#include "Entity.hpp"
+#include "EntityDerivative.hpp"
#include "EntityState.hpp"
#include "Player.hpp"
#include "World.hpp"
#include <algorithm>
#include <cmath>
+#include <iostream>
#include <limits>
#include <glm/gtx/io.hpp>
#include <glm/gtx/quaternion.hpp>
, name("anonymous")
, bounds()
, state()
+, tgt_vel(0.0f)
, ref_count(0)
, world_collision(false)
, dead(false) {
}
-
void Entity::Position(const glm::ivec3 &c, const glm::vec3 &b) noexcept {
state.chunk_pos = c;
state.block_pos = b;
state.AdjustPosition();
}
+glm::mat4 Entity::Transform(const glm::ivec3 &reference) const noexcept {
+ return state.Transform(reference);
+}
+
+glm::mat4 Entity::ViewTransform(const glm::ivec3 &reference) const noexcept {
+ glm::mat4 transform = Transform(reference);
+ if (model) {
+ transform *= model.EyesTransform();
+ }
+ return transform;
+}
+
Ray Entity::Aim(const Chunk::Pos &chunk_offset) const noexcept {
- glm::mat4 transform = Transform(chunk_offset);
+ glm::mat4 transform = ViewTransform(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);
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 {
- state.Update(dt);
-}
-
EntityState::EntityState()
: chunk_pos(0)
}
-void EntityState::Update(int dt) noexcept {
- float fdt = float(dt);
- block_pos += velocity * fdt;
- orient = delta_rot(ang_vel, fdt) * orient;
- AdjustPosition();
-}
-
void EntityState::AdjustPosition() noexcept {
while (block_pos.x >= Chunk::width) {
block_pos.x -= Chunk::width;
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 * 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);
- }
+ 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;
+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 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 = 1kg
+ 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 = 10.0f; // spring constant
+ constexpr float b = 10.0f; // damper constant
+ const glm::vec3 x(-entity.TargetVelocity()); // endpoint displacement from equilibrium, by 1s, in m
+ const glm::vec3 v(state.velocity); // relative velocity between endpoints in m/s
+ return ((-k) * x) - (b * v); // times 1kg/s, in kg*m/s²
+}
+
+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;
+ }
+ min_pen = min(min_pen, local_pen);
+ max_pen = max(max_pen, local_pen);
}
- 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;
+ glm::vec3 correction(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()) {
+ correction[i] = -min_pen[i];
+ }
} else {
- final_disp[axis] = min_disp[axis];
+ correction[i] = -max_pen[i];
}
- } else if (std::abs(max_disp[axis]) > std::numeric_limits<float>::epsilon()) {
- final_disp[axis] = max_disp[axis];
}
+ // correction may be zero in which case normalize() returns NaNs
+ if (dot(correction, correction) < std::numeric_limits<float>::epsilon()) {
+ return glm::vec3(0.0f);
+ }
+ glm::vec3 normal(normalize(correction));
+ glm::vec3 normal_velocity(normal * dot(state.velocity, normal));
+ // apply force proportional to penetration
+ // use velocity projected onto normal as damper
+ constexpr float k = 1000.0f; // spring constant
+ constexpr float b = 10.0f; // damper constant
+ const glm::vec3 x(-correction); // endpoint displacement from equilibrium in m
+ const glm::vec3 v(normal_velocity); // relative velocity between endpoints in m/s
+ return (((-k) * x) - (b * v)); // times 1kg/s, in kg*m/s²
+ } 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) {