in function USkinnedMeshComponent::GetCPUSkinnedVertices
// Recreate render state and flush the renderer
RecreateRenderState_Concurrent();
this would empty the active morph targets.
To slove this bug:
replace:
// Recreate render state and flush the renderer
RecreateRenderState_Concurrent();
with:
// Recreate render state and flush the renderer
// Cached the active morph targets, so that this function could work properly
TArray<FActiveMorphTarget> CachedActiveMorphTargets = ActiveMorphTargets;
TArray<float> CachedMorphTargetWeights = MorphTargetWeights;
if (bRenderStateCreated)
{
check(IsRegistered()); // Should never have render state unless registered
DestroyRenderState_Concurrent();
checkf(!bRenderStateCreated, TEXT("Failed to route DestroyRenderState_Concurrent (%s)"), *GetFullName());
}
if (IsRegistered() && GetWorld()->Scene)
{
ActiveMorphTargets = CachedActiveMorphTargets;
MorphTargetWeights = CachedMorphTargetWeights;
CreateRenderState_Concurrent();
checkf(bRenderStateCreated, TEXT("Failed to route CreateRenderState_Concurrent (%s)"), *GetFullName());
}