PxsMaterialCombiner.h

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//  * Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//  * Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//  * Neither the name of NVIDIA CORPORATION nor the names of its
//    contributors may be used to endorse or promote products derived
//    from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Copyright (c) 2008-2022 NVIDIA Corporation. All rights reserved.
// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.  
 
#ifndef PXS_MATERIAL_COMBINER_H
#define PXS_MATERIAL_COMBINER_H
 
#include "PxsMaterialCore.h"
 
namespace physx
{
    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal combineScalars(PxReal a, PxReal b, PxI32 combineMode)
    {
        switch (combineMode)
        {
            case PxCombineMode::eAVERAGE:
                return 0.5f * (a + b);
            case PxCombineMode::eMIN:
                return PxMin(a,b);
            case PxCombineMode::eMULTIPLY:
                return a * b;
            case PxCombineMode::eMAX:
                return PxMax(a,b);
            default:
                return PxReal(0);
        }   
    }
 
    PX_CUDA_CALLABLE PX_FORCE_INLINE PxReal PxsCombineRestitution(const PxsMaterialData& mat0, const PxsMaterialData& mat1)
    {
        return combineScalars(mat0.restitution, mat1.restitution, ((mat0.flags | mat1.flags) & PxMaterialFlag::eCOMPLIANT_CONTACT) ? 
            PxCombineMode::eMIN : PxMax(mat0.getRestitutionCombineMode(), mat1.getRestitutionCombineMode()));
    }
 
    //ML:: move this function to header file to avoid LHS in Xbox
    //PT: also called by CUDA code now
    PX_CUDA_CALLABLE PX_FORCE_INLINE void PxsCombineIsotropicFriction(const PxsMaterialData& mat0, const PxsMaterialData& mat1, PxReal& dynamicFriction, PxReal& staticFriction, PxU32& flags)
    {
        const PxU32 combineFlags = (mat0.flags | mat1.flags); //& (PxMaterialFlag::eDISABLE_STRONG_FRICTION|PxMaterialFlag::eDISABLE_FRICTION); //eventually set DisStrongFric flag, lower all others.
 
        if (!(combineFlags & PxMaterialFlag::eDISABLE_FRICTION))
        {
            const PxI32 fictionCombineMode = PxMax(mat0.getFrictionCombineMode(), mat1.getFrictionCombineMode());
            PxReal dynFriction = 0.0f;
            PxReal staFriction = 0.0f;
 
            switch (fictionCombineMode)
            {
            case PxCombineMode::eAVERAGE:
                dynFriction = 0.5f * (mat0.dynamicFriction + mat1.dynamicFriction);
                staFriction = 0.5f * (mat0.staticFriction + mat1.staticFriction);
                break;
            case PxCombineMode::eMIN:
                dynFriction = PxMin(mat0.dynamicFriction, mat1.dynamicFriction);
                staFriction = PxMin(mat0.staticFriction, mat1.staticFriction);
                break;
            case PxCombineMode::eMULTIPLY:
                dynFriction = (mat0.dynamicFriction * mat1.dynamicFriction);
                staFriction = (mat0.staticFriction * mat1.staticFriction);
                break;
            case PxCombineMode::eMAX:
                dynFriction = PxMax(mat0.dynamicFriction, mat1.dynamicFriction);
                staFriction = PxMax(mat0.staticFriction, mat1.staticFriction);
                break;
            }   
 
            //isotropic case
            const PxReal fDynFriction = PxMax(dynFriction, 0.0f);
 
            // PT: TODO: the two branches aren't actually doing the same thing:
            // - one is ">", the other is ">="
            // - one uses a clamped dynFriction, the other not
#ifdef __CUDACC__
            const PxReal fStaFriction = (staFriction - fDynFriction) > 0 ? staFriction : dynFriction;
#else
            const PxReal fStaFriction = physx::intrinsics::fsel(staFriction - fDynFriction, staFriction, fDynFriction);
#endif
            dynamicFriction = fDynFriction;
            staticFriction = fStaFriction;
            flags = combineFlags;
        }
        else
        {
            flags = combineFlags | PxMaterialFlag::eDISABLE_STRONG_FRICTION;
            dynamicFriction = 0.0f;
            staticFriction = 0.0f;
        }
    }
}
 
#endif