Working with Texture Atlases in Three.js

Three.js doesn't have a built-in texture atlas loader or packer based on the documentation. However, you can still work with texture atlases effectively using the standard texture capabilities.

Approaches for Working with Texture Atlases

The most common approach is to:

1. Create a texture using the standard Texture class or one of its variants like CanvasTexture
2. Adjust the UV coordinates of your geometry to map to specific regions of the atlas

Here's a basic example of how you might implement this:

JAVASCRIPTCopied
// Load the atlas texture
const textureLoader = new THREE.TextureLoader();
const atlasTexture = textureLoader.load('path/to/atlas.png');

// Create a material using the atlas
const material = new THREE.MeshBasicMaterial({ 
  map: atlasTexture,
  transparent: true 
});

// Create geometry and adjust UVs to point to a specific region of the atlas
const geometry = new THREE.PlaneGeometry(1, 1);
const uvs = geometry.attributes.uv;

// Example: Map to a region that starts at (0.25, 0.25) and has size (0.5, 0.5) in UV space
// This assumes your atlas is divided into a grid
const region = {
  x: 0.25,
  y: 0.25,
  width: 0.5,
  height: 0.5
};

// Update UVs to point to the specific region
for (let i = 0; i < uvs.count; i++) {
  const u = uvs.getX(i) * region.width + region.x;
  const v = uvs.getY(i) * region.height + region.y;
  uvs.setXY(i, u, v);
}

// Create the mesh
const mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);

While Three.js doesn't provide specific atlas tools, you can use the standard texture classes like Texture, CanvasTexture, or VideoTexture as the base for your atlas implementation, depending on your source material.