//
// Copyright 2018 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#include "pxr/imaging/hdSt/extCompGpuPrimvarBufferSource.h"

#include "pxr/imaging/hd/bufferSpec.h"
#include "pxr/imaging/hd/tokens.h"

PXR_NAMESPACE_OPEN_SCOPE

HdStExtCompGpuPrimvarBufferSource::HdStExtCompGpuPrimvarBufferSource(
        TfToken const &name,
        HdTupleType const &valueType,
        int numElements,
        SdfPath const& compId)
 : HdNullBufferSource()
 , _name(name)
 , _tupleType(valueType)
 , _numElements(numElements)
 , _compId(compId)
{
}

/* virtual */
TfToken const &
HdStExtCompGpuPrimvarBufferSource::GetName() const
{
    return _name;
}

/* virtual */
size_t
HdStExtCompGpuPrimvarBufferSource::ComputeHash() const
{
    // Simply return a hash based on the computation and primvar names, 
    // instead of hashing the contents of the inputs to the computation.
    // This effectively disables primvar sharing when using computed primvars.
    size_t hash = 0;
    boost::hash_combine(hash, _compId);
    boost::hash_combine(hash, _name);
    return hash;
}

/* virtual */
bool
HdStExtCompGpuPrimvarBufferSource::Resolve()
{
    if (!_TryLock()) return false;
    _SetResolved();
    return true;
}

/* virtual */
bool
HdStExtCompGpuPrimvarBufferSource::_CheckValid() const
{
    return true;
}

/* virtual */
size_t
HdStExtCompGpuPrimvarBufferSource::GetNumElements() const
{
    return _numElements;
}

/* virtual */
HdTupleType
HdStExtCompGpuPrimvarBufferSource::GetTupleType() const
{
    return _tupleType;
}

/* virtual */
void
HdStExtCompGpuPrimvarBufferSource::GetBufferSpecs(
        HdBufferSpecVector *specs) const
{
    specs->emplace_back(_name, _tupleType);
}


PXR_NAMESPACE_CLOSE_SCOPE