void FPhysXVehicleManager::UpdateTireFrictionTableInternal()
{
const PxU32 MAX_NUM_MATERIALS = 128;
// There are tire types and then there are drivable surface types.
// PhysX supports physical materials that share a drivable surface type,
// but we just create a drivable surface type for every type of physical material
PxMaterial* AllPhysicsMaterials[MAX_NUM_MATERIALS];
PxVehicleDrivableSurfaceType DrivableSurfaceTypes[MAX_NUM_MATERIALS];
// Gather all the physical materials
GPhysXSDK->getMaterials(AllPhysicsMaterials, MAX_NUM_MATERIALS);
uint32 NumMaterials = GPhysXSDK->getNbMaterials();
uint32 NumTireTypes = UTireType::AllTireTypes.Num();
for ( uint32 m = 0; m < NumMaterials; ++m )
{
// Set up the drivable surface type that will be used for the new material.
DrivableSurfaceTypes[m].mType = m;
}
// Release the previous SurfaceTirePairs, if any
if ( SurfaceTirePairs )
{
SurfaceTirePairs->release();
SurfaceTirePairs = NULL;
}
// Set up the friction values arising from combinations of tire type and surface type.
SurfaceTirePairs = PxVehicleDrivableSurfaceToTireFrictionPairs::allocate( NumTireTypes, NumMaterials );
SurfaceTirePairs->setup( NumTireTypes, NumMaterials, (const PxMaterial**)AllPhysicsMaterials, DrivableSurfaceTypes );
for ( uint32 m = 0; m < NumMaterials; ++m )
{
UPhysicalMaterial* PhysMat = FPhysxUserData::Get<UPhysicalMaterial>(AllPhysicsMaterials[m]->userData);
for ( uint32 t = 0; t < NumTireTypes; ++t )
{
TWeakObjectPtr<UTireType> TireType = UTireType::AllTireTypes[t];
float TireFrictionScale = 1.0f;
if ( PhysMat != NULL )
{
TireFrictionScale *= PhysMat->GetTireFrictionScale( TireType );
}
else if ( TireType != NULL )
{
TireFrictionScale *= TireType->GetFrictionScale();
}
SurfaceTirePairs->setTypePairFriction( m, t, TireFrictionScale );
}
}
}
float UPhysicalMaterial::GetTireFrictionScale( TWeakObjectPtr<UTireType> TireType )
{
float Scale = (TireType != NULL) ? TireType->GetFrictionScale() : 1.0f;
Scale *= TireFrictionScale;
for ( int32 i = TireFrictionScales.Num() - 1; i >= 0; --i )
{
if ( TireFrictionScales[i].TireType == TireType.Get() )
{
Scale *= TireFrictionScales[i].FrictionScale;
break;
}
}
return Scale;
}