Compressed cubemap textures end up black on Android

[guygodin]

Bringing this issue from the old repository because it is still there. If I import a Cubemap texture (.dds in A8R8G8B8 format created with DirectX Texture Tool) then check the "Compress" option in Xenko Editor, the resulting texture will be completely black in game (I load the texture asset using Content.Load(...) and don't rely on the skybox asset). The texture format in game is correctly ETC2_RGBA_SRgb but the contents is all black with any texture quality setting (Fast, High, Best, etc.). If I don't check "Compress", it shows up correctly. If I manually compress the texture in PVRTexTool and import as a RawAsset it also works correctly (althrough the gamma is off).

[guygodin]

Found the source of the problem. I have tweaked the code too much in my branch to submit a PR but essentially the issue was with mipmapped cubemaps and the TransposeFaceData call not doing the correct thing because the PixelFormatExtensions doesn’t initialize the sizeOfInBits array for the Android specific texture compressions. Solution is to initialize the array to proper values for the ETC and other compressions.