Has anyone a working example of a GL shader which acts as IBL environment?
Three.js does include an envmap, but this is not what I’m looking for - thanks.
If by IBL you mean light baked into the texture, envmaps do support that kind of textures (this example does not have any lights in the scene.)
To load an HDRI texture as a light source, all you need to change is to use RGBELoader instead of TextureLoader. Then you just assign the environment / envMap as usual:
scene.environment = hdriEnvMap;