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Some README improvements. 

(More needed...)
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Par Winzell 2019-04-07 22:12:31 -07:00
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README.md
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@ -28,47 +28,64 @@ Or perhaps, as part of a more complex pipeline:
You can always run the binary with --help to see what options it takes:
```
FBX2glTF 2.0: Generate a glTF 2.0 representation of an FBX model.
Usage:
FBX2glTF [OPTION...] [<FBX File>]
FBX2glTF 0.9.6: Generate a glTF 2.0 representation of an FBX model.
Usage: FBX2glTF [OPTIONS] [FBX Model]
-i, --input arg The FBX model to convert.
-o, --output arg Where to generate the output, without suffix.
-e, --embed Inline buffers as data:// URIs within
generated non-binary glTF.
Positionals:
FBX Model FILE The FBX model to convert.
Options:
-h,--help Print this help message and exit
-v,--verbose Include blend shape tangents, if reported present by the FBX SDK.
-V,--version
-i,--input FILE The FBX model to convert.
-o,--output TEXT Where to generate the output, without suffix.
-e,--embed Inline buffers as data:// URIs within generated non-binary glTF.
-b,--binary Output a single binary format .glb file.
-d, --draco Apply Draco mesh compression to geometries.
--long-indices (never|auto|always)
Whether to use 32-bit indices.
--compute-normals (never|broken|missing|always)
When to compute vertex normals from mesh geometry.
--flip-u Flip all U texture coordinates.
--flip-v Flip all V texture coordinates (default
behaviour!)
--no-flip-v Suppress the default flipping of V texture
coordinates
--pbr-metallic-roughness Try to glean glTF 2.0 native PBR attributes
from the FBX.
--khr-materials-unlit Use KHR_materials_unlit extension to specify
Unlit shader.
--blend-shape-normals Include blend shape normals, if reported
present by the FBX SDK.
--blend-shape-tangents Include blend shape tangents, if reported
present by the FBX SDK.
--long-indices arg Whether to use 32-bit indices
(never|auto|always).
--compute-normals arg When to compute normals for vertices
(never|broken|missing|always).
-k, --keep-attribute arg Used repeatedly to build a limiting set of
vertex attributes to keep.
-v, --verbose Enable verbose output.
-h, --help Show this help.
-V, --version Display the current program version.
--no-flip-u Don't flip U texture coordinates.
--flip-v Flip all V texture coordinates.
--no-flip-v Don't flip V texture coordinates.
--no-khr-lights-punctual Don't use KHR_lights_punctual extension to export FBX lights.
--user-properties Transcribe FBX User Properties into glTF node and material 'extras'.
--blend-shape-normals Include blend shape normals, if reported present by the FBX SDK.
--blend-shape-tangents Include blend shape tangents, if reported present by the FBX SDK.
-k,--keep-attribute (position|normal|tangent|binormial|color|uv0|uv1|auto) ...
Used repeatedly to build a limiting set of vertex attributes to keep.
Materials:
--pbr-metallic-roughness Try to glean glTF 2.0 native PBR attributes from the FBX.
--khr-materials-unlit Use KHR_materials_unlit extension to request an unlit shader.
Draco:
-d,--draco Apply Draco mesh compression to geometries.
--draco-compression-level INT in [0 - 10]=7
The compression level to tune Draco to.
--draco-bits-for-position INT in [1 - 32]=14
How many bits to quantize position to.
--draco-bits-for-uv INT in [1 - 32]=10
How many bits to quantize UV coordinates to.
--draco-bits-for-normals INT in [1 - 32]=10
How many bits to quantize nornals to.
--draco-bits-for-colors INT in [1 - 32]=8
How many bits to quantize colors to.
--draco-bits-for-other INT in [1 - 32]=8
How many bits to quantize all other vertex attributes to.
```
Some of these switches are not obvious:
- `--embed` is the way to get a single distributable file without using the
binary format. It encodes the binary buffer(s) as a single enormous
base64-encoded `data://` URI. This is a very slow and space-consuming way to
accomplish what the binary format was invented to do simply and efficiently,
but it can be useful e.g. for loaders that don't understand the .glb format.
binary format. It encodes the binary buffer(s) as a single base64-encoded
`data://` URI. This is a very slow and space-consuming way to accomplish what
the binary format was invented to do simply and efficiently, but it can be
useful e.g. for loaders that don't understand the .glb format.
- `--flip-u` and `--flip-v`, when enabled, will apply a `x -> (1.0 - x)`
function to all `u` or `v` texture coordinates respectively. The `u` version
is perhaps not commonly used, but flipping `v` is **the default behaviour**.
@ -104,15 +121,20 @@ Some of these switches are not obvious:
## Building it on your own
This build process has been tested on Linux, Mac OS X and Windows. It requires
CMake 3.5+ and a reasonably C++11 compliant toolchain.
Building FBX2glTF has become slightly more ornery because we now require a full
C++17 toolchain including std::filesystem implementation.
For now, this means Visual Studio 2019 for Windows, and GCC 8.* the Unix based
systems. We could likely support Clang again, too, but there were complications
on Mac OS X; pull requests welcome.
We currently depend on the open source projects
[Draco](https://github.com/google/draco),
[MathFu](https://github.com/google/mathfu),
[Json](https://github.com/nlohmann/json),
[cppcodec](https://github.com/tplgy/cppcodec),
[cxxopts](https://github.com/jarro2783/cxxopts),
[CLI11](https://github.com/CLIUtils/CLI11),
[stb](https://github.com/nothings/stb),
and [fmt](https://github.com/fmtlib/fmt);
all of which are automatically downloaded, configured and built.
@ -120,18 +142,31 @@ You must manually download and install the
[Autodesk FBX SDK](https://www.autodesk.com/products/fbx/overview) and
accept its license agreement.
**At present, only version 2018.1.1 of the FBX SDK is supported**. The
**At present, only version 2019.2 of the FBX SDK is supported**. The
build system will not successfully locate any other version.
### Linux and MacOS X
Compilation on Unix machines should be as simple as:
Compilation on Unix machines might look like:
```
> cd <FBX2glTF directory>
> cmake -H. -Bbuild -DCMAKE_BUILD_TYPE=Release
> make -Cbuild -j4 install
> CC=gcc-8 CXX=g++8 \
> cmake -H. -Bbuild \
> -DCMAKE_BUILD_TYPE=Release \
> -DFBXSDK_SDKS=/home/zell/FBXSDK
> make -Cbuild -j12 install
```
Acquiring and installing GCC 8.* is a bit outside of the mandate for this
README, but on a Linux machine you might try:
```
> sudo add-apt-repository ppa:ubuntu-toolchain-r/test
> sudo apt update
> sudo apt-get install gcc-8 g++-8
```
and on Mac, Homebrew's stable GCC is at 8.3 at the time of writing.
If all goes well, you will end up with a statically linked executable.
### Windows
@ -141,12 +176,9 @@ install it and [run it](https://cmake.org/runningcmake/) on the FBX2glTF
checkout (choose a build directory distinct from the source).
As part of this process, you will be asked to choose which generator
to use. **At present, only Visual Studio 2017 is supported.** Older
to use. **At present, only Visual Studio 2019 is supported.** Older
versions of the IDE are unlikely to successfully build the tool.
*(MinGW support is plausible. The difficulty is linking statically against the
FBX SDK .lib file. Contributions welcome.)*
Note that the `CMAKE_BUILD_TYPE` variable from the Unix Makefile system is
entirely ignored here; it is when you open the generated solution that
you will be choose one of the canonical build types — *Debug*,