Function Combine

Source/Engine/CSG/CSGBuilder.cpp:154–219

    }

    Mesh* Combine(Actor* actor, MeshesLookup& cache, Mesh* combineParent)
    {
        ASSERT(actor);
        Mesh* result = nullptr;
        Mesh* myBrush = nullptr;
        cache.TryGet(actor, myBrush);

        // Get first child mesh with valid data (has additive brush)
        int32 childIndex = 0;
        while (childIndex < actor->Children.Count())
        {
            auto child = Combine(actor->Children[childIndex], cache, combineParent);

            childIndex++;
            if (child)
            {
                // If brush was based on additive brush or current actor is a brush we can stop searching
                if (child->HasMode(Mode::Additive) || myBrush)
                {
                    // End searching
                    result = child;
                    break;
                }

                if (combineParent)
                {
                    // Combine
                    combineParent->PerformOperation(child);
                }
            }
        }

        // Check if has any child with CSG brush
        if (result)
        {
            // Check if has own brush
            if (myBrush)
            {
                // Combine with first child
                myBrush->PerformOperation(result);

                // Set this actor brush as a result
                result = myBrush;
            }

            // Merge with the other children
            while (childIndex < actor->Children.Count())
            {
                auto child = Combine(actor->Children[childIndex], cache, result);
                if (child)
                {
                    // Combine
                    result->PerformOperation(child);
                }

                childIndex++;
            }
        }