STLLoader class

Description: A THREE loader for STL ASCII files, as created by Solidworks and other CAD programs.

Supports both binary and ASCII encoded files, with automatic detection of type.

The loader returns a non-indexed buffer geometry.

Limitations: Binary decoding supports "Magics" color format. There is perhaps some question as to how valid it is to always assume little-endian-ness. ASCII decoding assumes file is UTF-8.

Usage:

 final loader = STLLoader();
 final geometry = await loader.fromAsset( 'assets/models/stl/slotted_disk.stl');
 scene.add(Mesh(geometry));

For binary STLs geometry might contain colors for vertices. To use it: // use the same code to load STL as above

 if (geometry.hasColors) {
   material = MeshPhongMaterial({ MaterialProperty.opacity: geometry.alpha, MaterialProperty.vertexColors: true });
 } else { .... }
 final mesh = Mesh( geometry, material );

For ASCII STLs containing multiple solids, each solid is assigned to a different group. Groups can be used to assign a different color by defining an array of materials with the same length of geometry.groups and passing it to the Mesh constructor:

final mesh = Mesh( geometry, material );

For example:

 final materials = [];
 final nGeometryGroups = geometry.groups.length;

 final colorMap = ...; // Some logic to index colors.

 for (int i = 0; i < nGeometryGroups; i++) {

		final material = MeshPhongMaterial({
			MaterialProperty.color: colorMap[i],
			MaterialProperty.wireframe: false
		});

 }

 materials.add(material);
 final mesh = Mesh(geometry, materials);