PxContact.h

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#ifndef PX_CONTACT_H
#define PX_CONTACT_H

#include "foundation/PxVec3.h"
#include "foundation/PxAssert.h"

#if !PX_DOXYGEN
namespace physx
{
#endif

#if PX_VC
#pragma warning(push)
#pragma warning(disable: 4324)  // Padding was added at the end of a structure because of a __declspec(align) value.
#endif

#define PXC_CONTACT_NO_FACE_INDEX 0xffffffff

PX_ALIGN_PREFIX(16)
struct PxMassModificationProps
{
    PxReal mInvMassScale0;
    PxReal mInvInertiaScale0;
    PxReal mInvMassScale1;
    PxReal mInvInertiaScale1;
}
PX_ALIGN_SUFFIX(16);

PX_ALIGN_PREFIX(16)
struct PxContactPatch
{
    enum PxContactPatchFlags
    {
        eHAS_FACE_INDICES = 1,              
        eMODIFIABLE = 2,                    
        eFORCE_NO_RESPONSE = 4,             
        eHAS_MODIFIED_MASS_RATIOS = 8,      
        eHAS_TARGET_VELOCITY = 16,          
        eHAS_MAX_IMPULSE = 32,              
        eREGENERATE_PATCHES = 64,       
        eCOMPRESSED_MODIFIED_CONTACT = 128
    };

    PX_ALIGN(16, PxMassModificationProps mMassModification);            //16
    PX_ALIGN(16, PxVec3 normal);                                    //28
    PxReal  restitution;                                            //32

    PxReal  dynamicFriction;                                        //36
    PxReal  staticFriction;                                         //40
    PxU8    startContactIndex;                                      //41
    PxU8    nbContacts;                                             //42  //Can be a U8

    PxU8    materialFlags;                                          //43  //Can be a U16
    PxU8    internalFlags;                                          //44  //Can be a U16
    PxU16   materialIndex0;                                         //46  //Can be a U16
    PxU16   materialIndex1;                                         //48  //Can be a U16
    
    
}
PX_ALIGN_SUFFIX(16);

PX_ALIGN_PREFIX(16)
struct PxContact
{
    PxVec3  contact;                            //12
    PxReal  separation;                         //16
}
PX_ALIGN_SUFFIX(16);

PX_ALIGN_PREFIX(16)
struct PxExtendedContact : public PxContact
{
    PX_ALIGN(16, PxVec3 targetVelocity);        //28
    PxReal  maxImpulse;                         //32
}
PX_ALIGN_SUFFIX(16);

PX_ALIGN_PREFIX(16)
struct PxModifiableContact : public PxExtendedContact
{
    PX_ALIGN(16, PxVec3 normal);                    //44
    PxReal  restitution;                            //48
    
    PxU32   materialFlags;                          //52
    
    PxU16   materialIndex0;                         //54
    PxU16   materialIndex1;                         //56
    PxReal  staticFriction;                         //60
    PxReal dynamicFriction;                         //64
}
PX_ALIGN_SUFFIX(16);

struct PxContactStreamIterator
{
    enum StreamFormat
    {
        eSIMPLE_STREAM,
        eMODIFIABLE_STREAM,
        eCOMPRESSED_MODIFIABLE_STREAM
    };
    PxVec3 zero;
    const PxContactPatch* patch;

    const PxContact* contact;

    const PxU32* faceIndice;


    PxU32 totalPatches;
    
    PxU32 totalContacts;

    PxU32 nextContactIndex;
    
    PxU32 nextPatchIndex;

    /*
    \brief Size of contact patch header 
    \note This varies whether the patch is modifiable or not.
    */
    PxU32 contactPatchHeaderSize;
    PxU32 contactPointSize;
    StreamFormat mStreamFormat;
    PxU32 forceNoResponse;

    bool pointStepped;

    PxU32 hasFaceIndices;

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxContactStreamIterator(const PxU8* contactPatches, const PxU8* contactPoints, const PxU32* contactFaceIndices, PxU32 nbPatches, PxU32 nbContacts) 
        : zero(0.f)
    {       
        bool modify = false;
        bool compressedModify = false;
        bool response = false;
        bool indices = false; 
        
        PxU32 pointSize = 0;
        PxU32 patchHeaderSize = sizeof(PxContactPatch);

        const PxContactPatch* patches = reinterpret_cast<const PxContactPatch*>(contactPatches);

        if(patches)
        {
            modify = (patches->internalFlags & PxContactPatch::eMODIFIABLE) != 0;
            compressedModify = (patches->internalFlags & PxContactPatch::eCOMPRESSED_MODIFIED_CONTACT) != 0;
            indices = (patches->internalFlags & PxContactPatch::eHAS_FACE_INDICES) != 0;

            patch = patches;

            contact = reinterpret_cast<const PxContact*>(contactPoints);

            faceIndice = contactFaceIndices;

            pointSize = compressedModify ?  sizeof(PxExtendedContact) : modify ? sizeof(PxModifiableContact) : sizeof(PxContact);

            response = (patch->internalFlags & PxContactPatch::eFORCE_NO_RESPONSE) == 0;
        }


        mStreamFormat = compressedModify ? eCOMPRESSED_MODIFIABLE_STREAM : modify ? eMODIFIABLE_STREAM : eSIMPLE_STREAM;
        hasFaceIndices = PxU32(indices);
        forceNoResponse = PxU32(!response);

        contactPatchHeaderSize = patchHeaderSize;
        contactPointSize = pointSize;
        nextPatchIndex = 0;
        nextContactIndex = 0;
        totalContacts = nbContacts;
        totalPatches = nbPatches;
        
        pointStepped = false;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE bool hasNextPatch() const
    {
        return nextPatchIndex < totalPatches;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxU32 getTotalContactCount() const
    {
        return totalContacts;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxU32 getTotalPatchCount() const
    {
        return totalPatches;
    }

