll.depth) {
-				coll.entity = &cur_entity;
-				coll.depth = cur_dist;
-				coll.normal = cur_normal;
+				coll = EntityCollision(&cur_entity, cur_dist, cur_normal);
 			}
 		}
 	}
 
-	return coll.entity;
+	return coll;
+}
+
+bool World::Intersection(const Entity &e, const EntityState &s, std::vector<WorldCollision> &col) {
+	glm::ivec3 reference = s.pos.chunk;
+	glm::mat4 M = s.Transform(reference);
+
+	ExactLocation::Coarse begin(reference - 1);
+	ExactLocation::Coarse end(reference + 2);
+
+	bool any = false;
+	for (ExactLocation::Coarse pos(begin); pos.z < end.z; ++pos.z) {
+		for (pos.y = begin.y; pos.y < end.y; ++pos.y) {
+			for (pos.x = begin.x; pos.x < end.x; ++pos.x) {
+				Chunk *chunk = chunks.Get(pos);
+				if (chunk && chunk->Intersection(e, M, chunk->Transform(reference), col)) {
+					any = true;
+				}
+			}
+		}
+	}
+	return any;
 }
 
-bool World::Intersection(const Entity &e, std::vector<WorldCollision> &col) {
-	AABB box = e.Bounds();
-	Chunk::Pos reference = e.ChunkCoords();
-	glm::mat4 M = e.Transform(reference);
+bool World::Intersection(
+	const AABB &box,
+	const glm::mat4 &M,
+	const glm::ivec3 &reference,
+	std::vector<WorldCollision> &col
+) {
 	bool any = false;
 	for (Chunk &cur_chunk : chunks) {
-		if (manhattan_radius(cur_chunk.Position() - e.ChunkCoords()) > 1) {
+		if (manhattan_radius(cur_chunk.Position() - reference) > 1) {
 			// chunk is not one of the 3x3x3 surrounding the entity
 			// since there's no entity which can extent over 16 blocks, they can be skipped
+			// TODO: change to indexed (like with entity)
 			continue;
 		}
 		if (cur_chunk.Intersection(box, M, cur_chunk.Transform(reference), col)) {
@@ -364,23 +874,10 @@ bool World::Intersection(const Entity &e, std::vector<WorldCollision> &col) {
 	return any;
 }
 
-
-namespace {
-
-std::vector<WorldCollision> col;
-
-}
-
 void World::Update(int dt) {
+	float fdt(dt * 0.001f);
 	for (Entity &entity : entities) {
-		entity.Update(dt);
-	}
-	for (Entity &entity : entities) {
-		col.clear();
-		if (entity.WorldCollidable() && Intersection(entity, col)) {
-			// entity collides with the world
-			Resolve(entity, col);
-		}
+		entity.Update(*this, fdt);
 	}
 	for (Player &player : players) {
 		player.Update(dt);
@@ -394,36 +891,88 @@ void World::Update(int dt) {
 	}
 }
 
-void World::Resolve(Entity &e, std::vector<WorldCollision> &col) {
+void World::ResolveWorldCollision(
+	const Entity &entity,
+	EntityState &state
+) {
+	col.clear();
+	if (!entity.WorldCollidable() || !Intersection(entity, state, col)) {
+		// no collision, no fix
+		return;
+	}
+	glm::vec3 correction = CombinedInterpenetration(state, col);
+	// correction may be zero in which case normalize() returns NaNs
+	if (iszero(correction)) {
+		return;
+	}
+	// if entity is already going in the direction of correction,
+	// let the problem resolve itself
+	if (dot(state.velocity, correction) >= 0.0f) {
+		return;
+	}
+	// apply correction, maybe could use some damping, gotta test
+	state.pos.block += correction;
+	// kill velocity?
+	glm::vec3 normal_velocity(proj(state.velocity, correction));
+	state.velocity -= normal_velocity;
+}
+
+glm::vec3 World::CombinedInterpenetration(
+	const EntityState &state,
+	const std::vector<WorldCollision> &col
+) noexcept {
 	// determine displacement for each cardinal axis and move entity accordingly
-	glm::vec3 min_disp(0.0f);
-	glm::vec3 max_disp(0.0f);
+	glm::vec3 min_pen(0.0f);
+	glm::vec3 max_pen(0.0f);
 	for (const WorldCollision &c : col) {
 		if (!c.Blocks()) continue;
-		glm::vec3 local_disp(c.normal * c.depth);
+		glm::vec3 normal(c.normal);
 		// swap if neccessary (normal may point away from the entity)
-		if (dot(c.normal, e.Position() - c.BlockCoords()) < 0) {
-			local_disp *= -1;
+		if (dot(normal, state.RelativePosition(c.ChunkPos()) - c.BlockCoords()) < 0) {
+			normal = -normal;
+		}
+		// check if block surface is "inside"
+		Block::Face coll_face = Block::NormalFace(normal);
+		BlockLookup neighbor(c.chunk, c.BlockPos(), coll_face);
+		if (neighbor && neighbor.FaceFilled(Block::Opposite(coll_face))) {
+			// yep, so ignore this contact
+			continue;
+		}
+		glm::vec3 local_pen(normal * c.depth);
+		min_pen = min(min_pen, local_pen);
+		max_pen = max(max_pen, local_pen);
+	}
+	glm::vec3 pen(0.0f);
+	// only apply correction for axes where penetration is only in one direction
+	for (std::size_t i = 0; i < 3; ++i) {
+		if (min_pen[i] < -std::numeric_limits<float>::epsilon()) {
+			if (max_pen[i] < std::numeric_limits<float>::epsilon()) {
+				pen[i] = min_pen[i];
+			}
+		} else {
+			pen[i] = max_pen[i];
 		}
-		min_disp = min(min_disp, local_disp);
-		max_disp = max(max_disp, local_disp);
-	}
-	// for each axis
-	// if only one direction is set, use that as the final
-	// if both directions are set, use average
-	glm::vec3 final_disp(0.0f);
-	for (int axis = 0; axis < 3; ++axis) {
-		if (std::abs(min_disp[axis]) > std::numeric_limits<float>::epsilon()) {
-			if (std::abs(max_disp[axis]) > std::numeric_limits<float>::epsilon()) {
-				final_disp[axis] = (min_disp[axis] + max_disp[axis]) * 0.5f;
-			} else {
-				final_disp[axis] = min_disp[axis];
+	}
+	return pen;
+}
+
+glm::vec3 World::GravityAt(const ExactLocation &loc) const noexcept {
+	glm::vec3 force(0.0f);
+	ExactLocation::Coarse begin(loc.chunk - 1);
+	ExactLocation::Coarse end(loc.chunk + 2);
+
+	for (ExactLocation::Coarse pos(begin); pos.z < end.z; ++pos.z) {
+		for (pos.y = begin.y; pos.y < end.y; ++pos.y) {
+			for (pos.x = begin.x; pos.x < end.x; ++pos.x) {
+				const Chunk *chunk = chunks.Get(pos);
+				if (chunk) {
+					force += chunk->GravityAt(loc);
+				}
 			}
-		} else if (std::abs(max_disp[axis]) > std::numeric_limits<float>::epsilon()) {
-			final_disp[axis] = max_disp[axis];
 		}
 	}
-	e.Position(e.Position() + final_disp);
+
+	return force;
 }
 
