#include "physics.h"
+#include <algorithm>
#include <msp/game/transform.h>
#include "physicalentity.h"
+using namespace std;
using namespace Msp;
Physics::Physics(Game::Stage &s):
observer(stage.get_event_bus())
{
observer.observe<Game::Events::EntityCreated>([this](auto &e){ entity_added(e); });
+
+ stage.synthesize_initial_events(observer);
}
void Physics::entity_added(const Game::Events::EntityCreated &e)
{
Game::Handle<Game::Transform> transform = entity.entity->get_transform();
entity.position = transform->get_position().slice<2>(0);
+ const Geometry::Quaternion<float> &r = transform->get_rotation();
+ entity.rotation = Geometry::atan2<float>(2*(r.a*r.d+r.b*r.c), 1-2*(r.c*r.c+r.d*r.d));
if constexpr(is_fixture)
entity.inverse_mass = 0.0f;
{
Game::Handle<RigidBody> body = entity.entity->get_body();
entity.inverse_mass = 1.0f/body->get_mass();
+ entity.moment_of_inertia = body->get_moment_of_inertia();
+ entity.external_force = body->get_force();
+ entity.external_torque = body->get_torque();
entity.velocity = body->get_velocity();
+ entity.angular_velocity = body->get_angular_velocity();
}
}
{
Game::Handle<Game::Transform> transform = entity.entity->get_transform();
transform->set_position(compose(entity.position, 0.0f));
+ transform->set_rotation(Geometry::Quaternion<float>::rotation(entity.rotation, LinAl::Vector<float, 3>(0, 0, 1)));
if constexpr(!is_fixture)
{
Game::Handle<RigidBody> body = entity.entity->get_body();
body->set_velocity(entity.velocity);
+ body->set_angular_velocity(entity.angular_velocity);
+ body->clear_forces();
}
}
LinAl::Vector<float, 2> new_velocity = entity.velocity+entity.external_force*dt_secs*entity.inverse_mass;
entity.position += (entity.velocity+new_velocity)*(dt_secs/2);
entity.velocity = new_velocity;
+
+ Geometry::Angle<float> new_angular_velocity = entity.angular_velocity+Geometry::Angle<float>::from_radians(entity.external_torque*(dt_secs/entity.moment_of_inertia));
+ entity.rotation = wrap_positive(entity.rotation+(entity.angular_velocity+new_angular_velocity)*(dt_secs/2));
+ entity.angular_velocity = new_angular_velocity;
}
}
ColliderType type2 = entity2->get_collider()->get_type();
if(type1==ColliderType::CIRCLE && type2==ColliderType::CIRCLE)
collide_circle_circle(i, j);
+ else if(type1==ColliderType::CIRCLE && type2==ColliderType::BOX)
+ collide_circle_box(i, j);
+ else if(type1==ColliderType::BOX && type2==ColliderType::CIRCLE)
+ collide_circle_box(j, i);
}
}
}
collision.normal = -collision.normal;
}
}
+
+void Physics::collide_circle_box(unsigned i, unsigned j)
+{
+ const LinAl::Vector<float, 2> &pos1 = entities[i].position;
+ const LinAl::Vector<float, 2> &pos2 = entities[j].position;
+ float radius = entities[i].entity->get_collider()->get_radius();
+ LinAl::Vector<float, 2> half_size = entities[j].entity->get_collider()->get_size()/2.0f;
+
+ LinAl::Vector<float, 2> delta = pos1-pos2;
+ float c = cos(entities[j].rotation);
+ float s = sin(entities[j].rotation);
+ LinAl::Vector<float, 2> local_delta(c*delta.x+s*delta.y, c*delta.y-s*delta.x);
+ LinAl::Vector<float, 2> local_closest(clamp(local_delta.x, -half_size.x, half_size.x), clamp(local_delta.y, -half_size.y, half_size.y));
+ LinAl::Vector<float, 2> local_cdelta = local_delta-local_closest;
+ float d_sq = inner_product(local_cdelta, local_cdelta);
+ if(d_sq<radius*radius)
+ {
+ Collision &collision = get_collision(i, j);
+ collision.normal = normalize(LinAl::Vector<float, 2>(c*local_cdelta.x-s*local_cdelta.y, c*local_cdelta.y+s*local_cdelta.x));
+ collision.depth = radius-sqrt(d_sq);
+ collision.point = pos1-collision.normal*(radius-collision.depth/2);
+ if(collision.body1!=i)
+ collision.normal = -collision.normal;
+ }
+}