threejs-performance

Three.js Performance

Targets three.js r186. Examples use WebGLRenderer; the WebGPU and TSL section uses WebGPURenderer.

Quick Start

import * as THREE from "three";

const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

const scene = new THREE.Scene();
scene.add(new THREE.HemisphereLight(0xffffff, 0x445566, 1));
const sun = new THREE.DirectionalLight(0xffffff, 2);
sun.position.set(3, 6, 4);
scene.add(sun);

const camera = new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 0.1, 100);
camera.position.set(0, 2, 8);

const mesh = new THREE.Mesh(new THREE.SphereGeometry(1, 32, 16), new THREE.MeshStandardMaterial({ color: 0x4488ff }));
scene.add(mesh);

function animate() {
  mesh.rotation.y += 0.01;
  renderer.render(scene, camera);
  // the counters reset at the start of every render() call, so these cover the frame just drawn
  console.log(`${renderer.info.render.calls} calls, ${renderer.info.render.triangles} triangles, ${renderer.info.memory.textures} textures`);
}

renderer.setAnimationLoop(animate);

Measure First

Optimize what the numbers name, not what a hunch suspects. WebGLRenderer's renderer.info object is read after render():

function animate() {
  renderer.render(scene, camera);
  console.table({
    calls: renderer.info.render.calls, // draw calls submitted by this render
    triangles: renderer.info.render.triangles,
    lines: renderer.info.render.lines,
    points: renderer.info.render.points,
    geometries: renderer.info.memory.geometries, // geometry buffers live on the GPU
    textures: renderer.info.memory.textures,
    programs: renderer.info.programs.length, // compiled shader programs in the cache
  });
}

renderer.setAnimationLoop(animate);

Details worth knowing when reading these:

• The counters reset at the start of every render() call while info.autoReset is true (the default). Reading them before render() reports the previous frame, and a frame with several render() calls (picking, reflections, post passes) shows only the last one's numbers.
• Shadow-map drawing runs through the same counters: each shadow-casting light re-draws its casters from the light's view inside render(), and those draws appear in calls and triangles. Toggling a light's castShadow is directly visible here.
• info.memory.geometries and info.memory.textures count uploads, not bytes; they drop when the matching dispose() runs. Geometries and textures upload once and are shared by every mesh that references them.