unsafe void CalculateMipInfosNoncompressed(int mipCount, int pitch, out int chainSize)
{
if (mipCount == -1)
mipCount = 1;
int bytesPerPixel = Helper.FormatBits(DxgiFormat, D3DFormat) / 8;
if (pitch == -1)
{
pitch = Width * bytesPerPixel;
if ((pitch & 0x3) != 0)
pitch += 4 - (pitch & 0x3);
}
MipInfos = new MipInfo[mipCount];
fixed (MipInfo* infos = MipInfos)
{
infos[0] = new MipInfo
{
Width = Width,
Height = Height,
Depth = Depth,
OffsetInBytes = 0,
SizeInBytes = Height * pitch
};
for (int i = 1; i < mipCount; i++)
{
infos[i] = new MipInfo
{
Width = Math.Max(1, infos[i - 1].Width / 2),
Height = Math.Max(1, infos[i - 1].Height / 2),
Depth = Math.Max(1, infos[i - 1].Depth / 2),
OffsetInBytes = infos[i - 1].OffsetInBytes + infos[i - 1].SizeInBytes,
};
int mipPitch = infos[i].Width * bytesPerPixel;
if ((mipPitch & 0x3) != 0)
mipPitch += 4 - (mipPitch & 0x3);
infos[i].SizeInBytes = mipPitch * infos[i].Height * infos[i].Depth;
}
chainSize = infos[mipCount - 1].OffsetInBytes + infos[mipCount - 1].SizeInBytes;
}
}
unsafe void CalculateMipInfosCompressed(int mipCount, int linearSize, out int chainSize)
{
if (mipCount == -1)
mipCount = 1;
int multiplyer =
DxgiFormat == DxgiFormat.BC1_TYPELESS || DxgiFormat == DxgiFormat.BC1_UNORM ||
DxgiFormat == DxgiFormat.BC1_UNORM_SRGB || D3DFormat == D3DFormat.Dxt1
? 8
: 16;
if (linearSize == -1)
linearSize = Math.Max(1, Width / 4) * Math.Max(1, Height / 4) * multiplyer;
MipInfos = new MipInfo[mipCount];
fixed (MipInfo* infos = MipInfos)
{
infos[0] = new MipInfo
{
Width = Width,
Height = Height,
Depth = Depth,
OffsetInBytes = 0,
SizeInBytes = linearSize
};
for (int i = 1; i < mipCount; i++)
{
infos[i] = new MipInfo
{
Width = Math.Max(1, infos[i - 1].Width / 2),
Height = Math.Max(1, infos[i - 1].Height / 2),
Depth = Math.Max(1, infos[i - 1].Depth / 2),
OffsetInBytes = infos[i - 1].OffsetInBytes + infos[i - 1].SizeInBytes,
};
infos[i].SizeInBytes =
Math.Max(1, infos[i].Width / 4) * Math.Max(1, infos[i].Height / 4)
* infos[i].Depth * multiplyer;
}
chainSize = infos[mipCount - 1].OffsetInBytes + infos[mipCount - 1].SizeInBytes;
}
}
