Display 25000 lines at 60FPS in THREEJS

Question

I display 25000 lines in THREEJS and the performance is pretty poor. (<5FPS)

I follow the "simplest" approach by creating 1 mesh per line and adding it to the scene:

  // trks is an array that contains 25000 geometries
  var trks = ...;

  var material = new THREE.LineBasicMaterial({ vertexColors: THREE.VertexColors });

  for(var i = 0; i<trks.length; i++) {
    var line = new THREE.Line( trks[i].geometry, material);
    scene.add( line );
  }

I generate regular geometries (vs buffer geometries) as:

var geometry = new THREE.Geometry();
...
// push n vertices
geometry.vertices.push(new THREE.Vector3(track.points[k][0], track.points[k][1], track.points[k][2]));
...
// push n colors
geometry.colors.push(new THREE.Color(diff[0], diff[1], diff[2]));

Live JSFiddle: http://jsfiddle.net/16fnyb8k/34/

Geometry creation: https://github.com/FNNDSC/ami/blob/dev/src/loaders/loaders.trk.js#L328-L408

Should I merge all the geometries together somehow? Use buffer geometries instead (would that have any impact on performace)? both?

=== UPDATE ===

I did a dummy test with N BufferGeometries but it doesn't seem to really have any impact:

  for(var i = 0; i<trks.length; i++) {

    // create buffer geometry per track
    var bufferGeometry = new THREE.BufferGeometry();
    var vertices = [];
    for(var j=0; j<trks[i].geometry.vertices.length; j++) {
      vertices.push(trks[i].geometry.vertices[j].x);
      vertices.push(trks[i].geometry.vertices[j].y);
      vertices.push(trks[i].geometry.vertices[j].z);
     }
     var fvertices = new Float32Array(vertices);
     bufferGeometry.addAttribute( 'position', new THREE.BufferAttribute( fvertices, 3 ) );

    // create mesh
    var line = new THREE.Line( bufferGeometry, material);
    line.applyMatrix(series[0].stack[0].ijk2LPS);
    scene.add( line );
  }

Live Fiddle: http://jsfiddle.net/16fnyb8k/51/

=== UPDATE 2 ===

Using buffer geometries and merging all lines together makes it much smoother, however all the lines are now connected:

var bufferGeometry = new THREE.BufferGeometry();
var vertices = [];
var colors = [];

for(var i = 0; i<trks.length; i++) {

  for(var j=0; j<trks[i].geometry.vertices.length; j++) {

    vertices.push(trks[i].geometry.vertices[j].x);
    vertices.push(trks[i].geometry.vertices[j].y);
    vertices.push(trks[i].geometry.vertices[j].z);

    colors.push(trks[i].geometry.colors[j].r);
    colors.push(trks[i].geometry.colors[j].g);
    colors.push(trks[i].geometry.colors[j].b);

  }

}

var fvertices = new Float32Array(vertices);
var fcolors = new Float32Array(colors);
bufferGeometry.addAttribute( 'position', new THREE.BufferAttribute( fvertices, 3 ) );
bufferGeometry.addAttribute( 'color', new THREE.BufferAttribute( fcolors, 3 ) );

var line = new THREE.Line( bufferGeometry, material);
line.applyMatrix(series[0].stack[0].ijk2LPS);
scene.add( line );

JS Fiddle: http://jsfiddle.net/16fnyb8k/59/

Thanks

Answer 1

Create line segments from a buffer geometry.

Live demo: http://jsfiddle.net/16fnyb8k/61/

var material = new THREE.LineBasicMaterial({ vertexColors: THREE.VertexColors });
var bufferGeometry = new THREE.BufferGeometry();

var vertices = [];
var colors = [];

for(var i = 0; i<trks.length; i++) {
  for(var j=0; j<trks[i].geometry.vertices.length; j++) {

    vertices.push(trks[i].geometry.vertices[j].x);
    vertices.push(trks[i].geometry.vertices[j].y);
    vertices.push(trks[i].geometry.vertices[j].z);

    colors.push(trks[i].geometry.colors[j].r);
    colors.push(trks[i].geometry.colors[j].g);
    colors.push(trks[i].geometry.colors[j].b);

    if(j > 0 && j<trks[i].geometry.vertices.length - 1) {
      vertices.push(trks[i].geometry.vertices[j].x);
      vertices.push(trks[i].geometry.vertices[j].y);
      vertices.push(trks[i].geometry.vertices[j].z);

      colors.push(trks[i].geometry.colors[j].r);
      colors.push(trks[i].geometry.colors[j].g);
      colors.push(trks[i].geometry.colors[j].b);
    }
  }

}

var fvertices = new Float32Array(vertices);
var fcolors = new Float32Array(colors);
// itemSize = 3 because there are 3 values (components) per vertex
bufferGeometry.addAttribute( 'position', new THREE.BufferAttribute( fvertices, 3 ) );
bufferGeometry.addAttribute( 'color', new THREE.BufferAttribute( fcolors, 3 ) );
var line = new THREE.LineSegments( bufferGeometry, material);
line.applyMatrix(series[0].stack[0].ijk2LPS);
scene.add( line );