b2_broad_phase.h

// MIT License
 
// Copyright (c) 2019 Erin Catto
 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
 
#ifndef B2_BROAD_PHASE_H
#define B2_BROAD_PHASE_H
 
#include "b2_api.h"
#include "b2_settings.h"
#include "b2_collision.h"
#include "b2_dynamic_tree.h"
 
struct B2_API b2Pair
{
    int32 proxyIdA;
    int32 proxyIdB;
};
 
class B2_API b2BroadPhase
{
public:
 
    enum
    {
        e_nullProxy = -1
    };
 
    b2BroadPhase();
    ~b2BroadPhase();
 
    int32 CreateProxy(const b2AABB& aabb, void* userData);
 
    void DestroyProxy(int32 proxyId);
 
    void MoveProxy(int32 proxyId, const b2AABB& aabb, const b2Vec2& displacement);
 
    void TouchProxy(int32 proxyId);
 
    const b2AABB& GetFatAABB(int32 proxyId) const;
 
    void* GetUserData(int32 proxyId) const;
 
    bool TestOverlap(int32 proxyIdA, int32 proxyIdB) const;
 
    int32 GetProxyCount() const;
 
    template <typename T>
    void UpdatePairs(T* callback);
 
    template <typename T>
    void Query(T* callback, const b2AABB& aabb) const;
 
    template <typename T>
    void RayCast(T* callback, const b2RayCastInput& input) const;
 
    int32 GetTreeHeight() const;
 
    int32 GetTreeBalance() const;
 
    float GetTreeQuality() const;
 
    void ShiftOrigin(const b2Vec2& newOrigin);
 
private:
 
    friend class b2DynamicTree;
 
    void BufferMove(int32 proxyId);
    void UnBufferMove(int32 proxyId);
 
    bool QueryCallback(int32 proxyId);
 
    b2DynamicTree m_tree;
 
    int32 m_proxyCount;
 
    int32* m_moveBuffer;
    int32 m_moveCapacity;
    int32 m_moveCount;
 
    b2Pair* m_pairBuffer;
    int32 m_pairCapacity;
    int32 m_pairCount;
 
    int32 m_queryProxyId;
};
 
inline void* b2BroadPhase::GetUserData(int32 proxyId) const
{
    return m_tree.GetUserData(proxyId);
}
 
inline bool b2BroadPhase::TestOverlap(int32 proxyIdA, int32 proxyIdB) const
{
    const b2AABB& aabbA = m_tree.GetFatAABB(proxyIdA);
    const b2AABB& aabbB = m_tree.GetFatAABB(proxyIdB);
    return b2TestOverlap(aabbA, aabbB);
}
 
inline const b2AABB& b2BroadPhase::GetFatAABB(int32 proxyId) const
{
    return m_tree.GetFatAABB(proxyId);
}
 
inline int32 b2BroadPhase::GetProxyCount() const
{
    return m_proxyCount;
}
 
inline int32 b2BroadPhase::GetTreeHeight() const
{
    return m_tree.GetHeight();
}
 
inline int32 b2BroadPhase::GetTreeBalance() const
{
    return m_tree.GetMaxBalance();
}
 
inline float b2BroadPhase::GetTreeQuality() const
{
    return m_tree.GetAreaRatio();
}
 
template <typename T>
void b2BroadPhase::UpdatePairs(T* callback)
{
    // Reset pair buffer
    m_pairCount = 0;
 
    // Perform tree queries for all moving proxies.
    for (int32 i = 0; i < m_moveCount; ++i)
    {
        m_queryProxyId = m_moveBuffer[i];
        if (m_queryProxyId == e_nullProxy)
        {
            continue;
        }
 
        // We have to query the tree with the fat AABB so that
        // we don't fail to create a pair that may touch later.
        const b2AABB& fatAABB = m_tree.GetFatAABB(m_queryProxyId);
 
        // Query tree, create pairs and add them pair buffer.
        m_tree.Query(this, fatAABB);
    }
 
    // Send pairs to caller
    for (int32 i = 0; i < m_pairCount; ++i)
    {
        b2Pair* primaryPair = m_pairBuffer + i;
        void* userDataA = m_tree.GetUserData(primaryPair->proxyIdA);
        void* userDataB = m_tree.GetUserData(primaryPair->proxyIdB);
 
        callback->AddPair(userDataA, userDataB);
    }
 
    // Clear move flags
    for (int32 i = 0; i < m_moveCount; ++i)
    {
        int32 proxyId = m_moveBuffer[i];
        if (proxyId == e_nullProxy)
        {
            continue;
        }
 
        m_tree.ClearMoved(proxyId);
    }
 
    // Reset move buffer
    m_moveCount = 0;
}
 
template <typename T>
inline void b2BroadPhase::Query(T* callback, const b2AABB& aabb) const
{
    m_tree.Query(callback, aabb);
}
 
template <typename T>
inline void b2BroadPhase::RayCast(T* callback, const b2RayCastInput& input) const
{
    m_tree.RayCast(callback, input);
}
 
inline void b2BroadPhase::ShiftOrigin(const b2Vec2& newOrigin)
{
    m_tree.ShiftOrigin(newOrigin);
}
 
#endif