Add operator* to AABB, use in physics (#86)

include/vierkant/intersection.hpp

@@ -7,9 +7,9 @@
 
 #pragma once
 
+#include <vector>
 #include <vierkant/math.hpp>
 #include <vierkant/transform.hpp>
-#include <vector>
 
 namespace vierkant
 {
@@ -317,6 +317,21 @@ struct AABB
         return *this;
     }
 
+    AABB operator*(float grow_factor) const
+    {
+        AABB ret(*this);
+        ret *= grow_factor;
+        return ret;
+    }
+
+    AABB &operator*=(float grow_factor)
+    {
+        auto c = center();
+        min = c + (min - c) * grow_factor;
+        max = c + (max - c) * grow_factor;
+        return *this;
+    }
+
     inline explicit operator bool() const { return valid(); }
 
     inline bool operator==(const AABB &aabb) const { return min == aabb.min && max == aabb.max; }

src/physics_context.cpp

@@ -1014,6 +1014,7 @@ void PhysicsScene::remove_object(const Object3DPtr &object)
 {
     if(object)
     {
+        // remove all children
         vierkant::LambdaVisitor visitor;
         visitor.traverse(*object, [this](const auto &obj) -> bool {
             if(auto phy_cmp_ptr = obj.template get_component_ptr<vierkant::physics_component_t>())
@@ -1022,6 +1023,10 @@ void PhysicsScene::remove_object(const Object3DPtr &object)
             }
             return true;
         });
+
+        // grow aabb by a factor, wake up other objects there
+        constexpr float aabb_grow_factor = 1.2f;
+        m_context.body_interface().activate_in_aabb(object->aabb() * aabb_grow_factor);
     }
     vierkant::Scene::remove_object(object);
 }