bgfx/docs/tools.rst

Tools
=====

Geometry Compiler (geometryc)
-----------------------------

Converts Wavefront .obj, or glTF 2.0 mesh files to a format which is optimized for use with bgfx.

Usage::

    geometryc -f <in> -o <out>

Supported input file formats:

  ====== ============================
  Format Description
  ====== ============================
  .obj   Wavefront
  .gltf  glTF 2.0
  .glb   glTF 2.0
  ====== ============================

Options:

  -h, --help               Display this help and exit.
  -v, --version            Output version information and exit.
  -f <file path>           Input's file path.
  -o <file path>           Output's file path.
  -s, --scale <num>        Scale factor.
  --ccw                    Front face is counter-clockwise winding order.
  --flipv                  Flip texture coordinate V.
  --obb <num>              Number of steps for calculating oriented bounding box.
 
		Defaults to 17.

		Less steps = less precise OBB.

		More steps = slower calculation.
  --packnormal <num>       Normal packing.
       0 - unpacked 12 bytes. (Default)
       1 - packed 4 bytes.
  --packuv <num>           Texture coordinate packing.
       0 - unpacked 8 bytes. (Default)
       1 - packed 4 bytes.
  --tangent                Calculate tangent vectors. (Packing mode is the same as normal)
  --barycentric            Adds barycentric vertex attribute. (Packed in bgfx::Attrib::Color1)
  -c, --compress           Compress indices.
      --[l/r]h-up+[y/z]    Coordinate system. Defaults to '--lh-up+y' — Left-Handed +Y is up.

Geometry Viewer (geometryv)
---------------------------

A geometry viewer.

Shader Compiler (shaderc)
-------------------------

Shader Compiler is used to compile bgfx's cross-platform shader language, which based on GLSL.
It uses an ANSI C pre-processor to transform the GLSL-like language into HLSL.
This method has certain drawbacks,
but overall it's simple and allows for quick authoring of cross-platform shaders.

Some differences between bgfx's shaderc flavor of GLSL and vanilla GLSL:

-  ``bool/int`` uniforms are not allowed; all uniforms must be ``float``.
-  Attributes and varyings can only be accessed from ``main()``.
-  ``SAMPLER2D/3D/CUBE/etc.`` macros replace the ``sampler2D/3D/Cube/etc.`` tokens.
-  ``vec2/3/4_splat(<value>)`` replaces the ``vec2/3/4(<value>)`` constructor.
   ``vec2/3/4`` constructors with multiple values are still valid.
-  ``mtxFromCols/mtxFromRows`` must be used for constructing matrices.
- ``mul(x, y)`` must be used when multiplying vectors with matrices.
-  A ``varying.def.sc`` file must be used to define input/output semantics and types,
   instead of using ``attribute/in`` and ``varying/in/out``.
   This file cannot include comments, and typically only one is necessary.
-  ``$input/$output`` tokens corresponding to inputs and outputs defined in
   ``varying.def.sc`` must be used at the beginning of shader.

For more info, see the `shader helper macros
<https://github.com/bkaradzic/bgfx/blob/master/src/bgfx_shader.sh>`__.

Options:

  -h, --help                Display this help and exit.
  -v, --version             Output version information and exit.
  -f <file path>            Input's file path.
  -i <include path>         Include path. (for multiple paths use -i multiple times)
  -o <file path>            Output's file path.
  --bin2c <array name>      Generate C header file. If array name is not specified base file name will be used as name.
  --depends                 Generate makefile style depends file.
  --platform <platform>     Target platform.
  -p, --profile <profile>   Shader model.

  							Defaults to GLSL.
  --preprocess              Only pre-process.
  --define <defines>        Add defines to preprocessor. (semicolon separated)
  --raw                     Do not process shader. No preprocessor, and no glsl-optimizer. (GLSL only)
  --type <type>             Shader type.
  
  							Can be 'vertex', 'fragment, or 'compute'.
  --varyingdef <file path>  A varying.def.sc's file path.
  --verbose                 Be verbose.

(DX9 and DX11 only):

  --debug                   Debug information.
  --disasm                  Disassemble a compiled shader.
  -O <level>                Set optimization level.

							Can be 0–3.
  --Werror                	Treat warnings as errors.

Building shaders
~~~~~~~~~~~~~~~~

Shaders can be compiled for all renderers by using the ``shaderc`` tool.
A Makefile to simplify building shaders is provided in the `bgfx examples
<https://github.com/bkaradzic/bgfx/tree/master/examples>`__.
D3D shaders can be only compiled on Windows.

Texture Compiler (texturec)
---------------------------

Convert PNG, TGA, DDS, KTX, and PVR textures into bgfx-supported texture formats.

Usage::

  texturec -f <in> -o <out> [-t <texture format>]

Supported file formats:

  ====== ================ ============================
  Format In/Out           Description
  ====== ================ ============================
  .bmp   (input)          Windows Bitmap.
  .dds   (input, output)  Direct Draw Surface.
  .exr   (input, output)  OpenEXR.
  .gif   (input)          Graphics Interchange Format.
  .jpg   (input)          JPEG Interchange Format.
  .hdr   (input, output)  Radiance RGBE.
  .ktx   (input, output)  Khronos Texture.
  .png   (input, output)  Portable Network Graphics.
  .psd   (input)          Photoshop Document.
  .pvr   (input)          PowerVR.
  .tga   (input)          Truevision TGA.
  ====== ================ ============================

Options:

  -h, --help               	Display this help and exit.
  -v, --version            	Output version information and exit.
  -f <file path>           	Input's file path.
  -o <file path>           	Output's file path.
  -t <format>              	Output format type. (BC1/2/3/4/5, ETC1, PVR14, etc.)
  -q <quality>             	Encoding quality.

						   	Can be 'default', 'fastest', or 'highest'.
  -m, --mips               	Generate mip-maps.
  --mipskip <N>            	Skip <N> number of mips.
  -n, --normalmap          	Input texture is normal map. (Implies --linear)
  --equirect               	Input texture is equirectangular projection of cubemap.
  --strip                  	Input texture is horizontal strip of cubemap.
  --sdf                    	Compute SDF texture.
  --ref <alpha>           	Alpha reference value.
  --iqa                    	Image Quality Assessment
  --pma                    	Premultiply alpha into RGB channel.
  --linear                 	Input and output texture is linear color space. (Gamma correction won't be applied)
  --max <max size>         	Maximum width/height. (Image will be scaled down and aspect ratio will be preserved)
  --radiance <model>       	Radiance cubemap filter.

					       	Model can be 'Phong', 'PhongBrdf', 'Blinn', 'BlinnBrdf', or 'GGX'.
  --as <extension>         	Save as.
  --formats                	List all supported formats.
  --validate               	**DEBUG** Validate that output image produced matches after loading.

Texture Viewer (texturev)
-------------------------

A texture viewer.