Basic trail renderer for Three.js. This library allows for the straight-forward attachment of motion trails to any 3D object. The programmer simply has to specify the shape of the trail and its target (the target must be a Three.js Object3D instance). The update of the trail is handled automatically by the library.
The shape of the trail is specified by supplying a list of 3D points. These points make up the local-space head of the trail. During the update phase for the trail, a new instance of the head is created by transforming the local points into world-space using the target Object3D instance's local-to-world transformation matrix. These points are then connected to the existing head of the trail to extend the trail's geometry.
The trail renderer currently supports both textured and non-textured trails. Non-textured trails work well with many trail shapes in both translucent and opaque modes. Textured trails work well with many shapes as long as the trail is opaque; if the trail is not opaque, flat shapes work best.
Demo of the effect can be seen here
The following code shows how to attach a trail renderer in a scene named 'scene' to an existing Object3D instance named 'trailTarget'.
// specify points to create planar trail-head geometry
var trailHeadGeometry = [];
trailHeadGeometry.push(
new THREE.Vector3( -10.0, 0.0, 0.0 ),
new THREE.Vector3( 0.0, 0.0, 0.0 ),
new THREE.Vector3( 10.0, 0.0, 0.0 )
);
// create the trail renderer object
var trail = new THREE.TrailRenderer( scene, false );
// create material for the trail renderer
var trailMaterial = THREE.TrailRenderer.createBaseMaterial();
// specify length of trail
var trailLength = 150;
// initialize the trail
trail.initialize( trailMaterial, trailLength, false, 0, trailHeadGeometry, trailTarget );