从 Direct3D 开始，简单的三角形不呈现

一段时间的制作游戏，首先使用 SDL，然后使用 SFML。为我完成基础知识真是太好了，但现在我想再迈出一步，从头开始学习如何制作图形。因此，我正在尝试学习 Direct3D 的诀窍，并且一直在阅读有关 D3D 11 的几个教程以开始使用。我只是想通过在深色背景上绘制一个白色三角形来获得绝对的基础......但我无法让它工作。

我使用的是Visual Studio 2012 RC和Windows 8 SDK，所以这里有一些C++11语法，而且没有D3DX。我已经设法设置了窗口，Direct3D 的初始化似乎很好。它运行主循环的渲染部分，因为它以我指定的颜色清除屏幕。但是，我花哨的白色三角形不会出现。我已经浏览了好几次我的代码，由于我缺乏经验，我无法判断它有什么问题。我已经删除了窗口初始化/d3d关闭和其他不相关的部分，但是如果其中一些与我的问题相关，我害怕切断太多，所以...代码大墙警告。

我想我已经准备好了所有必要的步骤;我创建设备、设备上下文、交换链和呈现目标。然后我创建一个顶点着色器+输入布局和一个像素着色器。之后，我创建一个顶点缓冲区，为我的三角形添加顶点并将原始拓扑设置为 TRIANGLELIST，这就是初始化。在我的主循环中，我将 D3D 指向我的顶点/像素着色器，并告诉它绘制我插入缓冲区的 3 个顶点。但只显示调用 ClearRenderTargetView 时的深蓝色背景;没有三角形。我是否错过了任何步骤，或者在途中做错了什么？

这是我拥有的代码（我会羞愧地承认在这个代码约定上有点懈怠，所以在指针变量等之前没有p）：

主循环：

while ( msg.message != WM_QUIT )
{
    if ( PeekMessage( &msg, 0, 0, 0, PM_REMOVE ))
    {
        TranslateMessage( &msg );
        DispatchMessage( &msg );
    }
    else
    {
        g_d3dContext->ClearRenderTargetView( g_renderTarget, clearColor );
        g_d3dContext->VSSetShader( g_vertexShader, nullptr, 0 );
        g_d3dContext->PSSetShader( g_pixelShader, nullptr, 0 );
        g_d3dContext->Draw( 3, 0 );
        g_swapChain->Present( 0, 0 );
    }
}

