William Moberg
362 lines
13 KiB
C++
362 lines
13 KiB
C++
#ifndef Octree_h__
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#define Octree_h__
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#include <type_traits>
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#include "../Common.h"
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#include "AABB.h"
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#include "Frustum.h"
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//Fwd declarations.
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class Ray;
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namespace OctSpace
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{
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struct Output;
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struct ContainedObject;
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struct Child;
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}
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//T needs to be AABB, or inherit from AABB.
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//T also needs to have a default constructor.
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template<typename T>
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class Octree
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{
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public:
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Octree() = delete;
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~Octree();
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//For the root Octree, [octreeBounds] should be a box containing the entire level.
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Octree(const AABB& octreeBounds, int subDivisions);
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//We cannot copy the Octree as of now, because of the recursive dynamic allocation.
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//Define these if the Octree suddenly needs to be copied, think of the children Child* ptrs.
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Octree(const Octree& other) = delete;
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Octree(const Octree&& other) = delete;
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Octree& operator= (const Octree& other) = delete;
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//Add a dynamic object (one that moves around) into the tree.
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void AddDynamicObject(const T& object);
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//Add a static object (that does not move) into the tree.
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void AddStaticObject(const T& object);
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//Get the objects that are in the same area as the input [box], the objects are put in [outObjects].
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//The type Box must be AABB, or inherit from AABB.
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template<typename Box>
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void ObjectsInSameRegion(const Box& box, std::vector<T>& outObjects);
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//Get the objects that are inside the frustum, the objects are put in outObjects.
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void ObjectsInFrustum(const Frustum& frustum, std::vector<T>& outObjects);
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//Get objects, which AABB the input ray intersects, the objects are put in outObjects.
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void ObjectsPossiblyHitByRay(const Ray& ray, std::vector<T>& outObjects);
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//Empty the tree of all objects, static and dynamic.
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void ClearObjects();
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//Empty the tree of all dynamic objects. Static objects remain in the tree.
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void ClearDynamicObjects();
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//Returns true if the ray collides with something in the tree. Result is written to [data].
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bool RayCollides(const Ray& ray, OctSpace::Output& data);
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//Returns true if the box collides with something in the tree.
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//On collision with a box, that box is written to [outBoxIntersected].
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//Note: More efficient than calling ObjectsInSameRegion from outside and testing there.
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bool BoxCollides(const AABB& boxToTest, AABB& outBoxIntersected);
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private:
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OctSpace::Child* m_Root;
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std::vector<OctSpace::ContainedObject> m_StaticObjects;
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std::vector<OctSpace::ContainedObject> m_DynamicObjects;
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void falsifyObjectChecks();
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};
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namespace OctSpace
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{
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struct Output
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{
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float CollideDistance;
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};
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struct ContainedObject
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{
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ContainedObject()
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: Box(nullptr)
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, Checked(false)
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{}
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template<typename BoxlikeObject>
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ContainedObject(const BoxlikeObject& box)
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: Box(new BoxlikeObject(box))
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, Checked(false)
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{}
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std::unique_ptr<AABB> Box;
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bool Checked;
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};
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struct Child
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{
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~Child();
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Child(const AABB& octTreeBounds,
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int subDivisions,
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std::vector<ContainedObject>& staticObjects,
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std::vector<ContainedObject>& dynamicObjects);
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Child(const Child& other) = delete;
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Child(const Child&& other) = delete;
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Child& operator= (const Child& other) = delete;
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void AddDynamicObject(const AABB& box);
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void AddStaticObject(const AABB& box);
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template<typename T, typename Box>
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void ObjectsInSameRegion(const Box& box, std::vector<T>& outObjects) const;
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template<typename T>
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void ObjectsInFrustum(const Frustum& frustum, std::vector<T>& outObjects, bool takeAllDontTest) const;
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template<typename T>
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void ObjectsPossiblyHitByRay(const Ray& ray, std::vector<T>& outObjects) const;
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void ClearObjects();
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void ClearDynamicObjects();
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bool RayCollides(const Ray& ray, Output& data) const;
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bool BoxCollides(const AABB& boxToTest, AABB& outBoxIntersected) const;
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Child* m_Children[8];
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//Indices into the lists in Octree.
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std::vector<int> m_StaticObjIndices;
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std::vector<int> m_DynamicObjIndices;
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AABB m_Box;
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//Reference to the lists in Octree.
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std::vector<ContainedObject>& m_StaticObjectsRef;
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std::vector<ContainedObject>& m_DynamicObjectsRef;
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inline bool hasChildren() const { return m_Children[0] != nullptr; }
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int childIndexContainingPoint(const glm::vec3& point) const;
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std::vector<int> childIndicesContainingBox(const AABB& box) const;
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};
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//To be able to sort child nodes and contained objects based on distance to ray origin.