 World::EntityHandle World::RemoveEntity(EntityHandle &eh) {
@@ -443,11 +992,77 @@ World::EntityHandle World::RemoveEntity(EntityHandle &eh) {
 
 void World::Render(Viewport &viewport) {
 	DirectionalLighting &entity_prog = viewport.EntityProgram();
-	entity_prog.SetLightDirection(light_direction);
 	entity_prog.SetFogDensity(fog_density);
 
+	glm::vec3 light_dir;
+	glm::vec3 light_col;
+	glm::vec3 ambient_col;
 	for (Entity &entity : entities) {
-		entity.Render(entity.Transform(players.front().GetEntity().ChunkCoords()), entity_prog);
+		glm::mat4 M(entity.Transform(players.front().GetEntity().ChunkCoords()));
+		if (!CullTest(entity.Bounds(), entity_prog.GetVP() * M)) {
+			GetLight(entity, light_dir, light_col, ambient_col);
+			entity_prog.SetLightDirection(light_dir);
+			entity_prog.SetLightColor(light_col);
+			entity_prog.SetAmbientColor(ambient_col);
+			entity.Render(M, entity_prog);
+		}
+	}
+}
+
+// this should interpolate based on the fractional part of entity's block position
+void World::GetLight(
+	const Entity &e,
+	glm::vec3 &dir,
+	glm::vec3 &col,
+	glm::vec3 &amb
+) {
+	BlockLookup center(chunks.Get(e.ChunkCoords()), e.Position());
+	if (!center) {
+		// chunk unavailable, so make it really dark and from
+		// some arbitrary direction
+		dir = glm::vec3(1.0f, 2.0f, 3.0f);
+		col = glm::vec3(0.025f); // ~0.8^15
+		return;
+	}
+	glm::ivec3 base(center.GetBlockPos());
+	int base_light = center.GetLight();
+	int max_light = 0;
+	int min_light = 15;
+	glm::ivec3 acc(0, 0, 0);
+	for (glm::ivec3 offset(-1, -1, -1); offset.z < 2; ++offset.z) {
+		for (offset.y = -1; offset.y < 2; ++offset.y) {
+			for (offset.x = -1; offset.x < 2; ++offset.x) {
+				BlockLookup block(&center.GetChunk(), center.GetBlockPos() + offset);
+				if (!block) {
+					// missing, just ignore it
+					continue;
+				}
+				// otherwise, accumulate the difference times direction
+				acc += offset * (base_light - block.GetLight());
+				max_light = std::max(max_light, block.GetLight());
+				min_light = std::min(min_light, block.GetLight());
+			}
+		}
+	}
+	dir = acc;
+	col = glm::vec3(std::pow(0.8f, 15 - max_light));
+	amb = glm::vec3(std::pow(0.8f, 15 - min_light));
+}
+
+namespace {
+
+PrimitiveMesh::Buffer debug_buf;
+
+}
+
+void World::RenderDebug(Viewport &viewport) {
+	PrimitiveMesh debug_mesh;
+	PlainColor &prog = viewport.WorldColorProgram();
+	for (const Entity &entity : entities) {
+		debug_buf.OutlineBox(entity.Bounds(), glm::vec4(1.0f, 0.0f, 0.0f, 1.0f));
+		debug_mesh.Update(debug_buf);
+		prog.SetM(entity.Transform(players.front().GetEntity().ChunkCoords()));
+		debug_mesh.DrawLines();
 	}
 }