cmd: Fix physics obstacles

Physics contacts can be checked iterating through the contact list of a
body, but some controls are needed in order to exclude invalid values.

include/component/physics.h

@@ -28,9 +28,8 @@ class PhysicsComponent
 
     void set_enabled(bool e);
 
-    /// @brief Called by a physics listener, it is used to update
-    /// the current obstacle flags and list of obstacle bodies
-    void update(b2Contact& contact);
+    /// @brief Updates current obstacle flags and list of obstacle bodies
+    void update(b2ContactEdge& contact);
 
     void update();
 

src/component/physics.cpp

@@ -156,49 +156,58 @@ inline b2WorldManifold get_world_manifold(const b2Contact& contact)
     return wm;
 }
 
-void PhysicsComponent::update(b2Contact& contact)
+void PhysicsComponent::update(b2ContactEdge& contact)
 {
-    b2Body* other = contact.GetFixtureA()->GetBody();
-    if (other == body) {
-        other = contact.GetFixtureB()->GetBody();
+    b2Body* other = contact.other;
+    ASSERT(other);
+
+    auto normal = get_normal(*contact.contact);
+
+    // Skip abnormal values
+    if (normal.x > 1.0 || normal.y > 1.0 || normal.x < -1.0 || normal.y < -1.0) {
+        return;
     }
 
-    auto normal = get_normal(contact);
+    const f32 threshold = 0.80f;
 
-    if (normal.x < -0.99f) {
+    if (normal.x < -threshold) {
         obstacle |= DirectionFlags::RIGHT;
         obstacles_dir[Direction::RIGHT].emplace_back(other);
     }
 
-    if (normal.x > 0.99f) {
+    if (normal.x > threshold) {
         obstacle |= DirectionFlags::LEFT;
         obstacles_dir[Direction::LEFT].emplace_back(other);
     }
 
-    if (normal.y > 0.99f) {
+    if (normal.y > threshold) {
         obstacle |= DirectionFlags::DOWN;
         obstacles_dir[Direction::DOWN].emplace_back(other);
     }
 
-    if (normal.y < -0.99f) {
+    if (normal.y < -threshold) {
         obstacle |= DirectionFlags::UP;
         obstacles_dir[Direction::UP].emplace_back(other);
     }
 }
 
 void PhysicsComponent::reset()
 {
-    // Update some variables
+    // Clear list of obstacles from previous frame
     for (auto& obstacles : obstacles_dir) {
         obstacles.clear();
     }
-
     obstacle = DirectionFlags::NONE;
 }
 
 void PhysicsComponent::update()
 {
-    // Clear list of obstacles from previous frame
+    reset();
+
+    for (auto contact = body->GetContactList(); contact; contact = contact->next) {
+        update(*contact);
+    }
+
     // Apply air resistance
     auto vel = -body->GetLinearVelocity();
     auto vel_len = vel.LengthSquared();

src/entity.cpp

@@ -108,6 +108,10 @@ void Entity::update(const f32 dt)
 {
     assert(enabled);
 
+    if (physics) {
+        physics->update();
+    }
+
     for (auto& command : commands) {
         command->execute(*this);
     }
@@ -124,10 +128,6 @@ void Entity::update(const f32 dt)
     if (state) {
         state->update(*this);
     }
-
-    if (physics) {
-        physics->update();
-    }
 }
 
 } // namespace jmp

src/game.cpp

@@ -105,8 +105,6 @@ void Game::update(const f32 dt)
         // @todo Move this somewhere else? Possibly PhysicsSystem?
         // Update entity from body
         entity.transform.node->setPosition(entity.get_physics()->get_position());
-
-        entity.get_physics()->reset();
     }
 
     // Update tilemap entities from their bodies
@@ -119,7 +117,6 @@ void Game::update(const f32 dt)
 
         if (auto& physics = entity->get_physics()) {
             entity->transform.node->setPosition(physics->get_position());
-            physics->reset();
         }
     }
 

src/system/physics/destruction.cpp

@@ -86,14 +86,6 @@ b2Fixture* get_enemy_or_null(b2Contact& contact)
 
 void DestructionListener::PostSolve(b2Contact* contact, const b2ContactImpulse* impulse)
 {
-    // TODO move this into a generic contact listener
-    {
-        auto& a = Entity::from(*contact->GetFixtureA());
-        auto& b = Entity::from(*contact->GetFixtureB());
-        a.get_physics()->update(*contact);
-        b.get_physics()->update(*contact);
-    }
-
     float impulse_factor = 1.0f;
 
     if (auto player_fixture = get_player_or_null(*contact)) {