Direct3D init：

HRESULT hr = S_OK;
RECT rc;
GetClientRect( g_hWnd, &rc );
float width = static_cast<float>( rc.right - rc.left );
float height = static_cast<float>( rc.bottom - rc.top );
uint createDeviceFlags = 0;
const uint numDriverTypes = 3;
D3D_DRIVER_TYPE driverTypes[ numDriverTypes ] =
{
    D3D_DRIVER_TYPE_HARDWARE,
    D3D_DRIVER_TYPE_WARP,
    D3D_DRIVER_TYPE_REFERENCE
};
const uint numFeatureLevels = 3;
D3D_FEATURE_LEVEL featureLevels[ numFeatureLevels ] =
{
    D3D_FEATURE_LEVEL_11_0,
    D3D_FEATURE_LEVEL_10_1,
    D3D_FEATURE_LEVEL_10_0
};
DXGI_SWAP_CHAIN_DESC sd = { 0 };
sd.BufferCount                          = 1;
sd.BufferDesc.Width                     = static_cast<uint>( width );
sd.BufferDesc.Height                    = static_cast<uint>( height );
sd.BufferDesc.Format                    = DXGI_FORMAT_R8G8B8A8_UNORM;
sd.BufferDesc.RefreshRate.Numerator     = 60;
sd.BufferDesc.RefreshRate.Denominator   = 1;
sd.BufferUsage                          = DXGI_USAGE_RENDER_TARGET_OUTPUT;
sd.OutputWindow                         = g_hWnd;
sd.SampleDesc.Count                     = 1;
sd.SampleDesc.Quality                   = 0;
sd.Windowed                             = true;
for( uint driverTypeIndex : driverTypes )
{
    g_driverType = driverTypes[ driverTypeIndex ];
    hr = D3D11CreateDeviceAndSwapChain( nullptr, g_driverType, nullptr, createDeviceFlags, featureLevels, numFeatureLevels,
                                        D3D11_SDK_VERSION, &sd, &g_swapChain, &g_d3d, &g_featureLevel, &g_d3dContext );
    if( SUCCEEDED( hr ))
        break;
}
if( FAILED( hr ))
    return hr;
// Create a render target view
ID3D11Texture2D* backBuffer = nullptr;
hr = g_swapChain->GetBuffer( 0, __uuidof( ID3D11Texture2D ), reinterpret_cast<void**>( &backBuffer ));
if( FAILED( hr ))
    return hr;
hr = g_d3d->CreateRenderTargetView( backBuffer, nullptr, &g_renderTarget );
backBuffer->Release();
if( FAILED( hr ))
    return hr;
g_d3dContext->OMSetRenderTargets( 1, &g_renderTarget, nullptr );
// Setup the viewport
D3D11_VIEWPORT vp = { 0 };
vp.Width    = width;
vp.Height   = height;
vp.MinDepth = 0.0f;
vp.MaxDepth = 1.0f;
vp.TopLeftX = 0;
vp.TopLeftY = 0;
g_d3dContext->RSSetViewports( 1, &vp );
// Create vertex shader and input layout
ID3DBlob* vsBlob = nullptr;
ID3DBlob* errorBlob = nullptr;
hr = D3DCompileFromFile( L"VertexShader.hlsl", nullptr, nullptr, "main", "vs_4_0", 0, 0, &vsBlob, &errorBlob );
if ( FAILED( hr ))
    return hr;
hr = g_d3d->CreateVertexShader( vsBlob->GetBufferPointer(), vsBlob->GetBufferSize(), nullptr, &g_vertexShader );
if ( FAILED( hr ))
{
    vsBlob->Release();
    return hr;
}
D3D11_INPUT_ELEMENT_DESC ied = { 0 };
ied.AlignedByteOffset       = 0;
ied.Format                  = DXGI_FORMAT_R32G32B32_FLOAT;
ied.InputSlotClass          = D3D11_INPUT_PER_VERTEX_DATA;
ied.InputSlot               = 0;
ied.InstanceDataStepRate    = 0;
ied.SemanticIndex           = 0;
ied.SemanticName            = "POSITION";
hr = g_d3d->CreateInputLayout( &ied, 1, vsBlob->GetBufferPointer(), vsBlob->GetBufferSize(), &g_inputLayout );
vsBlob->Release();
if ( FAILED ( hr ))
    return hr;
g_d3dContext->IASetInputLayout( g_inputLayout );
// Create pixel shader
ID3DBlob* psBlob = nullptr;
errorBlob = nullptr;
hr = D3DCompileFromFile( L"PixelShader.hlsl", nullptr, nullptr, "main", "ps_4_0", 0, 0, &psBlob, &errorBlob );
if ( FAILED( hr ))
    return hr;
hr = g_d3d->CreatePixelShader( psBlob->GetBufferPointer(), psBlob->GetBufferSize(), nullptr, &g_pixelShader );
psBlob->Release();
if ( FAILED( hr ))
    return hr;
// Put some vertices up in this bitch
Vector3f vertices[] =
{
    Vector3f( 0.5f, -0.5f, 0.5f ),
    Vector3f( 0.5f, -0.5f, 0.5f ),
    Vector3f( -0.5f, -0.5f, 0.5f )
};
D3D11_BUFFER_DESC bd = { 0 };
bd.BindFlags            = D3D11_BIND_VERTEX_BUFFER;
bd.ByteWidth            = sizeof( Vector3f ) * 3;
bd.CPUAccessFlags       = 0;
bd.MiscFlags            = 0;
bd.StructureByteStride  = 0;
bd.Usage                = D3D11_USAGE_DEFAULT;
D3D11_SUBRESOURCE_DATA initData = { 0 };
initData.pSysMem            = vertices;
initData.SysMemPitch        = 0;
initData.SysMemSlicePitch   = 0;
hr = g_d3d->CreateBuffer( &bd, &initData, &g_vertexBuffer );
if ( FAILED( hr ))
    return hr;
uint stride = sizeof( Vector3f );
uint offset = 0;
g_d3dContext->IASetVertexBuffers( 0, 1, &g_vertexBuffer, &stride, &offset );
g_d3dContext->IASetPrimitiveTopology( D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST );
return S_OK;

我的顶点类型：

struct Vector3f
{
    Vector3f( float ix, float iy, float iz )
        : x( ix ), y( iy ), z( iz ) {}
    float x;
    float y;
    float z;
};

我的顶点着色器：

float4 main( float4 pos : POSITION ) : SV_POSITION
{
    return pos;
}

我的像素着色器：

float4 main() : SV_TARGET
{
    return float4( 1.0f, 1.0f, 1.0f, 1.0f );
}