Apple provides the texturetool tool to cook textures into the PowerVR compressed texture format. My toolchain runs on Windows so I would like to create this texture data on a Windows PC. It looks like this will be simple because Imagination provides a tool and SDK that runs on windows. So I've downloaded PVRTexTool and will use that in my existing in-house texture cooking tool. Has anyone tried this? I'm wondering if there are any known incompatibilities between this and the iOS OpenGL ES implementation.
I now have this working and did not have any issues of compatibility with iOS.
One thing that confused me at first is that the standard formats that the tool does processing on are all ABGR format. You can convert your original data (mine was ARGB) into a standard format using the DecompressPVR function (even though my original data is not compressed).
Other issues that came up along the way: - Compressed textures have to be square. You can use the ProcessRawPVR function to resize non-square textures to square - the layout of the generated mipmaps in the resulting buffer is not obvious. You end up with one buffer containing all the mipmaps but, at runtime you need to add each mip map separately using glCompressedTexImage2D or glTexImage2D.