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struct RaySorterInfo
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{
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int Index;
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float Distance;
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};
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bool isFirstLower(const RaySorterInfo& first, const RaySorterInfo& second);
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}
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template<typename T>
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Octree<T>::Octree(const AABB& octTreeBounds, int subDivisions)
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: m_Root(new OctSpace::Child(octTreeBounds, subDivisions, m_StaticObjects, m_DynamicObjects))
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{
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static_assert(std::is_base_of<AABB, T>::value, "template argument type T in Octree must be a subclass of AABB.");
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}
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template<typename T>
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Octree<T>::~Octree()
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{
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delete m_Root;
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}
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template<typename T>
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void Octree<T>::AddDynamicObject(const T& object)
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{
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m_Root->AddDynamicObject(object);
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m_DynamicObjects.emplace_back(object);
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}
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template<typename T>
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void Octree<T>::AddStaticObject(const T& object)
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{
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m_Root->AddStaticObject(object);
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m_StaticObjects.emplace_back(object);
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}
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template<typename T>
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template<typename Box>
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void Octree<T>::ObjectsInSameRegion(const Box& box, std::vector<T>& outObjects)
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{
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static_assert(std::is_base_of<AABB, Box>::value, "template argument type Box in Octree<T>::ObjectsInSameRegion must be a subclass of AABB.");
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falsifyObjectChecks();
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m_Root->ObjectsInSameRegion(box, outObjects);
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}
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template<typename T>
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void Octree<T>::ObjectsInFrustum(const Frustum& frustum, std::vector<T>& outObjects)
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{
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falsifyObjectChecks();
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m_Root->ObjectsInFrustum(frustum, outObjects, false);
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}
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template<typename T>
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void Octree<T>::ObjectsPossiblyHitByRay(const Ray& ray, std::vector<T>& outObjects)
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{
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falsifyObjectChecks();
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m_Root->ObjectsPossiblyHitByRay(ray, outObjects);
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}
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template<typename T>
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void Octree<T>::ClearObjects()
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{
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m_StaticObjects.clear();
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m_DynamicObjects.clear();
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m_Root->ClearObjects();
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}
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template<typename T>
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void Octree<T>::ClearDynamicObjects()
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{
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m_DynamicObjects.clear();
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m_Root->ClearDynamicObjects();
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}
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template<typename T>
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bool Octree<T>::RayCollides(const Ray& ray, OctSpace::Output& data)
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{
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falsifyObjectChecks();
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data.CollideDistance = -1;
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return m_Root->RayCollides(ray, data);
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}
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template<typename T>
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bool Octree<T>::BoxCollides(const AABB& boxToTest, AABB& outBoxIntersected)
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{
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falsifyObjectChecks();
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return m_Root->BoxCollides(boxToTest, outBoxIntersected);
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}
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template<typename T>
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void Octree<T>::falsifyObjectChecks()
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{
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for (auto& obj : m_StaticObjects) {
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obj.Checked = false;
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}
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for (auto& obj : m_DynamicObjects) {
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obj.Checked = false;
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}
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}
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template<typename T, typename Box>
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void OctSpace::Child::ObjectsInSameRegion(const Box& box, std::vector<T>& outObjects) const
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{
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if (hasChildren()) {
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for (auto i : childIndicesContainingBox(box)) {
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m_Children[i]->ObjectsInSameRegion(box, outObjects);
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}
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} else {
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size_t startIndex = outObjects.size();
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int numDuplicates = 0;
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outObjects.resize(outObjects.size() + m_StaticObjIndices.size() + m_DynamicObjIndices.size());
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for (size_t i = 0; i < m_StaticObjIndices.size(); ++i) {
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ContainedObject& obj = m_StaticObjectsRef[m_StaticObjIndices[i]];
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if (obj.Checked) {
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++numDuplicates;
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} else {
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obj.Checked = true;
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outObjects[startIndex + i - numDuplicates] = *static_cast<T*>(obj.Box.get());
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}
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}
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for (size_t i = 0; i < m_DynamicObjIndices.size(); ++i) {
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ContainedObject& obj = m_DynamicObjectsRef[m_DynamicObjIndices[i]];
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if (obj.Checked) {
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++numDuplicates;
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} else {
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obj.Checked = true;
