void PhysicsSystem::update(GameComponents& components, Entities const& entities, float dt) {
std::vector<Contact> contacts;
std::vector<StaticContact> static_contacts;
std::vector<Collider*> colliders(entities.size());
int collider_index = 0;
float top = 600.0f;
float bottom = 40.0f;
// find contacts
for (Entities::const_iterator it0 = entities.begin(); it0 != entities.end(); ++it0) {
Entity entity0 = *it0;
Collider* collider0 = &components.get<ColliderComponent>(entity0);
collider0->touching.clear();
colliders[collider_index++] = collider0;
static_contacts.push_back({
top - collider0->position(1) - collider0->radius,
Mth::make_cvector(0.0f, 1.0f),
collider0,
entity0,
0.0f
});
static_contacts.push_back({
collider0->position(1) - bottom - collider0->radius,
Mth::make_cvector(0.0f, -1.0f),
collider0,
entity0,
0.0f
});
Entities::const_iterator it1 = it0; ++it1;
for (; it1 != entities.end(); ++it1) {
Entity entity1 = *it1;
Collider* collider1 = &components.get<ColliderComponent>(entity1);
if ((collider0->group == CG_PB && collider1->group == CG_PB) ||
(collider0->group == CG_EB && collider1->group == CG_EB) ||
(collider0->group == CG_PB && collider1->group == CG_EB) ||
(collider0->group == CG_EB && collider1->group == CG_PB) ||
(collider0->group == CG_P && collider1->group == CG_PB) ||
(collider0->group == CG_PB && collider1->group == CG_P) ||
(collider0->group == CG_E && collider1->group == CG_EB) ||
(collider0->group == CG_EB && collider1->group == CG_E)) {
continue;
}
Mth::CVector<float, 2> d = collider1->position - collider0->position;
Contact c {
Mth::length(d) - collider0->radius - collider1->radius,
Mth::normal(d),
collider0,
collider1,
entity0,
entity1,
0.0f
};
contacts.push_back(c);
}
}
// solve contacts
int iterations = 4;
for (int i = 0; i < iterations; ++i) {
for (auto& contact : static_contacts) {
float relative_velocity = Mth::dot(-contact.collider->velocity, contact.normal);
float remove_impuls = contact.distance / dt + relative_velocity;
float new_impuls = std::min(contact.impuls + remove_impuls, 0.0f);
float impuls_change = new_impuls - contact.impuls;
contact.impuls = new_impuls;
contact.collider->velocity += contact.normal * impuls_change;
}
for (auto& contact : contacts) {
float relative_velocity = Mth::dot(contact.collider1->velocity - contact.collider0->velocity, contact.normal);
float remove = contact.distance / dt + relative_velocity;
float remove_impuls = remove / 2.0f;
float new_impuls = std::min(contact.impuls + remove_impuls, 0.0f);
float impuls_change = new_impuls - contact.impuls;
contact.impuls = new_impuls;
contact.collider0->velocity += contact.normal * impuls_change;
contact.collider1->velocity -= contact.normal * impuls_change;
if (i == iterations-1) {
if (new_impuls < 0.0f) {
contact.collider0->touching.push_back(contact.entity1);
contact.collider1->touching.push_back(contact.entity0);
}
}
}
}
// evaluate simulation
for (Collider* collider : colliders) {
collider->position += collider->velocity * dt;
collider->velocity = Mth::make_cvector(0.0f, 0.0f);
}
}
// ---
void QGAMES::Scene::drawOn (QGAMES::Screen* s, const QGAMES::Position& p)
{
assert (_activeMap);
if (!_entitiesPerLayer.empty ())
{
// This means, there are entities that has to be drawn in an specific layer.
// So it starts to iterate over the layers,
// drawing them, and the entities (or characters) in each
// and also keeping control which one are drawn in each layer
// to avoid they to be drawing on top of all layers.
// At this point on the code, we don't still know which entities are in each layer
std::vector <int> ePainted; // The entities that are being painted in its specific layer...
QGAMES::Layers l = _activeMap -> layers (); // Let's go to iterate per layer...
for (QGAMES::Layers::const_iterator i = l.begin (); i != l.end (); i++)
{
(*i) -> drawOn (s, p); // First of all the layer is drawn..
QGAMES::EntitiesPerLayer::const_iterator j;
// Is there something in this specific layer to be drawn?.
if ((j = _entitiesPerLayer.find ((*i) -> name ())) != _entitiesPerLayer.end ())
{
// The list of the entities and characteres to be drawn...
std::vector <int> es = (*j).second;
// ...then the entities are drawn (if they have been defined in the layer)
for (Entities::const_iterator k1 = _entities.begin ();
k1 != _entities.end (); k1++)
{
bool eFound = false;
for (std::vector <int>::const_iterator l = es.begin ();
l != es.end () && !eFound; l++)
{
if ((*k1).second ->id () == (*l))
{
eFound = true;
ePainted.push_back ((*l));
}
}
if (eFound)
(*k1).second -> drawOn (s); // The entities are drawn where they are...
}
// ...and the characters too (if they have been defined in the layer as well)
for (Entities::const_iterator k2 = _characteres.begin ();
k2 != _characteres.end (); k2++)
{
bool eFound = false;
for (std::vector <int>::const_iterator l = es.begin ();
l != es.end () && !eFound; l++)
{
if ((*k2).second ->id () == (*l))
{
eFound = true;
ePainted.push_back ((*l));
}
}
if (eFound)
(*k2).second -> drawOn (s); // The entities are drawn where they are...
}
}
}
// Entities and characteres are put into the same structure
// ...and ordered to be painted...
Entities eTP = _entities;
eTP.insert (_characteres.begin (), _characteres.end ()); // Add the characters...
eTP = orderEntitiesToDraw (eTP); // Order the set...
for (Entities::const_iterator k3 = eTP.begin ();
k3 != eTP.end (); k3++)
{
bool eFound = false;
for (std::vector <int>::const_iterator l = ePainted.begin ();
l != ePainted.end () && !eFound; l++)
if ((*k3).second ->id () == (*l))
eFound = true;
if (!eFound) // If the entity was not drawn before...
(*k3).second -> drawOn (s); // Every entity is drawn where it is...
}
}
else
{
// This means that there are no specific entities per layer...
_activeMap -> drawOn (s, p); // It is possible to alter where the map is drawn...
Entities eTP = _entities;
eTP.insert (_characteres.begin (), _characteres.end ()); // Add the characters...
eTP = orderEntitiesToDraw (eTP); // Order everything...
for (Entities::const_iterator i = eTP.begin (); i != eTP.end (); i++)
(*i).second -> drawOn (s); // ...but the entities are drawn where they are...
}
}
