Converting and Loading COLLADA Models

The O3D sample COLLADA converter, described in detail in Importing Scene Files, has been extended to support the WebGL implementation of O3D. New command line arguments cause the output assets to be written into a directory containing a set of flat files that can be used directly by a Web browser. This document describes the changes to the converter and the model loading process.

Command syntax

The command to run the converter is o3dConverter, with arguments as specified below.

• --no-condition
• --up-axis=x, y, z
• --/your_path/your_filename.zip
• --/your_path/your_output_directory.o3dtgz
• --no-binary
• --no-archive
• --convert-dds-to-png
• --convert-cg-to-glsl

where

--no-condition

Prevents conditioning of the shaders from COLLADA form to the form expected by O3D. Use this option if you know that the shaders have already been conditioned. Otherwise, omit it.

--up-axis=x, y, z

Specifies the x, y, and z values for the up axis in the model file.

--/your_path/your_filename.zip

Specifies the path to the COLLADA file to be converted (or to the .zip archive containing the file).

--/your_path/your_output_directory.o3dtgz

Specifies the output path. If you specify --no-archive, the output is actually written to output_directory rather than to the archive output_directory.o3dtgz.

--no-binary

Puts all vertex and index data directly into the scene.json file

--no-archive

Writes multiple files into one directory instead of producing an .o3dtgz archive. (Note that with this command line argument, the converter takes an .o3dtgz file name as the output path but does not actually write out an archive.)

--convert-dds-to-png

Converts textures in the DirectDraw Surface file format to PNG, a Web standard.

--convert-cg-to-glsl

Converts all Cg shaders to GLSL format, using the cg-to-glsl converter script.

Example invocation

The following command line converts the O3D teapot asset into a format compatible with the WebGL implementation of O3D:

 o3dConverter --no-condition --up-axis=0,1,0 --no-binary
--no-archive --convert-dds-to-png --convert-cg-to-glsl
../o3dassets/samples/convert-assets/teapot.zip
../samples/assets/teapot.o3dtgz

The first two command line arguments, --no-condition and --up-axis, are identical to those used when converting this asset for use with the plug-in implementation of O3D. ../o3dassets/samples/convert-assets/teapot.zip specifies the path to the COLLADA file or, in this case, the .zip archive containing it. ../samples/assets/teapot.o3dtgz specifies the output path. Note that because the --no-archive command line argument is specified, the output is actually written into the directory ../samples/assets/teapot/ rather than to the file teapot.o3dtgz.

Loading the converted model

To load the converted model in the WebGL implementation of O3D, simply pass the URL of the converted scene.json rather than the .o3dtgz file to o3d.ArchiveRequest.open. See the helloworld.html O3D/WebGL sample for a simple example of how to load and display a model.