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outObjects[startIndex + i - numDuplicates] = *static_cast<T*>(obj.Box.get());
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}
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}
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for (size_t i = 0; i < numDuplicates; ++i) {
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outObjects.pop_back();
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}
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}
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}
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template<typename T>
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void OctSpace::Child::ObjectsInFrustum(const Frustum& frustum, std::vector<T>& outObjects, bool takeAllDontTest) const
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{
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if (hasChildren()) {
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for (const Child* c : m_Children) {
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Frustum::Output out = Frustum::Output::Inside;
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if (!takeAllDontTest) {
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out = frustum.VsAABB(c->m_Box);
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if (out == Frustum::Output::Outside) {
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continue;
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}
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}
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c->ObjectsInFrustum(frustum, outObjects, out == Frustum::Output::Inside);
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}
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} else {
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size_t startIndex = outObjects.size();
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int numDuplicates = 0;
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outObjects.resize(outObjects.size() + m_StaticObjIndices.size() + m_DynamicObjIndices.size());
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for (size_t i = 0; i < m_StaticObjIndices.size(); ++i) {
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ContainedObject& obj = m_StaticObjectsRef[m_StaticObjIndices[i]];
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if (obj.Checked || frustum.VsAABB(*obj.Box) == Frustum::Output::Outside) {
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++numDuplicates;
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} else {
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obj.Checked = true;
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outObjects[startIndex + i - numDuplicates] = *static_cast<T*>(obj.Box.get());
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}
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}
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for (size_t i = 0; i < m_DynamicObjIndices.size(); ++i) {
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ContainedObject& obj = m_DynamicObjectsRef[m_DynamicObjIndices[i]];
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if (obj.Checked || frustum.VsAABB(*obj.Box) == Frustum::Output::Outside) {
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++numDuplicates;
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} else {
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obj.Checked = true;
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outObjects[startIndex + i - numDuplicates] = *static_cast<T*>(obj.Box.get());
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}
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}
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for (size_t i = 0; i < numDuplicates; ++i) {
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outObjects.pop_back();
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}
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}
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}
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template<typename T>
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void OctSpace::Child::ObjectsPossiblyHitByRay(const Ray& ray, std::vector<T>& outObjects) const
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{
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//If the node AABB is missed, everything it contains is missed.
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if (Collision::RayAABBIntr(ray, m_Box)) {
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//If the ray shoots the tree, and it is a parent.
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if (hasChildren()) {
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//Sort children according to their distance from the ray origin.
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std::vector<RaySorterInfo> childInfos;
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childInfos.resize(8);
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for (int i = 0; i < 8; ++i) {
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childInfos[i] = { i, glm::distance(ray.Origin(), m_Children[i]->m_Box.Origin()) };
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}
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std::sort(childInfos.begin(), childInfos.end(), isFirstLower);
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//Loop through the children, starting with the one closest to the ray origin. I.e the first to be hit.
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for (const RaySorterInfo& info : childInfos) {
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m_Children[info.Index]->ObjectsPossiblyHitByRay(ray, outObjects);
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}
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} else {
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//Check against boxes in the node.
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bool intersected = false;
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float dist;
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//Sort all contained objects according to the distance from the ray origin to
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//the intersection, if they are intersecting.
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std::vector<RaySorterInfo> objectHitInfos;
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objectHitInfos.reserve(m_StaticObjIndices.size() + m_DynamicObjIndices.size());
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for (int i : m_StaticObjIndices) {
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//If we haven't tested against this object before, and the ray hits.
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if (!m_StaticObjectsRef[i].Checked &&
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Collision::RayVsAABB(ray, *m_StaticObjectsRef[i].Box, dist)) {
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objectHitInfos.push_back({ i, dist });
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}
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m_StaticObjectsRef[i].Checked = true;
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}
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for (int i : m_DynamicObjIndices) {
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//If we haven't tested against this object before, and the ray hits.
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if (!m_DynamicObjectsRef[i].Checked &&
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Collision::RayVsAABB(ray, *m_DynamicObjectsRef[i].Box, dist)) {
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objectHitInfos.push_back({ i + (int)m_StaticObjIndices.size(), dist });
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}
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m_DynamicObjectsRef[i].Checked = true;
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}
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std::sort(objectHitInfos.begin(), objectHitInfos.end(), isFirstLower);
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int startSize = (int)outObjects.size();
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outObjects.resize(startSize + objectHitInfos.size());
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for (int i = 0; i < objectHitInfos.size(); ++i) {
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outObjects[startSize + i] = (objectHitInfos[i].Index < m_StaticObjIndices.size()) ?
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*static_cast<T*>(m_StaticObjectsRef[objectHitInfos[i].Index].Box.get()) :
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*static_cast<T*>(m_DynamicObjectsRef[objectHitInfos[i].Index - m_StaticObjIndices.size()].Box.get());
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}
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}
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}
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}
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#endif |