That works fine as long as there's no physically-based emission (say based off temperature or heat blackbody). Averaging (filtering) temperature values will giv

That works fine as long as there's no physically-based emission (say based off temperature or heat blackbody). Averaging (filtering) temperature values will give you slightly incorrect results at the edges. For WebGL stuff, that's probably not a problem, but it shows up in production offline rendering and needs to be dealt with differently.