Editor: Add support for importing OBJ/MTL assets with textures.

Description of the problem

The obj format model is a very commonly used format. When importing obj and mtl, you need zip. . After importing, the geometry and material can be loaded normally, but the texture map has an error. After checking, I found that it is related to the following code. It is not useful to process the material-related pictures in the zip. . This is not necessarily a bug, but it affects the experience more.

//editor/js/Loader.js( function handleZip() )
// Poly

if ( zip.files[ 'model.obj' ] && zip.files[ 'materials.mtl' ] ) {

	var materials = new MTLLoader().parse( zip.file( 'materials.mtl' ).asText() );
	var object = new OBJLoader().setMaterials( materials ).parse( zip.file( 'model.obj' ).asText() );
	editor.execute( new AddObjectCommand( editor, object ) );

}

Three.js version

• Dev
• r118
• …

Browser

• All of them

OS

• Windows

Hardware Requirements (graphics card, VR Device, …)

[Mugen87]

Just checking because I seemed to have the same experience as the original poster.

Using a zip archive like described above makes it possible to load an OBJ with an accompanying MTL file. However, textures are not supported since MTLLoader is going to take the texture name and append it to the editor’s URL path (e.g. https://threejs.org/editor/). This is not yet fixed.

[kylemcdonald]

When I tried importing the .obj and .mtl files into the editor either separately or at the same time, the .mtl was not applied. When I created a zip file and imported the zip file, the .mtl was applied correctly.