//
//   Copyright 2013 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 "../osd/d3d11VertexBuffer.h"
#include "../far/error.h"

#include <D3D11.h>
#include <cassert>

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

namespace Osd {

#define SAFE_RELEASE(p) { if(p) { (p)->Release(); (p)=NULL; } }

D3D11VertexBuffer::D3D11VertexBuffer(int numElements, int numVertices)
    : _numElements(numElements), _numVertices(numVertices), _buffer(0),
      _uploadBuffer(0), _uav(0) {
}

D3D11VertexBuffer::~D3D11VertexBuffer() {

    SAFE_RELEASE(_buffer);
    SAFE_RELEASE(_uploadBuffer);
    SAFE_RELEASE(_uav);
}

D3D11VertexBuffer*
D3D11VertexBuffer::Create(int numElements, int numVertices,
                          ID3D11DeviceContext *deviceContext) {
    D3D11VertexBuffer *instance =
        new D3D11VertexBuffer(numElements, numVertices);

    ID3D11Device *device;
    deviceContext->GetDevice(&device);
    if (instance->allocate(device)) return instance;
    delete instance;
    return NULL;
}

void
D3D11VertexBuffer::UpdateData(const float *src, int startVertex, int numVertices,
                              ID3D11DeviceContext *deviceContext) {

    assert(deviceContext);

    D3D11_MAPPED_SUBRESOURCE resource;
    HRESULT hr = deviceContext->Map(_uploadBuffer, 0,
                                    D3D11_MAP_WRITE_DISCARD, 0, &resource);

    if (FAILED(hr)) {
        Far::Error(Far::FAR_RUNTIME_ERROR, "Failed to map buffer\n");
        return;
    }

    unsigned int size = GetNumElements() * numVertices * sizeof(float);

    memcpy((float*)resource.pData + startVertex * _numElements, src, size);

    deviceContext->Unmap(_uploadBuffer, 0);

    D3D11_BOX srcBox = { 0, 0, 0, size, 1, 1 };
    deviceContext->CopySubresourceRegion(_buffer, 0, 0, 0, 0,
                                         _uploadBuffer, 0, &srcBox);
}

int
D3D11VertexBuffer::GetNumElements() const {

    return _numElements;
}

int
D3D11VertexBuffer::GetNumVertices() const {

    return _numVertices;
}

ID3D11Buffer *
D3D11VertexBuffer::BindD3D11Buffer(ID3D11DeviceContext *deviceContext) {

    return _buffer;
}

ID3D11UnorderedAccessView *
D3D11VertexBuffer::BindD3D11UAV(ID3D11DeviceContext *deviceContext) {

    return _uav;
}

bool
D3D11VertexBuffer::allocate(ID3D11Device *device) {

    D3D11_BUFFER_DESC hBufferDesc;
    hBufferDesc.ByteWidth = _numElements * _numVertices * sizeof(float);
    hBufferDesc.Usage = D3D11_USAGE_DEFAULT;
    hBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER | D3D11_BIND_UNORDERED_ACCESS | D3D11_BIND_SHADER_RESOURCE;
    hBufferDesc.CPUAccessFlags = 0;
    hBufferDesc.MiscFlags = 0;
    hBufferDesc.StructureByteStride = sizeof(float);

    HRESULT hr = device->CreateBuffer(&hBufferDesc, NULL, &_buffer);
    if (FAILED(hr)) {
        Far::Error(Far::FAR_RUNTIME_ERROR,
                 "Failed to create vertex buffer\n");
        return false;
    }

    hBufferDesc.ByteWidth = _numElements * _numVertices * sizeof(float);
    hBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
    hBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER | D3D11_BIND_SHADER_RESOURCE;
    hBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
    hBufferDesc.MiscFlags = 0;
    hBufferDesc.StructureByteStride = sizeof(float);

    hr = device->CreateBuffer(&hBufferDesc, NULL, &_uploadBuffer);
    if (FAILED(hr)) {
        Far::Error(Far::FAR_RUNTIME_ERROR,
                 "Failed to create upload vertex buffer\n");
        return false;
    }

    D3D11_UNORDERED_ACCESS_VIEW_DESC uavd;
    ZeroMemory(&uavd, sizeof(uavd));
    uavd.Format = DXGI_FORMAT_R32_FLOAT;
    uavd.ViewDimension = D3D11_UAV_DIMENSION_BUFFER;
    uavd.Buffer.FirstElement = 0;
    uavd.Buffer.NumElements = _numElements * _numVertices;
    hr = device->CreateUnorderedAccessView(_buffer, &uavd, &_uav);
    if (FAILED(hr)) {
        Far::Error(Far::FAR_RUNTIME_ERROR,
                 "Failed to create unordered access resource view\n");
        return false;
    }
    return true;
}

}  // end namespace Osd

}  // end namespace OPENSUBDIV_VERSION
}  // end namespace OpenSubdiv