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// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// SPDX-FileCopyrightText: Copyright (c) 2008-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: Apache-2.0
#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 0.0f;
}
}
PX_CUDA_CALLABLE PX_FORCE_INLINE void PxsCombineMaterials(const PxsMaterialData& mat0Data, const PxsMaterialData& mat1Data,
PxReal& combinedStaticFriction, PxReal& combinedDynamicFriction,
PxReal& combinedRestitution, PxU32& combinedMaterialFlags, PxReal& combinedDamping)
{
const PxReal r0 = mat0Data.restitution;
const PxReal r1 = mat1Data.restitution;
const bool compliant0 = r0 < 0.0f;
const bool compliant1 = r1 < 0.0f;
const bool exactlyOneCompliant = compliant0 ^ compliant1;
const bool bothCompliant = compliant0 & compliant1;
const bool compliantAcc0 = !!(mat0Data.flags & PxMaterialFlag::eCOMPLIANT_ACCELERATION_SPRING);
const bool compliantAcc1 = !!(mat1Data.flags & PxMaterialFlag::eCOMPLIANT_ACCELERATION_SPRING);
const bool exactlyOneAccCompliant = compliantAcc0 ^ compliantAcc1;
// combine restitution
{
// For rigid-rigid or compliant-compliant interactions, follow the user's choice of combine mode but make sure it stays negative for multiply.
// For rigid-compliant interactions, we go with the compliant behavior.
// For forceCompliant-accelerationCompliant, we go with the accelerationCompliant behavior
if (bothCompliant && exactlyOneAccCompliant)
{
combinedRestitution = compliantAcc0 ? r0 : r1;
}
else
{
const PxCombineMode::Enum combineMode =
exactlyOneCompliant ? PxCombineMode::eMIN
: PxMax(mat0Data.getRestitutionCombineMode(), mat1Data.getRestitutionCombineMode());
const PxReal flipSign = (bothCompliant && (combineMode == PxCombineMode::eMULTIPLY)) ? -1.0f : 1.0f;
combinedRestitution = flipSign * combineScalars(r0, r1, combineMode);
}
}
// combine damping
{
// For rigid-rigid or compliant-compliant interactions, follow the user's choice of combine mode.
// For rigid-compliant interactions, we go with the compliant behavior.
// For forceCompliant-accelerationCompliant, we go with the accelerationCompliant behavior
const PxReal d0 = mat0Data.damping;
const PxReal d1 = mat1Data.damping;
if (bothCompliant && exactlyOneAccCompliant)
{
combinedDamping = compliantAcc0 ? d0 : d1;
}
else
{
const PxCombineMode::Enum combineMode =
exactlyOneCompliant ? PxCombineMode::eMAX
: PxMax(mat0Data.getDampingCombineMode(), mat1Data.getDampingCombineMode());
combinedDamping = combineScalars(d0, d1, combineMode);
}
}
// combine isotropic friction
{
const PxU32 combineFlags = (mat0Data.flags | mat1Data.flags); //& (PxMaterialFlag::eDISABLE_STRONG_FRICTION|PxMaterialFlag::eDISABLE_FRICTION); //eventually set DisStrongFric flag, lower all others.
if (!(combineFlags & PxMaterialFlag::eDISABLE_FRICTION))
{
const PxI32 fictionCombineMode = PxMax(mat0Data.getFrictionCombineMode(), mat1Data.getFrictionCombineMode());
PxReal dynFriction = 0.0f;
PxReal staFriction = 0.0f;
dynFriction = combineScalars(mat0Data.dynamicFriction, mat1Data.dynamicFriction, fictionCombineMode);
staFriction = combineScalars(mat0Data.staticFriction, mat1Data.staticFriction, fictionCombineMode);
//isotropic case
const PxReal fDynFriction = PxMax(dynFriction, 0.0f);
#if PX_CUDA_COMPILER
const PxReal fStaFriction = (staFriction - fDynFriction) >= 0 ? staFriction : fDynFriction;
#else
const PxReal fStaFriction = physx::intrinsics::fsel(staFriction - fDynFriction, staFriction, fDynFriction);
#endif
combinedDynamicFriction = fDynFriction;
combinedStaticFriction = fStaFriction;
combinedMaterialFlags = combineFlags;
}
else
{
combinedMaterialFlags = combineFlags | PxMaterialFlag::eDISABLE_STRONG_FRICTION;
combinedDynamicFriction = 0.0f;
combinedStaticFriction = 0.0f;
}
}
}
}
#endif