Question

我在使用Direct3D时遇到了一些问题。即顶点缓冲区及其ByteWidth成员。

我想绘制两个四边形，所以我创建了我的顶点缓冲区，如下所示：

struct Vertex
{
    XMFLOAT3 pos;
    XMFLOAT3 normal;
    XMFLOAT2 texCoord;
};

    ....

void GameWindow::CreateVerticesAndBuffer()
{
    Vertex vertices[] =
    {
        { XMFLOAT3(-1.0f, -1.0f, -1.0f), XMFLOAT3(0.0f, 0.0f, -1.0f), XMFLOAT2(0.0f, 1.0f) },
        { XMFLOAT3(-1.0f, 1.0f, -1.0f), XMFLOAT3(0.0f, 0.0f, -1.0f), XMFLOAT2(0.0f, 0.0f) },
        { XMFLOAT3(1.0f, 1.0f, -1.0f), XMFLOAT3(0.0f, 0.0f, -1.0f), XMFLOAT2(1.0f, 0.0f) },
        { XMFLOAT3(1.0f, -1.0f, -1.0f), XMFLOAT3(0.0f, 0.0f, -1.0f), XMFLOAT2(1.0f, 1.0f) },

        { XMFLOAT3(-1.0f, -1.0f, 1.0f), XMFLOAT3(0.0f, 0.0f, -1.0f), XMFLOAT2(0.0f, 1.0f) },
        { XMFLOAT3(-1.0f, 1.0f, 1.0f), XMFLOAT3(0.0f, 0.0f, -1.0f), XMFLOAT2(0.0f, 0.0f) },
        { XMFLOAT3(1.0f, 1.0f, 1.0f), XMFLOAT3(0.0f, 0.0f, -1.0f), XMFLOAT2(1.0f, 0.0f) },
        { XMFLOAT3(1.0f, -1.0f, 1.0f), XMFLOAT3(0.0f, 0.0f, -1.0f), XMFLOAT2(1.0f, 1.0f) }
    };

    D3D11_BUFFER_DESC desc;
    ZeroMemory(&desc, sizeof(desc));
    desc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
    desc.CPUAccessFlags = 0;
    desc.Usage = D3D11_USAGE_DEFAULT; //Will not ever change after creation (??)
    desc.MiscFlags = 0;
    desc.ByteWidth = sizeof(Vertex) * 8;
    desc.StructureByteStride = 0;

    D3D11_SUBRESOURCE_DATA data;
    ZeroMemory(&data, sizeof(data));
    data.pSysMem = vertices;

    HR(device->CreateBuffer(
        &desc,
        &data,
        &vertexBuffer));

    UINT stride = sizeof(Vertex);
    UINT offset = 0;
    deviceContext->IASetVertexBuffers(0, 1, &vertexBuffer, &stride, &offset);
}

此代码会产生一些奇怪的结果，如here所示。由于某种原因，背面是镜像的。

但是，如果我改变了

desc.ByteWidth = sizeof(Vertex) * 8

到

desc.ByteWidth = sizeof(Vertex) * 9

是drawn correctly。

有没有人知道为什么会这样？

编辑：这是我的CreateInputLayout：

D3D11_INPUT_ELEMENT_DESC inputDesc[] = {
    { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 },
    { "NORMAL", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 12, D3D11_INPUT_PER_VERTEX_DATA, 0  },
    { "TEX", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 24, D3D11_INPUT_PER_VERTEX_DATA, 0  }
};

hRes = device->CreateInputLayout(
    inputDesc,
    ARRAYSIZE(inputDesc),
    vertexShaderSource->GetBufferPointer(),
    vertexShaderSource->GetBufferSize(),
    &vertexInputLayout);

Answer 1

您已为TEX成员指定了DXGI_FORMAT_R32G32B32_FLOAT（float3）。将其更改为DXGI_FORMAT_R32G32_FLOAT，它应该可以正常工作。

D3D11_BUFFER_DESC字节宽度“不工作”

1 个答案: