}
-
void Entity::Position(const glm::ivec3 &c, const glm::vec3 &b) noexcept {
state.chunk_pos = c;
state.block_pos = b;
return Ray{ glm::vec3(from), glm::normalize(glm::vec3(to - from)) };
}
-namespace {
-
-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);
- }
-}
-
-}
-
-void Entity::Update(int dt) noexcept {
- float fdt = float(dt);
-
- // euler
- //state.block_pos += state.velocity * fdt;
- //state.velocity += ControlForce(state) * fdt;
- //state.orient = delta_rot(state.ang_vel, fdt) * state.orient;
- //state.AdjustPosition();
-
- // RK4
- EntityDerivative a(CalculateStep(state, 0.0f, EntityDerivative()));
- EntityDerivative b(CalculateStep(state, fdt * 0.5f, a));
- EntityDerivative c(CalculateStep(state, fdt * 0.5f, b));
- EntityDerivative d(CalculateStep(state, fdt, 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);
- f.orient = sixth * ((a.orient + 2.0f * (b.orient + c.orient)) + d.orient);
-
- state.block_pos += f.position * fdt;
- state.velocity += f.velocity * fdt;
- state.orient = delta_rot(f.orient, fdt) * state.orient;
- state.AdjustPosition();
-}
-
-EntityDerivative Entity::CalculateStep(
- const EntityState &cur,
- float dt,
- const EntityDerivative &delta
-) const noexcept {
- EntityState next(cur);
- next.block_pos += delta.position * dt;
- next.velocity += delta.velocity * dt;
- next.orient = delta_rot(cur.ang_vel, dt) * cur.orient;
- next.AdjustPosition();
-
- EntityDerivative out;
- out.position = next.velocity;
- out.velocity = ControlForce(next); // plus other forces and then by mass
- return out;
-}
-
-glm::vec3 Entity::ControlForce(const EntityState &cur) const noexcept {
- constexpr float k = 1.0f; // spring constant
- constexpr float b = 1.0f; // damper constant
- constexpr float t = 0.01f; // 1/time constant
- const glm::vec3 x(-tgt_vel); // endpoint displacement from equilibrium
- const glm::vec3 v(cur.velocity); // relative velocity between endpoints
- return (((-k) * x) - (b * v)) * t; // times mass = 1
-}
-
EntityState::EntityState()
: chunk_pos(0)
return coll.entity;
}
-bool World::Intersection(const Entity &e, std::vector<WorldCollision> &col) {
+bool World::Intersection(const Entity &e, const EntityState &s, std::vector<WorldCollision> &col) {
AABB box = e.Bounds();
- Chunk::Pos reference = e.ChunkCoords();
- glm::mat4 M = e.Transform(reference);
+ Chunk::Pos reference = s.chunk_pos;
+ glm::mat4 M = s.Transform(reference);
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
continue;
}
-namespace {
-
-std::vector<WorldCollision> col;
-
-}
-
void World::Update(int dt) {
+ float fdt(dt);
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);
- }
+ Update(entity, fdt);
}
for (Player &player : players) {
player.Update(dt);
}
}
-void World::Resolve(Entity &e, std::vector<WorldCollision> &col) {
- // determine displacement for each cardinal axis and move entity accordingly
- glm::vec3 min_disp(0.0f);
- glm::vec3 max_disp(0.0f);
- for (const WorldCollision &c : col) {
- if (!c.Blocks()) continue;
- glm::vec3 local_disp(c.normal * c.depth);
- // swap if neccessary (normal may point away from the entity)
- if (dot(c.normal, e.Position() - c.BlockCoords()) < 0) {
- local_disp *= -1;
- }
- min_disp = min(min_disp, local_disp);
- max_disp = max(max_disp, local_disp);
+namespace {
+
+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);
}
- // 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];
+}
+
+}
+
+void World::Update(Entity &entity, float dt) {
+ EntityState state(entity.GetState());