    PX_CUDA_CALLABLE PX_INLINE void nextPatch()
    {
        PX_ASSERT(nextPatchIndex < totalPatches);
        if(nextPatchIndex)
        {
            if(nextContactIndex < patch->nbContacts)
            {
                PxU32 nbToStep = patch->nbContacts - this->nextContactIndex;
                contact = reinterpret_cast<const PxContact*>(reinterpret_cast<const PxU8*>(contact) + contactPointSize * nbToStep);
            }
            patch = reinterpret_cast<const PxContactPatch*>(reinterpret_cast<const PxU8*>(patch) + contactPatchHeaderSize);
        }
        nextPatchIndex++;
        nextContactIndex = 0;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE bool hasNextContact() const
    {
        return nextContactIndex < (patch->nbContacts);
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE void nextContact()
    {
        PX_ASSERT(nextContactIndex < patch->nbContacts);
        if(pointStepped)
        {
            contact = reinterpret_cast<const PxContact*>(reinterpret_cast<const PxU8*>(contact) + contactPointSize);
            faceIndice++;
        }
        nextContactIndex++;
        pointStepped = true;
    }


    PX_CUDA_CALLABLE PX_FORCE_INLINE const PxVec3& getContactNormal() const
    {
        return getContactPatch().normal;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getInvMassScale0() const
    {
        return patch->mMassModification.mInvMassScale0;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getInvMassScale1() const
    {
        return patch->mMassModification.mInvMassScale1;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getInvInertiaScale0() const
    {
        return patch->mMassModification.mInvInertiaScale0;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getInvInertiaScale1() const
    {
        return patch->mMassModification.mInvInertiaScale1;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getMaxImpulse() const
    {
        return mStreamFormat != eSIMPLE_STREAM ? getExtendedContact().maxImpulse : PX_MAX_REAL;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE const PxVec3& getTargetVel() const
    {
        return mStreamFormat != eSIMPLE_STREAM ? getExtendedContact().targetVelocity : zero;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE const PxVec3& getContactPoint() const
    {
        return contact->contact;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getSeparation() const
    {
        return contact->separation;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxU32 getFaceIndex0() const
    {
        return PXC_CONTACT_NO_FACE_INDEX;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxU32 getFaceIndex1() const
    {
        return hasFaceIndices ? *faceIndice : PXC_CONTACT_NO_FACE_INDEX;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getStaticFriction() const
    {
        return getContactPatch().staticFriction;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getDynamicFriction() const
    {
        return getContactPatch().dynamicFriction;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal getRestitution() const
    {
        return getContactPatch().restitution;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxU32 getMaterialFlags() const
    {
        return getContactPatch().materialFlags;
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxU16 getMaterialIndex0() const
    {
        return PxU16(getContactPatch().materialIndex0);
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE PxU16 getMaterialIndex1() const
    {
        return PxU16(getContactPatch().materialIndex1);
    }

    bool advanceToIndex(const PxU32 initialIndex)
    {
        PX_ASSERT(this->nextPatchIndex == 0 && this->nextContactIndex == 0);
    
        PxU32 numToAdvance = initialIndex;

        if(numToAdvance == 0)
        {
            PX_ASSERT(hasNextPatch());
            nextPatch();
            return true;
        }
        
        while(numToAdvance)
        {
            while(hasNextPatch())
            {
                nextPatch();
                PxU32 patchSize = patch->nbContacts;
                if(numToAdvance <= patchSize)
                {
                    contact = reinterpret_cast<const PxContact*>(reinterpret_cast<const PxU8*>(contact) + contactPointSize * numToAdvance);
                    nextContactIndex += numToAdvance;
                    return true;
                }
                else
                {
                    numToAdvance -= patchSize;
                }
            }
        }
        return false;
    }

private:

    PX_CUDA_CALLABLE PX_FORCE_INLINE const PxContactPatch& getContactPatch() const
    {
        return *static_cast<const PxContactPatch*>(patch);
    }

    PX_CUDA_CALLABLE PX_FORCE_INLINE const PxExtendedContact& getExtendedContact() const
    {
        PX_ASSERT(mStreamFormat == eMODIFIABLE_STREAM || mStreamFormat == eCOMPRESSED_MODIFIABLE_STREAM);
        return *static_cast<const PxExtendedContact*>(contact);
    }

};


#if PX_VC
#pragma warning(pop)
#endif

#if !PX_DOXYGEN
} // namespace physx
#endif

#endif