koctree.h

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#ifndef KOCTREE_H
#define KOCTREE_H
 
#include "kexport.h"
#include "kdatatype.h"
 
#include <vector>
#include <memory>
#include <unordered_set>
#include <functional>
 
namespace kemena
{
    class kMesh;
    class kScene;
    class kObject;
 
    // -----------------------------------------------------------------------

    enum class kFrustumTestResult
    {
        Outside,      
        Intersecting, 
        Inside        
    };

    class KEMENA3D_API kFrustum
    {
    public:
        void extractFromMatrix(const kMat4 &viewProjection);

        kFrustumTestResult testAABB(const kAABB &aabb) const;

        bool intersectsAABB(const kAABB &aabb) const;
 
    private:
        kVec4 planes[6]; // (nx, ny, nz, d) — positive half-space is inside
    };
 
    // -----------------------------------------------------------------------

    class KEMENA3D_API kOctree
    {
    public:
        kOctree(int maxDepth = 6, int maxObjectsPerNode = 8);

        ~kOctree();

        void build(kScene *scene);

        std::vector<kMesh*> queryVisible(const kFrustum &frustum) const;

        void clear();

        int getNodeCount()  const;

        int getMeshCount()  const { return totalMeshes; }

        void traverse(const std::function<void(const kAABB &, int, bool)> &visitor) const;
 
    private:
        struct Node
        {
            kAABB bounds;                         
            std::vector<kMesh*> meshes;           
            std::unique_ptr<Node> children[8];    
            bool leaf = true;                     

            void subdivide();

            void insert(kMesh *mesh, const kAABB &meshBounds, int depth,
                        int maxDepth, int maxObj);

            void collectAll(std::vector<kMesh*> &out) const;

            void query(const kFrustum &frustum, std::vector<kMesh*> &out) const;

            void traverse(const std::function<void(const kAABB &, int, bool)> &visitor,
                          int depth) const;

            int  nodeCount() const;
        };
 
        std::unique_ptr<Node> root; 
        int maxDepth;               
        int maxObjectsPerNode;      
        int totalMeshes = 0;        

        static void collectMeshes(kObject *node, std::vector<kMesh*> &out);
    };
}
 
#endif // KOCTREE_H