# Simple HDR cubemap to longlat(longitude latitude. or known as equirectangular) converter.
## Requirements
* C++11 compiler
## Coordinate definition.
* Y-up
* Right-handed
* Center is -z
## Usage
Assume cubemap image is given by 6 images(6 faces).
```
$ ./cube2longlat px.exr nx.exr py.exr ny.exr pz.exr nz.exr 512 longlat.exr (phi_offset)
```
Optional `phi_offset` is used to add offset(by angle) to phi to rotate X and Z faces.
## Supported input image format
* [ ] RGBM(Filament's RGBM encoding. Multiplier is 16, and gamma corrected) Implemented but not tested.
* [x] EXR
## Supported output image format
* [ ] RGBM(Filament's RGBM encoding. Multiplier is 16, and gamma corrected) Implemented but not tested.
* [x] EXR
* [x] RGBE
## Note
When you create cubemap using Filament's cmgen
https://github.com/google/filament/tree/master/tools/cmgen , its generated cubemap images are mirrored by X direction.
Use `--mirror` when invoking `cmgen` if required.
## TODO
* Single cubemap image(cross layout)
* Better antialiasing
* theta offset
* Mirroring.