..
  SPDX-License-Identifier: BSD-3-Clause
  Copyright Contributors to the OpenEXR Project.

exrenvmap
#########

::
   
    exrenvmap [options] infile outfile

Description
-----------

Convert an OpenEXR latitude-longitude environment map
into a cube-face environment map or vice versa.
Reads an environment map image from infile, converts
it, and stores the result in outfile.

If the input file name contains a '%' character, then an
input cube-face environment map is assembled from six
square sub-images that represent the six faces of the cube.
The names of the six image files are generated by replacing
the % with +X, -X, +Y, -Y, +Z and -Z respectively.

If the output file name contains a '%' character and
the program has been instructed to produce a cube-face
environment map, then the output image is split into six
square sub-images that are saved in six separate output
files.  The names of the files are generated by replacing
the % with +X, -X, +Y, -Y, +Z and -Z respectively.

Options:
--------

.. describe:: -o

              produces a ONE_LEVEL output file (default)

.. describe:: -m

              produces a MIPMAP_LEVELS output file (-m has
              no effect if the output image is split into
              multiple files)

.. describe:: -c

              the output file will be a cube-face environment
              map (default)

.. describe:: -l

              the output file will be a latitude-longitude
              environment map

.. describe:: -ci

              the input file is interpreted as a cube-face
              environment map, regardless of its envmap
              attribute

.. describe:: -li

              the input file is interpreted as a latitude-
              longitude environment map, regardless of its
              envmap attribute (-li has no effect if the
              input image is assembled from multiple files)

.. describe:: -w x

              sets the width of the output image to x pixels
              (default is 256).  The height of the output image
              will be x*6 pixels for a cube-face map, or x/2
              pixels for a latitude-longitude map.

.. describe:: -f r n

              sets the antialiasing filter radius to r
              (default is 1.0) and the sampling rate to
              n by n (default is 5 by 5).  Increasing r
              makes the output image blurrier; decreasing r
              makes the image sharper but may cause aliasing.
              Increasing n improves antialiasing, but
              generating the output image takes longer.

.. describe:: -b

              blurs the environment map image by applying a
              180-degree-wide filter kernel such that point-
              sampling the blurred image at a location that
              corresponds to 3D direction N returns the color
              that a white diffuse reflector with surface
              normal N would have if it was illuminated using
              the original non-blurred image.
              Generating the blurred image can be fairly slow.

.. describe:: -t x y

              sets the output file's tile size to x by y pixels
              (default is 64 by 64)

.. describe:: -p t b

              if the input image is a latitude-longitude map,
              pad the image at the top and bottom with t*h
              and b*h extra scan lines, where h is the height
              of the input image.  This is useful for images
              from 360-degree panoramic scans that cover
              less than 180 degrees vertically.

.. describe:: -d

              sets level size rounding to ROUND_DOWN (default)

.. describe:: -u

              sets level size rounding to ROUND_UP

.. describe:: -z x

              sets the data compression method to x
              (none/rle/zip/piz/pxr24/b44/b44a/dwaa/dwab,
              default is zip)

.. describe:: -v

              verbose mode

.. describe:: -h, --help

              print this message

.. describe:: --version

              print version information

