DX11以编程方式填充3D纹理

Question

I'm trying to fill a 3D texture with arbitrary data (either -1 or 1) using the map, write and unmap method mentioned on the MSDN, but I haven't been able to find any actual code examples of how to do this, using the row and depth pitches etc.

The texture description is:

D3D11_TEXTURE3D_DESC m_3DTexDesc;
m_3DTexDesc.Height = 33;
m_3DTexDesc.Width = 33;
m_3DTexDesc.Depth = 33;
m_3DTexDesc.MipLevels = 1;
m_3DTexDesc.Format = DXGI_FORMAT_R32_FLOAT;
m_3DTexDesc.Usage = D3D11_USAGE_DYNAMIC;
m_3DTexDesc.BindFlags = D3D10_BIND_SHADER_RESOURCE;
m_3DTexDesc.CPUAccessFlags = D3D10_CPU_ACCESS_WRITE;
m_3DTexDesc.MiscFlags = 0;

result = p_device->CreateTexture3D(&m_3DTexDesc, NULL, &m_voxels);

The code I'm using to fill the texture is:

D3D11_MAPPED_SUBRESOURCE mappedTex;

result = p_context->Map(m_voxels, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedTex);

float* pVoxels = (float*)mappedTex.pData;
// DepthPitch * 33 + RowPitch * 33 + 33;
float* pTexels = (float*)malloc(287265*4);

for( UINT dep = 0; dep < m_3DTexDesc.Depth; dep++ )
{
    UINT depStart = mappedTex.DepthPitch*dep;
    for( UINT row = 0; row < m_3DTexDesc.Width; row++ )
    {
        UINT rowStart = mappedTex.RowPitch*row;
        for( UINT col = 0; col < m_3DTexDesc.Height; col++ )
        {
            if(pos.y + col < 0.0f) pTexels[depStart + rowStart + col] = -1.0f;
            else pTexels[depStart + rowStart + col] = 1.0f;
        }
    }
}
memcpy(pVoxels, (void*)pTexels, 287265);

p_context->Unmap(m_voxels, 0 );

free((void*)pTexels);

Using this method, some of the data in the texture is fine but the rest is drastically wrong. Can someone explain the correct way to use these pointers and pitches to step through the texture and initialise it?

For reference DepthPitch = 8448 and RowPitch = 256.

Answer 1

Okay I finally worked out what I was doing wrong. I had to divide rowStart and depStart by 4 to convert from byte to float and it fixed everything.

UINT depStart = mappedTex.DepthPitch/4*dep;
for( UINT row = 0; row < m_3DTexDesc.Width; row++ )
{
    UINT rowStart = mappedTex.RowPitch/4*row;
    for( UINT col = 0; col < m_3DTexDesc.Height; col++ )
    {
        if(pos.y + col < 0.0f) pTexels[depStart + rowStart + col] = -1.0f;
        else pTexels[depStart + rowStart + col] = 1.0f;
    }
}