threejs-loaders

Use GLTFLoader from three/addons/loaders/GLTFLoader.js and call loader.load with the model URL and a callback. The callback receives a gltf object whose scene property you add to your Three.js scene, and whose animations array can be played with AnimationMixer.

Use THREE.LoadingManager and pass it to each loader's constructor. Set manager.onProgress to receive per-file updates with loaded and total counts, and manager.onLoad to detect when all assets finish loading.

Yes, GLTFLoader supports Draco compression through DRACOLoader. Create a DRACOLoader, set the decoder path to the Draco decoder files, call preload, then pass it to gltfLoader.setDRACOLoader before loading the compressed GLB file.

Use RGBELoader to load .hdr files or EXRLoader for .exr files, then set texture.mapping to THREE.EquirectangularReflectionMapping. For PBR rendering, pass the texture through PMREMGenerator.fromEquirectangular before assigning it to scene.environment.

The texture color space is likely misconfigured. Set tex.colorSpace to THREE.SRGBColorSpace for color and albedo maps, and use linear color space for data maps like normal and roughness textures, then set tex.needsUpdate to true.

Three.js loaders use callbacks, but you can wrap loader.load in a Promise that resolves on success and rejects on error. This enables async/await syntax and Promise.all for loading multiple assets concurrently.