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JulienLebot

DX11 How to save mipmaps in a DDS file manually ?

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Hi everyone,

I'm trying to save a mip-map chain generated with D3DX11FilterTexture into a DDS file.
I'm using Humus' Framework 3 image class to save as DDS and the ATI Texture Compressor library to compress the texture.

I generate the mipmaps before compressing each one individually and when I save it I end up with the following image and mip-maps:
[attachment=7507:DDS_M0.PNG]
[attachment=7508:DDS_M1.PNG]
[attachment=7509:DDS_M2.PNG]

The first image is correct, the second contains all the mip-maps and the remaining mip-maps are black, so it sounds to me like it's a problem saving the image. I've assumed all along that in a DDS file the mip-maps are stored one after the other and this doc seems to correlate with that.

Here is the code where I generate and store the mip-maps in the in-memory image:


D3D11_TEXTURE2D_DESC desc;
finalTexture->GetDesc(&desc);
desc.MiscFlags = 0;
// Generate mip-map chain
if (mipLevels > 1)
{
if (D3DX11FilterTexture(m_ctx, finalTexture, 0, mipFilter) != S_OK)
{
SAFE_RELEASE(finalTexture);
return -1;
}
}
FW3Imaging::FORMAT format = FW3Imaging::FORMAT_NONE;
for (int i = 0; i < elementsOf(formats); ++i)
if (formats == desc.Format)
format = (FW3Imaging::FORMAT)i;
// TODO: error handling
ID3D11Texture2D* staging = NULL;
desc.BindFlags = 0;
desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
desc.Usage = D3D11_USAGE_STAGING;
if ((hr = m_device->CreateTexture2D(&desc, NULL, &staging)) != S_OK)
{
SAFE_RELEASE(finalTexture);
return -1;
}
m_ctx->CopyResource(staging, finalTexture);
D3D11_MAPPED_SUBRESOURCE subresource;
if ((hr = m_ctx->Map(staging, D3D11CalcSubresource(0,0,mipLevels), D3D11_MAP_READ, 0, &subresource)) != S_OK)
{
SAFE_RELEASE(finalTexture);
SAFE_RELEASE(staging);
return -1;
}
unsigned char* data = (unsigned char*)subresource.pData;
size_t pixelsSize = GetMipMappedSize(desc.Width, desc.Height, 1, format, 0, mipLevels);
unsigned char* dest_pixels = new unsigned char[pixelsSize];
unsigned char* pixels = dest_pixels;
unsigned int width = desc.Width;
unsigned int height = desc.Height;
for (unsigned int nMip = 0; nMip < mipLevels; ++nMip)
{
unsigned int dest_pitch = getBytesPerPixel(format) * width;
// Copy the pixels row by row
for (unsigned int i = 0; i < height; ++i)
{
// Copy this row into the pixels
memcpy(pixels, data, dest_pitch);
pixels += dest_pitch;
data += subresource.RowPitch;
}
width = max(1, width >> 1);
height = max(1, height >> 1);
}
outImage->Load(dest_pixels, format, desc.Width, desc.Height, 1, mipLevels, false);
delete[] dest_pixels;
// That only works for power of two textures.
//outImage->Load(subresource.pData, format, desc.Width, desc.Height, 1, 1, false);
m_ctx->Unmap(staging, 0);
SAFE_RELEASE(finalTexture);
SAFE_RELEASE(staging);


All the outImage->Load function does is copy the data.
The code that compresses the image (and each mip-map) is as follow:


bool Image::Compress(const FORMAT newCompressedFormat, const CompressionOptions* pOptions)
{
if (!isCompressedFormat(newCompressedFormat))
return false;
if (getChannelCount(this->format) >= 3)
Swap(0,2); // Need to swap R & B to get BGR
const CompressionOptions& options = *pOptions;
ATI_TC_CompressOptions ati_options;
memset(&ati_options, 0, sizeof(options));
ati_options.dwSize = sizeof(ati_options);
ati_options.bUseChannelWeighting = options.UseChannelWeighting;
ati_options.fWeightingRed = options.WeightingRed;
ati_options.fWeightingGreen = options.WeightingGreen;
ati_options.fWeightingBlue = options.WeightingBlue;
ati_options.bUseAdaptiveWeighting = options.UseAdaptiveWeighting;
ati_options.bDXT1UseAlpha = options.DXT1UseAlpha;
ati_options.nAlphaThreshold = options.AlphaThreshold;
ati_options.bDisableMultiThreading = options.DisableMultiThreading;
ati_options.nCompressionSpeed = (ATI_TC_Speed)options.Speed;
uint32 mwidth = this->width;
uint32 mheight = this->height;
unsigned char *data = this->pixels;
std::vector<ATI_TC_Texture> mipMaps(nMipMaps);
for (int i = 0; i < nMipMaps; ++i)
mipMaps.pData = NULL;
bool error = false;
for (int i = 0; i < nMipMaps; ++i)
{
unsigned int pitch = getBytesPerPixel(format) * mwidth;
// Init src texture
ATI_TC_Texture srcTexture;
srcTexture.dwSize = sizeof(srcTexture);
srcTexture.dwWidth = mwidth;
srcTexture.dwHeight = mheight;
srcTexture.dwPitch = pitch;
srcTexture.format = GetATI_TC_Format(this->format);
srcTexture.dwDataSize = ATI_TC_CalculateBufferSize(&srcTexture);
srcTexture.pData = (ATI_TC_BYTE*)data;
// Init dest texture
ATI_TC_Texture& destTexture = mipMaps;
destTexture.dwSize = sizeof(destTexture);
destTexture.dwWidth = mwidth;
destTexture.dwHeight = mheight;
destTexture.dwPitch = getBytesPerPixel(newCompressedFormat) * mwidth;
destTexture.format = GetATI_TC_Format(newCompressedFormat);
destTexture.dwDataSize = ATI_TC_CalculateBufferSize(&destTexture);
destTexture.pData = new ATI_TC_BYTE[destTexture.dwDataSize];
ATI_TC_ERROR ati_tc_error = ATI_TC_ConvertTexture(&srcTexture, &destTexture, &ati_options, NULL, NULL, NULL);
if (ati_tc_error != ATI_TC_OK)
{
error = true;
break;
}
data += srcTexture.dwDataSize;
mwidth = max(1, mwidth >> 1);
mheight = max(1, mheight >> 1);
}
if (!error)
{
Free();
size_t newSize = 0;
// Compute new global size
for (int i = 0; i < nMipMaps; ++i)
newSize += mipMaps.dwDataSize;
// Re-allocate memory
this->pixels = new unsigned char[newSize];
data = this->pixels;
// Copy each mip-map into the new pixels
for (int i = 0; i < nMipMaps; ++i)
{
memcpy(data, mipMaps.pData, mipMaps.dwDataSize);
data += mipMaps.dwDataSize;
}
this->format = newCompressedFormat;
}
for (int i = 0; i < nMipMaps; ++i)
{
if (mipMaps.pData != NULL)
delete[] mipMaps.pData;
}
return error;
}


The save function simply writes the header out and then saves all the pixels in one go:


// Generate header
...


swrite(&header, sizeof(header), 1, file);
if (headerDX10.dxgiFormat)
swrite(&headerDX10, sizeof(headerDX10), 1, file);
int size = GetMipMappedSize(0, nMipMaps);
swrite(pixels, size, 1, file);


Any ideas on what I'm doing wrong ?

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