Creates a modern HDR equirectangular image from 6 VTF/PNG/other HDR cubemap faces (up, lf, ft, rt, bk, dn).
Works best with VTF hdr images used with Source games.
Uses VTFLib for reading VTF files and DevIL to create HDR image.
Projection conversion code is a port of CubemapToEquirectangular for Unity.
Start program and give folder containing all 6 faces, or pass path as launch arg.
xoffset, yoffset (0 - 1): Offset the final HDR, useful if you want to rotate the hdr but cannot in some software.
scale: Scale the output HDR file. Can help improve quality.
exposureshift: Shift exposure up/down for generic image based inputs.