+
+ EntityDerivative a(CalculateStep(entity, state, 0.0f, EntityDerivative()));
+ EntityDerivative b(CalculateStep(entity, state, dt * 0.5f, a));
+ EntityDerivative c(CalculateStep(entity, state, dt * 0.5f, b));
+ EntityDerivative d(CalculateStep(entity, state, 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);
+ f.orient = sixth * ((a.orient + 2.0f * (b.orient + c.orient)) + d.orient);
+
+ state.block_pos += f.position * dt;
+ state.velocity += f.velocity * dt;
+ state.orient = delta_rot(f.orient, dt) * state.orient;
+ state.AdjustPosition();
+
+ entity.SetState(state);
+}
+
+EntityDerivative World::CalculateStep(
+ const Entity &entity,
+ const EntityState &cur,
+ float dt,
+ const EntityDerivative &delta
+) {
+ EntityState next(cur);
+ next.block_pos += delta.position * dt;
+ next.velocity += delta.velocity * dt;
+ next.orient = delta_rot(cur.ang_vel, dt) * cur.orient;
+ next.AdjustPosition();
+
+ EntityDerivative out;
+ out.position = next.velocity;
+ out.velocity = CalculateForce(entity, next); // by mass = 1
+ return out;
+}
+
+glm::vec3 World::CalculateForce(
+ const Entity &entity,
+ const EntityState &state
+) {
+ return ControlForce(entity, state) + CollisionForce(entity, state) + Gravity(entity, state);
+}
+
+glm::vec3 World::ControlForce(
+ const Entity &entity,
+ const EntityState &state
+) {
+ constexpr float k = 1.0f; // spring constant
+ constexpr float b = 1.0f; // damper constant
+ constexpr float t = 0.01f; // 1/time constant
+ const glm::vec3 x(-entity.TargetVelocity()); // endpoint displacement from equilibrium
+ const glm::vec3 v(state.velocity); // relative velocity between endpoints
+ return (((-k) * x) - (b * v)) * t; // times mass = 1
+}
+
+namespace {
+
+std::vector<WorldCollision> col;
+
+}
+
+glm::vec3 World::CollisionForce(
+ const Entity &entity,
+ const EntityState &state
+) {
+ col.clear();
+ if (entity.WorldCollidable() && Intersection(entity, state, col)) {
+ // determine displacement for each cardinal axis and move entity accordingly
+ glm::vec3 min_pen(0.0f);
+ glm::vec3 max_pen(0.0f);
+ for (const WorldCollision &c : col) {
+ if (!c.Blocks()) continue;
+ glm::vec3 local_pen(c.normal * c.depth);
+ // swap if neccessary (normal may point away from the entity)
+ if (dot(c.normal, state.RelativePosition(c.ChunkPos()) - c.BlockCoords()) > 0) {
+ local_pen *= -1;
}
- } else if (std::abs(max_disp[axis]) > std::numeric_limits<float>::epsilon()) {
- final_disp[axis] = max_disp[axis];
+ min_pen = min(min_pen, local_pen);
+ max_pen = max(max_pen, local_pen);
}
+ glm::vec3 penetration(min_pen + max_pen);
+ glm::vec3 normal(normalize(penetration) * -1.0f);
+ glm::vec3 normal_velocity(normal * dot(state.velocity, normal));
+ // apply force proportional to penetration
+ // use velocity projected onto normal as damper
+ constexpr float k = 1.0f; // spring constant
+ constexpr float b = 1.0f; // damper constant
+ constexpr float t = 0.001f; // 1/time constant
+ const glm::vec3 x(penetration); // endpoint displacement from equilibrium
+ const glm::vec3 v(normal_velocity); // relative velocity between endpoints
+ return (((-k) * x) - (b * v)) * t; // times mass = 1
+ } else {
+ return glm::vec3(0.0f);
}
- e.Position(e.Position() + final_disp);
+}
+
+glm::vec3 World::Gravity(
+ const Entity &entity,
+ const EntityState &state
+) {
+ return glm::vec3(0.0f);
}
World::EntityHandle World::RemoveEntity(EntityHandle &eh) {
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