DDS files that specify DDS_PITCH load more reliably

[TheFlipbook]

• Some files define Pitch instead of LinearSize
• The files sometimes also have RGBBitCount
• However, many do not, such as those in the NVTT test suite -- https://github.com/castano/nvidia-texture-tools/blob/master/data/testsuite/lightmap/cottage.dds
• In other cases, DX10 formats more fully specify the data.
• In cases where we have no better path, use dwPitchOrLinearSize as pitch -- Microsoft recommends recomputing pitch instead -- https://docs.microsoft.com/en-us/windows/desktop/direct3ddds/dx-graphics-dds-pguide -- However, had no convenient way to select correct method