UVAtlasTool

This UVAtlas sample is an implementation of the uvatlas command-line sample from the DirectX SDK using UVAtlas, DirectXTex, and DirectXMesh rather than D3DX. This tool imports geometry and generates an isochart mesh.

The original tool imported from legacy X files. This version imports from Wavefront OBJ or VBO files.

Syntax

UVAtlas.exe uses the following command syntax:

uvatlas [-q <level>] [-n <number>] [-st <float>] [-g <float>]
[-w <number>] [-h <number>]
[-ta | -ga] [-nn | -na | -ne] [-tt | -tb] [-cw] [-c] [-t] [-it <filename>]
[-iv <channel>] [-sdkmesh | -cmo | -vbo] [-nodds] [-flip] [-flipv] [-flipz]
[-o <filename] [-y] [-nologo] <file-name(s)>

The optional command-line switches are described in the following table.

Optional Switches Description

• -q level: sets quality level to DEFAULT, FAST or QUALITY. With DEFAULT, the tool uses QUALITY for meshes below a threshold, and FAST otherwise.

• -n number: sets the maximum number of charts to generate. The default of 0 uses max-stretch as the limit. Note this is a soft limit.

• -st float: sets the maximum amount of stretch 0.0..1.0, defaulting to 0.16667

• -g float: is the the gutter width between charts in texels, which defaults to 2.0

• -w, -h: number texture width/height for the atlas, defaults to 512x512.

• -ta: when generating adjacency use topological adjacency (the default)

• -ga: when generating adjacency use geometric adjacency (uses epsilon of 1e-5f)

• -nn: generate normals weighted by angle

• -na: generate normals weighted by area

• -ne: generate normals weighted equally

• -tt: generate tangents.

• -tb: generate tangents and bi-tangents (aka bi-normals).

• -cw: faces are clockwise (defaults to counter-clockwise) for generating normal

• -c: generate mesh with colors showing charts (replaces the materials set and attributes in the output).

• -t: generates a separate mesh with uvs as position information to allow visualization of the isochart. Output name has _texture appended.

• -it filename: calculates IMT for the mesh using this texture map

• -iv channel: calculates IMT using per-vertex data where channel is NORMAL, COLOR, or TEXCOORD

• -sdkmesh: output an SDKMESH file (the default)

• -cmo: output a CMO file (requires normals, tangents and texture coordinates).

• -vbo: output a VBO file (requires normals and texture coordinates).

• -nodds: prevents extension renaming in exported materials. By default, texture filenames are converted from an existing image extension to .dds assuming they are going to be processed by 'texconv'. This flag prevents the renaming and leaves the original extension.

• -flip: reverses the winding of faces

• -flipv: inverts the v texture coordinate (Direct3D vs. OpenGL image orientation)

• -flipz: negates the z component (RH vs. LH view systems)

• -o filename: specifies output filename which is otherwise generated from the input file name. Use of this switch supports only one input file.

• -y: overwrite existing output file if any. By default, the tool will abort if the output file already exists.

• -nologo: suppress copyright message

Example

uvatlas cup.obj -t -c

This loads the geometry in a Wavefront OBJ file 'cup.obj', generates normals (using weight by angle), generates an isochart, and then writes the result to cup.sdkmesh as well as a visualization to cup_texture.sdkmesh both using a material set that colors each face by which chart it belongs to in the atlas.