GteDX11IndexBuffer.cpp

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// David Eberly, Geometric Tools, Redmond WA 98052
// Copyright (c) 1998-2017
// Distributed under the Boost Software License, Version 1.0.
// http://www.boost.org/LICENSE_1_0.txt
// http://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
// File Version: 3.0.0 (2016/06/19)

#include <GTEnginePCH.h>
#include <Graphics/DX11/GteDX11IndexBuffer.h>
using namespace gte;

DX11IndexBuffer::DX11IndexBuffer(ID3D11Device* device, IndexBuffer const* ibuffer)
    :
    DX11Buffer(ibuffer),
    mFormat(ibuffer->GetElementSize() == sizeof(unsigned int) ?
        DXGI_FORMAT_R32_UINT : DXGI_FORMAT_R16_UINT)
{
    // Specify the buffer description.
    D3D11_BUFFER_DESC desc;
    desc.ByteWidth = ibuffer->GetNumBytes();
    desc.BindFlags = D3D11_BIND_INDEX_BUFFER;
    desc.MiscFlags = D3D11_RESOURCE_MISC_NONE;
    desc.StructureByteStride = 0;
    Resource::Usage usage = ibuffer->GetUsage();
    if (usage == Resource::IMMUTABLE)
    {
        desc.Usage = D3D11_USAGE_IMMUTABLE;
        desc.CPUAccessFlags = D3D11_CPU_ACCESS_NONE;
    }
    else if (usage == Resource::DYNAMIC_UPDATE)
    {
        desc.Usage = D3D11_USAGE_DYNAMIC;
        desc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
    }
    else
    {
        desc.Usage = D3D11_USAGE_DEFAULT;
        desc.CPUAccessFlags = D3D11_CPU_ACCESS_NONE;
    }

    // Create the buffer.
    ID3D11Buffer* buffer = nullptr;
    HRESULT hr;
    if (ibuffer->GetData())
    {
        D3D11_SUBRESOURCE_DATA data;
        data.pSysMem = ibuffer->GetData();
        data.SysMemPitch = 0;
        data.SysMemSlicePitch = 0;
        hr = device->CreateBuffer(&desc, &data, &buffer);
    }
    else
    {
        hr = device->CreateBuffer(&desc, nullptr, &buffer);
    }
    CHECK_HR_RETURN_NONE("Failed to create index buffer");
    mDXObject = buffer;

    // Create a staging buffer if requested.
    if (ibuffer->GetCopyType() != Resource::COPY_NONE)
    {
        CreateStaging(device, desc);
    }
}

std::shared_ptr<GEObject> DX11IndexBuffer::Create(void* device, GraphicsObject const* object)
{
    if (object->GetType() == GT_INDEX_BUFFER)
    {
        return std::make_shared<DX11IndexBuffer>(
            reinterpret_cast<ID3D11Device*>(device),
            static_cast<IndexBuffer const*>(object));
    }

    LogError("Invalid object type.");
    return nullptr;
}

void DX11IndexBuffer::Enable(ID3D11DeviceContext* context)
{
    if (mDXObject)
    {
        ID3D11Buffer* dxBuffer = static_cast<ID3D11Buffer*>(mDXObject);
        context->IASetIndexBuffer(dxBuffer, mFormat, 0);
    }
}

void DX11IndexBuffer::Disable(ID3D11DeviceContext* context)
{
    if (mDXObject)
    {
        context->IASetIndexBuffer(0, DXGI_FORMAT_UNKNOWN, 0);
    }
}