filter method
- MeshGeometry mesh
override
Returns a copy of the mesh with any filter transforms applied.
Implementation
@override
MeshGeometry filter(MeshGeometry mesh) {
final newAttribs = List<VertexAttrib>.from(mesh.attribs);
if (mesh.getAttrib('NORMAL') == null) {
newAttribs.add(VertexAttrib('NORMAL', 3, 'float'));
}
final output = MeshGeometry(mesh.triangleVertexCount, newAttribs);
final p0 = Vector3.zero(), p1 = Vector3.zero(), p2 = Vector3.zero();
final srcPosition = mesh.getViewForAttrib('POSITION');
final destPosition = output.getViewForAttrib('POSITION');
final normals = output.getViewForAttrib('NORMAL');
if (srcPosition is! Vector3List ||
destPosition is! Vector3List ||
normals is! Vector3List) {
throw UnimplementedError();
}
final srcAttribs = <VectorList<Vector>>[];
final destAttribs = <VectorList<Vector>>[];
for (var attrib in mesh.attribs) {
if (attrib.name == 'POSITION' || attrib.name == 'NORMAL') {
continue;
}
srcAttribs.add(mesh.getViewForAttrib(attrib.name)!);
destAttribs.add(output.getViewForAttrib(attrib.name)!);
}
for (var i = 0; i < output.length; i += 3) {
final i0 = mesh.indices![i];
final i1 = mesh.indices![i + 1];
final i2 = mesh.indices![i + 2];
srcPosition
..load(i0, p0)
..load(i1, p1)
..load(i2, p2);
destPosition[i] = p0;
destPosition[i + 1] = p1;
destPosition[i + 2] = p2;
// Store the normalized cross product of p1 and p2 in p0.
p1.sub(p0);
p2.sub(p0);
p1.crossInto(p2, p0).normalize();
normals[i] = p0;
normals[i + 1] = p0;
normals[i + 2] = p0;
// Copy the remaining attributes over
for (var j = 0; j < srcAttribs.length; ++j) {
destAttribs[j][i] = srcAttribs[j][i0];
destAttribs[j][i + 1] = srcAttribs[j][i1];
destAttribs[j][i + 2] = srcAttribs[j][i2];
}
}
return output;
}